The Norwegian Food Safety Authority has approved a genetically modified canola oil that can be used in salmon feeds – providing a welcome boost for the industry, which has seen the global demand for feed ingredients containing marine omega-3 fatty acids exceed the current supply.
Nofima Senior Scientist Bente Ruyter has conducted research over many years to find out how farmed salmon can get a higher content of omega-3 in the body. Her work confirmed one option is oil from modified canola, with the plant producing marine omega-3 fatty acids.
“Many years of research together with the industry has brought us to this point,” Ruyter said.
Canola is a variant of common rapeseed. The canola that provides the oil researched by Nofima has been genetically modified and developed by the Australian research organisation CSIRO in collaboration with the company Nuseed. It contains more of the omega-3 fatty acids that salmon need to stay healthy, and that humans benefit from.
The oil is extracted from the canola seeds and does not carry any of the plant’s genetic material that has been modified.
Nofima explained that historically it has been difficult to get high enough levels of the omega-3 fatty acids EPA and DHA in farmed salmon, whereas in nature, marine microalgae produce them. Crustaceans then eat these microalgae, and the fish eat the crustaceans so that EPA and DHA end up in the fish.
To overcome this, microalgae genes have been inserted into canola so it can also make the same fatty acids. When the oil is used in fish feed, scientists found that the fish perform better, get more omega-3, fewer dark spots and better red colour in the fillet.
“Global production of fish oil is stable: catching more wild fish is not sustainable. Therefore, fish oil is becoming less and less available for the aquaculture industry every year as the industry grows,” Ruyter said.
In 2000, 30% of salmon feed consisted of fish oil. In 2020, this was down to 10%.
“Our research shows that it is not healthy for salmon to have such low levels of omega-3 in the feed. They become less robust and their flesh has poorer colour. The industry has therefore started to increase the level of omega-3 fatty acids in the feed again.
“The production of genetically modified canola has great potential for growth, and will probably become an important new source of omega-3 in the fish feed,” Ruyter said.
Nofima also pointed out that it makes the fish healthier than if they were only fed standard plant oil, and that salmon need a certain level of omega-3 in their feed in order for their muscles to get the delicate pink colour.
Its research also showed the omega-3-rich canola oil reduced the prevalence and severity of dark melanin spots in salmon fillets. Nofima has previously shown that the fatty acid DHA has this effect.
In order to document the properties of the oil in salmon, scientists carried out trials in fresh water, in closed tanks and finally in net-pens at sea.
“It is now approved for use. Whether the industry uses it is another matter. But I think it will force its way in,” Ruyter said.
The research was financed by the Norwegian Seafood Research Fund (FHF) and was conducted in collaboration with the Institute of Marine Research, Nuseed and Mowi.
