Research conducted in Norway suggests that selective breeding of farm-raised salmon may influence the omega-3 fatty acid composition of the fish and help them better utilize omega-3s in feed more effectively.

On Oct. 4, Siri Storteig Horn with Nofima defended her doctoral thesis regarding research on breeding and omega-3 in Atlantic salmon at the Norwegian University of Life Sciences (NMBU).

“Uncovering the metabolic differences between individuals with high and low omega-3 levels can help farmed salmon utilize omega-3 in feed more effectively,” Storteig Horn said.

Previous studies have shown a potential for selective breeding to increase overall levels of omega-3 fatty acids in salmon, but knowledge about the connection between individual omega-3 fatty acids and other traits has been lacking, the announcement from Nofima said.

The overall goal of her doctoral thesis was to identify the genetic basis and underlying biological mechanisms associated with omega-3 content in salmon fillets, Nofima said. It has resulted in four pieces of research work, three of which have been published.

The work included the study of families of farmed salmon that lived under the same conditions and were fed the same diet throughout life so that environmental factors were reduced to a minimum.

There was large individual variation in the content of the omega-3s eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the muscle tissues of the fish, and both EPA and DHA were hereditary properties, with heritability at 9% and 26%, respectively, according to the announcement.

“This means that 9% and 26% of the differences between salmon are due to genes. Therefore, it is possible to change the fatty acid composition in salmon muscle by breeding,” Storteig Horn explained.

Researchers have also seen that omega-3 levels in muscles are connected with fat deposition and metabolic processes such as carbohydrate metabolism and with genes related to muscle growth, the announcement said.

"In addition, we have identified a region on the salmon genome that is associated with omega-3 level variation, where they can continue to try to find which genes govern the omega-3 content of salmon fillets," Storteig Horn said. "This can help us understand why some salmon have more omega-3 than others and can also be useful in breeding.”

Her doctoral research is part of the “Genomics of Omega-3 in Atlantic Salmon” project. The four-year project was funded by the Research Council of Norway and was a collaboration among Nofima, NMBU, the University of Southampton and SalmoBreed.

Based in Norway, Nofima is a leading institute for applied research within the fields of fisheries, aquaculture and food research.

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