The company GenoMar has highlighted that a scientific study has succeeded in demonstrating that tilapia farming with fingerlings genetically selected to be resistant to streptococcosis obtained significant additional benefits in both ponds and cages. This particular breeding was achieved even with low levels of disease-related mortality. The report published in Nature – Scientific Reports has been highlighted by the company GenoMar, which has been marketing this type of fry under the name GenoMar Strong for the past year.

GenoMar launched the product after five years of R&D work and field trials. “The documented protection against streptococcosis of 30-35% RPS (Relative Survival Percentage) was used in an economic equilibrium analysis,” explained from the company. Now, the study analyzed the cost-benefit ratio of using genetically selected streptococcosis-resistant fry in Nile tilapia farming and the results have been clear.

“This study to perform the economic evaluation will help the farmers to understand the economic value of using genetically selected tilapia fingerlings for their production”, according to Rajesh Joshi, Senior Researcher in GenoMar Genetics Group.

Promising innovation

Breeding animals for increased genetic tolerance/resistance to disease is presented as a promising innovation that has proven its value in other livestock and aquatic species. In the case of breeding for resistance to streptococcosis in tilapia, GenoMar explains, there are a number of advantages of the technology for the tilapia industry.

One of the advantages is that it is accessible to farmers of all sizes and has no barriers to adoption; other one is that lasts the entire life of the fish and genetic gain in resistance is accumulative over generations of breeding; also, there is no cost of administration since the innovation is already inside the genetic makeup of the fish.

In addition, genetically resistant fingerlings will contribute to increased survival, increased feed efficiency, and better growth leading to higher net return, says Marina Delphino, Fish Health and Welfare Manager in GenoMar Genetics Group.


Profitable for farmers in both, pond and cage culture systems

Bottom line, the results showed that genetically selected streptococcosis resistant tilapia fingerlings were profitable for farmers in both pond and cage culture systems where streptococcosis is the production constraint.

The cost of buying streptococcosis resistant tilapia fingerlings is higher compared to standard fingerlings prices because R&D and phenotyping (measurement of observed physical traits) cost are higher. The study showed a significant higher return of investments in both ponds and cages with streptococcosis outbreaks, even if the amount paid for genetically selected streptococcosis resistant tilapia fingerlings was double the amount paid for standard fingerlings. Even with low Streptococcus related mortality (1-5%), the net profit is in favour of Streptococcus resistance fingerlings if the extra amount paid for resistant fingerlings over the standard fingerlings is up to 30% (Figure 1).

The direct economic benefits and costs of rearing disease resistant tilapia are important for the farmers to consider. However, there are also social and environmental benefits of using the technology such as improved overall fish resilience, reduced use of antibiotics, lower generation of mortality waste and higher resource efficiency. All these contributions will support the development of a more sustainable aquaculture value chain”, says Alejandro Tola Alvarez, CEO in GenoMar Genetics Group.

Replacing antibiotics

Streptococcosis is one of the most important infectious diseases affecting tilapia aquaculture worldwide. The disease causes reduced survival, downgraded product quality and seriously impacts profitability in tilapia enterprises.

In most parts of the world and specially among small and medium-sized tilapia farmers, the only control measures farmers have at hand is to make husbandry changes in their production systems such as reduce feeding or increased aeration and water exchange.

Antibiotics are also commonly used and accessible for tilapia farmers. The number of approved aquatic antimicrobials is however extremely limited. The indiscriminate and inaccurate application of oral antibiotics for control of aquatic diseases is a growing concern for veterinary and public health authorities due to risk of developing anti-microbial resistance.

Vaccination strategies by intraperitoneal injection are gaining momentum within the most professional farmers. The uptake in Asian tilapia aquaculture, where small and medium scale farmers are the norm is limited due to requirements for a minimum size at vaccination of 10-15 grams and complex administration.


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