Genetic background key to health outcomes in sterile triploid salmon, study finds.
A new Norwegian research project has found that the genetic lineage of triploid Atlantic salmon plays a more significant role in determining health and growth outcomes than the precision of pressure treatment used to induce sterility.
Triploid salmon are created by exposing fertilised eggs to high hydrostatic pressure, resulting in fish with three sets of chromosomes. These sterile fish cannot reproduce with wild salmon, reducing the risk of genetic introgression. However, triploid salmon have been associated with a range of health issues, including skeletal deformities, cataracts, cardiac defects, infections, and skin lesions.
Researchers working under the TripGenWelfare project—funded by the Research Council of Norway—tested whether these health challenges could be linked to sub-optimal pressure treatment. The study exposed salmon eggs from different family lines to five treatment conditions: one untreated (diploid control), one optimal pressure (triploid control), and three varying degrees of under-pressurisation.
Results showed that low-pressure treatments often led to chromosomal inheritance issues, and in most cases, the eggs failed to hatch. Among those that survived, some developed normally as diploids, while others became triploids despite sub-optimal treatment.
The research concluded that while sub-optimal pressure contributed to developmental issues, the genetic background of the fish was a more decisive factor in overall health and growth performance. Triploid salmon from some families displayed minimal deformities and better survival, while others exhibited significantly higher rates of skeletal problems and mortality.
“The data clearly show that some family lines perform significantly better than others under triploid conditions,” said lead researcher Aurélien Delaval. “This suggests that selective breeding could be an effective strategy to improve welfare outcomes in triploid salmon.”
The TripGenWelfare project will continue to investigate how selective breeding can be used to enhance the robustness of sterile salmon stocks.
