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HATCHERY FEED & MANAGEMENT
ADVANCES IN ROTIFER SUBSTITUTION FOR MARINE FISH SPECIES 16
A feed line designed to reduce reliance on rotifers was tested on tropical species such as Barramundi, yellowtail amberjack, snapper, and totoaba.
ADVANCES IN ARTEMIA REPLACEMENT IN SHRIMP HATCHERIES 12
A biosecure larval diet that can help reduce bacterial loads in larval shrimp tanks and support higher survival rates.
A DECADE OF COPEPOD INNOVATION 28
Norwegian-based company is offering copepods as feeds for the early stages of aquaculture hatcheries as it celebrates its 10th anniversary.
SCIENCE-BASED SOLUTIONS TO DISEASE PROBLEMS 30
By integrating advanced genetic strategies, robust health monitoring programs, and effective management practices, the industry can enhance shrimp health and productivity.
THE GREY MULLET ALL-FEMALE PROJECT:
An interview with Prof. Lior David and Itay Oz
An interview with Prof. Lior David and Itay Oz, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem
HFM: Can you provide an overview of the Grey Mullet All-Female Project?
IO: The project, under the supervision of Prof. Lior David from the Robert H. Smith Faculty of Agriculture, aims to produce an all-female grey mullet population by establishing a broodstock of regular females and sex-reversed males. The project began with a collaboration between Dagon, Prof Lior David, and the Fisheries research station at Dor (part of the Ministry of Agriculture and Food Security). To date, this project is administered by Dagon Aquaculture and Lior David’s Lab.
HFM: Could you describe the biological mechanism underlying this process?
LD: In grey mullet fish, sex determination follows an XX/XY system, where males are XY and females are XX,
meaning the male is responsible for determining the sex of the offspring. This is distinct from species with WZ/ZZ systems, such as birds and some fish species, where the female determines the offspring sex.
Establishing that the grey mullet is an XY species was a crucial first step in our research. Secondly, to obtain sex-reversed males (XX males), this natural genetic mechanism of sex determination had to be overruled by the administration of a masculinizing hormone to normal groups, containing both XX and XY progeny. This hormonal manipulation drove the development of testis in XX progeny. Thirdly, based on mapping of the gene that naturally determines sex, a set of genetic markers was developed, allowing screening of hormonally manipulated progeny to identify XX males. Understanding all these allowed us to design our approach for creating an all-female population.
HFM: What are the primary markets for this project, and what potential do they hold?
IO: Female grey mullets grow faster and larger than males, making them more profitable for aquaculture. Further, since females have a faster growth rate than males, growing only females yields more uniform sizes at harvest. Additionally, females produce eggs that are used to make Karasumi and Bottarga, high-value delicacies in Mediterranean, Japanese, Taiwanese, and Korean cuisines. Since the sex of fish is indistinguishable until maturation, growing fish to produce these delicacies entails growing also males, which is inefficient. This dual market potential for meat and egg products significantly enhances the economic potential of the project.
HFM: Can you outline the main stages and objectives of the project?
LD: The project’s main goal is to produce grey mullet meat and egg products. Female grey mullets develop
gonads and hatch only in seawater, although they are nursed and fattened in freshwater ponds. Our strategy involves creating genetically female mullets with male phenotypes as brood fish. When these males breed, their offspring are all-female XX. Initially, we fed the grey mullet broodstock with feed coated in different dosages of testosterone. Timing the hormone treatment to coincide with the fish’s sex differentiation was critical. At maturation, we examined approximately 100 fish to identify gonad types, expecting over 50% to exhibit male characteristics as a preliminary success indicator. During breeding, males produce sperm early, while females are identified by their abdominal gonads. We separated females and genotyped the males, removing those with XY genotypes. The remaining males, which were XX, received hormonal boosts to facilitate sperm production. Our first successful hatch yielded 300mL of all-female eggs.
HFM: Where does the project stand today at the Dagon and Dor research centers, and what are the next steps for the Volcani Institute?
IO: We currently have a few males with female genotypes as brood fish. Another fingerling group is undergoing testosterone feeding to produce more. With these males, we started producing all-female seeds alongside our production of regular mixed progeny groups. Our main barrier now is obtaining more male phenotype females to establish larger broodstock. Our future research will focus on breeding during the next natural hatching season to create all-female groups and test their growth to establish their advantages.
Itay Oz graduated from the Ruppin Academic Center with a BSc in Marine Sciences and earned a master’s degree in Neurobiology from Tel Aviv University. Oz is currently pursuing a PhD at the Volcani Institute, and Robert H. Smith Faculty of Agriculture, Food and Environment, under the supervision of Dr. Matan Golan and Prof. Lior David, focusing on the molecular and morphological characterization of Grey Mullet larval development and metamorphosis.
Lior David is a professor in fish genetics at the Dept. of Animal Sciences, RH Smith Faculty of Agriculture, Food and Environment of the Hebrew University of Jerusalem, Israel. Lior received his undergraduate degree in animal sciences and graduate degree, studying common carp genetics, both from the Hebrew University. He then continued his post-doctoral research at the Dept. of Genetics of Stanford University School of Medicine, CA, USA. Since his return to Israel, the research in his group has harnessed various genetic tools to study different aspects and traits in fish, focusing on solving problems in fish aquaculture. Once Dagon hatchery had started with controlled reproduction of flathead grey mullet, Prof. David and Itay Oz worked together with the hatchery professional staff on genetic improvements in this fish, developing brood fish to produce allfemale progeny groups.
Interview by Lior Shak
Marine biologist, Dagon Aquaculture
NEWS REVIEW
Highlights of recent news from Hatcheryfm.com
Global partnership to enable advanced shrimp breeding programs
Genics has partnered with Weatherby’s Scientific, a global leader in high throughput genotyping, to offer ShrimpID to the world as a bespoke genetic analysis suite for shrimp breeding programs. With 60,000 markers for L. vannamei, and 7,800 markers for P. monodon, ShrimpID provides selective breeding programs with unrivaled data quality to drive commercial performance gains — all made possible thanks to the partnership between Genics and Weatherby’s Scientific.
Major acquisition in the shrimp genetic market
SyAqua Group acquired Primo Broodstock USA, a company that has been known for its pioneering work in the development of Specific Pathogen Free (SPF) and disease-tolerant genetic lines. The acquisition aims to not only bolster SyAqua existing portfolio but also pave the way for new market opportunities, and most importantly, to protect its strain security with another genetic nucleus and broodstock multiplication facility in the USA. Primo has been the first to leverage SPF populations out of Ecuador to address disease challenges in major
AquaBounty to sell Canadian broodstock and egg production operation
AquaBounty Technologies has made the decision to sell its Rollo Bay farm operation. The farm, located on Prince Edward Island in Canada, was purchased by the company in 2016 and further developed into a broodstock and egg production operation. David Melbourne, chief executive officer of AquaBounty, said that the “Rollo Bay farm was purchased and developed to support an expansion plan for five large
land-based grow-out farms. Since we will not require the egg output from the Rollo Bay farm in the near to mid-term timeframe, and since we will retain sufficient egg production capacity for our Ohio farm from our hatchery in Bay Fortune, we have determined that the Rollo Bay farm can be sold at this time to resolve the company’s immediate cash requirements, without impacting our long-term strategy.”
Oyster breeding center opens in the US
NOAA Fisheries and the U.S. Department of Agriculture’s Agricultural Research Service launched a new, state-of-the-art Northeast Oyster Breeding Center in June 2024. The center is an investment that will bolster shellfish farming in the Northeast. Scientists will use advanced selective breeding methods to develop better-performing lines of Eastern oysters to boost production. They aim to breed disease-resistant, resilient oysters in the face of current and changing environmental conditions in the Northeast’s diverse oyster-growing areas.
Billund Aquaculture files for bankruptcy, Pure Salmon Technology acquires its assets
Danish RAS supplier Billund Aquaculture has announced the company’s closure due to financial challenges. Chairman Jon Refsnes expressed deep regret to the company’s customers and employees, emphasizing that there were no other options in a press release. The company’s finances were adversely affected by the pandemic and the Ukraine war.
Pure Salmon Technology acquired all intellectual property (IP) assets of Billund Aquaculture Denmark. Additionally, Pure Salmon Technology has secured the exclusive rights to purchase Billund Aquaculture Australia and Billund Aquaculture Chile, a major step forward in expanding its footprint in the global aquaculture industry.
INVE Aquaculture partners with Reed Mariculture for US and Canada distribution
INVE Aquaculture signed a partnership with Reed Mariculture to enhance the distribution network in the United States and Canada. “We will leverage Reed Mariculture’s extensive expertise and market presence to better serve our customers. Our commitment includes unparalleled customer service and technical support that both companies are known for,” INVE said. Reed Mariculture will integrate INVE products into its offerings. This will reinforce INVE’s commitment to improving aquaculture practices, maintaining competitive prices, and providing excellent technical and customer support across North America and Canada.
Skretting, Zooca introduce copepod feed for marine juveniles
Calanus finmarchicus is a tiny marine copepod rich in essential nutrients abundant in the Norwegian Sea. The companies are now introducing it as a ready-to-use copepod for fish and shrimp hatcheries. With a size of 2-4 mm, it is a good feed for transition after hatchery and in combination with dry feeds, it can help as a feed uptake enhancer.
MSD Animal Health completes acquisition of Elanco’s aqua business
MSD Animal Health completed the acquisition of the aqua business of Elanco Animal Health Incorporated. As a result of the acquisition, MSD Animal Health now owns innovative products such as CLYNAV®, a new generation DNA-based vaccine that protects Atlantic salmon against pancreas disease and IMVIXA®, an anti-parasitic sea lice treatment and water treatment products for warm water production, complementing MSD Animal Health’s vaccine portfolio.
India reduces customs duties on shrimp feeds and broodstock
Indian Finance Minister Nirmala Sitharaman announced financial support for the country’s shrimp industry by reducing customs duties and supporting the establishment of a network of nucleus breeding centers for shrimp broodstocks. Custom duties for fish and shrimp feeds have been reduced from 15% to 5% and vannamei and monodon broodstock from 10% to 5%, among others.
Skretting upgrades salmon broodstock feed in the face of new challenges
Skretting has upgraded its broodstock feed line Vitalis. This new generation of diets brings new capacities to optimize reproductive rates in fish farms and RAS centers. Vitalis 2G acts through a synergy of vitamins, minerals, additives and long-chain fatty acids, delivering high-impact results, without compromising the reproductive capacity of the fish.
Norway signs free trade agreement with Chile for fish vaccines
Norway and the other three countries that are members of the European Free Trade Association (EFTA) have signed a free trade agreement with Chile. The agreement gives Norway zero customs duty on all industrial goods and Norwegian fish vaccines.
“Chile is one of the most important markets for Norwegian aquaculture vaccines. The new agreement gives duty-free treatment for Norwegian fish vaccines, that will benefit several players,” Fisheries and Oceans Minister Marianne Sivertsen Næss.
Canada bans open net-pen salmon farms in British Columbia by 2029
The government of Canada announced that it will ban open net-pen salmon aquaculture in British Columbia coastal waters by June 30, 2029. The move aims to “protect wild salmon and promote more sustainable aquaculture practices.” After July 1, 2024, only marine or land-based closed-containment systems will be considered for salmon aquaculture licenses in coastal British Columbia. The government of Canada recognizes that such systems are likely to come with increased investment costs. To provide greater predictability, Minister Lebouthillier also announced her intention to issue nine-year licenses to successful closedcontainment production applicants.
PEOPLE IN THE NEWS
Nick King
Daniel Arana
SalmoGen Company has appointed Nick King as general manager to oversee daily operations and development activities.
INVE Aquaculture announced the retirement of Wim Tackaert, regional sales director for the Americas. Daniel Arana has joined the company as his successor.
STIM to acquire Pharmaq Analytiq services in Scotland and Ireland
STIM has entered an agreement with Pharmaq Analytiq, a Zoetis subsidiary, to acquire its fish health and environmental services in the UK and Ireland. The acquisition will build on STIM’s business supplying pharmaceuticals and fish health products to aquaculture companies in the UK and Ireland. STIM and Pharmaq Analytiq are both committed to advancing aquatic health and sustainability. Subject to the completion of the transaction, the Pharmaq Analytiq Veterinary and Environmental services team, along with related operating assets in Inverness, Scotland, and Galway, Ireland will transfer to STIM. STIM’s proposed investment will enhance and broaden their offering, helping them to better deliver on their customers’ needs.
A teacher, veterinary
talented veterinarian who drove veterinary science into aquaculture and vice versa, created the world-renowned Institute of Aquaculture, at the University of Stirling, and inspired countless vets into the aquatic world.
Juan Pablo Ramírez Torrealba
Recent advances on Artemia replacement in shrimp hatcheries
Mark Rowel Napulan, Peter Van Wyk, Ramir Lee, Zeigler Bros.
Artemia nauplii have been a critical component of the feeding protocol for penaeid shrimp larvae since the birth of the commercial shrimp aquaculture industry in the 1970s. Artemia nauplii are rich in essential fatty acids, proteins and other nutrients required by shrimp larvae for normal growth and development. Another factor that has contributed to the widespread use of Artemia nauplii in larviculture is the fact that Artemia cysts can be easily stored and hatched on demand. The size of Artemia nauplii also makes them easy for shrimp larvae to eat. Despite all these advantages, Artemia nauplii are not a perfect food source.
Issues with Artemia nauplii
The nutritional value of Artemia nauplii can be highly variable. The nutritional value of an Artemia nauplius is at its maximum right after it hatches. However, Instar 1 nauplii are unable to feed and rely entirely on the energy and nutrients stored in their yolk reserves to sustain their metabolism and activity. Therefore, the nutritional value of the Instar 1 nauplii declines continuously with time after hatching. Another issue is that the nutritional value of Artemia nauplii can vary considerably from one batch to another, especially between nauplii from different geographic sources.
A common practice in commercial shrimp hatcheries is to parboil and then freeze Artemia nauplii prior to feeding. Feeding dead Artemia nauplii makes it much easier for the shrimp larvae to capture and eat the nauplii and eliminates the risk of ending up with a tank
full of grown Artemia, which is the result of overfeeding with live Artemia. However, the process of parboiling and freezing of Artemia nauplii leads to the degradation of some proteins and further loss of nutritional value. The biggest drawback associated with the use of Artemia nauplii in hatcheries is that they represent a major biosecurity risk. It is well known that hatched nauplii are an important pathway for introduction of Vibrio into larval-rearing tanks (Lavilla-Pitogo et al., 1990; Lopez-Torrez et al., 2001). Glycerol released by the cysts during the hatching process provides an ideal culture medium for Vibrio (Van Stappen et al., 2024). As a result, Vibrio loads in both the hatching water and the Artemia nauplii themselves can be extraordinarily high (Table 1). Decapsulation of the cysts prior to hatching reduces Vibrio loads only slightly. Disinfection of hatched nauplii prior to feeding reduces Vibrio counts but is not 100% effective.
Artemia replacement diet
In response to these issues, in 1997 Zeigler Bros. developed EZ Artemia, a biosecure liquid microencapsulated Artemia replacement diet. EZ Artemia does not contain any Artemia but was formulated with marine protein and lipid sources to meet or exceed the nutritional value of enriched Artemia nauplii. All of the marine protein sources are PCR tested to guarantee the final product is free from Vibrio and all WOAH-listed shrimp pathogens. In addition, EZ Artemia contains Vpak,
Vibrio counts
Table 1. Vibrio counts isolated from Artemia hatching water and Artemia nauplii from hatching tanks stocked with non-decapsulated and decapsulated cysts (after Interaminense et al ., 2014).
a blend of ingredients that promote improved immune function in the larvae.
In 2021, Zeigler launched EZ Artemia Ultra, the product of nearly 25 years of continuous research and development. Compared to the original EZ Artemia, EZ Artemia Ultra has a higher nutrient density and improved ingredient digestibility. The microcapsules are nearly neutrally buoyant and will remain suspended in the water column almost indefinitely with minimal aeration. However, the most important improvement is the inclusion of probiotics in the product. Rescue, a proprietary blend of four species of Bacillus bacteria selected for their ability to control the most pathogenic species of Vibrio, is included in the microcapsules at a density of 1 x 107 CFU/gram of feed. Remediate, a blend of Bacillus species selected for their ability to digest organic matter and control ammonia, has been added to the liquid fraction EZ Artemia Ultra. In studies Zeigler
conducted in collaboration with the University of the Philippines Visayas, it was demonstrated that Rescue administered in the feed effectively colonized the gut and provided significant improvement in challenge trials with V. parahaemolyticus and V. harveyii (Fig. 1).
Commercial trials
Trials at Zeigler’s Aquaculture Research Center (Z-ARC) have shown that EZ Artemia Ultra is capable of replacing 100% of the Artemia nauplii in the larval rearing protocol. Nevertheless, most hatcheries prefer to use EZ Artemia Ultra to replace 30-50% of the Artemia nauplii in the diet. Even when used as a partial Artemia replacement, many hatcheries obtain higher survival rates than when Artemia nauplii are fed at 100% of the normal rate. In recent trials at an Indonesian hatchery (Fig. 2), survival improved by 32% when live Instar 1 Artemia nauplii were 100% replaced with EZ Artemia Ultra
Figure 1. Results of challenge trials in which the survival of juvenile shrimp fed with feed top-coated with Rescue is compared with the survival of shrimp fed with feed without Rescue. The graph on the left shows results when challenged with Vibrio harveyii , while the graph on the right shows results when challenged with Vibrio parahaemolyticus .
Figure 2. Comparison of survivals in tanks fed with EZ Artemia Ultra replacing a percentage of the Artemia nauplii in the feed protocol. The graph on the left shows the results of a trial in which 100% of the Artemia nauplii were replaced with EZ Artemia Ultra from Z3 – PL1, while the graph on the right shows the results of a trial in which 33% of the Artemia nauplii were replaced with EZ Artemia Ultra from PL1 – PL8.
between Zoea 3 and PL1. Artemia nauplii were fed as normal from PL 2-8. In a second trial at the same hatchery, 33% of the Artemia nauplii were replaced with EZ Artemia Ultra from PL 1-8. In this trial, survival for the EZ Artemia Ultra treatment group was 33% higher than in the control group. In both trials, the final weights of the PLs harvested were the same for both treatments.
EZ Artemia Ultra usage recommendations
Zeigler recommends replacing 100% of Artemia nauplii from first feeding (Z2 or Z3) through PL1, and 25-50% of Artemia nauplii from PL2 to harvest (Fig. 3).
Table 2 provides a guide for calculating the amount of EZ Artemia Ultra required to replace Artemia nauplii in a feeding protocol, depending on the Artemia product
form (cysts, Instar 1 nauplii, or Artemia paste) the protocol is based on.
Economics of Artemia replacement
Replacing Artemia nauplii in the feeding protocol can potentially reduce production costs. When cost is compared based on equivalent usage rates, EZ Artemia Ultra is likely to be cheaper than using Artemia nauplii, whether hatched from cysts or purchased prehatched as an Artemia nauplii paste (Table 3). There are additional costs associated with hatching Artemia cysts that also must be considered. However, when comparing the economics associated with the use of Artemia nauplii with the use of EZ Artemia Ultra, one must also consider how differences in survival
the best just got better
Figure 3. Guidelines for replacing Artemia nauplii with EZ Artemia Ultra in larval shrimp feeding protocols.
*The price of Artemia cysts can vary widely based on quality, origin, and annual supply.
affect hatchery profitability. If the improvements in biosecurity and reduced viral loading result in higher survival rates, revenues from the sale of post larvae will be increased. The impact of higher survival on revenues will often have a much larger impact on hatchery profitability than the impact of the price differences for different feeding protocols.
Summary
Artemia nauplii have been demonstrated to be a major vector for the introduction of pathogenic Vibrio into larval rearing tanks, causing severe diseases such as Acute Hepatopancreatic Necrosis Disease (AHPND) and Transparent Postlarva Disease (TPD). These diseases can lead to high mortality rates in hatcheries, significantly impacting hatchery productivity and profitability. When Vibrio infected shrimp are introduced into farms, the bacteria can result in outbreaks and major losses for the farms. EZ Artemia Ultra is a biosecure larval diet that can help reduce bacterial loads in larval shrimp tanks and support higher survival rates. EZ Artemia Ultra is an economical and convenient biosecure alternative to Artemia nauplii.
References
Interaminense et al. (2014). Vibrio spp. control at brine shrimp, Artemia, hatching and enrichment. J. World Aqua. Society 45(1): 65-74. doi: 10.1111/jwas.12096
Lavilla-Pitogo, C. R., Baticados, M. C. L., Cruz-Lacierda, E. R., & De la Peña, L. D. (1990). Occurrence of Vibrio species, including Vibrio harveyi, in Penaeus monodon hatcheries in the Philippines. Aquaculture, 91(1), 1-13.
Lopez-Torres, M. A. & M. L. Lizarraga-Partida. (2001) Bacteria isolated on TCBS media associated with hatched Artemia cysts of commercial brands. Aquaculture 194:11–20.
Van Stappen, G., Sorgeloos, P. & Rombaut, G., eds. (2024) Manual on Artemia production and use. FAO Fisheries and Aquaculture Technical Papers, No. 702. Rome, FAO. https://doi.org/10.4060/cd0313en
More information:
Mark Rowel Napulan
Asia Sales Manager Zeigler Bros., Inc. E: mark.napulan@zeiglerfeed.com
Peter Van Wyk
Global Technical Sales Manager Zeigler Bros.
Ramir Lee
Regional Technical Manager Zeigler Bros., Inc. E: ramir.lee@zeiglerfeed.com
Table 2. EZ Artemia Ultra equivalency table
Table 3. Cost per EZ Artemia Ultra, Artemia cysts, and Artemia nauplii paste expressed as cost per 100 million Artemia nauplii equivalent amount.
Proof of major advances in rotifer substitution for marine fish species
Jessica Teske, Valentina Carbone, Thomas Raynaud, INVE Aquaculture
Larval rearing is a crucial phase in marine finfish aquaculture, marked by significant developmental changes in fish larvae. Initially, larvae rely on yolk sac reserves for nutrition as they lack functional eyes and have a rudimentary digestive system. As the yolk sac is absorbed, their vision develops, and the digestive system matures, allowing the larvae to start exogenous feeding with live prey.
Current challenges and innovations
Marine fish hatcheries typically depend on live prey like rotifers (Brachionus sp.) and Artemia nauplii. Despite advancements in live food culture protocols and enrichment products, maintaining the required quantity and quality of rotifers remains a challenge. These challenges often lead to inconsistencies in larval nutrition, impacting growth and survival rates. In 2022, INVE Aquaculture revolutionized the industry with the introduction of Natura pRo, a premium feed line designed to reduce reliance on rotifers.
This innovation results from decades of dedicated research and collaboration with the scientific community to understand marine larvae’s physiology and nutritional needs. The Natura pRo features an unique formulation available in two different sizes, optimized for early larval development.
Natura feed line: A game changer
“The introduction of the Natura feed line is a significant step forward in aquaculture. By reducing dependency on live prey, we improve the efficiency of larval rearing and create more sustainable practices. This innovation helps hatcheries maintain high standards of fish health and growth while ensuring consistent feed quality,” said Jessica Teske, R&D engineer at INVE Aquaculture. The development of the Natura feed line involved extensive research and testing. The feeds are designed to:
• Be attractive to larvae and encourage capture and ingestion with the proper particle size and behavior in water
• Be easily digestible and assimilable by the larvae’s undeveloped digestive system.
• Efficiently convert into energy to support proper growth and survival.
Trials conducted at INVE’s research center demonstrated that these feeds could significantly reduce the need for rotifers. For instance, rotifer use was reduced by up to 80% for seabream and completely for seabass when using the “Green Water Technique.” These reductions were achieved without compromising the growth or survival rates of the larvae.
Expanding horizons
Following the success in European hatcheries, the Natura feed strategy was tested on tropical species such as Barramundi, yellowtail amberjack, snapper, and totoaba. The results were impressive, showing not only good growth and survival rates but also reduced cannibalism and better stress resistance compared to traditional feeding protocols.
“The new Natura pRo feed is a game-changer for marine fish hatcheries. It offers a practical solution to the perennial problem of rotifer supply, allowing farmers to achieve consistent, high-quality results. This advancement shows our commitment to providing innovative solutions that support the growth and sustainability of the aquaculture industry,” said Thomas Raynaud, product manager at INVE Aquaculture.
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Over the past two years, INVE’s Technical Support Team has conducted commercial validation trials, tailoring feeding protocols to specific hatchery needs. This approach has confirmed the versatility
Figure 1. Rotifer consumption and reduction levels
and effectiveness of the Natura feed line across different species and hatchery conditions.
Performance and benefits
The trials revealed that the weaning protocols with Natura reduced rotifer consumption by 50% or more, depending on the species (Fig. 1). This significant reduction did not compromise other growth parameters. In some cases, survival rates were even higher with the Natura protocol, such as with Barramundi and Totoaba.
Natura feeds ensured proper growth across all species tested, with good diet acceptance from the beginning of exogenous feeding. Although survival rates for seriola and snapper were slightly lower than the control, the growth rates were similar, and the population was more homogeneous, reducing cannibalism (Fig. 2, 3).
“Using Natura feeds in hatcheries worldwide has shown remarkable results. We have seen improved survival rates and growth in various species, and we’ve also reduced the environmental impact of live prey cultivation. This progress is crucial for securing sustainable food sources for our growing global population and ensuring the long-term success of aquaculture operations,” said Valentina Carbone, global technical support fish at INVE Aquaculture.
Fish robustness is crucial for the sustainability of marine fish hatcheries. The trials showed that fish fed with Natura had similar or better quality, with lower deformity rates in species like totoaba and yellowtail amberjack (Fig. 4). This indicates that Natura provides all the essential nutrients for healthy development.
Figure 2. Survival at first grading
Figure 3. Length at first grading
Figure 4. Quality control: Total fish without deformity
Future directions
To keep making progress in reducing live food dependency and simplifying the larval rearing process, we need to combine new scientific knowledge with industry insights and hatchery expertise. Recent studies highlight the importance of feed production technology in controlling particle behavior in water and ensuring feed nutritional integrity. Ongoing refinement of dietary formulations will improve digestibility, and understanding metabolic and biological processes will be crucial. This incremental approach aims to fully substitute live food, emphasizing the need for sustained research and innovative thinking to meet the demands of improved aquaculture practices. The way forward for aquaculture requires a commitment to innovation and collaboration. By leveraging advanced research and industry experience, we can develop sustainable and efficient feeding strategies that secure the health and growth of marine fish larvae. INVE Aquaculture’s dedication to these key advancements aligns with our vision for an aquaculture industry with less environmental impact and improved productivity, contributing to a more sustainable and secure global food supply.
More information: Jessica Teske R&D Engineer INVE Aquaculture
Valentina Carbone Global Technical Support Fish INVE Aquaculture
Thomas Raynaud Product Manager INVE Aquaculture
Figure 5. How NATURA pRo appears in the gut: A) 7-day-old seabream larvae; B) 8-day-old grouper larvae; C) 7-day-old larvae; D) 5-day-old yellowtail amberjack larvae; E) 3-day-old barramundi larvae; F) 10-day-old snapper larvae; G) 5-day-old Eu larvae; H) 7-day-old Totoaba macdonaldi larvae.
Enhancing skin and gill defenses in aquaculture
Vivi Koletsi, Alltech
In aquaculture, maintaining proper fish health is crucial to avoid incurring significant economic losses. While gut health often takes center stage, the skin and gills are also critical first lines of defense.
Prebiotics
Prebiotics are generally included in aquafeed formulations as functional feed materials to help support normal immune functions and enhance nutrient absorption, digestion and, ultimately, the animal’s performance. Gibson & Roberfroid
(1995) defined a prebiotic as “an indigestible fiber that can enhance the growth and activity of health-promoting bacteria in the intestine and beneficially affect the host.” Along with their ability to effectively outcompete pathogenic bacteria and discourage adhesion, these health-promoting bacteria can also ferment prebiotic substrates, resulting in the production of short-chain fatty acids, which helps boost intestinal functions by increasing mucus and also affects the immune response (Fatima & Mansell, 2019).
From the gut to skin and gill health
While much research has focused on the effects of prebiotics on fish gut health, other mucosal surfaces — such as the skin and gills — are often overlooked. Nevertheless, skin and gills also act as a critical first line of defense for a fish’s overall health, as these large surface areas are exposed to the aquatic environment and, therefore, serve as primary targets for pathogen attachment and invasion in finfish. The mucus layer covering the epidermal and gill epithelial surfaces is not just a physical barrier; it contains potent immunologically active molecules, underlying mucosaassociated lymphoid tissue elements and microbiota, which facilitate the development and homeostasis of the host fish’s immunity (Cabillon & Lazado, 2019). However, under stressful fish farming conditions (e.g., high stocking densities, fluctuating temperatures in open systems due to climate change), a disruption of the symbiotic host-microbiome relationship can lead to significant changes in the microbiota structure — which favors the growth of opportunistic pathogens (Debnath et al., 2023).
Pathogenic challenges
Disease outbreaks in aquaculture stem from complex interactions between fish hosts, farming conditions and pathogens (Fig. 1; adapted from Moreira et al.,
2021). These outbreaks can lead to welfare challenges for animals and financial losses for producers. Bacterial and parasitic agents cause severe, unpredictable and difficult-to-treat infections on the skin and gill surfaces. For example, the parasitic copepod Lepeophtheirus salmonis, which is responsible for sea lice infestations in salmon farms that cause skin wounds and secondary infections, significantly impacted revenues and led to financial losses estimated at USD 436 million for the Norwegian industry in 2011 (Abolofia et al., 2017). As aquaculture evolves, sustainable disease management strategies will be required to protect animal welfare, health, the environment and the producer’s profitability (Lieke et al., 2020).
Mannan-rich fraction
According to Bondad-Reantaso et al. (2023), since the European ban on subtherapeutic antibiotics in animals, including fish, mannan oligosaccharides have become a primary alternative strategy for disease management in aquaculture. Mannan-rich fraction (MRF), the refined version of mannan oligosaccharides is characterized by α-(1,2)- and α-(1,3)-D-mannose branches connected to extended α-(1,6)-D-mannose chains (Hu et al., 2024). Alltech’s MRF is derived from the cell wall of a select strain of Saccharomyces cerevisiae and is among the most studied functional feed materials in farmed
Figure 1. The main factors influencing the interactions between pathogens, hosts and the farming environment in fish disease outbreaks.
FEEDS
animals (Spring et al., 2015). Research findings support MRF’s protective role against various health challenges in skin and gills across different fish species, including salmonids (salmon and trout), freshwater species (catfish and tilapia), marine species (greater amberjack) and ornamental fish (goldfish). Some of those key findings are summarized in Table 1.
Protective roles
Feeding trials without pathogenic challenges have already shown the potential of MRF to support normal functions of the mucosal immune barrier. In a study of rainbow trout, skin mucus production increased after 12 weeks of feeding MRF (Rodriguez-Estrada et al., 2013), and in studies in goldfish (Huang et al., 2022; Liu et al., 2024), longer gill lamellae, greater thickness of the dermal dense layer of skin, the number of mucous cells in the tissues of skin and gills, and an upregulated expression of genes related to Mucin-2, mannose receptors, phagocytosis and inflammation were noted after 60 days of feeding MRF. The results of other trials across different fish host species have
confirmed the activation of the necessary mechanisms that support normal functioning of the mucosal immune barriers, discourage the adhesion of pathogenic bacteria and impact the immunological responses of the challenged fish fed with MRF. For instance, the dietary supplementation of MRF in the diets of Atlantic salmon (Dimitroglou et al., 2011) was associated with a reduced total number of the parasitic copepods Lepeophtheirus salmonis and Caligus elongatus attached to the epidermis – which was also reflected in the reduced number of fish infected by sea lice (Fig. 2A).
In grass carp, supplementation with MRF helped alleviate the skin damage (Fig. 2D) caused by the bacterium Aeromonas hydrophila (Lu et al., 2021).
A similar observation was noted for greater amberjack challenged by the monogenean flatworm parasite Neobenedenia girellae (Fernández-Montero et al., 2019), which experienced a significantly reduced number of parasites per fish surface and a decreased total length for the parasites associated with feeding MRF (Fig. 2B). In goldfish challenged by the parasitic
What if your feed could do more?
Our range of technologies optimizes health of skin, gut and gills, to enhance fish nutrition and farm performance.
protozoa
white spot disease, also known as ich – another research group demonstrated a significantly lower number of white spots and a diminished infection rate after feeding diets that included MRF (Huang et al., 2022; Fig. 2C).
The protective influence of MRF has been evaluated not only through demonstrations of lower parasitic counts and clinical symptoms on skin and gill surfaces but also by increased resilience in infected fish. Several
studies have reported significantly higher cumulative survival rates — including rainbow trout fed MRF and Estrada et al., 2013), channel catfish fingerlings fed MRF and challenged by Flavobacterium columnare (Zhao et al., 2015) and goldfish fed MRF and challenged by ich (Huang et al., 2022). These studies attributed this protection to the positive impact of MRF, which is correlated with the altered expression of inflammatory cytokines and immunoactive substances (e.g., lysozyme
Figure 2. MRF studies in different fish species. (A) Salmon: A reduced number of sea lice and number of infected fish (Dimitroglou et al ., 2011). (B) Greater amberjack: A reduced number of parasites and parasite length (Fernández-Montero et al ., 2019). (C) Goldfish: Reduced white spot counts, infection rates and mortality (Huang et al ., 2022). (D) Grass carp: Reduced red-skin morbidity (Lu et al ., 2021).
and alkaline phosphate activities) that favor resolution and repair processes.
To further increase our understanding of the mode of action of MRF, research was recently conducted in goldfish using ich as a model health challenge (Liu et al., 2024). New insights from the transcriptome data from the study of Liu et al. (2024) suggests that MRF binds to the mannose receptors in fish macrophages, stimulating their phagocytic function, promoting non-specific immunity, and alleviating parasitic infections through the MRF immunomodulatory role.
Conclusion
Diseases cause significant losses to aquaculture operations. As such, investing in control and mitigation techniques is essential for a farm’s economic sustainability – especially considering the unknown impacts of climate change on infectious agents.
As the research has shown, natural dietary tools such as MRF technology are cost-effective solutions that can help nutritionists formulate diets that boost physical mucous barriers, discourage the adhesion of pathogenic bacteria and support normal immune responses. This extensive research demonstrates the holistic protection of MRF beyond gut health, highlighting additional protective effects on the skin and gill surfaces across various species.
More information: Vivi Koletsi Global Technical
Support Specialist
Alltech
Table 1. Summary of studies in various fish species that investigated the potential role of MRF in protecting skin and gill health during common health challenges in aquaculture.
Optimizing aquaculture outcomes to feed the increasing world population
Mario Roman, ADM Animal Nutrition
Aquaculture plays a crucial role in feeding the growing global population by providing an efficient source of high-quality protein. As the demand for seafood continues to rise, aquaculture helps meet this need by producing fish and shellfish in controlled environments, reducing the pressure on wild fish stocks and enhancing food security.
With advancements in nutrition and farming practices, aquaculture not only supports economic development but also contributes to responsible sourcing, making it an essential component in the future of global food production.
Aquaculture now accounts for over 50% of the global seafood supply, a figure expected to rise as traditional fisheries face depletion (FAO). By 2050, the global population is projected to exceed 9.7 billion (UN Population Reports), and aquaculture is anticipated to play a vital role in addressing the estimated 40% increase in demand for animal protein (World Resources Institute), making it indispensable in efforts to ensure global food security.
Key pillars of aquaculture success:
Sustainability, performance and profitability
Economic viability, particularly profitability, is a primary concern for commercial aquaculture farms. Improvements in critical parameters such as average daily growth (ADG), feed conversion ratio (FCR), and survival rates are key in ensuring overall farm performance and, thus resilience. Additionally, attributes like size, weight and fillet quality are crucial in determining the market value of the final product. However, aquaculture production is fraught with challenges that complicate its daily operations. Various rearing systems, transportation, handling, grading and vaccination expose aquatic species to multiple stressors, including hypoxia, injury, fluctuating water qualities and infectious agents.
These challenges are often encountered during the juvenile stages of the fish, a period when they are especially vulnerable due to immature digestive and immune systems. Such vulnerabilities can lead to suboptimal performance up to mortalities, ultimately impacting the entire production cycle.
Figure 1. Number of granular hemocytes and total hemocytes.
Figure 2. V. harveyi cells remaining in hemolymph 3 hours following challenge.
ADM is committed to supporting the health and nutritional needs of aquatic species through its science-backed solutions and services that enhance aquaculture productivity and mitigate environmental impacts. To this end, ADM provides tailored nutritional and performance solutions that cater to the specific needs of fish and shrimp species throughout their lifecycle, from early development to reproduction and harvest. Through precision nutrition, ADM helps farmers optimize growth, physiological functions and overall health, thereby improving aquaculture efficiency and performance.
Enhancing resilience in fish and shrimp
ADM’s latest innovation in aquaculture nutrition is Aquatrax, a product based on inactivated Pichia guilliermondii. This cutting-edge yeast technology, characterized by its unique morphological and structural properties, is designed to support the immune systems of fish and shrimp. Developed through advanced fermentation and heat-conditioning processes, Aquatrax is composed of whole-cell Pichia guilliermondii, a yeast characterized by a high surface area to volume ratio: 25 grams of Aquatrax presents an approximate 100m² surface area available for interaction.
Figure 3. Survivability: Percentage of live shrimp remaining in each group at weekly live shrimp counts.
Figure 4. Survivability: Percentage of live shrimp remaining in each group at live shrimp counts between day 0 and day 35 post initial challenge.
The high hydrophobicity of Pichia guilliermondii facilitates its diffusion through the intestinal environment. The yeast cell wall contains critical components, such as mannans and β-glucans, that are integral to immune support and the binding of noxious microbial agents. Notably, the mannans within the yeast cell wall interact specifically with Gram-negative enterobacteria, binding to type-1 fimbriated bacteria via mannose-specific lectins, potentially preventing bacterial colonization of the intestinal epithelium (Cardozo et al.,2018). This product helps strengthen defense against health challenges by supporting and optimizing gut function, gut integrity and body defense responses, thereby strengthening production.
Recent studies
ADM’s internal research has consistently demonstrated the efficacy of Pichia guilliermondii in supporting immune responses and improving productivity in shrimp. In a trial conducted in Thailand, Pacific whiteleg shrimp (Litopenaeus vannamei) subjected to a Vibrio harveyi challenge have shown improved immune response when supplemented with Aquatrax, including an increased proportion of granular hemocytes and enhanced clearance of V. harveyi cells from the hemolymph, compared to non-supplemented groups (Fig. 1, 2; ADM internal research).
Moreover, Pichia guilliermondii has been demonstrated as effective on a White Spot Syndrome Virus (WSSV) challenge stress tests, as evidenced by a study in Peru where post-larval (PL16) L. vannamei shrimp supplemented with the yeast
product exhibited an 84% higher survival rate than the control group (Fig. 3; ADM internal research).
In another trial addressing Acute Hepatopancreatic Necrosis Disease (AHPND), also known as Early Mortality Syndrome (EMS) caused by Vibrio parahaemolyticus, L. vannamei shrimp fed with Pichia guilliermondii showed a 76% higher survival rate compared to those on a control diet (Fig. 4; ADM internal research).
Even under unchallenged conditions, Aquatrax has been shown to improve shrimp performance. Two parallel trials at an ADM experimental facility in Vietnam revealed that sub-adult L. vannamei shrimp supplemented with Aquatrax for 48 days achieved significantly higher body weights – by 9% in a cage system and 10% in a tank system – compared to those on a standard diet (Fig. 5; ADM internal research).
In conclusion, the incorporation of Aquatrax into shrimp diets has been consistently linked with supporting immune responses and overall performance improvements. ADM is also actively exploring the benefits of Pichia guilliermondii in major commercial fish species.
As exemplified by its Aquatrax solution, ADM’s specialized aquaculture teams collaborate closely with feed formulators and health specialists to provide customized solutions tailored to the specific concerns of shrimp and fish producers across the globe. Feed mills and farmers can benefit not only from innovative feed additives but also from cutting-edge technology and production processes designed to maximize efficiency. These connections are instrumental to address the pressing demand for efficient and environmentally responsible food production to support a rapidly growing global population.
Figure 5. Average shrimp body weight gain over the study periods
Marking a decade of copepod innovation
In wild ecosystems, almost all fish larvae diets are based on copepods. When feeding with copepods, essential fatty acids, such as DHA and EPA, and essential amino acids are easily assimilated by the larvae improving fish growth and feeding behavior and reducing skeletal anomalies. However, in aquaculture hatcheries, live feeds have been traditionally based on rotifers and Artemia with no affordable options for sourcing copepods.
The Norwegian-based company, CFEED, is now offering copepods as feeds for the early stages of aquaculture hatcheries. Currently celebrating its 10th anniversary, the company is primarily serving the Nordic and European markets together with a few, selected clients in Asia. CFEED aims to significantly expand its reach to larger clients and global markets in the coming years as it simultaneously increases its production capacity.
The beginnings
It all began in the early 2000s with scientists at SINTEF Ocean. “They were analyzing the value chain in marine fish farming, particularly the early stages of farming and the challenges faced by hatcheries. Many farmed species around the world were experiencing high mortality rates, slow growth, and deformities, leading to significant costs not just in hatcheries but also in the grow-out stages until harvest. The scientists began to explore what fish fry consume in the wild as their first feed and why it works well in nature,” said Tore Remman, CEO of CFEED.
“This led them to Acartia tonsa, a type of plankton that we now breed and produce eggs from. It quickly became apparent that it could address many of the issues associated with traditional hatchery feeding. However, it took nearly 15 years of R&D to reach the point where we could establish a company and build the first pilot. This demonstrates just how challenging it is to farm plankton,” Remman explained.
Performance
With a strong R&D background, CFEED copepods have been tested in several species with positive results. “The strength of our product lies in its consistent performance across various species. It helps reduce mortality, increase growth, and decrease deformities –often all at once. However, the most significant highlight is the improvement in feed conversion ratio (FCR), which ultimately reduces overall feed costs for farmers. Since feed costs are the largest expense for fish farmers, this is a substantial benefit,” Remman stated. “Imagine significantly reducing your feed costs, cutting down the
expenses of sorting out deformed fish, and possibly even achieving an extra production cycle per year. This is what you could gain in the long run by using the right feed from the start. We simply provide the ‘mother’s milk’ for the fry industry.”
Hatcheries are increasingly receptive to incorporating new live feeds into their procedures, recognizing the value and proven effectiveness of our products. “This evolving mindset is creating new opportunities for introducing our solutions, even in the most established
and traditionally cautious markets,” Remman said. “New species, as well as those with traditionally low survival rates or high deformity challenges, are eagerly adopting our product. While established farmed species tend to be more selective, we are confident that the significant improvements we have demonstrated in feed conversion ratios (FCR) will soon encourage these markets to embrace our solution as well.”
“From a sustainability perspective, this is also massive. Although fish farming is far more sustainable than producing red meat, about 70% of CO2 emissions from fish farming are related to feed and feed production. Looking at the global feed production, and knowing that more food needs to be farmed in the oceans, the result we gain in using our product is massive,” said Remman.
Celebrating its 10th anniversary CFEED is celebrating 10 years and the journey was not without challenges. “Over the years, the challenges have evolved, but since I joined in 2016, a major shift has been building a culture focused on production rather than just research and innovation. Coming from the labs at SINTEF, this was challenging, particularly as we needed to scale up and commercialize our operations. At that time, we also lacked significant experience in how to use our product and fully understand its core benefits. We therefore launched an extensive testing regime, passing over 25 species and 40 commercial trials. This has greatly improved our understanding of both our markets and the strengths of our product, leading to a high demand for it, which is a major achievement,” Remman said.
“Additionally, we have successfully attracted new investors in recent years, providing us with a solid foundation for further expansion. This was not only a significant financial achievement but also allowed us to strengthen an already excellent team,” said Remman.
Looking forward
In the coming years, the company aims to quadruple its production capacity, starting the first phase of construction this fall which will provide CFEED with a robust business for further expansion into new markets. “We are currently following our strategy closely in terms of market expansion, and now we just need to deliver more products to meet market demand,” Remman concluded.
Copepod nauplii with algae
Science-based genetic and management solutions to disease problems
Dr. Natthinee Munkongwongsiri, Dr. Tanatchaporn Utairungsee, Daniel Fegan, Craig Browdy, SyAqua
Global aquaculture production has exceeded production from capture fisheries since 2022 (FAO, 2024). However, disease continues to be a major factor affecting the production of aquaculture species with annual losses measured in billions of US dollars. Within the global shrimp aquaculture industry, the Pacific white shrimp (Penaeus vannamei) is the major species but emerging
diseases, including white feces syndrome, TPD, CMNV, and DIV1, pose significant threats to shrimp farming operations, especially in Asia.
At SyAqua, we understand that providing solutions to help manage these disease challenges is vital to improving our customer’s productivity and sustainability. Our approach focuses on gaining a
deeper understanding of shrimp disease pathology and epidemiology, enabling us to develop more effective disease management strategies.
Pathology and epidemiology are complementary and essential approaches for understanding disease and developing control strategies. They essentially look at disease from different viewpoints:
• Pathology refers to the study of the nature and causes of diseases, including their effects on the host organism. Understanding pathology aids in identifying symptoms and unraveling disease mechanisms.
• Epidemiology deals with the patterns, distribution, frequency, and determinants of diseases in populations. Understanding epidemiology is crucial for tracking disease spread, assessing risk factors and developing control strategies in the field.
For example, during the first outbreaks of white spot disease in the 1990s, epidemiological studies identified postlarvae as the most likely source of disease transmission, months before the causative agent was identified. This allowed some basic control strategies to be adopted to reduce the risk of transmission. The later identification of white spot virus as the causative agent allowed the development of
PCR tests which further improved the ability to screen postlarvae and identify other routes of transmission. This in turn led to the development of improved control strategies.
The widespread adoption of PCR testing has revolutionized our understanding of pathogens and diseases. PCR, particularly qPCR, is a highly sensitive diagnostic tool but like all diagnostic tools, it has intrinsic weaknesses so interpretation of test results must take these into account.
Differentiation between “Infection,” “Test Positive” and “Disease”
In shrimp health management, it is essential to distinguish between the terms “infection,” “test positive,” and “disease.”
• Infection: The presence of a transmissible pathogen within an organism, which may or may not lead to illness (disease).
• Test positive: The detection of a pathogen, or its genetic material, through diagnostic tools. This indicates exposure to the pathogen but does not necessarily confirm true infection or the eventual development of clinical symptoms.
Figure 1. Conceptual model of interactions among rearing conditions, pathogens and shrimp in the pond environment (Xiong, 2018)
• D isease: A clinical condition characterized by observable symptoms and adverse health effects caused, or influenced by, environmental factors, shrimp genetics, nutrition, or pathogens. Diseases can be categorized as either infectious or non-infectious:
o Infectious diseases are caused by pathogenic microorganisms such as bacteria, viruses, fungi, or parasites. These diseases are contagious and can be transmitted from one animal to another.
o Non-infectious diseases result from environmental stressors, nutritional imbalances, or genetic defects. Although these conditions can lead to mass mortality or serious health effects, they are not contagious and do not spread between animals. Distinguishing between these terms is vital for accurate diagnosis and effective management. Misinterpreting them can lead to unnecessary treatments and costs, inappropriate management actions, and either a false sense of security or unnecessary panic.
In veterinary epidemiology, “disease” can refer to any negative impact (death, deformity, slow growth, poor feed conversion, financial loss, etc.) of an infection. These are often dependent on the prevalence, transmission, infectivity and virulence of the pathogen but also on other factors such as environment, nutrition and genetics. In this situation, the pathogen is not necessarily the “cause” of a disease since other factors influence (“cause”) the development of disease in the population. In other words, the presence of the pathogen is a “necessary” but not “sufficient” cause of the disease (e.g. the presence of white spot virus is necessary for white spot disease to occur but under certain conditions, it can be managed to prevent clinical disease outbreaks in the population). This is one basis for the development of disease management strategies.
This concept is neatly shown in Figure 1.Healthy shrimp have several defense mechanisms against pathogens. However, poor environmental conditions can result in stress and increased presence and/or virulence of pathogens. This can result in the immune system being overloaded and the development of clinical disease, and mortality.
Importance of having the right tools to develop solutions
To develop effective solutions for shrimp health management, having the right tools and methodologies are essential.
Sampling
Effective sampling is fundamental to any health management strategy. Representative and systematic sampling ensures that the collected data accurately reflects the health status of the entire population. Methods include random sampling and stratified sampling, which help in obtaining a comprehensive view of health and disease distribution within the hatchery and farm.
Two things determine the best sampling methodology –the size of the population and the expected
Table 1. Sample sizes giving 95% confidence of detecting a pathogen at different prevalences.
GENETICS
prevalence or cutoff prevalence of the disease. Sampling tables (Table 1) can be used to determine the optimal sample size to test populations for infection at different prevalences. In practice, the sample size is often a tradeoff between the level of confidence desired and the cost of running the tests.
When testing PL, for example, sample sizes are often between 30 and 50 pcs, usually in a pooled sample. Referring to Table 1, a sample of 30 PL from a batch of 300,000 PL (anything over 10,000 individuals uses the values for infinity) would contain at least one infected PL if the prevalence was over 10%. Alternatively, if we wanted to detect a prevalence of at least 2%, we would have to take a sample of 149 PL. Whether these prevalence limits are acceptable or not depends on the level of acceptable risk around the disease(s) of concern.
Interpretation of test results
Accurate data interpretation is critical in managing shrimp diseases. The widespread adoption of PCR testing has revolutionized our understanding of pathogens and diseases. PCR, particularly qPCR, is a highly sensitive diagnostic tool but like all diagnostic tools, it has intrinsic weaknesses so the interpretation of test results must take these into account. Common challenges include distinguishing between false positives and true positives and understanding the
significance of the results in the context of overall shrimp health. Solutions involve using validated diagnostic tools and integrating results with clinical observations and farm management practices.
At SyAqua we have studied the limits of detection in quantitative PCR for EMS to determine the reliability of PCR test data (Fig. 2). The graph shows the LOD (“Limit of Detection”) value (minimum number of copies that gives a positive PCR result in all replicates tested). The estimated LOD95% was calculated as 4.2 copies.
Health Monitoring Program
A farm Health Monitoring Program (HMP) is essential for ongoing surveillance and management of shrimp health. The HMP involves various tools and methods such as physical evaluation, examination under a microscope, PCR for pathogen detection and microbiological testing for pathogens (bacteria, fungi). The HMP workflow includes regular inspections, data collection, and analysis to ensure timely interventions and shrimp health management.
Figure 2. A) Graphical representation of the determination of limit of detection (LOD). B) The data in the table show the number of positive samples/all analyzed samples (signal ratio).
Figure 3. Shrimp exhibiting White Feces Syndrome (WFS) showing both non-WFS and WFS animals. The white gut content in infected individuals is shown by the red arrows.
GENETICS
At SyAqua, we continuously improve our health monitoring practices and diagnostic tools to ensure accurate and reliable results, helping to prevent and manage shrimp diseases effectively.
Strategies for breeding more robust stocks
Genetic strategies also play a role in enhancing disease resistance in Penaeus vannamei
Effective challenge systems to measure resistance
SyAqua’s breeding program includes an EMS challenge system using live VPAHPND bacteria to simulate disease conditions, mirroring the natural infection route. Effective challenge trials are designed by selecting appropriate pathogen strains, optimizing exposure conditions, and assessing shrimp responses to evaluate genetic resistance.
Recently, SyAqua researchers successfully induced EHP infection to establish a White Feces Syndrome (WFS) model to enable testing of potential solutions or treatments for WFS and integration in our Genetics Improvement Program. Preliminary results suggest that different genetic lines in the domestic market exhibit varied responses to WFS (combined EHP + V. parahaemolyticus challenge), as shown in Figure 4, where the control group was exposed to EHP infection only. This approach will enable us to explore potential genetic and phenotypic
correlations between the two diseases. If a correlation is identified, a single disease challenge test could be sufficient to identify shrimp lines resistant to both EMS and WFS.
Advanced genomic selection protocols
Genomic selection is a powerful tool for improving shrimp stocks. It involves using genomic information to guide breeding decisions, leading to more precise selection for disease resistance traits. To determine breeding value, DNA from both dead and surviving shrimp in each generation is analyzed to identify markers associated with EMS-resistant traits. Since introducing genomic selection to the SyAqua Genetics Improvement Program in 2019, we have achieved a 22% increase in resistance to EMS (Fig. 5).
Biosecurity for applying management solutions that enable and maximize performance from improved stocks
To support genetically improved shrimp stocks, effective management strategies are necessary. Robust biosecurity protocols must be in place to control pathogens, maintain optimal production conditions and promote shrimp health. Best practices include implementing strict hygiene protocols, monitoring environmental conditions, and controlling access to shrimp farms.
Figure 4. Results from two genetic lines on survival rates in White Feces challenge test. Note: control group was subjected to EHP infection only.
Conclusion
Sound science is indispensable in developing effective genetic and management solutions for shrimp aquaculture. By integrating advanced genetic strategies, robust health monitoring programs, and effective management practices, the industry can enhance shrimp health, increase productivity, and ensure sustainability Looking ahead, continued advancements in disease management and breeding technologies hold promise for further improvements in shrimpaquaculture.
References
FAO. 2023. Evaluation of FAO’s Support to Life below Water (SDG 14). Hundred and Thirty-seventh Session of the Programme Committee, Rome, 6–10 November 2023. Rome. https://www.fao.org/3/ nn072en/nn072en.pdf
Xiong J. Progress in the gut microbiota in exploring shrimp disease pathogenesis and incidence. Appl Microbiol Biotechnol 2018 Sep;102(17):7343-7350. doi: 10.1007/s00253-018-9199-7 Epub 2018 Jul 7 PMID: 29982924.
More information: Dr. Natthinee Munkongwongsiri Field Research Manager SyAqua E: natthinee.m@syaqua.com
Dr. Tanatchaporn Utairungsee Laboratory Manager SyAqua E: tanatchaporn.u@syaqua.com
Daniel Fegan Technical Director SyAqua E: dan.fegan@syaqua.com
Figure 5. The improvement of EMS resistance of SyAqua genetics from 2013 to 2022.
Genetics is an investment, not a cost
Xelect and Kames Fish Farming
Kames Fish Farming was established in 1972 at Loch Melfort on the Scottish Atlantic Coast and was an original pioneer of farming rainbow trout in cages in both freshwater and seawater. Over the past 50 years, Kames has diversified into cage and equipment manufacturing, seabass and seabream farming in the Mediterranean, Atlantic salmon farming, and the production of halibut. But by 2021, Kames streamlined its activities and is now focused 100% on the production of rainbow trout primarily in seawater. This is known as Steelhead – rainbow trout that migrates to the sea, where it grows big, athletic and more silver than its river counterpart. It is renowned for its firm texture and delicate flavor – quality and taste.
In the wild, sea-going strains breed in freshwater and only a percentage of the new generation will go to sea, ranging between 20% and 60%. This is an evolutionary defense mechanism to avoid the entire year class being
in one environment that may prove unfavorable in a particular year, but in the wild, the individual fish will make the choice of whether it is capable of migrating or not into full-strength seawater. In the farming situation where the whole population is put into full-strength seawater, the non-migratory element of the population struggles to perform and a percentage will fail to thrive, stop eating and result in a higher mortality.
Back in the 1970s, Kames Fish Farming was able to secure a strain of steelhead that had a high tolerance to seawater, and for some ten years, bred from this stock selecting the individuals that survived a full seawater cycle (ultimately achieving a consistent 92% survival through the seawater cycle).
However, this program came to an abrupt end in the 1980s when Bacterial Kidney Disease (BKD) was detected during a routine statutory disease test. Since BKD was (and still is) a notifiable disease, the entire
Paul Luckhoff, Freshwater Production Manager at Kames
broodstock population had to be slaughtered, and Kames then had to rely on imported eggs which brings its own challenges – prohibition of eggs if disease detected, lack of supply of steelhead strain, seeing fish unable to achieve the survival and performance levels previously seen in natural steelhead egg supplies. This has had serious financial implications for the cost of production in Kames, affecting juvenile or smolt costs (to accommodate higher losses at sea), operating costs (from additional grading operations to remove failing fish before it becomes a welfare issue), higher feed costs and lower harvest volumes.
Forming its own breeding program
To protect themselves against import bans and provide security of supply, Kames began to work with a UK trout breeder on developing of their own broodstock, selected specifically for seawater survival
and performance, resulting in the formation of a unique nucleus population for further development. In 2021, Kames engaged with fellow Scottish-based company Xelect as a genetics partner, providing longterm support for the program. Also, cryo-preservation methods were introduced with the help of Norwegian company Cryogenetics, to preserve elite genetic material and allow crossing between year-classes to homogenize the population.
Xelect was founded 11 years ago, in response to the growing demand from aquaculture companies for access to the same kind of advanced genetics services that terrestrial farming, such as beef and poultry, have applied for many decades. Aquaculture may have been slower than land-based farming to embrace the potential of genetics, but the pace of adoption has accelerated as companies recognize that the returns from a genetics program can be very significant. For example, recent programs managed by Xelect resulted in fish that grew 16% faster every generation.
Lidia de los Ríos Pérez, is Xelect’s senior breeding program manager for Kames. “When people think about genetics, they often imagine high-tech laboratories and lots of expensive scientific equipment. While it’s true that we do have a highly sophisticated laboratory at our base in St. Andrews, it’s impossible to separate a genetics program from the practical reality on the ground at the farm. We spend a lot of time working directly with our customers in their hatchery, understanding exactly how they are set up and helping train their team and optimize their processes. Kames is an excellent example of that relationship working perfectly.”
Examples of this close collaboration include site visits during the sampling of the candidate broodstock and the production of the families for the breeding program. In both events, Xelect has worked with Kames to develop working templates to optimize and automate processes, establish methods for individual and family traceability and increase the accuracy of the data collected. Kames has done a fantastic job of embracing these new technologies.
“Rather than feeling like outsourcing our genetics program, the reality has been that Xelect has come in and educated us, and now an in-depth understanding of the entire process – spawning the next generation nucleus, stripping, fertilizing, cryo-preserving, and then
GENETICS
care of those eggs into early fry stage – has become a part of our regular husbandry and cycle. Xelect comes down, gets stuck in, is there on hand to guide us forward, but has also empowered us to better understand and protect our fish into the future,” said Ben Leigh, broodstock manager.
Xelect also works closely with its customers to align the genetics program directly with the commercial priorities of the farm. For example, they can run advanced simulations that will allow them to predict how even small changes in the design of the program – for example, what traits they focus on, or how many fish are sampled – will affect the profitability of a breeding program.
“When we began working with Kames, our first step was to conduct a genetic audit of their existing broodstock, so that they had a clear picture of the genetic diversity and potential of their fish and have since then implemented strategies to build a solid foundation. We then worked closely with them to understand what traits would have the biggest positive impact on them. In the case of Kames, this was growth (faster-growing fish) and survival in seawater. Only once we fully understood how Kames works and what matters most to them did we actually design a program for them,” said Lidia.
According to Xelect, more and more aquaculture companies see genetics not just as a way to get
faster growth, but as an essential aspect of modern, responsible farming in a changing world.
Xelect’s global head, Chris Wallard, commented that “fast growth and survival are always likely to be key traits in aquaculture, but we’re increasingly seeing more advanced traits coming into play. For example, we are working with customers to develop more temperaturetolerant fish that
continue to perform well as sea temperatures increase. No two farms are alike, and having your own genetics program allows you to have fish or shellfish that are designed to thrive in your own production conditions. We’re also working with customers to select fish that can make more efficient use of feed – a trait which has enormous commercial advantages, due to the increasing cost of feed, and the need for sustainable use of resources.”
“The progress in aquaculture genetics has been rapid in the past few years, and we’re also now exploring the potential for other new technologies, such as gene editing and other advanced breeding technologies. When it comes to the potential for genetics to significantly improve the sustainability and unlock the potential of aquaculture we’re only just getting started”
Andrew Cannon, MD of Kames said that “genetics is an investment, not a cost, and with our own broodstock we are able to breed fish proven to thrive in our production environment sustainably, with any gains building cumulatively from one generation to the next. The initial program goals are based on seawater tolerance and growth to harvest. But in the longer term, Kames can introduce other traits of commercial interest, particularly in relation to our farming techniques and the environment, including rising sea temperatures. It gives us the potential to adapt and thrive in a challenging climate future.”
The Xelect team provide hands-on support for the programme at key times of the year.
Marine finfish farming in Brazil: Opportunity or illusion?
Viviana Lisboa, Blue Economy Program, Ricardo Camurça Correia Pinto, Marine Fish Farming Research Unit, João Felipe Nogueira Matias, Blue Economy Program
The first marine fish farming attempted in Brazil dates back to the 17th century. Wild fingerlings were captured (Centropomus, Mugil and Eugerres) and confined in tidal ponds for extensive aquaculture (Lisboa et al., 2020). Currently, Brazil has two small-scale commercial production farms. Maricultura Costa Verde (Angra dos Reis-RJ) (Fig. 1), which carries out cobia (Rachycentron canadum) grow-out in near-shore cages, and Marine Farm Prime Seafood (Alcobaça – BA) (Fig. 2) that carries out dusky grouper (Epinephelus marginatus) production in lined tanks using a flow-through system.
Both companies also serve as training facilities in collaboration with research institutions. The fact is that, until now, these entrepreneurs have embodied a pioneering spirit to pursue the challenges of commercial fish farming in Brazil.
The small number of companies and research institutions working with marine fish culture in Brazil result in low demand for larviculture products: enrichment emulsion for live feed and commercial diets discourage local suppliers to import these products. The quality and availability of grow-out diets are also a limiting factor for the development of the Brazilian marine fish farm industry. Besides that, the lack of a continuous supply of marine finfish fry also limits the success of the activity. Moreover, the complex and slow process of obtaining environmental licenses is also a major bottleneck for Brazilian marine fish production (Kuhnen et al., 2022).
The fact is that marine fish farming in Brazil is still an unconsolidated activity, limited to small-scale commercial farms and a few research institutions, among them the Laboratory of Marine Fish Farming (LAPEM/ FURG), Marine Fish Farming Laboratory (LAPMAR/UFSC), Marine Fish Farming Research Unit (UPMAR/LABOMAR/ UFC) and Dusky Grouper Project (FUNCAP).
Figure 1. Grow-out of cobia Rachycentron canadumin nearshore cages at Maricultura Costa Verde (Angra do Reis, Rio de Janeiro, Brazil).
Credits: Cristina Vaz Avelar de Carvalho
Figure 2. Production of dusky grouper Epinephelus marginatus in a flow-through system at Marine Farm Prime Seafood (Alcobaça, Bahia Brazil). Credits: Marcelo Lacerda
Laboratory of Marine Fish Farming
The Laboratory of Marine Fish Farming (LAPEM) (Fig. 3) of the Federal University of Rio Grande –FURG has already developed research activities with several fish species, including flounder (Paralichthys orbignyanus), pompano (Trachinotus marginatus), pejerey (Odontesthes argentinensis), mullet (Mugil liza) and cobia (R. canadum). The Southern black drum (Pogonias courbina) has been the focus of attention at LAPEM since 2019. Studies on reproduction, larviculture and fingerling production have been successful. In addition to their use in fish farming, these fingerlings have also been considered for stock enhancement projects, as this is a species threatened with extinction. Together with other laboratories at the Oceanographic Institute at FURG, LAPEM is also studying the inclusion of macroalgae and halophytes in diets for marine fish. The projects developed at FURG on marine fish farming have the support of several funding agencies, such as CNPq, CAPES, FAPERGS and the European Community.
Marine Fish Farming Laboratory
The Marine Fish Farming Laboratory (LAPMAR), at the Federal University of Santa Catarina (UFSC) was founded in September 1990. LAPMAR successfully developed a methodology for breeding sardines (Sardinella brasiliensis) (Fig. 4) in captivity in a project called “Live Bait”, with a focus on minimizing the wild capture of sardines used as live bait for tuna fishing.
Six generations of sardines have been produced at LAPMAR, and in 2024, new wild broodstock fish are also added to maintain genetic variability.
The laboratory also had success breeding Mugil liza (Fig. 5). Spawning of wild broodstock along with F1 and F2 generations resulted in good quality eggs for the production of larvae in captivity. New research species include Southern black drum (P. cromis) and snowy grouper (Hyporthodus niveatus).
Currently, in partnership with LAPEM/FURG and institutions from Spain, Portugal, Poland, Italy, Sweden, UK and Finland, LAPMAR advanced the “Blueboost”
Figure 3. Southern black drum Pogonias courbina broodstock tank kept in a recirculating aquaculture system at the Marine Fish Farming Laboratory, at the Federal University of Rio Grande – FURG. Credits: Luís André Sampaio
Marine Fish Farming Research Unit
Founded in 2005, as marine finfish laboratory research at the Institute of Marine Sciences (LABOMAR), of Federal University of Ceará (UFC), the Marine Fish Farming Research Unit (UPMAR) was created especially to develop technologies for native marine finfish artificial reproduction. Currently, UPMAR has been restructured, constituting and conditioning Lutjanidae broodstock to establish captive breeding and larviculture protocols, aiming to provide fingerling research and production on grow-out farms supply.
Dusky Grouper Project
Project, investigating integrated multitrophic aquaculture (IMTA) in nearshore cages at Penha (Santa Catarina, Brazil) using fish, mollusk and macroalgae in order to develop indicators of growth, reuse of nutrients, ecological footprint, carbon emissions and blue economy.
The Dusky Grouper Project started in 2021 with a goal to spread technological innovations to provide socioeconomic contributions through diversification of the aquaculture sector and encourage public and private actions for the development of marine finfish farming in the state of Ceará, Brazil. The project is organized by the Cearense Foundation of Support for Scientific
Figure 4. Sardine Sardinella brasiliensis fingerlings produced at the Marine Fish Farming Laboratory (LAPMAR) at the Federal University of Santa Catarina (UFSC). Credits: Caio Mignotti
Figure 5. Mullet ( Mugil liza ) broodstock maintained at the Marine Fish Farming Laboratory (LAPMAR) of the Federal University of Santa Catarina (UFSC). Credits: Caio Mignotti
and Technological Development (FUNCAP), through the Chief Scientist Program, currently associated with Ceará Secretariat of Fisheries and Aquaculture (SAP) and UPMAR/LABOMAR/UFC. It is the first pilot project to assess the adaptability and feasibility of grouper aquaculture in northeastern Brazil.
Besides the Dusky Grouper Project becoming even more relevant in the search to add efforts to overcome the inconceivable stagnation in this process of bringing marine fish farming to the reality of Brazilian aquaculture activities, similar to the national scenario, it also currently faces the lack of financial resources to maintain its execution.
The Dusky Grouper Project is a relevant actor aiming to add efforts to overcome the difficulties currently faced in the process to establish a marine fish farming industry in Brazil. However, it is important to maintain sustainable funding in order to keep these activities
Conclusion
Marine fish farming is not only important for food security and the socio-economic landscape, but it can also contribute to conservation efforts by producing fingerlings for stock enhancement projects. Despite its undeniable potential for marine finfish farming, Brazil has yet to establish a productive industry. The limited supply of essential inputs, such as fry, and a bureaucratic, slow licensing process create uncertainties for the marine fish farming sector in Brazil.
Potential entrepreneurs show great interest in engaging in this new commercial venture, but they
Figure 6. Marine Fish Farming Research Unit (UPMAR/LABOMAR) Lutjanidae broodstock at the Federal University of Ceará (UFC). Credits: Viviana Lisboa
Figure 7. Juvenile Epinephelus marginatus produced by Dusky Grouper Project in partnership with Marine Fish Farming Research Unit (UPMAR) at Federal University of Ceará (UFC). Credits: Ricardo Camurça
seek profitable businesses and are not willing to take significant risks. It is important to consider that the development of any productive activity requires investment in interdisciplinary research and the development of appropriate technology. The public and private partners must collaborate with each other, each fulfilling their responsibilities, such as offering streamlined licensing protocols, providing financial support, training personnel, and developing technology for local species. This is key to ensuring marine fish farming can become a viable industry in Brazil.
References
Lisboa V., Eloy H.R.F., Catter K.M., Vidigal R.C.A.B., Souza R.L., Matias J.F.N. Brazilian Marine Fish Farming: Challenges and Prospects for its Development in the State of Ceará. Sistemas & Gestão, Niterói, v. 15, n. 2, p. 113-122, ago. 2020. DOI https://doi.org/10.20985/19805160.2020.v15n2.1636
Kuhnen V.V., Hopkins K., Dos Santos Mota L., Sousa O.M., Sanches E.G. Challenges and lessons from marine finfish farming in Brazil. Marine Policy, Amsterdam, v. 138, n. 104979, abr. 2022. DOI https://doi. org/10.1016/j.marpol.2022.104979
Viviana Lisboa Research fellow Blue Economy Scientist Chief Program (FUNCAP) E: viviana.lisboa.lisboa@gmail.com
Ricardo Camurça Correia Pinto Coordinator UPMAR
João Felipe Nogueira Matias Scientist Chief Blue Economy Program (FUNCAP)
Figure 8. Fish Farming Research Unit (UPMAR) recirculating aquaculture systems (RAS)
CSIRO investigates the giant oystercracker for aquaculture’s next big success story
Dr Pollyanna Hilder, Stuart Arnold, Dr. Mathew Cook, CSIRO
This fish, a large pompano, is ticking all the critical boxes for successful commercialization.
Australia’s national science agency CSIRO has been investigating Trachinotus anak for aquaculture in Australia. Lead CSIRO researcher Dr. Polly Hilder says identifying new species with characteristics suited to modern aquaculture could provide an important opportunity to diversify and strengthen the growing Australian white flesh fish industry.
“Our primary focus at CSIRO has been new species development in Australia, however, we have taken this
work one step further, looking at a holistic approach incorporating sustainability and welfare,” Hilder said. “To expand on this, the project encompasses two key objectives: firstly, to produce a safe, healthy, and nutritious protein source that is commercially viable within the Australian context. And secondly, to establish farming practices prioritizing sustainability and animal welfare, which will also support other existing and emerging aquaculture industries.”
With increasing global production of aquaculture species, there is a rapidly growing demand to develop novel, affordable farming and processing technologies to ensure sustainable growth.
Current Australian white flesh fish industries are highly successful and are increasing production with a high level of biological and economic knowledge.
Developing novel technologies that can support current production, such as waste utilization, inclusive of processing and farming waste and welfare practices, requires significant investment and access to an incredibly diverse range of capabilities, resources, and expertise.
CSIRO plans to utilize its research capacity in areas such as biotechnology, animal husbandry, breeding, economics and food innovation to evaluate and refine technologies with the aim of finding solutions to promote cost-effective sustainable farming with high animal welfare values.
Giant oystercracker
Dr. Hilder says the fish CSIRO has targeted for new species development is T. anak, due to the highly desirable aquaculture attributes the fish possesses.
“Of particular note, the fish is endemic to northern Australia, robust and fast-growing, possesses excellent flesh qualities, produces a high fillet yield and proven commercialization overseas”.
In January 2023, CSIRO achieved a major breakthrough with the first spawning and juvenile rearing of T. anak in Australia. The control of reproduction of wild marine finfish is challenging and further complicated when the species is large (maturation > 6 kg) and can grow to more than 25 kg.
Through the utilization of large RAS broodstock facilities (100-tonne culture tank), photothermal manipulation and evaluation of a suite of reproductive hormone applications, CSIRO has achieved successful spawnings in 2023 and 2024.
The research has determined important biological characteristics of the species relevant to hatchery operations such as egg development, hatching timeframes, larval development and feeding behavior.
The fish have a larval cycle typical of many marine finish broadcast spawning species, egg development is rapid with larvae hatching around 24 hours post-fertilization. The larvae are reliant on an endogenous yolk supply
at hatch and commence exogenous feeding on rotifers (Brachionus plicatilis) three days post-hatching. Larval development is rapid with the larvae quickly transitioning onto Artemia followed by weaning onto an aquafeed crumble.
Successful T. anak breeding has provided CSIRO the opportunity to assess growth performance of offspring to allow the pilot investigation of market and economic analysis as well as hatchery protocol development.
To date, the fish have passed with flying colors, all of which are essential for successful industry development.
Conservative growth trials have seen early rapid growth with the fish easily reaching 1 kg in the first year with expected growth to exceed 4 kg by the second year.
Dr. Hilder says that in addition to strong biological traits the flesh quality is premium. This fish has firm, sweet flesh with a long shelf life (> 20 days), large bones and excellent fillet yield.
An important competitive advantage for the commercial production of this species over other species is that it does not exhibit cannibalism at weaning or aggression during the entire production cycle. “This has immediate economic and welfare gains,” Dr. Hilder said.
This breakthrough in spawning and juvenile production now paves the way for commercial trials. Dr. Hilder says these commercial grow-out trials will commence shortly and will be used to validate CSIRO economic modeling and further proof test the species.
“We are hoping to develop the framework for an infant pompano industry within the next three years and expand this to commercial production within the next five years with early adoption of an applied breeding program for production of superior robust juvenile stock,” Dr. Hilder said. “And the big positive is that this will all be designed around sustainability and welfare and is set to be a major addition to the future Australian aquaculture landscape.”
