Cost benefits of functional health additives

Dr Ruth Garcia

Gomez,

Business Development Manager

for Aquatic

Health

and Farm Care Products at APAC/ ISC sub-regions for Adisseo, said that today, incidences of disease outbreaks are not only linked to increased intensification but also to increased farming stressors, including less digestible diets, changes in environmental conditions, extreme weather events and limited availability of veterinary medicines in aquaculture. For the shrimp industry, an evaluation indicated that by 2050, there may be around 40% losses due to infectious diseases. She said this when presenting “What are the cost implications of using functional health additives for farmers and what will the incentives be for feed millers to change” at TARS 2022 Aquafeeds: A New Equilibrium in October.

Garcia Gomez said, “We face multifactorial infections –very often in aquaculture, there is no single pathogen but co-infections and multifactorial disease scenarios, such as in tilapia farming in Thailand. In open aquaculture systems, along the production cycle from the hatchery until after the end of the grow-out, farmers face different bacterial, viral and external and internal parasitic infections.”

Disease management in the livestock sector is well organised considering epidemiology and early diagnosis, genetic selection towards pathogen resistance, active vaccination programs as well as strong on-farm biosecurity strategies and improved husbandry. However, the aquaculture sector has a different set of challenges. As a veterinarian, Garcia Gomez asked whether the aquaculture sector is investing enough in prevention and will a single bullet – a single veterinary medicine work against multiple infectious diseases?

In terms of preventive approaches and on how to evaluate their economic value, Garcia Gomez stated, “We believe in prevention approaches and promote the idea of the broader spectrum health additives with multiple modes of action. Organic acids have a clear impact on the pathogenic loadreducing bacterial quantities. Whereas phyto-biotics have a clear impact in the host, increasing disease resistance through gut flora modulation, improving and maintaining gut integrity and structure, limiting quorum sensing and therefore, promoting growth and profitability. The concept of a balanced immune system is important towards stress reduction and enhanced immunocompetence.

“There is a need for a change in mindset on functional health additives when backed and validated with scientific data obtained via in vivo and in vitro trials. However, we need clear and coherent regulatory frameworks at national and regional level in promoting these types of preventive approaches. It also requires commitment from key stakeholders within the aquaculture sector at all levels,” said Garcia Gomez adding, “Preventive approaches and alternatives to antimicrobial use which can reduce antimicrobial resistance are going to be always well accepted by the public. In most cases, they are safe and traceable.”

Preventive health programs

Indonesia: To reduce the impact of WFS

Garcia Gomez discussed some results from commercial field trials conducted with Penaeus vannamei shrimp in Indonesia. The trial looked at reducing the impact of white faeces syndrome (WFS) using a phyto-biotic-based additive.

The significance of this trial was paralleled with the presentation by Dr Olivier Decamp, Grobest, on the impact of Enterocytozoon hepatopenaei (EHP) in shrimp farming in Vietnam and its combination with WFS and vibriosis (see pages 8-12). In this trial, WFS was detected at days of culture (DOC) 30-40 in the last 4 crops at the farm. EHP was positive by PCR. The maximum survival rate was 50% and feed conversion ratio (FCR) was 1.7. The Vibrio load was at more than 10 2 CFU/mL.

Garcia Gomez discussed results from supplementation under the two different strategies (corrective and preventive). There were improvements in survival (+164%), FCR (-32%) and biomass at harvest (64%). Additionally, the use of the preventive dosage throughout the entire cycle maintained growth and survival rates to pre-WFS levels and ROI (1:40).

“Also important is that the environmental evaluation to assess the kilograms of CO 2 per kg of shrimp showed that the corrective approach gave a significant reduction in total CO 2 production by 16% while the combination of preventive and corrective approach reduced this further to 39%.”

Vietnam: To reduce the impact of external parasites

This is the result of a completely different farm trial which on the brown marble grouper Epinephelus fuscoguttatus together with the National Agricultural University in Hanoi. The objective of the trial was to validate the efficacy of a health additive based on essential oils towards reduction of impact of external parasites over the 90 day-culture period. The impact of a medium and high dose on the prevalence of four groups of parasites ( Dactylogyrus sp, Argulus sp., Zeylanicobdella sp and Trichodina sp. ) was calculated.

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Figure 1. Results on supplementation of phyto-biotic-based additive in Indonesia: corrective to mitigate signs of infection (ROI 1:18) and preventive and corrective to maintain growth rates and survival rate to pre -WFS levels (ROI 1:40)

10x10). Statistical method ANOVA.

“The interesting outcome was that the decrease in the ectoparasite infestation intensity had a clear impact on the general health status of the fish, its immune system as well as on the general performance and profitability. The final biomass increased 10.9% with the high dose and 8.5% with the medium dose.”

Conclusion

Finally, Garcia Gomez compared the cost benefits of health additives for shrimp and finfish farmers and feed millers. She cautioned that functionality should be hand in hand with improved husbandry and biosecurity strategies to optimise the results. “There are clear benefits for farmers to start working and thinking about prevention and of course improve performance and profitability. Feed millers must make changes in feed formulation, depend on availability of additives as well as on farmers’ acceptance and motivation. They also need to make species-specific adaptations and validate customised products.”

As the industry contemplates the benefits of functional additives, Garcia Gomez asked “Does the industry have sufficient evidence of the positive impact of functional additives and do players needs to change its mindset towards prevention in aquaculture? Additionally, should the sector continue to invest in research, development and innovation?”

Reference Ruth Garcia Gomez. 2022. “What are the cost implications of using functional health additives for farmers and what will the incentives be for feed millers to change? Presentation at TARS 2022, Ho Chi Minh City, Vietnam, 6-7 October, 2022.