Benchmark Genetics and collaborators from Spring Genetics and the Aquatic Animal Health Research Unit, USDA have published a paper describing the phenotypic and functional effects of marker-assisted selection (MAS) for resistance to this important bacterial pathogen affecting Nile tilapia farming.
Following on from the team’s earlier discovery of a major QTL affecting resistance to S. iniae, these results confirm the striking phenotypic effect of the MAS, with 100% survival in the resistant line and only 10% in the susceptible line.
Furthermore, lesions were observed in the anterior kidney, spleen, and brain of susceptible tilapia, showing classical signs of histiocytic meningitis, splenitis, nephritis, and the presence of the bacteria. In contrast, the severity of lesions was much less in resistant fish, and no bacterial load was detected.
