BORRADOR Magazine AviNews International March 2025

INFECTIOUS BURSAL DISEASE

VIRUS VARIANTS: A CHALLENGE FOR COMMERCIAL VACCINES? p. 60

Gloria C. Ramirez-Nieto, Arlen P. Gomez, Maria Paula Urian Avila

SALMONELLA EFFORTS, BURSAL DISEASE, FLHS SOLUTIONS

& HYPOCHLOROUS ACID IN WATER

In this issue of March 2025, we will look at Salmonella Initiatives in the U.S. Poultry Industry during 2024 and why Infectious Bursal Disease virus variants are a challenge for commercial vaccines. Dra. Mabel Sibonginkosi from Zimbabwe shares with us the excellent article Cleaning and Disinfection of Open Sided Houses and Humid Season Broiler Production, while Dr. Winfridus Bakker shows us How to benefit most from Van Gent Community nests.

Humberto Marques Lipori gives us his vision in an article entitled “Factors and Strategies that Help to Improve the Thermal Comfort of Birds”; among the pillars of the production chain in the poultry sector, the environment is an important factor that has advanced, due to better facilities, more efficient equipment, technologies that provide us with quick data and how to manage the different modes and thus favor the thermal comfort of the birds.

Dr. Eliana Icochea D’Arrigo, in her article Newcastle Disease: Knowing the Virus Better to Make the Best Control Decisions. Part I, establishes that Newcastle disease is prevented by biosecurity and vaccination, and even though several types of effective live and inactivated vaccines are applied, ND continues to be a problem in many countries around the world.

For this issue we once again count on the valuable participation of Dr. Edgar Oviedo, who in his article Research Highlights from International Poultry Scientific Forum 2025, tells us key

aspects of the presentations about breeders, reproduction, and feed processing areas. He encourages readers to attend this event next year and get a better idea of the research quality presented in this meeting.

On the other hand, Dr. Oviedo also shows us the Potential Solutions to the Fatty Liver Hemorrhagic Syndrome in Laying Hens; in the past five years, there has been great interest in evaluating multiple plant extracts to prevent or treat FLHS. This disease has also been adopted as a study model for the human condition called nonalcoholic fatty liver disease (NAFLD), also referred to as metabolic-associated fatty liver disease (NAFLD). This boom in biomedical research using laying hens suffering from FLHS may help create new efficacious solutions for this poultry disease.

José Luis Valls García tells us in his article “Hypochlorous Acid, a New Era in Water Purification” that the advantage of hypochlorous acid is its effectiveness, potency and capacity to be used as a natural disinfectant in different areas, being considered ideal because it has properties that make it highly effective in the area or surface to be treated.

For this edition, we had the privilege of interviewing Fahad Alfayez, Project Manager for the Saudi Agriculture exhibition, on the occasion of The 41st Saudi Agriculture Exhibition, held from October 21-24, 2024, at the Riyadh International Convention & Exhibition Center, Riyadh, Saudi Arabia.

Enjoy reading it!

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Bill Potter MBA, MS, PhD, Assoc. Professor, Poultry Food Safety & Processing Extension Specialist University of Arkansas

The U.S. poultry industry is continuing to make improvements to minimize risks of Salmonella illnesses.

Salmonella Initiatives in the U.S. Poultry Industry during 2024, Cleaning and Disinfection of Open Sided Houses and Humid Season Broiler Production Chick Quality. Part II Managing Floor Eggs in Broiler Breeders

H&N Technical Team

The article aims to guide hatchery and farm managers in evaluating chick quality, focusing on three main categories: preincubation, incubation, and post-incubation.

Mabel Sibonginkosi Ndebele Poultry Production Consultant, Bulawayo, Zimbabwe

There are several factors that can contribute to slow growth rates, stunted growth and high mortalities in broiler production and in this article the focus was on cleaning and disinfection.

Marlon Garcia

Technical Service Advisor, Cobb LatCan

It is important to take a proactively manage floor egg production. Train pullets early in rearing with an emphasis on good mobility. Ensure the nest boxes in production are attractive and easy to access.

Winfridus Bakker winfridus.bakker@gmail.com

House set-up is crucial in reducing out-of-nest eggs to a minimum, especially when using higher bird densities. The right type of nest is essential to attract the females.

Humberto Marques Lipori MSc. Zootechnics

New technologies and structures are emerging every day that allow greater control of the environment in broiler production.

Potential Solutions to the Fatty Liver Hemorrhagic Syndrome in Laying Hens

Edgar O. Oviedo-Rondón

Prestage Department of Poultry Science, North Carolina State University. Raleigh, NC

Fatty liver hemorrhagic syndrome (FLHS) is one of the leading causes of mortality for laying hens, mainly those housed in cages.

Newcastle Disease: Knowing the Virus Better to Make the Best Control Decisions. Part I 46 54

Eliana Icochea D’Arrigo Avian Pathology Laboratory, Faculty of Veterinary Medicine, UNMSM-Lima-Peru

Newcastle disease (ND) is considered one of the most important infectious diseases of poultry because velogenic strains of the virus can cause outbreaks with high morbidity, mortality and restriction of international trade.

Infectious Bursal Disease Virus Variants: A Challenge for Commercial Vaccines? 60

Gloria C. Ramirez-Nieto, Arlen P. Gomez, Maria Paula Urian Avila

Molecular Biology and Virology Laboratory, Faculty of Veterinary Medicine and Zootechnics, Universidad Nacional de Colombia

IBD remains a significant challenge for the poultry industry due to the virus’s rapid mutation, genetic reassortment, and the emergence of new, highly virulent variants.

Vaccinating For Marek’s? Don’t Be Thrown Off by PFU Levels 68

Isabel M. Gimeno

Professor, North Carolina State University, Zoetis Content

With the use of vector vaccines growing across the globe, the topic of plaque-forming units (PFUs) continues to be a misunderstood term in the poultry industry.

Research Highlights from International Poultry Scientific Forum 2025 72

Edgar O. Oviedo-Rondón Prestage Department of Poultry Science, North Carolina State University. Raleigh, NC

The International Poultry Scientific Forum (IPSF) 2025 was held on January 27 and 28 in Atlanta, GA, before the International Production and Processing Expo (IPPE).

Fahad Alfayez Interview 78

Fahad Alfayez

Project Manager for the Saudi Agriculture exhibition

Questions for the project manager of the Saudi Agriculture Exhibition, Mr. Fahad Alfayez.

Hypochlorous Acid, a New Era in Water Purification! 82

José Luis Valls García Poultry Veterinary Consultant

Hypochlorous Acid in situ is one of the biocides that in recent years is being used more and more, because of its high oxidizing power, combined with its low application cost and i ts simple production in situ.

SALMONELLA INITIATIVES IN THE U.S. POULTRY INDUSTRY DURING 2024

Bill

Potter

MBA, MS, PhD

Assoc. Professor, Poultry Food Safety & Processing Extension Specialist

University of Arkansas

The poultry industry in the United States has done a tremendous job over the past two decades in reducing Salmonella prevalence on poultry carcasses and products at processing plants. During the same time, the per capita consumption of chicken has increased steadily (www.nationalchickencouncil.org).

However, the rates of Salmonella illnesses in the United States from all sources has remained relatively constant over this time frame, and poultry remains among the sources of Salmonella illness (cdc.gov/ifsac/php/dataresearch/annual-reports/).

During 2024 the U.S. government proposed tightened regulations, while researchers have continued to seek effective technologies, and industry leaders have focused on Salmonella control systems.

Below is a list of 10 significant themes related to Salmonella in poultry that have received a lot of attention in recent years:

1

SALMONELLA FRAMEWORK PROPOSED REGULATIONS

In August 2024, the United States Department of Agriculture Food Safety Inspection Service (USDA - FSIS) issued a proposed “Salmonella Framework” for poultry after years of considering various regulatory options (U.S. Fed. Register vol. 89 no. 152).

At the time of this article, the proposed framework was still not yet finalized or approved.

One of the debated components of the framework was that USDA would declare poultry products adulterated if containing 10 cfu/mL(g) or greater of certain Salmonella serotypes in chicken carcasses, parts, comminuted chicken, and comminuted turkey.

These certain serotypes for chicken products included Enteritidis, Typhimurium, and I 4, [5], 12:i:- (also called monophasic Typhimurium), and for turkey included Hadar, Typhimurium, and Muenchen.

In addition, the framework would require processing plants to implement Microbial Monitoring Plans based on Statistical Process Control principles.

However, the extent of these proposed Salmonella Framework regulations that will actually be implemented is yet to be determined, due to the numerous public comments submitted challenging various components of the framework from a scientific & regulatory perspective.

2

SALMONELLA CROSS-FUNCTIONAL TEAMS

Poultry companies have proven that food safety success requires a team approach.

The advantage of having both preharvest and processing food safety expertise is that different team members have knowledge that can be used to collectively lead to continuous improvement.

Many poultry companies utilize their Food Safety Managers or Directors to help organize these team initiatives and foster communication.

Poultry veterinarians, live production managers, and nutritionists help companies determine which interventions to administer at preharvest, while consistently monitoring trends.

Processing Plant Operations Managers are leveraging plant technologies, antimicrobials, and engineering expertise to further reduce pathogen loads.

Lab Managers and statistical experts provide trends in microbial results.

Prudent food safety teams also determine when they need to contact outside resources and subject matter experts to help optimize pathogen reduction.

DEVELOPING UPDATED SALMONELLA MONITORING & SAMPLING PROGRAMS 3

Any effective food safety program in live production or processing requires a written plan.

Food Safety Professionals can provide valuable skills in formulating food safety programs from preharvest through processing, which include the purpose, scope, monitoring procedures, and recordkeeping systems.

Specific actions taken for Salmonella reduction in breeders, hatcheries, commercial broilers/ turkeys, and processing plants have been incorporated into many written plans.

Poultry industry scientists are increasingly working to understand which sampling methods and monitoring plans are the most effective.

Sampling and monitoring for Salmonella is valuable anywhere in the vertical integration process.

It is recommended that each complex within an integrated complex have a formal, engaged cross-functional Salmonella management team.

Samples can be collected at designated time-intervals, or at a set frequency of number of flocks per the written plan.

When possible, samples can be collected in a non-destructive manner, such as: boot socks at the farm, litter samples, hatchery eggshells and fluff just after chicks or poults are hatched, environmental swab samples, cloaca swabs of breeders, bird rubs or rinses at the farms, and carcass/parts rinses at multiple steps during poultry processing.

Indirect measures such as litter moisture, darkling beetle counts, and antimicrobial concentrations are also being monitored.

When evaluating the impact of interventions that may impact gut microbiota (i.e. feed additives, water treatments, etc.), collecting samples of ceca and pooled liver/spleen at the farm or early during bird processing are informative measurements of the impacts of those interventions.

4

QUANTITATIVE SALMONELLA LAB TESTING

Traditionally, the simplest methods of qualitative (presence/absence) testing for Salmonella have been preferred, using a method that mirrors FSIS or is AOAC approved.

However, the value of quantitative Salmonella assessment is being realized across many complexes.

It is commonplace for corporate poultry labs or plant labs to have quantitative polymerase chain reaction (qPCR) instruments to help identify Salmonella trends.

These can be utilized in conjunction with periodic Most Probable Number (MPN) lab techniques.

Most qPCR instruments provide quantitative approximations of Salmonella in major sample types, such as farm environmental samples, boot socks, bird carcass rinses, parts, and ground poultry.

The benefits of quantitative Salmonella assessments are that over time, baselines can be established based on quantitative values, which can then serve as targets for continuous reduction of log counts in preharvest and processing.

5

SALMONELLA SEROTYPE PROFILES

Serotype analysis has become more commonplace when testing for Salmonella in poultry operations.

Salmonella serotypes information is especially valuable when trying to determine what type of interventions are needed at preharvest, and where the sources of Salmonella originate.

Serotypes profiles can also be used to develop autogenous vaccines based on specific serotypes.

In order to identify serotypes, several techniques are being used in the U.S. These include antigen agglutination, biochemical identification, next generation sequencing or whole-genome sequencing.

Newer techniques have also been published that reveal serotypes via analysis of genome CRISPR regions (Richards et al., 2022, Letters in Appl. Micro. 75(4): 899-907).

Salmonella reduction requires multiple interventions, and many processors are working to optimize vaccinations as part of their overall pathogen reduction strategy.

SALMONELLA VACCINATION 7

This trend in enhanced vaccination is consistent with successes seen in U.S. and other countries with Salmonella reduction in egg layers due to vaccines.

Pilot studies were also submitted to FSIS in 2024 by multiple companies and complexes that were realizing the benefits of vaccinating broilers.

Salmonella reduction requires multiple interventions, and many processors are working to optimize vaccinations as part of their overall pathogen reduction strategy. Many U.S. poultry companies continue to use combinations of attenuated live Salmonella vaccines, inactivated commercial Salmonella vaccines, and/or autogenous vaccines to address certain serotypes (Fig. 1).

Some salmonella Vaccine Types available for optional use in US Poultry Breeders and comercial Egg Layers

Broilers

Turkeys Live, attenuated vaccines

Inactivated, commercial or autogenous bacterins

While the majority of vaccines are currently given to breeders and layers, many complexes are also realizing the benefits of live Salmonella vaccines in broiler and turkey operations.

Further development of vaccines to address selected serotypes will be important to address expected shifts in predominant strains.

Some researchers and veterinarians have also utilized blood antibody testing to look for immune responses in order to understand the effectiveness of vaccines.

ENHANCED BEST FARM MANAGEMENT PRACTICES AND BIRD HEALTH

The reduction of pests such as darkling beetles is gaining renewed emphasis in

Some companies are beginning to understand how the reduction of darkling beetles can correlate to reduced pathogen loads at the farm and ultimately in processing.

Controlled studies have shown that the in poultry gut tissues increases with darkling beetles compared to those without (Roche et al.,

Also, rodent management remains critical to reduce some of the most predominant serotypes, such as serovars of Salmonella Infantis that have been shown to proliferate in some poultry operations (Umali, et al., 2012. Avian Dis. 56(2): 288-294.).

PROCESSING PLANT ANTIMICROBIAL OPTIMIZATIONS

In U.S. poultry plants, many variations and combinations of designs have led to facilities having to be creative in how antimicrobials are used to reduce pathogens.

Some operations may utilize very little chemical compounds, while other operations use combinations of dips, sprays, brushes, and rinses to achieve pathogen reduction requirements.

Automated sensors are frequently used to regulate consistent flow of chemicals when utilized.

Sanitary carcass dressing procedures are now frequently monitored ongoing with digital electronic controls of ongoing machine checks by production, QA, and/or maintenance staff.

Veterinarians and nutritionists have continued their multi-hurdle approaches to achieve gut health through Eimeria control using a variety of feed additives and vaccines.

Biosecurity practices put in place to prevent Avian Influenza also are beneficial to reducing exposure to the introduction of Salmonella, Campylobacter, and other pathogens

Poultry slaughter plants commonly use indicator organisms to compare microbial loads early in the process, such as at hot rehang, to microbial loads downstream after chilling.

Statistical Process Control or data analytic systems are being used by many plants to monitor machine performance, and track trends to ensure the expected microbial reductions occur consistently throughout the plant.

Quantitative Salmonella cfu/mL(g) is now also commonly measured in addition to indicator organisms such as aerobic plate count or Enterobacteriaceae.

MICROBIOME EMPHASIS IS GROWING IN POULTRY RESEARCH

ONE HEALTH APPROACH

With the continued development of streamlined technologies for whole genome sequencing, researchers across the U.S. and other countries have been taking a deeper look at the effects of Salmonella reduction strategies on microbiome indicators.

The value of this approach to studying Salmonella pathogenesis is that a complete picture of microorganisms proliferating in poultry samples can be evaluated across the vertical integration process (Marmion, et al., 2021. Food Micro. 99:103823).

Artificial intelligence can be a key component in the future to utilize during genome sequence analysis. This tool may be able to help explain the relationship between biological indicators that can be controlled in order to address pathogenic bacteria.

Some researchers already are studying combinations of interventions simultaneously using these techniques of microbiome analysis (Graham et al., 2020. Front. in Micro., 10:3064).

There is a growing trend in the U.S. for scientists to consider all facets of “One Health” when implementing biological system changes. One Health refers to the concept of working to simultaneously achieve healthy people, animals, plants, and environment (Figure 2).

The U.S. Centers for Disease Control has emphasized coordinating, communicating, and collaborating as keys to achieving sustained progress in OneHealth initiatives (cdc.gov/one-health/about/index.html).

In a similar manner, for the U.S. poultry industry to continue to drive down Salmonella incidence rates, ongoing communication and feedback will continue to be necessary between all facets of live operations, processing, academia, researchers, and biotechnology firms.

In summary, the U.S. poultry industry is continuing to make improvements to minimize risks of Salmonella illnesses.

The integration of holistic farm-to-plant strategies, in combination with data driven continuous improvement are major areas of focus for the poultry industry. Researchers and biotechnology companies are continuously looking at new methods to understand the causes of Salmonella, while developing effective mitigation strategies.

*References upon request to the author

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CLEANING AND DISINFECTION OF OPEN SIDED HOUSES AND HUMID SEASON BROILER PRODUCTION

Mabel Sibonginkosi Ndebele

Poultry Production Consultant Bulawayo, Zimbabwe

OVERVIEW

Hello poultry farmer, the rainy season is upon us!

In Zimbabwe and most Sub-Saharan countries with similar climate seasons, most small-scale poultry farmers struggle during the rainy season, with challenges of effectively managing a broiler production batch when humidity levels are high, and this promotes bacterial infections.

Slow growth rate and stunted growth is seemingly the order of the season for most small-scale poultry farmers and some large-scale farmers.

Around this season, I am often faced with one question in particular from many farmers,

“Why are my birds not growing”?

In the case of the Zimbabwean poultry community, this trend has brought about a widespread belief amongst small scale farmers that chick and feed suppliers do not value quality as they aim to push volumes for the Christmas market rush.

However, there is also one common factor that is always often overlooked, which affects farmers around this time, Humidity!

Towards the festive season, placement of broiler batches almost always clashes with the beginning of the rainy season. Bear in mind, this is also the season almost every farmer is trying to maximize returns from batches and produce a broiler batch that will be just ready in time for the Christmas market by doing multiple batches at a time.

The result is often linked with taking short cuts on critical activities such as cleaning and disinfection and cutting down the fowl run/ site downtime resting period, then production problems arise, these factors are often overlooked.

This trend has resulted in some poultry farmers in Zimbabwe resorting to taking production breaks during the rainy season, with the fear of the challenges they encounter yearly around this time, such as high mortalities, slow growth rate and stunted growth.

However, this is not efficient, and it reduces the farmer’s annual returns.

It is therefore important to look at the main factor that is often overlooked to achieving success through this season. Understanding the major root of the problem for broiler farmers during the rainy season is an essential step towards achieving a solution that enables farmers to produce all year round, without seasonal breaks and with limited challenges.

The beginning of a broiler production cycle starts with the end of the previous batch.

The success of the next batch is dependent on how well the cleanout is done for the previous batch.

In Zimbabwe commercial small scale and large-scale farmers aim to produce broiler batches on a 9- week cycle, all things being equal. This means they will place a batch every 9 weeks.

broiler

9-week Broiler Production Cycle

To be profitable, broiler farmers need to consider religiously following the standard cycle to attain maximum possible annual returns while observing best practice. The figure below provides details on the cycles per year a broiler farmer can do, in the Zimbabwean context.

Broiler production cycles per year (9-week cycle)

Figure 1. The 9-week Broiler Production Cycle

Figure 2. Broiler Production Cycles per year

When a farmer skips a batch, this negatively impacts their annual returns. Therefore, it is imperative to consider how farmers can maximize during this time by overcoming challenges to remain efficient.

Majority of small-scale farmers rely on the use open-sided housing systems and to be efficient, farmers need to invest more effort into best practice to be efficient and competitive all year round.

Small-scale farmers with open-sided housing systems, use either earth floors or concrete floors, with majority of smallscale poultry farmers using earth floors.

As highlighted earlier, the stage of cleaning and disinfection is critical in the broiler production cycle.

This is the start of the broiler cycle, and it is important to do this stage well as it sets the performance bar for the coming batch.

There should be no visible evidence of a previous flock on site.

Additionally, manure should be disposed carefully with caution to avoid contamination of the site by downwind influence of the old flocks’ manure.

General

Guidelines for Cleaning and Disinfection of Concrete and Earth/ Dirt Floors in an OpenSided Housing System

Cleaning and disinfection for earth floors and concrete floors differ in the cleaning process, it is important to follow the cleaning guidelines for the type of floor onsite in order to achieve the best results in the next batch.

Below are some general detailed steps that can help poultry farmers to clean and disinfect well and avoid challenges, that become more pronounced when the rainy season begins, and the humidity levels rise.

Stage 1- Dry Cleaning

A) B)

Removal of manure should generally begin on the day the last birds are depleted, and the aim for the farmer should be to complete this within 2 days.

Manure should be disposed of as far as possible from the fowl run, at least 500 m away from the site (in the case of small holder farmers with limited land space) or more, on the leeward side or composted. Some poultry farmers, use the grass for bedding and they retain the manure for their cattle, or they sell to cattle farmers.

broiler

It is always important to stick to timelines, to avoid disturbing the production cycle timelines. For farmers that process their chicken manure for cattle feeding, these general guidelines below can be followed:

D) 1 2 3 4

The manure should be turned and dried in the house for two days starting from the day the last birds go to the market.

On day 3 manure should be bagged and removed from the house, stored in a clean shade away from the fowl run awaiting collection the following day.

Cleaning of the house should start on the 4th day.

These timelines are critical to ensure adequate resting period before the next placement.

The roof, poles and fence should be cleaned by dusting removing all the cobwebs.

Thorough scrapping and sweeping should be done before the wet cleaning stage to make it easy to remove the compacted bedding remains on the floor, and to avoid further pasting onto the floor when water is poured.

Earth floors

The topsoil should be scrapped off.

All debris should be swept, with no trace of manure remaining.

Concrete floors

All the debris on the floor should be swept with no trace of manure remaining.

Figure 3. Forking and drying stage of manure in preparation for bagging and disposal

E)

Any repairs and maintenance work should also be done timely during the dry-cleaning stage.

Figure 5. Dry cleaned earth floor before wet cleaning begins.

Stage 2 -Wet Cleaning

F)

Plain clean water should be used to remove loose residual manure and dust from the whole house including the roof (often forgotten or overlooked by farmers).

G) H)

The poles, walls, roof, wire mash should all be thoroughly scrubbed with clean plain water first.

Equipment (manual feeders and drinkers) and curtains should be removed and cleaned/washed with clean plain water first.

6. Open-sided housing with concrete floor after wet cleaning

Figure

Stage 3 -Chemical Cleaning

I) J) K) L) M)

Once all the above steps have been thoroughly done, chemical cleaning can then begin followed by the disinfection process.

Equipment, curtains, poles, walls, roof and wire mash should be washed for the second time with a detergent by thoroughly scrubbing and allowing for recommended contact time before rinsing off with water thoroughly.

Before application of disinfectant, the house should be left to dry, this is to avoid dilution of residual water which can weaken the strength of the disinfectant (A disinfectant should not be applied before the detergent is correctly used.)

Mix the disinfectant to right quantities, using the recommended dilution rate.

Disinfect the house.

N) O) P)

For earth floors, disinfectant and diesel mixture for drenching the floors only is recommended, following the directions of the disinfectant used and application guidelines (Diesel creates an emulsion that helps to bind with the disinfectant into the floor and to achieve an adequate contact time).

New topsoil should be added, in the house after the first-floor disinfection.

Disinfection of the new topsoil should be done, by applying disinfectant mixture.

A non-corrosive disinfectant can be used for the walls and roof.

For concrete floors, apply the disinfectant mixture to the roof, walls and floors by following the directions of the disinfectant used and application guidelines.

For both earth and concrete floors, allow for adequate contact time for bacterial and virucidal kill.

Farmers should follow the manufacturer’s guidelines on dilution and mixing ratios for detergents and disinfectants to be used. It is always advisable to consult with a local poultry technical expert.

After the disinfection process is complete:

Rest the house for a minimum of 14-21 days.

A double disinfection is recommended, with the first disinfection done within 3-7days from last day of collection, and the second disinfection (light disinfection) at least 7 days before placement.

Summary of key steps in cleaning and disinfection for the two floor types

EARTH FLOORS

Removal and cleaning of all equipment, repairs and maintenance.

Removal and disposal of manure

Dusting to remove webs, sweeping and scraping of the topsoil, removal of residual manure.

Plain water cleaning.

Scrubbing the side walls, wire mesh and poles using a detergent and then rinse off with water thoroughly.

Drench disinfection for the floor.

Apply new topsoil

Topsoil Disinfection

Rest

CONCRETE FLOORS

Removal and cleaning of all equipment, repairs and maintenance.

Removal and disposal of manure

Dusting to remove webs, sweeping, scraping to remove residual manure on the floor.

Plain water cleaning.

Scrubbing the floor, side walls, wire mesh and poles using a detergent and then rinse off with water thoroughly.

Application of disinfectant.

Rest

Figure 7. Resting disinfected earth floor

CONCLUSION

There are several factors that can contribute to slow growth rates, stunted growth and high mortalities in broiler production, however in this article the focus was on cleaning and disinfection and how shortcuts during this stage are costing broiler farmers in the Zimbabwean context, especially when humidity level rise.

Moisture and warmth are an ingredient for bacterial activity and multiplication in a poultry house, and if not controlled it can have negative effects on the productivity of a broiler farm.

Cleaning and disinfection will not completely remove all bad microorganisms; however, it will reduce the population to give the new chicks a better chance to perform well without fighting infections from the very first day they are placed.

Routine hygiene swabs are advisable to check for cleaning standard, however the costs are prohibitive to small scale poultry farmers and often their ammunition is in maximizing the clean and disinfection stage with great precision.

NB: These are general guidelines. I wrote this article from my experiences in the poultry industry in Zimbabwe, to share knowledge and with small-scale poultry farmers in mind. I will always advise reader farmers to contact their local poultry technical expert for further farm specific recommendations, because farms are different.

Happy Broiler Farming!

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BIRD AND EQUIPMENT MANAGEMENT IN PRODUCTION

Have the slat height adjustable at 35 cm (1.15’) at the start of production and increase its height around 40 weeks of age when droppings are getting close to the slats. The increase of the slat height will then go to 45 cm (1.5’). This concept is only possible with a Van Gent (Vencomatic) community nest with rigid wooden slats setup.

Droppings should never touch the slats, whether wooden or plastic. Droppings coming through the slats will dirty the hens’ footpath, contaminate the nest pads, and hatching eggs, negatively affecting the broiler chicks.

Place a maximum of 2 cm (<1”) of litter height on the concrete floor and have this litter only placed against the wall. This facilitates the forklifts to move over the concrete floor. The birds will distribute the litter over the whole scratch (floor) area the next day.

Always keep the litter as low as possible, even after peak production. The best place for the hens to lay their eggs must be in the community nests.

At move, birds are dropped in the scratch area but should soon go up on the slats (jumping mobility created in the rearing period).

If some females or males do not go on the slats after 1 day, help them go up.

Feed distribution is done in the dark before the lights come on in the early morning. The dark-out period depends on the minutes it takes for the feed to go around. Once the feed is around, the chain stops, and the lights come on. More towards peak production, if needed, the chain is activated again after 10 minutes and runs till all the feed is gone.

Whatever the width of the house, 12 m (40’) or 14 m (46’), feeder loops or lines should have a winch system for tractors and forklifts to drive inside during delivery of birds and at cleanout. Besides this, one can have legs for the feeding system in the scratch area and place the feeder lines directly on the slats in a bracket. The winched system is used until peak production for the feeder lines in the scratch area but on the slats the feeding system stays in the brackets.

If floor and slat feeder lines are winched up as standard procedure during the whole production period, they must have a highprofile grill system, so birds cannot perch adding extra weight to the pulley system. Having the feeding system directly on the slats and not winched up in the scratch area avoids problems of the system falling down and creating significant issues in repair and stress for birds, besides potentially losing some egg production.

Males are being fed after the females start consuming their feed. The male feeding system is winched up after males finish feeding; intake is filled immediately in the air and checked for proper pan feed distribution daily. A new male feeding system is a chain or belt-type trough against the wall, giving more available floor space to the flock. Filling is done after the females eat.

In the first weeks after the move, put the birds to bed in the late afternoon by walking the floor and pushing them up the slats. Some tips:

The faster the birds (males and females) go up the slats after moving, the lower the floor eggs at the start of production.

It will also mean that males and females have found the nipple or drinker lines, so there are no issues with dehydrated birds.

The best thing is that most females sleep on the slats if slat size permits.

Walk daily along the side walls to push birds towards the slat area.

Floor eggs produced against the side walls are the most persistent, and hens are difficult to correct once accustomed to lay there.

Start floor walking more frequently once the first eggs are seen.

Keep the nests closed till 1st eggs are seen (with Van Gent nest). This concept is used when the expel system in the nest is a grill, and hens can stick their heads inside when nests are closed to explore a place to lay their eggs. Birds are inquisitive when changes happen in the house. Do not open the nest system after a move or before there is any egg production.

Watch the low litter quality. Ventilation must work well to keep the litter in good dry condition (tunnel curtain opening must be correct).

Having a good synchronization between the sexes and having active males helps push the females on the slats, resulting in fewer floor eggs.

In 1st week of production, run the egg belt only in the afternoon. In the second production week, determine the times you want to collect the hatching eggs.

The small plastic flaps that separate the egg belt from the nest area need to shield the eggs on the belt from the birds and avoid hens seeing the belt moving.

If hatching eggs (HE) are only collected with an egg collection table at the front of the house, the collection can be done several times daily, especially in the summer.

If using an egg packer, determine when to start it 6 to 7 hours after the lights come on and run it constantly until all the houses are done.

The Van Gent egg belt system permits accumulating the daily production on the belts, and this is used more in solidside production houses with normal temperatures or dependent on the environment.

The more the egg packer is activated and deactivated daily, the more wear will happen on the system.

Do not walk alongside the nest system in production in the morning when most activity is going on with hens entering and leaving the nest system. Walking and checking the nests should be done only in the afternoon when few hens are in the nests.

Open the nests 1 hour before the lights come on in the first weeks of production and then increase to 2 or 3 hours close to peak production so early birds can go inside if a night light (blue) is present.

Close the nests 11 hours after the lights come on, and after 33 weeks, increase this to 12 hours or more, depending on egg-laying behavior.

With natural light coming into the houses, the total hours of light can go towards 15-16 hours in the summer months, depending on the latitude. In those situations, there is no need to keep the nest open for this long, and after 12 hours, more or less, the expel system should close the nest.

Check constantly in the morning if the water (nipple) lines have the correct height and have the proper water flow. If water intake control is done, suspend it after the production has surpassed 50% going to peak production and only start back up after peak production at 32 weeks of age. Fast enough water intake after feeding is essential to avoid slat eggs and also avoid any water availability issues going to peak production. Water shortage going to peak, will affect egg production potential.

Normally,>90% of the total daily egg production is produced in the first 8 hours after the lights come on but check this for the different breeds used.

There is a difference between breeds and overtime in production more egg laying shifts towards the afternoon.

In solid-side production houses, the light program can start early, at 4 a.m.; by noon, most eggs will be on the egg belts.

Closing the nests on time to avoid hens dirtying the nest pads in the afternoon and should improve egg /chick quality.

In some situations, the nest pads are cleaned around 40 weeks of age, depending on nest management.

Table 1. Floor egg example of a normal and a problem house every week from start to peak production.

The table annexed is a floor egg example of a normal and a problem house every week from start to peak production.

In a 4-week period, the typical house drops to below 1% floor eggs while the problem house comes down from 17% to 6% and then stays in the upper 4% range in peak production and beyond. This last situation is unacceptable and often requires more manpower hours to pick up the eggs.

IN SUMMARY:

House set-up is crucial in reducing out-ofnest eggs to a minimum, especially when using higher bird densities.

slat or floor eggs.

Table 2 shows that in 4 days, a house drops from 20% to 1.6% floor eggs in a good situation, but it stays too high in a problem-case house. When floor eggs come down too slowly and stay too high, then clearly, some of the females are not inclined to use the nests. It can be lazy females, inadequate training, or management of deficient nests that birds do not like.

Out-of-nest eggs are the weakest spot for the community nest, and the objective is to have less than 1% in peak production.

There needs to be a proper balance between the slat and floor area for maximum production, hatching egg numbers, and fertility.

There are situations in which some of the hens will not come off the slats, thus lowering fertility rates, especially with overly aggressive males and when hens lose a lot of back feathers. Balance the sexual maturity between the sexes. Females should not be afraid to go on the floor area.

Adding scratch grain or oyster shells in the litter in the afternoon is an effective way to get the females off the slats and into the scratch area, avoid excessive males, and observe matings.

It is good to involve the breeder companies in all new housing projects or at least get their opinion. Many times, new houses are shown after construction is complete and equipment is purchased. Mistakes can be very costly and often cannot be changed easily.

Table 2. This table shows that in 4 days, a house drops from 20% to 1.6% floor eggs in a good situation, but it stays too high in a problem-case house.

How to benefit most from Van Gent Community nests Part 2 - The management DOWNLOAD PDF

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© Petersime 2025 - All rights reserved.

CHICK QUALITY PART II

H&N Technical Team

INTRODUCTION

This technical document emphasizes the importance of first impressions in the poultry industry, particularly in evaluating chick quality at hatchery and farm arrival. It highlights the need for proper procedures and tools to assess chick quality, ensuring optimal incubation conditions and making necessary adjustments.

The article aims to guide hatchery and farm managers in evaluating chick quality, focusing on three main categories: preincubation, incubation, and post-incubation. The goal is to improve chick quality through careful assessment of each stage, including transport and holding conditions.

INCUBATION FACTORS

IMPACTING ON CHICK QUALITY

Temperature: eggshell temperature should be between 100-101°F (37.8-38.3°C) until hatch. Higher or lower than optimal EST will impact on hatchability, incubation time and chick quality (see graph 1). This is the most important incubation factor.

The EST must be frequently evaluated, and a written procedure should be followed. Optimal body temperature must be followed post transfer to prevent overheating (dehydration) or chilling chicks in hatchers which will impact on chick livability.

When comparing with multistage setter (MS), single stage can produce better chick quality by maintaining the optimal EST during the incubation period. However, MS can still develop good quality chick when the machine is adequality managed.

Humidity: setter humidity must be set to achieve an egg weight loss (EWL) between 11,5-13,5% at transfer (18,5 days of incubation). Suboptimal EWL impact on hatchability (increase of late dead), chick quality and 7-day livability. Low EWL could produce chicks with a large yolk sac which affect hatchability and increases the risk of bacterial contamination.

It is critical to have a standard procedure to check EWL on a regular basis.

Turning: angle and frequency. Turning failure, suboptimal frequency (more than 60 minutes per turning) or angle (< 38 degrees) have a big impact on hatchability (see graph 2) and chick quality due to a poor development of chorion allantoid membrane, yolk utilization and eggshell temperature uniformity. It is important to regularly check the turning frequency (every day) and turning angle (at least evert 6 months.)

Transfer: transferring hatching eggs from setter to hatcher must be done at the right day (best is 18-19 days of incubation) to maximize hatchability and chick quality. Handling of the eggs is critical to prevent eggshell cracks and must be done fast to prevent the eggs staying for too long at room temperature.

Hatching window. The hatching window is a result from preincubation and incubation factors. The optimal range is between 20 to 28 hours in multistage and less than 18 hours in single stage machines. A long window means that incubation conditions were not uniform (low EST or not uniform ESTs), egg storage was long, egg sizes were not uniform, different parent flock ages, among other factors. This impact on chick quality, chicks become dehydrated, and body weight uniformity. Everything must be done to achieve optimal hatching window.

Pull-out time. Chicks must be pulled out from the hatcher on the right time to prevent dehydration or too green chicks. Both conditions impact on chick livability.

Adapted from Molenaar et al, 2011.

Graph 1. Impact of high EST on % of second grade chicks (first grade = best quality; second grade = poorer quality).

from Wineland, 2009.

Graph 2. Effect of turning angle on hatch of fertile %.

Table 1. Effect of relative humidity (RH) on incubation parameters and body weight at hatch (RH of 53% was optimal in this trial).

from Bruzual, 2000

POST-INCUBATION FACTORS IMPACTING ON CHICK QUALITY

1

During chicks processing

Evaluate the different areas during processing that can impact on chick quality. For example, chick counter, beak treatment, vaccine injection, sexing, among others.

2

Holding room and transportation of day-old chicks

Optimal temperature is 20 to 25°C with a relative humidity between 50 to 60%. Constant monitoring of these two parameters is essential and a data logger is the best option for an optimal evaluation.

Optimal ventilation allowing uniform temperature distribution, preventing chilling and overheating.

Always check vent temperature and behavior. The vent temperature should be 104-106°F (40-41°C). Monitor this temperature in each step of processing (pull out, sexing, vaccination, beak treatment, inside chick boxes, etc).

Transportation must be smooth and shortest as possible. Long transport impact on chick quality and livability (dehydration).

Clean and disinfected designated trucks (only for day old chicks transport) to prevent infectious diseases.

Brooding conditions 3

Temperature, feed, water, and ventilation are critical to achieve good 7-day livability. Incorrect temperature, wrong feed presentation or quality and lack of access to water will impact on chick quality and livability.

Chick quality

How should be a good batch of chicks?

Good livability

Good body weight (68% of fresh egg weight)

Good uniformity (>90%)

Disease free

Good level of maternal antibodies

Alert and active

Physically perfect

No signs of dehydration

Evaluation of chick quality

Areas to assess general chick quality and behavior

Prior or during pull out

On processing belt

After sexing

After vaccination and beak treatment

In chick boxes prior to delivery

Chicks behavior

At hatchery:

Do not lay down

Must be very active

Chicks should not be noisy. If they are making too much sounds means that they are under some stress (for example, low or high temperature)

At farm:

Chicks at placement must be very active

They must start eating and drinking almost immediately

There are qualitative, quantitative, semiquantitative and microbiology methods to precisely evaluate chick quality. Regardless of the method to is important to have a good representative sample and must be done after processing and selection.

Qualitative methods

Behavior (not moving? Laying down, etc)

Navel quality (black button, string, etc)

Beak quality (beak treatment, red dot on beak, etc)

Hocks and leg quality (red lesions, dehydration lesions, etc)

Abdomen characteristics (is it too big?)

Quantitative methods

Body weight and uniformity

Yolk free body mass (YFBM) and Residual yolk (RS)

Chick yield

Chick length

Semiquantitative methods

Scoring system: Tona, Pasgar or Cervantes

Body weight and uniformity

100 chicks per flock (individual weight) after processing and selection

Important are the uniformity (> 90%) and CV (<8)

Influenced by residual yolk weight, flock age, hatching window and pull-out time

The bigger the yolk the heavier the chicks. This is not always good because a good yolk utilization translates into better immunity, gut health, embryo and chick development

Yolk free body mass (YFBM) and Residual yolk (RS)

Weight each individual chick and the residual yolk

YFBM = BW (body weight) – RS

Optimal YFBM > 90% and goal is to achieve less than 10% residual yolk sac from BW at hatch

Higher the EST, lower the YFBM and quality

Good predictor but time consuming and destructive method

Chick yield

BW of chicks at hatch as a % of egg weight prior to setting (less than 7 days of storage)

3 setter trays per flock per machine

It is not necessary to weight individual chicks but all chicks that hatched from those 3 trays

Optimal result is between 67 to 68%

< 67% dehydrated (too much time in hatchers? high 7d mortality? High EWL?) and > 68% too “green” (lethargic, low EWL? prone to bacterial infection)

This method helps to evaluate chick quality, and at the same time setter and hatcher conditions

Tona, Pasgar and Cervantes Scores

Semiquantitative methods

Results could vary among evaluators

Based on morphological characteristics

Cervantes metho includes bacterial contamination

All three evaluate: activity, posture, belly, navel, legs, beak, and eyes

Pasgar score is more simple and more practical to use

Chick Length

Good relationship with yolk utilization and less time consuming and destructive method than YFBM method

Low sample number (25 should be enough)

Variability between people

Good method

It requires to develop your own standard. The optimal length depends on flock age

It is influenced by incubation conditions and flock age. Weight each individual chick and the residual yolk

YFBM = BW (body weight) – RS

Optimal YFBM > 90% and goal is to achieve less than 10% residual yolk sac from BW at hatch

Higher the EST, lower the YFBM and quality

Good predictor but time consuming and destructive method

Other evaluation methods

Hatch analysis and residual breakout. The % of chicks dead on hatcher tray must be 0%

Cull rate %: less than 0,5%

Dead on arrival: less than 0.2%

It is important to measure chick’s vent temperature in different areas of the hatchery: pull out, processing room and holding room.

A sample of 15 birds is a good number to do the evaluation. The goal is a temperature of 104-106°F. If temperature us lower or higher than the optimal, corrective measures need to be taken

7-day mortality: less than 1%

Crop fill score: evaluate 100 chicks at 12 hours upon arrival. The goal is to have >95% of chicks with feed in the crop

Chick check (ask technical team for detailed information)

It is a microbiology method to evaluate chick quality

Sampling 10 healthy chicks per flock (right after pulling out)

Yolk swabs for bacterial cultures

Assess bacteria growth on:

Blood agar

McConkey agar: for gram negative

PEA agar: for gram positive

Navel quality

Nave quality is affected mostly by egg storage, breeder age and incubation conditions.

Lung tissues for mold (Aspergillus spp) on SabDex agar

Pool of viscera and intestines for Salmonella culture

Always evaluate leg, navel, and yolk quality. Presence of gizzard erosions

This method helps to evaluate farm and hatchery sanitary conditions

A good option is to leave chicks for 48 hours under optimal conditions at the hatchery and after that period take the samples

Red Hocks

Red hocks are in general associated with high temperature and/or high humidity during incubation.

Big belly is associated with suboptimal incubation temperature and high humidity during incubation. It appears often associated with red hocks.

When too much meconium It is found on eggshells and hatcher trays means that chicks stayed for too long inside the hatchers. Corrective measures must be taken: adjust incubation hours, pull out earlier, evaluate egg shell temperature (maybe is too high) and check incubation humidity (maybe too low).

Chick Quality Part II DOWNLOAD PDF

MANAGING FLOOR EGGS IN BROILER BREEDERS

Marlon Garcia, Technical Service Advisor, Cobb LatCan

Nesting systems are designed to maximize the production of clean, settable eggs that are free of contamination and have not been exposure to moisture.

Unfortunately, a producer will occasionally have a flock that will reject the nests and lay eggs outside the nests (in the litter or on slats).

In extreme cases, if a significant portion of the flock is laying outside the nest, hatch performance and chick quality can suffer. Moreover, the collection of floor eggs requires extra labor and creates biosecurity risks in the hatchery.

BREAK HABITS BEFORE THEY BEGIN

Though floor eggs are a problem during the production period, there are management practices during rearing that can prevent floor eggs. In some cases, birds cannot easily access the nests because they did not learn how to jump in rearing.

Enrichments in rearing are a viable option to teach the bird how to climb and jump.

Choosing the right type of perch is also very important. If the birds are going to be transferred to an mechanical nest box system, choose flat perches (not A-type perches), preferably manufactured with the same slats (perches) as those found in production.

This will encourage the birds to jump up directly and quickly get accustomed to the

Once hens begin laying eggs outside the nest, it is very difficult to change the behavior.

Image 1. Walk through the flock slowly and calmly during rearing to stimulate bird movement and mobility. Continue the practice in production to help prevent hens laying eggs in the litter.

Positioning slat-type perches under one nipple line will also encourage jumping and create a positive association between jumping up on the slats and drinking. The height of the slats must be no higher than 45 cm.

Breeder

Feeder type can also impact mobility. With pan feeders, the bird travels underneath pan feeder.

Chain feeders in rearing stimulate mobility, but must be set low enough to encourage pullets to jump over the track.

When pan feeders are used in rearing, it is encouraged to incorporate enrichments. Enrichments can be implemented at placement with access ramps.

Image 2. If feeders are installed on the slats, ensure the height is correct so that hens can easily go over the feeders to access nests.

Light intensity may also lead to future floor egg problems. Very low light intensity (<1 lux) during rearing can reduce bird activity.

Therefore, light intensity should be maintained at a level that allows farm workers to perform normal duties and are high enough to promote bird activity (2 to 5 lux).

Note that light intensity in rearing over lux 5 can negatively affect female photo stimulation.

MAKE NESTS ATTRACTIVE AND EASILY ACCESSIBLE

Hens need to feel safe when laying eggs and will search for relatively dark areas to lay eggs. They are more likely to lay eggs in dark spots instead of the nest boxes which may be further away.

Therefore, prevent shadowed areas with uniform lighting and ensure there are no shadows next to the slat ends and no direct light shining on the nest boxes.

Hens may crowd around drinker lines if water access is insufficient and block nest entrances. Producers should always follow the manufacturers’ technical directions and not limit or exceed the suggested numbers of drinkers per bird.

Too much bedding on the floors may encourage hens to lay eggs outside the nest. Keep bedding height at 4 to 6 cm depending on the house setup and nest type.

Feeders and drinkers should never prevent access to nest boxes. Hang feeders at heights that allow the birds to pass under them or go over them placed directly on the slats. Ensure drinker heights, bird per nipple and pressure are correct.

Air drafts directed at the nest box opening instead of the roof can disturb the birds and cause them to leave the nests. Ensure that all ventilation settings and air movement is directed in the correct position.

Interiors of the nest boxes should be clean and parasite free. Ectoparasites, such as red mites, can disturb the hens and cause them to avoid nests. It is recommended to remove and wash soiled pads, then allow them to dry thoroughly before re-using.

Having a small surplus of pads (about 20%) on hand, will allow immediate replacement of soiled pads and prevent leaving nests without a pad.

Image 3. red mites

Breeder management

MINIMIZING AND TROUBLESHOOTING

Typically a floor egg ratio above 2% suggests a problem or that improvements need to be made. Collect floor eggs regularly so that the birds have minimal opportunity to associate eggs with the litter.

Collect floor egg 4 times per day until the flock is 27 weeks of age. Walking patterns are also useful to deter females from laying in corners or on the floor.

Determine if hens are having difficulty accessing the nests. If jumping seems to be a challenge check slat height (should be 45 cm or lower) and consider installing ramps as a quick solution.

Check water availability and determine if hens are crowding around nipple lines and blocking access to nests.

Ensure that there are a sufficient number of nests available. Since about 80 % of the flock will lay eggs within the same time frame, nest boxes can get crowded. Hens that cannot easily find a space will tend to lay in the floor.

CONCLUSIONS

It is important to proactively manage floor egg production. Train pullets early in rearing with an emphasis on good mobility. Ensure the nest boxes in production are attractive and easy to access.

If floor eggs do occur, the location and timing can provide clues about why the hen chose to lay on the floor rather than the nests.

Good observation and taking action at the first sign of floor egg production can help mitigate the issue early in production.

FACTORS AND STRATEGIES THAT HELP TO IMPROVE THE THERMAL COMFORT OF BIRDS

Humberto Marques Lipori MSc. Zootechnics

Among the pillars of the production chain in the poultry sector, the environment is an important factor that has advanced, due to better facilities, more efficient equipment, technologies that provide us with quick data and how to manage the different modes and thus favor the thermal comfort of the birds.

Birds are homeothermic animals and therefore depend on the temperature of the environment to maintain their body temperature at an average of 40.6°C.

In the first days of life, the major heat exchange of the birds occurs through conduction, which is the heat exchange between the bird and the litter. For this heat exchange to be zero, the litter needs to be at an average temperature of 30-32°C. Hence the importance of preheating the shed. Considering also that in the initial phase of the birds the thermoregulatory system is not yet fully formed.

If these birds go through temperature challenges, there is a drop in performance in which their metabolism is altered.

Considering the main types of heaters (oven and gas hood), before acquiring a heating system it is necessary to analyze all the variables and evaluate item by item, among which the main ones are:

Heater efficiency; Equipment life; Depreciation; Maintenance;

Labor hours to operate;

Labor cost according to heater type; Energy cost;

Worker safety; Equipment technical assistance;

When the temperature in the shed is lower than ideal for the birds, much of the nutrients in the feed that would be used for growth will be diverted to maintain their thermal regulation.

We have to take into account that on average, 80% of the nutrients ingested by chicks are destined for growth and the other 20% for basal metabolism.

Chicks have a very high weight gain potential in the first days of life, reaching 4.6 times their initial weight in 7 days.

Thus, any and all challenges faced by the birds will impair this weight gain ratio.

Availability of raw materials in the region;

Average cost/batch of raw materials.

On the other hand, if these birds experience heat stress, they will consume more water and less feed due to an increase in body temperature, and consequently an increase in the rate of feed passage, reducing nutrient absorption.

In addition, birds in high temperature conditions exchange heat by evaporation, a latent exchange that consumes a lot of body energy.

It is extremely important to control the environment in which the birds are kept, since the birds' biological heat exchange mechanisms are not very efficient.

Therefore, the more we control the temperature and all the factors that intervene in the environment inside the poultry house, the better the performance will be, since the bird in a thermal comfort zone is able to efficiently express its genetic potential, achieving good zootechnical and, consequently, economic results for the producer and the agribusiness.

In general, the sheds have made great progress in terms of:

Ventilation; Efficiency of heaters, Sealing; Sizing.

On the other hand, few poultry farms have invested in thermal insulation. In terms of thermal insulation, the poultry house will have less interference from the external temperature to the internal part,

in this way, the shed becomes a “thermal bottle”, if you place something cold or hot inside it, it will maintain the temperature at which it was initially placed for a longer period of time.

With this, the shed will maintain a better ideal temperature ratio for the birds, of course always observing their behavior, since this is the best “thermometer” to evaluate if the birds are in thermal comfort.

As for sealing and thermal insulation, besides being able to benefit from a better environment for the birds, it will help to reduce heating or cooling costs and increase the useful life of the equipment, i.e., any false air inlet and lower thermal insulation is an additional cost in production.

In fact, when we talk about environment, we need to analyze the whole, the structural part, the efficiency of the equipment, the maintenance, the raw material used as heating and, most importantly, how to operate all this equipment and programming to satisfy the thermal comfort of the birds.

It is important to reinforce this last item, having a good shed does not guarantee good zootechnical results, but it will bring less environmental challenges, since a wellmanaged shed allows to extract the best that it provides.

Isothermal panels, available on the market, are very efficient and contribute to an optimal sealing and longer life of the shed compared to those with curtains on the sides.

Another material available is glass wool or rock wool, which is placed on top of the shed lining, where it has great potential to help maintain the internal temperature, either when heating or cooling.

When it is in heating period, part of this heating rises and dissipates between the lining and the roof (attic), losing this heating.

In addition, during hot periods of the year, an air cushion is formed in the attic, where this insulating material also reduces this temperature interference inside the shed, also considering that the attic is the hottest part of the shed.

Even with heating in mind, sheds with air inlets are very efficient, as long as they are used when necessary and correctly, which is no easy task.

It is necessary to maintain good air dynamics and a correct distribution of ventilation, this will also help with the quality of the litter.

To achieve this, it is essential to have a good relationship between the number of inlets and the number of extractors, a static pressure according to the width of the shed and the correct opening of the inlets, otherwise this could have important negative effects on the performance of the flock.

Considering all these points mentioned above, equally important is the quality of the litter, which is directly related to health, but is also one of the key points to maintain a good temperature inside the shed.

The reason for the quality of the litter is that it is one of the factors that directly interferes with minimum ventilation.

The higher the humidity in the litter, the higher the production of ammonia, which is a very harmful gas for the birds, and to remove this ammonia from the shed it is necessary to ventilate the house more. Consequently, this will make it even more difficult to heat the shed.

That is why it is important to treat the litter well in the interval, a dry and quality litter not only reduces the amount of pathogens, but also reduces the formation of ammonia.

This will also depend on the interval days that are critical for good litter management.

In light of the above, we know that severe winters and wet litters pose great challenges to maintaining temperature and air quality.

Chicks do not tolerate high temperature ranges, for example, during the afternoon it reaches an average of 33°C and during the night it drops to 28°C, or depending on the situation, it reaches 24°C or less, which will result in important losses in performance and even high mortality.

However, in extreme cases of very low outside temperature and high ammonia level inside the shed, between choosing heating and complying with air quality, prioritize good air quality

It is less serious to have good air quality with a slightly below ideal temperature than to dampen and have high ammonia production inside the shed to try to achieve a better temperature.

Ammonia causes a lot of damage to performance and health.

Figure 1. Moisture in the litter interferes with shed ventilation.

Depending on the amount and length of time this bird is exposed to ammonia, it can cause blindness, but before that, ammonia causes major problems such as:

Immunosuppression;

Reduced water and feed consumption;

Causes respiratory problems;

Overloads the body's energy;

Decreases weight gain and,

Poorer feed conversion.

Another point of attention is the increasing challenges posed by aerosaculitis; the greater the exposure of these birds to poor conditions, the more this challenge will worsen.

New technologies and structures are emerging every day that allow greater control of the environment in broiler production.

However, the best structures and technologies do not guarantee good zootechnical results, it is necessary:

Good management;

Interpretation of data and facts;

Commitment and knowledge driving these new ways and technologies.

To extract the best they provide, thus maximizing production in a sustainable way and reducing production costs.

Factors and Strategies that Help to Improve the Thermal Comfort of Birds. DOWNLOAD PDF

POTENTIAL SOLUTIONS TO THE FATTY LIVER HEMORRHAGIC SYNDROME IN LAYING HENS

Edgar

O. Oviedo-Rondon

Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC

Fatty liver hemorrhagic syndrome (FLHS) is one of the leading causes of mortality for laying hens, mainly those housed in cages. This disease is observed mainly in hens in the middle and late stages of egg production.

During a post-mortem examination, severe fat buildup is noticed in the abdominal cavity and the visceral areas.

The liver is swollen, spherical, and extremely delicate or fragile.

Due to fat accumulation, its color changes from pale brown to yellow.

This condition commonly results in liver rupture, hemorrhages, and unexpected mortality due to internal hemorrhages.

It is relevant to remember that death from FLHS occurs only in extreme cases following massive liver hemorrhage, suggesting that a significant number of hens within a flock might suffer from “sub-acute and chronic FLHS”.

The chronic form of FLHS may cause a drop in egg production but little or no change in mortality. These hens may show reproductive dysfunction.

In 2021, researchers from Hebei Agricultural University in China concluded that liver metabolites and arachidonic acid metabolism were linked to the pathophysiology of FLHS.

Hens with FLSH have significantly higher levels of metabolites like alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein, total cholesterol, and triglycerides, decreased high-density lipoprotein, and hepatic steatosis.

The FLHS causes profound changes in liver function that can be detected by blood tests (Table 1).

In the layers with FLHS, liver carnitine and stearoyl carnitine are reduced.

As an essential factor in fatty acid metabolism, carnitine plays a key role in fatty acid transportation into mitochondria for oxidation.

The conditions of fatty liver disease promoted fatty acid oxidation to provide energy, accompanied by carnitine consumption.

Table 1. Blood metrics of hens depend on the incidence of FLHS.

Environmental factors that increase incidence

Data from diverse surveys and controlled studies worldwide have revealed that housing systems do not affect mortality rates or that mortality rates are lower in conventional cage systems than in free-range or organic systems. However, the cause of death is well related to the cage system. The most common cause of death in conventional cages is FLHS, with 58 to 74% of necropsied hens dying from this condition.

Conventional cage systems have decreased worldwide due to welfare concerns and governmental regulations, but they are still the predominant housing system worldwide.

Their utilization varies between continents and countries.

After 12 years of the conventional cage ban in the European Union, the replacement with “enriched cages,” and 6 years of the campaign “End the Cage Age,” the laying hen housing systems are expected to be distributed as described in Figure 1.

Figure 1. Structure of laying hens in EU countries by housing system. Source: DG AGRI statistics. https://agriculture. ec.europa.eu/farming/ animal-products/ eggs_en (accessed on 15 November 2024).

In 2018, it was reported that more than 90% of egg production in three of the largest egg-producing countries (China, Japan, and the United States) comes from caged hens. This figure is nearly 98% for the other four largest egg-producing countries (Turkey, India, Russia, and Mexico).

In Australia (2024), approximately 50% of eggs are produced in cage layer farms, with the balance coming from free-range (40%) and barns (8.5%).

The proportion of hens housed in conventional cage systems is expected to be lower now, with multiple large egg-producing companies in these countries adopting other housing systems.

However, the data indicates cage systems are still very important, and the associated disease issues, such as FLHS and cage fatigue, are still very relevant.

Multiple studies’ data indicate that increased body weight and high production of laying hens in conventional cages significantly increased mortality, in many cases, associated with fatty livers and FLHS.

Recent research has confirmed that hen metabolism is modified by housing.

Last year, María Herrera-Sanchez and collaborators from the University of Tolima in Colombia published a paper in the Journal of Veterinary Medicine International suggesting that differential expression of genes related to oxidative stress in liver tissues from hens housed in conventional cages compared to cage-free systems.

This study indicated that space and environmental conditions in the egg production system could impact the expression of oxidative stress and lipid synthesis genes, potentially leading to changes in hens’ metabolism and performance, including egg quality and the incidence of metabolic diseases like FLHS.

The conventional cage system may not allow sufficient movement and exercise for hens, mainly when high stocking densities are used.

Reduced exercise can affect muscle and bone metabolism, leading to systemic metabolic changes.

One of the main characteristics of FLHS is insulin resistance, which leads to lipotoxicity, oxidative stress, and the inflammatory cascade that causes cirrhosis and fat infiltration in the liver.

Flocks housed in “enriched” or “furnished” cages that provide more space, perches, nests, and a scratch area have lower FLHS incidence.

Generally, conventional cage housing and high stocking densities are highly associated with FLHS. However, elevated ambient temperatures, high humidity, low ventilation, and poor air quality can increase the incidence of FLHS.

A high body temperature inhibits the thyroid gland’s ability to secrete thyroid hormones and weakens lipolysis, which are risk factors for developing fatty liver disease. Immunological challenges from field pathogens or vaccines can also increase FLHS incidence.

Figure 2. FLHS in a laying hen.

Layers

Nutritional factors related to FLHS

The following dietary factors increase the incidence of FLHS in laying hens:

Unrestricted intake.

Low protein diets and high energy diets from fat.

Low levels of linoleic (C18:2 n-6) acid and choline.

The dietary content of linoleic acid should be at least 1.20% during rearing, and hens should consume between 1.40 and 1.60 grams per day during the laying phase. Linoleic acid supplementation could reduce lipid accumulation in the liver and egg of laying hens by regulating the expression of the hepatic low-density lipoprotein receptor and 3-hydroxy-3methylglutaryl coenzyme A reductase.

Meanwhile, increased biosynthesis of unsaturated fatty acids, linolenic acid, and linoleic acid in hens with FLHS might suggest alterations in lipid metabolism and mobilization of fats from the liver to other tissues.

Choline dietary content should be at least 2,000 mg/kg in the starter phase, 1,800 for the rest of the rearing period, and hens should ingest at least 180 mg/day of choline.

High levels of mycotoxins like aflatoxins and trichothecenes T2. The median lethal dose (LD50) of T2 for hens is 6.27 mg/kg of body weight. However, this mycotoxin can start causing hen liver damage at concentrations 20 times lower (0.31 mg/kg) after prolonged exposure or when aflatoxins and other mycotoxins are present.

Hens-fed maize-based diets have higher liver weights, liver fat content, and triglyceride levels 30 to 50% higher, and more livers with hemorrhagic scores related to FLHS than hens-fed diets containing wheat, oats, or barley.

In contrast, the following nutritional factors can prevent or mitigate FLHS:

Flaxseed, flax oil, and omega-3 supplements decrease hepatic fat content and may reduce FLHS incidence.

Higher (67%) dietary concentrations of branched-chain amino acids (2.00, 1.08, and 1.17% of Leucine, Isoleucine, and Valine compared to 1.20, 0.65, and 0.70%) inhibit the tryptophan-ILA-AHR axis and de novo lipogenesis, promoting ketogenesis and fatty acid β-oxidation.

Supplementation of the following vitamins and feed additives has shown promising results in minimizing FLHS incidence in laying hens:

Folic acid (13 mg/kg) positively influences lipogenesis and mitigates endoplasmic reticulum stress and hepatocyte apoptosis.

Lutein (30 to 120 mg/kg) could prevent FLHS in older laying hens through the modulation of lipid metabolism but, most importantly, antioxidative and antiinflammatory functions. It also enriches lutein in the eggs, improving the relative redness of the eggs without significant conversion into zeaxanthin or consequence on other physical parameters of the eggs.

Bile acids (0.01% and 0.02% of chenodeoxycholic acid or hyodeoxycholic acid), regulate lipid metabolism, bolster antioxidant defenses, reduce inflammation, and modulate the gut microbiota.

Mulberry leaf extract at 1.2% of the diet (polysaccharides 20%, flavonoids 3%, and alkaloids 2%) may regulate the mRNA expression of lipid metabolism-related genes and improve cecal microbiota balance and serum lipid levels to alleviate FLHS in laying hens and subsequently improve egg production performance.

Cysteamine, the aminothiol agent, at 100 mg/kg of feed in combination with Choline (trimethyl, β-hydroxy ethyl ammonium) at 4,124 mg/kg of feed can ameliorate the adverse effects of FLHS by regulating antioxidant enzyme activities, modulating hepatic lipid metabolism, and restoring production performance in laying hens.

Magnolol between 100 and 500 mg/ kg feed. Magnolol is the primary active component of the plant Magnoliae officinalis. This plant compound inhibits fatty acid synthesis and promotes fatty acid oxidation.

Poly-dihydromyricetin-fused zinc nanoparticles (PDMY-Zn NPs) resulting from the chemical combination of Zn and Dihydromyricetinat at 200 to 600 mg/kg of feed. This product was reported to alleviate FLHS by enhancing antioxidant capacity, regulating liver lipid metabolism, and maintaining intestinal health. Dihydromyricetin is a naturally occurring flavonoid compound primarily extracted from the traditional Chinese medicinal plant Ampelopsis grossedentata.

Layers

Berberine, a well-known quaternary ammonium alkaloid mainly extracted from various plants such as Coptis and Phellodendron, at 100 or 200 mg/kg alleviated FLHS by reshaping the microbial and metabolic homeostasis within the liver-gut axis.

Polysaccharides extracted from the plant Hericium erinaceus (250 –750 mg/kg) ameliorate the hepatic damage by improving intestinal barrier function and shaping gut microbiota and tryptophan metabolic profiles.

Silymarin, the predominant compound of milk thistle (Silybum marianum) seeds at 200 mg/kg BW, decreased liver weight, malondialdehyde content, expression of fatty acid synthase, and hepatic steatosis.

In the past five years, there has been great interest in evaluating multiple plant extracts to prevent or treat FLHS.

FLHS has also been adopted as a study model for the human condition called nonalcoholic fatty liver disease (NAFLD), also referred to as metabolicassociated fatty liver disease (NAFLD).

This boom in biomedical research using laying hens suffering from FLHS may help create new efficacious solutions for this poultry disease. We encourage readers to be attentive to these reports and validate the proposed solutions in their layer flocks.

Potential Solutions to the Fatty Liver Hemorrhagic Syndrome in Laying Hens DOWNLOAD PDF

KNOWING THE VIRUS NEWCASTLE DISEASE: BETTER TO MAKE THE BEST CONTROL DECISIONS. PART I

Eliana Icochea D’Arrigo Avian Pathology Laboratory

Faculty of Veterinary Medicine, UNMSM-Lima-Peru

Newcastle disease (ND) is considered one of the most important infectious diseases of poultry because velogenic strains of the virus can cause outbreaks with high morbidity, mortality and restriction of international trade.

This causes significant economic losses to the poultry industry. This is why the disease is included in the list of notifiable diseases to the World Organization for Animal Health (Miller and Koch, 2020).

Newcastle disease is prevented by biosecurity and vaccination, and even though several types of effective live and inactivated vaccines are applied, ND continues to be a problem in many countries around the world.

THE CAUSAL AGENT

The International Committee on Viral Taxonomy database classifies the virus as family Paramyxoviridae, subfamily Avulavirinae, the latter distributed in three genera:

Orthoavulavirus.

Metaavulavirus.

Paravulavirus.

Avian paramyxoviruses have been isolated from different avian species, and are classified into 21 serotypes by serological tests and phylogenetic analysis (WOAH, 2021).

Newcastle disease is caused by virulent strains of Avian Paramyxovirus type 1 (APMV-1), species Avian Orthoavulavirus type -1 (OAV-1).

Newcastle disease virus (NDV) has a single-stranded, unsegmented, negative-sense RNA genome measuring 15,186 nucleotides (Alexander, 2003).

The virion has a lipid bilayer envelope derived from the plasma membrane of the host cell (Mast y Demeestere, 2009).

The virus genome is composed of six genes in 3’-NP-P-M-F-HN-L-5’ order, encoding seven viral proteins:

Nucleoprotein (NP),

Phosphoprotein (P),

Matrix protein (M),

Fusion protein (F),

Hemagglutinin-neuraminidase (HN) and

RNA polymerase, called the large polymerase (L).

RNA editing of the P protein produces an additional protein, the V protein, with anti-interferon activity, which allows the virus to counteract the innate host cell response (Miller and Koch, 2020) (Figure 1).

Figure 1. Schematic representation of the ND virus genome and its proteins.

Pathology

The main biological property of the virus is to agglutinate red blood cells of birds, amphibians and reptiles, due to the action of the HN protein on the sialic acid receptors on the surface of red blood cells.

VIRAL REPLICATION

NDV replicates in the cytoplasm of the cell. Hemagglutinin (HN) recognizes the cellular receptor, activating the F protein to fuse the viral and cell membranes, allowing viral entry into the cytoplasm by endocytosis (Bergfeld, 2017; Miller and Koch, 2020).

Viral hemagglutination (HA) allows the determination of viral presence in viral cultures and allantoic fluid of chicken embryos (Miller and Koch, 2020), and the quantification of antibodies in bird serum by the hemagglutination inhibition test (HAI).

The oncolytic effect of some strains of NDV on human tumor cells and their use as a treatment for cancer in humans has been investigated for some time.

This effect is associated with the anti-interferon type I activity of the V protein.

The selective replication that the virus has in tumor cells is due to defects of these cells in the activation of type I IFN signaling pathways and apoptotic pathways among others (Schirrmacher, 2017).

The ribonucleoprotein (RPN) complex contains the RNA genome wrapped with the nucleoprotein (NP) associated with the polymerase complex composed of the phosphoprotein (P) and the large protein (L);

After entry of the viral nucleocapside into the cytoplasm, it dissociates from the M protein and is released to initiate the synthesis of the mRNA required for the translation of viral proteins.

The P protein mediates the binding of the polymerase complex to the nucleocapside and the L protein performs the catalytic activities of the polymerase (Dortmans et al.,2011; Cox and Plemper, 2017).

All genes code for a single major protein, however, the P gene mRNA results in the formation of two non-structural proteins, protein V and protein W (Vilela et al., 2022).

VIRAL PATHOGENICITY

According to the clinical signs they cause in infected birds, NDV strains are classified as follows:

Velogenic viscerotropic strains (vvVEN) and mesogenic strains (both causing Newcastle disease) and,

Lentogenic and enteric or apathogenic strains (used as vaccines).

The World Organization for Animal Health, WOAH, has determined that a strain of APMV1 is virulent when it has:

An intracranial pathogenicity index (IPIC) equal to or greater than 0.7 (taking into consideration minimum and maximum values from 0 to 2) or,

The F-protein cleavage site is multiple basic amino acids and has a phenylalanine at position 117 (WOAH, 2021).

F-glycoprotein is the key to viral virulence and pathogenesis, because cell entry depends on viral and cell membrane fusion after cleavage of the F0 protein into F1 and F2 by host proteases (Miller and Koch, 2020).

The difference between a virulent and a non-virulent virus is that:

Viruses with a monobasic amino acid sequence at the F0 cleavage site are apathogenic because:

This substrate is susceptible only to enzymes excreted in mucous membranes, such as trypsin, thus causing a localized infection.

Conversely, viruses with a dibasic sequence are pathogenic because they are:

Susceptible to ubiquitous intracellular enzymes, which allow the virus to spread and cause systemic and fatal infection (Czeglédi et al., 2006; Miller and Koch, 2020).

INTRACRANIAL PATHOGENICITY INDEX

The intracranial pathogenicity index (IPIC) is the best method to determine viral pathogenicity because it not only determines the pathogenicity of the strains, but also quantifies in values.

A virus is considered pathogenic when it has an IPIC equal to or greater than 0.7 (WOAH, 2021). There are great differences in pathogenicity among virus strains. Table 1 summarizes the pathogenicity index of the different pathotypes using different tests (Alexander, 1989 and 1998).

T able 1. Pathotypes and pathogenicity index of the ND virus.

Hertz ’33, Milano

Komarov

Hitchner B1, La Sota, Clone 30 Asymptomatic

Ulster 2C, V4, MC110

(Source: Alexander, 1998).

All APMV-1 isolates are considered to belong to a single serotype, however, some antigenic variations have been demonstrated among different isolates by various tests and, even when there are no antigenic variations among strains, genetic analysis has become the main method of characterization and has replaced the use of mAbs for typing NDV isolates.

Newcastle disease: Knowing the virus better to make the best control decisions. Part I DOWNLOAD PDF

DETERMINATION OF VIRAL GENOTYPES

NDV viruses have low recombination rates, however, over time certain antigenic differences have been detected that have led to the classification of strains into lineages or genotypes. Accordingly, strains are grouped into two main classes, class I viruses and class II viruses;

Class I viruses are of low pathogenicity and are found in wild birds.

Class II, on the other hand, are classified into multiple genotypes and can be non-pathogenic or virulent (Table 2).

The characterization of the NDV genotype is achieved by sequencing the complete F gene, which also allows determining its virulence;

To identify new genotypes a system based on a average evolutionary distance of 10% between genetic groups is used (Dimitrov KM et al 2016; Dimitrov KM et al, 2019).

Table 2. Classification of virus genotypes

Class I Genotype Bird type Virulence

The development of next-generation sequencing (NGS) has emerged as a tool for research and genetic characterization of pathogens.

However, this method is ideal for rapidly mutating RNA viruses, where evolutionary aspects also need to be analyzed (Butt et al., 2019).

The current genotype classification includes three new genotypes (XIX, XX and XXI), making a total of 21 viral genotypes within class II viruses (Dimitrov et al. (2019).

RESISTANCE TO PHYSICAL AND CHEMICAL AGENTS

I Wild Low (exc Aus 98)

PHLYMV42

II B1, La Sota, VG-GA

Class II I Wild Low (exc Ireland 90) Genotype Bird type Virulence

III-IX Virulent

X Wild domestic Low

XI-XXI Virulent

Being an enveloped virus, the viability of avian Paramyxoviruses is easily destroyed by physical and chemical agents such as: Heat, Ultraviolet light, Oxidation processes, pH and Treatment with most disinfectants. However, publications on virus survival times outside the host show differences attributed to temperature, humidity and the environment in which the virus was analyzed (Kinde et al., 2004).

INFECTIOUS BURSAL DISEASE VIRUS VARIANTS: A CHALLENGE FOR COMMERCIAL VACCINES?

Gloria C. Ramirez-Nieto, Arlen P. Gomez, Maria Paula Urian Avila

Molecular Biology and Virology Laboratory

Faculty of Veterinary Medicine and Zootechnics

Universidad Nacional de Colombia

Gumboro disease, also known as Infectious Bursal Disease (IBD) or Avian Infectious Bursitis, was first reported in Delaware, USA, in 1962. It is an immunosuppressive viral disease that primarily affects chickens between 3 to 6 weeks of age and has a global distribution.

The virus responsible for this disease belongs to Avibirnavirus genus, Birnaviridae family, and has two serotypes: I and II.

Serotype I has been detected in chickens, hens, pigeons, and guinea fowl (Kasanga et al., 2008) but is only pathogenic in chickens and hens.

Serotype I is further divided into two antigenic subtypes: classical and variants, while serotype II remains asymptomatic in turkeys, crows, ostriches, and ducks (Ogawa et al., 1998; Yilmaz et al., 2019).

Since its first report, numerous variants of the virus have been identified, complicating efforts to control the disease. Until the 1980s, vaccination was effective in control the disease, with mortality rates in broilers below 2%.

However, with continued mutation and reassortment of the virus, new antigenic variants emerged, leading to higher mortality rates, even in the presence of strict vaccination protocols.

These variants can appear subclinically, reducing growth and increasing susceptibility to secondary infections, which result in substantial economic losses for the poultry industry.

ZOOMING INTO THE VIRUS

The virus has an icosahedral shape, no envelope, and consists of two linear double-stranded RNA segments, designated as A and B.

Segment B encodes VP1, a viral polymerase RNA, while segment A produces the capsid proteins pVP2 and VP3, as well as the protease VP4 and VP5, a non-structural protein involved in regulatory functions and membrane disruption in infected cells (Mundt, 1999) (Figure 1).

Among the components mentioned above, the VP2 protein is particularly important as it determines the virus’s antigenicity, virulence, and pathogenicity.

It contains regions that antibodies can bind to, and when exposed to the immune response, it tends to undergo greater mutation, making it a highly variable region (Letzel et al., 2007).

The capsid protein VP2 contains three distinct domains: base (B), envelope (S), and projection (P).

The P domain is made up of four loop structures exposed on the virus surface.

The Pbc loop (amino acid positions 219 and 224) plays a role in stabilizing the antibody recognition site.

Figure 1. Structure and components of the Infectious Bursal Disease Virus (IBDV) genome.

Variant IBDV strain

South American viral strains

QYQPGG

QYQTGG

QYQPGG

QYQPGG

QYQTGG

QYQTGG

The remaining two loops, Pde (amino acids 250–254) and Pfg (amino acids 283–287), are associated with the virus’s ability to cause disease (Jackwood et al., 2018) (Figure 2). Classic IBDV

QTSVQG

KTSVQS

KTSVQS

KTSVQS

QTNVQN

QTNVQN

KSGGQAGDQ

KSDGQAGEQ

KSGGQAGDQ

KSGGQAGDQ

KKDGQPEDQ

KKDGQPEDQ

Figure 2. Amino acid sequences of the Pbc, Phi, Pde, and Pfg loops in classical viruses, variants, and South American strains. Variants (E/Del, V1 and F3) are in light blue rectangles, while classical viruses (strains F52-70, Bursa vac, Cu-1, STC and 228E) are in dark blue. Mismatched amino acids are underlined and unique sequences are shown in white.

The Phi domain (amino acids 315–324) is recognized by neutralizing antibodies and is the primary site for amino acid substitutions that enable the virus to evade the immune response.

In addition, the segmented nature of the virus genome facilitates genetic reassortment between strains during co-infection. For example, this allows a live vaccine strain and a wild-type virus to mix.

As a result, mutations and reassortment contribute to antigenic variability, which can reduce the effectiveness of commercial vaccines against the disease, leading to significant challenges in disease control (Gao et al, 2007).

ADVANCEMENTS IN VIRUS CLASSIFICATION SCHEMES

Since its first identification in 1962, strains were not categorized, as they were assumed to be similar in both antigenicity and pathogenicity.

However, in 1980, the discovery of serotype 2 led to the identification of antigenic variants, referred to as “variants”, as well as highly virulent strains, known as “very virulent strains” (vvIBDV).

As a result, the strains detected prior to these variants were classified as “classical strains”.

Alternative methods were used to name strains, based on the name of the scientist who first characterized the isolate (e.g., Winterfield, Lukert, Moulthrop, Baxendale), the location of the isolate (e.g., Del-A, Del-E, MD, OH), or alphanumeric codes (e.g., STC, D78, G603, S706, 228E).

Regarding the genome, vvIBDV share specific amino acid residues at positions 222 (Ala), 256 (Ile), 294 (Ile), and 299 (Ser) in the VP2 sequence.

In terms of pathogenicity, compared to classical strains, vvIBDV tend to cause higher mortality rates in specific pathogen-free chickens upon infection (Van Den Berg et al., 2004).

However, not all very virulent strains exhibit high pathogenicity, indicating that this classification is incomplete (Jackwood et al., 2018).

Subsequently, due to ongoing mutations and recombinations, new strains could not be classified using the traditional system.

As a result, Michel and Jackwood (2017) proposed a new classification based on the amino acid sequences of the hypervariable region of VP2. This approach led to the identification of 7 genogroups.

However, over time, characteristics related to the antigenicity, molecular structure, and pathogenicity of these categories were discovered.

This led to a traditional classification scheme, which divides strains into classical and variant, with the latter further subdivided into attenuated, virulent, and very virulent categories.

However, these genogroups did not account for new variant strains or attenuated strains.

Furthermore, due to the characteristic recombination of viral segments, a classification based solely on VP2 did not fully capture the complexity of the virus’s genogroups.

In 2021, Wang et al. proposed a new classification system that considers the molecular characteristics of VP1 and VP2, derived from the B and A segments, respectively.

This approach resulted in the identification of 9 genogroups for segment A and 5 genogroups for segment B.

Notably, genogroup A2 consists of 4 distinct lineages.

In this new classification, the genotypes A1B1, A2B1, A3B2, and A8B1 correspond to the classical, variant, highly virulent, and attenuated phenotypes, respectively.

PATHOGENESIS AND CLINICAL PRESENTATIONS

In its typical pathogenesis, the IBDV enters the body through the respiratory or fecaloral routes, where it initially replicates in macrophages and lymphoid cells in the intestine or surrounding areas.

This initial replication triggers primary viremia via portal circulation, allowing the virus to reach its main target organ, the bursa of Fabricius.

Within the bursa, the virus actively replicates in follicles and B lymphocytes, which are actively dividing in young chicks.

The infection causes degeneration and necrosis of the follicles, mainly affecting IgM+ B lymphocytes, and leads to the infiltration of heterophils.

These heterophils eventually undergo necrosis and are phagocytosed.

In the interfollicular areas, hyperplasia of reticuloendothelial cells is observed, resulting in progressive atrophy of the bursa (Müller et al., 2012).

Although the virus does not replicate in T lymphocytes, apoptosis of these cells is observed in the thymus, with recovery of microscopic lesions occurring days after infection (Jagdev et al., 2000).

Regarding secondary viremia, it begins approximately 11 hours after replication in the bursa.

During this phase, the virus enters the bloodstream and spreads to the kidneys, muscles, and other organs, leading to clinical signs such as depression, ruffled feathers, anorexia, and diarrhea.

In severe cases, this can result in the death of the animal (Eterradossi & Saif, 2008).

The virus stimulates B lymphocytes, increasing the expression of antiviral genes in the type I interferon (IFN) pathway, proapoptotic genes, and proinflammatory cytokines.

In addition, the VP2 and VP5 proteins induce apoptosis in B lymphocytes and other lymphoid cells.

During viral replication, there is a significant infiltration of T lymphocytes into the bursa, which persists until approximately 12 weeks post-infection.

From day 7 post infection, CD8+ (cytotoxic) T-lymphocytes outnumber CD4+ T-lymphocytes in proportion to CD4+ T-lymphocytes.

This increase in CD8+ T lymphocytes promotes cell killing by lysing cells that express viral antigens and by producing proinflammatory cytokines, such as IFN-γ

This cytokine triggers the release of nitric oxide by macrophages, increasing bursal tissue damage (Jagdev et al., 2000) and contributes to immune cell exhaustion.

Virus variants induce elevated levels of IFN-γ, IL-6, IL-8, IL-18, NLRP3, caspase 1, and TNF-α, promoting inflammation and altering the tissue microenvironment.

This strategy suppresses B-lymphocyte activity, enabling the virus to evade immune responses, resulting in increased bursal damage and more severe immunosuppression compared to classical strains (Jagdev et al., 2000; Li et al., 2023).

For instance, Li et al. (2023) demonstrated that the vvIBDV exhibits high pathogenicity, enhanced replication efficiency, and a significant capacity to damage the bursa and other tissues, leading to high lethality.

This strain spreads to the bursa, cecal tonsils, thymus, and spleen, and alters cytokine levels within the bursa.

In contrast, the SHG 19 variant from China, reported in 2020, exhibited reduced replication and did not cause mortality but still caused severe immune organ damage similar to the vvIBDV.

This variant caused extensive necrosis and disintegration of B lymphocytes, though these changes developed more slowly—approximately 12 hours later than with the highly virulent strain.

This delayed mechanism may contribute to the variant’s ability to excrete externally, potentially allowing it to become a dominant epidemic strain (Fan et al., 2020).

Figure 3. Reassortment between live vaccine virus and Infectious Bursal Disease Virus (IBDV) variant, resulting in a new variant.

CHALLENGE FOR COMMERCIAL VACCINES

Vaccination with genotypes different from wild-type viruses can lead to genetic diversity among circulating virus strains.

In such cases, reassortment may occur—such as between a very virulent A segment and a B segment from a classical strain—resulting in mortalities of up to 80% in chickens with acute bursal lesions (Pikuła et al., 2018) (Figure 3).

Moreover, the antigenic distance between the wild-type virus strain and the vaccine strain means that variants may not be effectively controlled by conventional serotype 1 vaccines.

CONCLUSION

IBD remains a significant challenge for the poultry industry due to the virus’s rapid mutation, genetic reassortment, and the emergence of new, highly virulent variants.

These variants contribute to severe immunosuppression, high mortality rates, and increased susceptibility to secondary infections, despite vaccination efforts.

The virus’s genetic complexity, particularly in the VP2 protein, complicates effective vaccine development, as antigenic variability can undermine vaccine efficacy.

Therefore, it is now recommended that vaccine production against IBDV include antigenic mapping, a computational method used to determine the antigenic distances between strains. This technique has already been successfully applied to equine and human influenza viruses.

On the other hand, it is important to assess cross-protection during the vaccine development process to ensure efficacy (Boudaoud et al., 2016).

The ongoing evolution of the virus calls for more sophisticated strategies, such as antigenic mapping and cross-protection assessment, to improve vaccine design and enhance control measures against this economically impactful disease.

*References upon request to the author

Infectious Bursal Disease Virus Variants: A Challenge for Commercial Vaccines? DOWNLOAD PDF

DON’T BE THROWN OFF VACCINATING FOR MAREK’S? BY PFU

LEVELS

Isabel M. Gimeno, DVM, PhD Professor, North Carolina State University Zoetis Content

With the use of vector vaccines growing across the globe, the topic of plaque-forming units (PFUs) continues to be a misunderstood term in the poultry industry.

Frequently, high PFU levels of herpesvirus of turkey (HVT) vaccines are inaccurately associated with greater protection; and worse, PFU levels are used to determine a vaccine’s possible dilution rate.

However, PFUs are not a measure of vaccine efficacy and there is no magic PFU number that guarantees protection. The number of PFUs necessary to achieve the greatest efficacy depends on the product.

PFUs UNIQUE TO EACH VACCINE

The amount of PFUs per dose relates to how adapted the vaccine virus is to cell culture. Even though all commercial HVT vaccines are derived from the FC-126 strain isolated by Witter, each vaccine manufacturer has its own seed virus and will do several passages to get to commercial levels.

Depending on several factors (cell type use, days between passages, number of passages, and culture media, among others), viruses adapt differently to grow in cell culture.

The more adapted the virus is, the higher PFUs per dose can be obtained. On the other hand, better growth in cell culture might lead to less replication

It is critical to follow the manufacturer’s recommended dosage for an HVT vaccine and not dilute it based on its PFU level. Any change in the recommended dose could result in subpar results, as shown in a 2016 study.

In this study, different HVT products including one conventional and three recombinant HVTs were administered ovo at 1,500 PFUs regardless of what the recommended dose was for those vaccines.

The results demonstrated that by reducing the dose to 1,500 PFU, some vaccines performed better than others (Figure 1).

Alternatively, increasing the dose might not be good in some cases. Adding a very high dose of Marek’s disease (MD) vaccine (i.e., CVI988) when mixing with a recombinant HVT (rHVT) has been shown to result in reduced rHVT replication, which emphasizes the relevance of following manufacturer recommendations (Figure 2).

PFU VARIABILITY

MD vaccines are cell associated, meaning that there is a mix of infected (5%-20%) and non-infected (80%-95%) cells in the vial instead of free infectious viral particles. Hence, they are extremely fragile (the virus dies if the cell dies) and there is great variability on the vaccine dose.

A study demonstrated that the PFU dose-to-dose variability at the time of reconstitution in each vial is between 10% and 34%. PFU ratings are averages.

Don’t think that because a vaccine has a particular PFU that every single dose has this PFU (Figure 3).

Effect of time and mixing on vaccine dose variability. Blue bars (0) represent titration under optimal conditions; red bars (60-Mixing) represent titration 1 hour postreconstitution with continuous mixing; black bars (60Not mixing) represent titration 1 hour postreconstitution with no mixing.

A recombinant HVT (rHVT) at the recommended dose (RD) was administered either in ovo (IO) or at day of age via subcutaneous (SC) alone or in combination with CVI988 at two different doses (SRD=standard recommended dose or DD= double dose). PI= protective index when challenged with vv+MDV strain 648A at day of age. Different lower case letters above the bars indicate that differences found were significantly different(P < 0.05).

Figure 2. Protocols need to be optimized to maximize rHVT replication ensuring MD protection.

Dose variability of a MD vaccine at the time of reconstitution. Each bar represents a vaccine dose.

Figure 3. Vaccine dose variability.

Vaccine dose variability can get worse as time goes by. The moment a vaccine is reconstituted, it has the maximum number of PFUs.

Over time, they begin to drop off. Improper handling and mixing as well as the use of antibiotics in combination with an HVT can lead to a very inconsistent PFU levels. In some cases, chickens might not receive enough dosage to confer protection.

PFU VARIABILITY

Overall, each HVT product – whether conventional or recombinant – is unique in their ability to protect against MD, while the rHVT have the advantage of providing immunity against other viral diseases.

Figure 4. Vaccine dose variability Lopez de Juan Abad et al. 2019 Avian Dis. 63:591-598

However, storing, handling, and administration of the vaccines are critical, and it is important to follow manufacturer’s instructions. To get the most out of a vector vaccine program, the focus should be on vaccine handling, preparation and timely administration – factors under the control of poultry veterinarians.

References upon request from the author

Vaccinating for Marek’s? Don’t be thrown off by PFU levels DOWNLOAD PDF

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RESEARCH HIGHLIGHTS FROM INTERNATIONAL POULTRY SCIENTIFIC FORUM 2025

Edgar O. Oviedo-Rondon

Prestage Department of Poultry Science, North Carolina State University. Raleigh, NC

The International Poultry Scientific Forum (IPSF) 2025 was held on January 27 and 28 in Atlanta, GA, before the International Production and Processing Expo (IPPE).

A greater variety of topics were observed, and talks were related to:

Reproduction,

Physiology (22 oral and 14 posters),

Poultry nutrition (107 oral presentations, 50% feed additives; and 86 posters with 60% from feed additives),

More than 1,630 attendees participated in this meeting, making it again one of the biggest annual poultry scientific gatherings worldwide.

This year, a record of 419 communications were presented, with 225 oral presentations and 194 posters.

Sessions started as early as 7:00 am, finishing at 5:00 pm.

Environment and management (18 oral presentations, and 18 posters),

Artificial intelligence and data management, Pathology and poultry disease prevention (64), Welfare and behavior (32),

Processing and products (12), Further processing, Food safety (55).

This article will highlight some of these presentations only in the breeders, reproduction, and feed processing areas. Readers are encouraged to attend this event next year and get a better idea of the research quality presented in this meeting.

BREEDERS AND REPRODUCTION

Cloacal feather trimming improves the reproductive performance of layer breeder roosters

Dr. Ricardo Pereira from the University of São Paulo discussed an experiment conducted under commercial conditions evaluating the monthly cloacal feather trimming of males to improve reproductive parameters.

Trimming feathers in roosters reduced infertility at 63 weeks between 1.14% and 3.26% compared to the control group.

Hatchability increased between 2.63% and 4.27%.

Dietary supplementation of spraydried plasma improves semen quality in aging broiler breeders

Mario Lopes from the University of São Paulo presented results indicating that supplementation of rooster diets with 1% spray-dried plasma reduced morphological spermatozoid defects at 63 weeks of age compared to the unsupplemented group.

Late embryonic mortality was also reduced.

Ricardo Rauber from Vetinova, Brazil, presented an interesting mycotoxin risk assessment using data on 13 broiler breeder flocks with data from 25 to 70 weeks of age.

Their results indicated that fumonisin and deoxynivalenol (DON) reduced fertility, and aflatoxin, fumonisin, and DON reduced hatchability.

A multi-antigen subunit vaccine enhances maternal and

offspring

immunity against Campylobacter in chickens

Mostafa Admed from Clemson University reported that a vaccine produced with the outer membrane proteins of C. jejuni and Toll-like receptor 21 ligand (CpG ODN) immunized layer breeders reducing fecal C. jejuni counts by 1.02 Log10 at week 4 and 1.37 lgo10 at 10 weeks post-immunization.

The vaccine increased egg yolk and chick immunoglobulins IgY and IgM levels compared to the control.

The impact of feeder removal on feed-restricted broiler breeder pullets’ post-feeding behaviors at 10 and 15 weeks of age

Mazette Croom from Texas A&M presented the results of this study, which evaluated the behaviors of pullet breeders during the period of maximum feed restriction.

Their observations indicated that feeder removal reduced locomotion in 3% at 10 weeks and 51.7% at 15 weeks and object pecking in 23.8% and 47.7%,

Feeder removal caused more birds to engage in maintenance (+4.9%), inactivity (+10.6%), and foraging (11.3%).

Researchers also observed differences among strains in object pecking behavior, with 44.4% more in one genetic line than in the other.

Feeder removal can help mitigate hunger stress, and it is necessary to tailor this management practice according to age and strain.

The immunity in the progeny lasts up to five weeks post-hatch.

Tanmaie Kalapala from the University of Arkansas also demonstrated that vaccines against C. jejuni were effective in inducing IgY, IgM, and IgA production, which can be transferred to the progeny.

This vaccination could be critical to controlling Campylobacter in poultry.

Antibody response to different 2-way and 4-way killed IBD, Reo, NDV, and IBV vaccines

This project evaluated the application of killed vaccines with Infectious Bursal Disease Virus (IBDV) and Reovirus (Reo) in two 2-way commercial vaccine

from the other manufacturer, A, caused an increase in antibody titers, though not as large as when both vaccines were used from manufacturer B.

This data indicated that killed vaccines induce different immune responses, depending on their origin, and this factor should be considered when designing a broiler breeder vaccine program to maximize protection.

FEED PROCESSING

Ambient and conditioning temperature interactions alter steam dynamics during the pelleting process

Alexis Renner from West Virginia University presented this paper.

Pelleting involves steam-conditioning mash, extruding the conditioned feed

increased conditioned mash and hot pellet moisture, regardless of ambient temperature.

Pellet mill motor load decreased with increasing conditioning temperature and numerically decreased with 16°C ambient temperature.

Moisture determined on pellets cooled for 12 minutes demonstrated an interaction between ambient and conditioning temperatures.

Pellet moisture did not change at 16°C ambient temperature across conditioning temperature but increased incrementally with increased conditioning temperature at -1°C ambient temperature.

The pellet production rate was affected by an interaction with ambient and conditioning temperatures.

Production rate did not change across conditioning temperature at -1°C ambient temperature.

However, the production rate increased by 4% from 74°C to 82°C at 16°C ambient temperature.

The 16°C ambient conditions produced steam that improved the production rate at 82°C and contained less moisture after cooling, likely due to more water being utilized for lubrication at the pellet die.

It is possible that the thermodynamic steam traps in the pilot feed mill opened more frequently at -1°C ambient temperatures, thus creating a dryer steam.

Conditioned mash moisture was not observed to increase at 16°C ambient temperatures, likely due to a more significant potential for steam flash off during measurement.

These data suggested that ambient temperatures may alter steam dynamics that ultimately influence the pelleting process.

Conditioning above 70oC and pelleting corn and soybean mealbased diets containing underprocessed soybean meal can alleviate the effects of antinutritional factors

An interaction between soybean meal type and conditioning temperature was identified, wherein birds fed the under-processed soybean meal diet gained more weight with increasing conditioning temperature.

In contrast, body weight gain decreased for the peak-processed diet.

This research group evaluated nine treatments resulting from a factorial experiment with three types of soybean meal (under, peak, and over-processed) and three conditioning temperatures (70, 80, and 90 °C) for 30 seconds.

Starter broiler diets were formulated based on digestible amino acid requirements, differing only in the type of soybean meal.

Diets were fed for 18 days, and contrasts were performed to explore differences between treatments.

The feed intake increased as the conditioning temperature increased.

Birds fed the over-processed diet gained the least and had the lowest feed intake.

All amino acids’ digestibility increased when the underprocessed diet’s conditioning temperature increased from 700 to 800 and did not change for the peak-processed diets.

This meeting will gather excellent scientists who will offer helpful information for industries in diverse sectors.

The following AviNews International articles will discuss more research findings presented at the IPSF.

The next meeting has been scheduled for January 26 and 27, 2026, again at the Georgia World’s Congress Center in Atlanta, GA.

A-ZUCAMI

FAHAD ALFAYEZ

INTERVIEW

QUESTIONS FOR THE PROJECT MANAGER OF THE SAUDI AGRICULTURE EXHIBITION, MR. FAHAD ALFAYEZ

The 41st Saudi Agriculture Exhibition, held from October 21-24, 2024, at the Riyadh International Convention & Exhibition Center, was a landmark event in the agricultural sector and AviNews International, committed as always to the development and dissemination of poultry farming worldwide, had the opportunity to speak with Mr. Fahad Alfayez, Project Manager for the Saudi Agriculture exhibition.

What

is Riyadh

Exhibitions Company Ltd. about?

Riyadh Exhibitions Company (REC) is the leading organizer of international trade Exhibitions and Conferences in Saudi Arabia. REC has been delivering a broad range of market-leading international trade exhibitions, conventions, conferences, seminars and providing event organizing services including operations for more than 44 years.

What was on offer at Saudi Agriculture 2024?

Saudi Agriculture brought over 370 exhibitors from 29 countries together, from around the world. The exhibition also hosted the Future of Agriculture International Summit, with more than 50 experts and policymakers from 17 countries speaking at the summit..

The Minister of Environment, Water and Agriculture His Excellency Eng. Abdulrahman AlFadley inaugurated the exhibition on Monday 21 October 2024.

The ministry, foreign trade bodies, and key Saudi companies hosted seminars and workshops on sustainability, technolgy and food security.

Is the 41st Saudi Agriculture 2024 the largest and most important agricultural event on the Asian continent?

Saudi Agriculture 2024 was the 41st edition of the largest exhibition for the agricultural sector in the Middle East. The exhibition attracts exhibitors and visitors from around the world.

Tell us about the role played by the poultry sector in your country

Saudi Arabia is the largest producer of poultry meat in the Middle East, accounting for around 71% of the region’s poultry production. The market value is projected to reach just over $5 Billion in 2024.

By the end of 2029, the plan is

How big was the poultry sector’s participation in Saudi Agriculture 2024?

Poultry meat, hen houses, hatcheries, slaughterhouses and equipment suppliers as well as feeds companies played a major role in the exhibition due to the size of the sector in Saudi Arabia.

The sector takes 22% of the total space at Saudi Agriculture.

What challenges is the SAUDI poultry industry currently facing?

High temperatures, water scarcity, cheap imports and outdated production methods alongside the threat of imported avian diseases are a challenge to the sector.

With the Ministry of Environment, Water and Agriculture’s plans to transform the sector through technological and human capacity building as well as strict disease control measures, the future of the sector is bright.

What initiatives or programs is the Riyadh Exhibitions Company Ltd promoting to foster research and development in the field of poultry farming?

REC is providing a central platform for the industry to come together to share knowledge and research to discuss the development of the sector.

Riyadh Exhibitions Company works closely with academic researchers from universities and governmental organizations including King Saud University, King Abdullah University of Science and Technology, the Centre of Excellence for Sustainable Food Security, the Seed Centre and Plant Resources Bank and National Centre for Meteorology.

Where is poultry farming going in Saudi Arabia?

The sector’s goal is total self-sufficiency in poultry meat production by 2029. Measures such as the IPO by the Arabian Company for Agricultural and Industrial Investment (ARASCO) to expand the sector and the Saudi Agricultural Development Fund offering financial support up to 70% for projects that employ modern technology are accelerating the expansion of the sector.

Do you expect more Latin American countries to participate in future editions of the 41st Saudi Agriculture 2024?

We are actively seeking interest from potential exhibitors in Latin America.

We are already talking to agents in Argentina, Brazil and Colombia to assess the potential of brining companies from Latin America to Saudi Arabia with poultry sector innovations and technologies.

Finally, what considerations can you tell us about on the future editions of the Saudi Agriculture Exhibition?

Saudi Agriculture will continue to engage with our international and local exhibitors and partners. We will expand our global reach to provide visitors with the latest innovations and technologies from around the world.

We will also expand our knowledge platform to increase knowledge transfer to industry through engaging with world leading experts and academics in the sector.

Interview with Fahaz Alfayez DOWNLOAD THE PDF

with Fahad Alfayez

ACID, A NEW ERA HYPOCHLOROUS

IN WATER PURIFICATION!

José Luis Valls García Poultry Veterinary Consultant

A few years ago, the key was found to produce HYPOCHLOROUS ACID IN SITU. One of the biocides that in recent years is being used more and more, because of its high oxidizing power, combined with its low application cost and its simple production in situ.

Water is an essential compound for life, to the point that life would not be possible without it, and it is also essential that it be chemically drinkable and microbiologically drinkable.

Commission Implementing Regulation (EU) 2021/347 of 25 February 2021 approves active chlorine released from hypochlorous acid as an active substance for use in biocidal products of types 2, 3, 4 and 5.

And Commission Implementing Regulation (EU) 2021/365 of 26 February 2021 approves active chlorine released from hypochlorous acid as an active substance for use in Type 1 biocidal products.

Advantages of using Hypochlorous Acid

In addition to its advantages as a result of its broad bactericidal, virucidal, fungicidal, sporicidal and biofilm eliminating action in water pipes, it does not present the disadvantages that can occur when using other biocides such as hypochlorites and chlorine dioxide, as no harmful chlorinated residues are formed.

In July 2022 the European Commission approved hypochlorous acid as an active substance for use as a Type 5 biocide.

Biocides group TP5 Drinking water includes those biocides used for the disinfection of drinking water, both for humans and animals.

It is effective and harmless to the environment , 100% biodegradable and safe to handle. Therefore, it is also perfect for use on ecological farms.

The advantage of hypochlorous acid is its effectiveness, potency and capacity to be used as a natural disinfectant in different areas, being considered ideal because it has properties that make it highly effective in the area or surface to be treated (Severino, 2023).

Methods for obtaining Hypochlorous Acid

Hypochlorous Acid can be obtained through three different methods:

Chlorine gas hydrolysis

Chlorine gas hydrolysis consists of the application of chlorine gas directly into water.

This method is widely used in water disinfection processes for swimming pools, aqueducts and industries.

However, the uses are limited, both because of the high concentrations of chlorinated species in solution and also because of the instability of the final product (Monarca et al., 2004; Lowe et al., 2013).

Salt solution electrolysis

Commercially, the new salt and water electrolysis method is increasingly used.

It allows the formation of stabilized hypochlorous acid in situ for its use, generating formulations with HOCl ideal for water disinfection processes, surfaces or sanitary medical devices.

The method consists of using an electrochemical cell, composed of cathodes and anodes that transmit an electrical pulse to a homogeneous mixture of water and salt buffers.

Hypochlorite acidification

Because hypochlorite is commercially available, this method is widely used

It allows the highest generation of HOCl in solution, with a high redox potential, but undesirable toxic residues can be obtained.

Unfortunately, in many cases the solutions obtained lack the stability necessary for prolonged use (Wang et al., 2007).

The electrical charge allows the increase of the oxidative potential of water (ORP >1000 mV).

The electrical phenomenon also allows the dismutation of salts and the subsequent release in very small quantities of chlorinated species in solution, including: NaOCl and NaCl, although hypochlorous acid is considered the active ingredient of formulations obtained through this system ( up to 500 ppm ) (Innoue et al., 1997; Landa-Solis et al., 2005).

Hypochlorous acid oxidants (HCIO) and hypochlorite (OCI) are formed at the anode.

The pH of the solution is mostly neutral and the free chlorine solution (1 ppm) is dominated by hypochlorous acid, which is the one with the microbicidal power acting with an immediate and a permanent effect as the redox potential produced remains.

Hypochlorous Acid, a new era in drinking water disinfection

Hypochlorous Acid is also produced naturally by macrophages and neutrophils to fight infections, in what is known as a “respiratory burst” during the fight against pathogens (Weiss, 1989)

This reinforces the fact that hypochlorous acid is one of the only non-toxic disinfection agents.

Its microbicidal spectrum is broad and effective, eliminating them quickly depending on the oxidation-reduction potential (ORP) value (ideally at least 650 mV).

To realize its activity, it should be noted that hypochlorous acid is 90 times more efficient at eliminating microbial pathogens than sodium hypochlorite (bleach) and 10 times more efficient than chlorine dioxide.

The doses of use are also totally harmless to humans, animals and the environment.

Redox Potential (ORP) is an effective measure of chemical oxidation-reduction energy by means of an electrode, converting it into electrical energy, which is used to determine the sanitation of drinking water.

It is expressed in millivolts - mV - and tells us about the oxidation or reduction potential. It is actually a measure of the activity of the electron compared to the activity of the reference electrode, which always keeps the potential constant.

The word “potential” refers to the capacity at the site of action. Potential energy is the energy stored and ready to be put into action.

In addition, temperature compensation is not necessary in the measurement of the ORP and is independent of the ppm of the biocide.

In practical terms with current knowledge, the value of the oxidation-reduction potential for chlorinated biocides can be interpreted for action on bacteria from:

ORP (Mv) Elimination time (E.Coli)

650 0 seconds

600 10 seconds

550 100 seconds

500 1 hour

450 E.Coli is not eliminated

At 650 mV, viral inactivation is also instantaneous.

In the case of treatment with hydrogen peroxide, the values will range between 250-275 mV when consumed with the reducing elements.

The ORP measurement must be correct and must be made at any point of the installation.

Gram-negative bacteria contain sulfur and heme (iron-rich) groups in their outer membrane that are essential for normal electron transport.

An irreversible enzymatic reaction of HOCl with membrane proteins produces structural damage that alters cell permeability and affects bacterial viability (Rosen & Klebanoff, 1982; Mckenna & Davies, 1988).

In Gram-positive bacteria , hypochlorous acid differs in point of action, acting on the amino groups of glycine present in peptidoglycan.

HOCl oxidizes and/or chlorinates endotoxins and exotoxins, neutralizing their action and also oxidizes cysteine residues in gingipains such as Rgp and Kgp.

HOCl interferes with the C5 component of the complement cascade, which upon activation produces two fractions, including C5b with lytic activity on the bacterial cell membrane.

In viruses, it acts by lipid peroxidation of the membrane covering the pathogen. The action occurs at only 500 ppm of free chlorine injection into the drinking water, unlike other chemical species such as chlorine dioxide and sodium hypochlorite which exceed 30,000 ppm of chlorine injection.

Knowing that they all range between 0.5 and 3 ppm once in the animal’s consumption line, we can have an idea of the toxic chlorates, haloacetic acids and trihalomethanes that are produced in the respective reactions with water with the latter products.

Hypochlorous Acid has anti-inflammatory and tissue proliferation effects. It inhibits histamine, interleukin 2 and leukotriene 4.

At low doses HOCl can activate metalloproteinase proforms (MMPs), collagenases and gelatinases. At high concentrations HOCl inhibits MMP-7, collagenase and gelatinase activity (Fu et al., 2003).

It may be applied when authorized (soon), in wounds caused by feather plucking and pecking both on the skin and caruncles, to facilitate the disinfection of wounds and their healing.

The advantages of HYPOCHLOROUS ACID can be specified in:

Very effective against gram + and gram -, viruses, fungi and highly sporicidal.

Fast acting, 99.99% destroyed in seconds.

Effective at low concentrations.

Effective in presence of organic matter.

Non-toxic and non-irritating.

It is not corrosive to plastic or metallic materials.

Total elimination of biofilm from pipes and drinking troughs.

Permanent eradication of algae in drinking troughs.

It is 100% biodegradable.

Ecological biocide: provides natural water without toxic residues.

It does not alter the smell or taste.

Does not stain. Does not discolor surfaces or fabrics.

Microorganisms do not develop resistance.

Decreases mortality.

Reduces medications.

Reduces enteric processes.

Reduces conversion rates.

Inexpensive to produce and assured availability upon production.

The product does not have any negative effect on health and environment. It is classified as NON HAZARDOUS according to the European Union Regulation and authorized with biocide for the sanitization of drinking water (TP5).

Problematic

In summary

The use of hypochlorous acid (HClO) to disinfect drinking water has several significant advantages:

There are currently several biocides used for the disinfection of drinking water that DO NOT COMPLY with the STANDARD of maintaining a stable ORP (Oxidation Reduction Potential) throughout the water supply line. In spite of partially achieving it, they do not reach the minimum value of 650 mV in all of it, leaving space for the microbial presence by not eliminating it totally or doing it slowly.

This is why modern poultry farming, in spite of having excellent management standards, sometimes finds itself with outbreaks of diseases caused by pathogens present in the drinking water, especially when temperatures rise or the pipes are not hygienically clean, due to inadequate or improper use of biocides.

But it is obvious and well known that when water contamination is eliminated, intestinal integrity is maintained and good production parameters are obtained, in addition to improving the quality of poultry products. High

Hypochlorous Acid, a New Era in Water Purification!