Recent research demonstrates a significant quantitative trait locus (QTL) affecting resistance to Streptococcus iniae in Benchmark Genetics’ high-performing strain of Nile tilapia. This discovery is the result of an awarded collaboration between the USDA's Aquatic Animal Health Research Unit (AAHRU) and Benchmark’s geneticist Sergio Vela-Avitúa and colleagues.

The QTL found by the team explained up to 26% of the genetic variation in resistance. Fish were then selectively bred for survival to S. inae using marker-assisted selection (MAS) to demonstrate resistance in fish classified as “resistant” or “susceptible”.

“The results were impressive, with a final cumulative percent mortality of only 1% for offspring from resistant parents, compared to 73% for offspring from susceptible parents. These results demonstrate that MAS for improved resistance to S. iniae is feasible and likely to be highly effective,” said Sergio Vela-Avitúa.

Benchmark Genetics has already implemented these results into their breeding and production of genetically improved Spring Tilapia® breeders and fingerlings.

Benjamin LaFrentz (right) and Craig Shoemaker (left) holding two tilapia following the successful completion of a Streptococcus agalactiae phenotyping study with Spring Genetics tilapia.

“We are thrilled to announce this breakthrough in the development of more disease-resistant tilapia strains,” said Morten Rye, director of genetics at Benchmark Genetics. “Our proprietary Spring Tilapia® strain is the result of years of pioneering research and innovation, and we are committed to using our expertise to improve the sustainability and profitability of the global tilapia industry. We are confident that this new development will provide significant benefits to our customers and the industry as a whole.”

Benchmark is committed to continuous research and innovation on selective breeding programs and genomic tools to support sustainable industry growth.