Could Streptococcus in tilapia soon be a thing of the past?

Benchmark Genetics claims a ‘significant breakthrough’ in the development of Streptococcus-resistant strains

Scientists at Benchmark Genetics say that they have identified genetic markers that indicate resistance to Streptococcus iniae in a strain of tilapia they have developed.

Their research demonstrates a significant quantitative trait locus (QTL) affecting resistance to Streptococcus iniae. This discovery came after a collaboration between the U.S.  Department of Agriculture’s Aquatic Animal Health Research Unit (AAHRU) and Benchmark’s geneticist Sergio Vela-Avitúa et al.

In their development of Streptococcus-resistant strains of tilapia, the QTL explained up to 26 percent of the genetic variation in resistance. They then selectively bred fish for survival to Streptococcus 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 percent for offspring from resistant parents, compared to 73 percent for offspring from susceptible parents,” said Vela-Avitúa. “These results demonstrate that MAS for improved resistance to S. iniae is feasible and likely to be highly effective.”

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

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