Currently, the global demand for aquafeed ingredients containing high omega-3 levels is greater than the supply. However, a researcher at Nofima has developed a new oil that has been approved for fish feed.
Bente Ruyter has been conducting research for many years to find out how farmed salmon can get a higher content of omega-3 in the body. One option, she has demonstrated, is oil from genetically modified canola.
“The Norwegian Food Safety Authority has approved a genetically modified canola oil that can be used in salmon feed. The plant produces marine omega-3 fatty acids,” stated Ruyter in a press release.
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. As a result, it contains more of the omega-3 fatty acids that salmon need to stay healthy, and which humans who eat the salmon will also benefit from.
Nofima highlights that because the oil is extracted from the canola seeds, it does not carry any of the plant’s genetic material that has been modified.
“Research has been carried out over many years to see if this oil can be used in fish feed,” Ruyter added. The scientists have found that it is suitable, and the Norwegian Food Safety Authority has also approved it.
EPA and DHA
It is all about the omega-3 fatty acids called EPA and DHA. In nature, marine microalgae produce these fatty acids. Crustaceans then eat these microalgae, and the fish eat the crustaceans. Therefore, EPA and DHA end up in the fish.
It has been difficult to get high enough levels of these fatty acids in farmed salmon. Therefore, microalgae genes have been inserted into canola so that it can also make the same fatty acids. When the oil is used in fish feed, the scientists have found that the fish perform better, get more omega-3, have fewer dark spots and a more appealing colour in the fillet.
“Global production of fish oil is stable: catching more wild fish though, is not sustainable. Therefore, fish oil is becoming less and less available for the aquaculture industry every year as the industry grows,” says Ruyter.
In 2000, 30 percent of salmon feed consisted of fish oil. In 2020, this was down to 10 percent.
“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,” she added.
Need for new omega-3 sources
“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,” said Ruyter.
Nofima claims that the addition of this new oil makes the fish healthier than if they were only fed standard plant oil.
They also stated that salmon need a certain level of omega-3 in their feed in order for their muscles to develop the delicate pink colour. Nofima’s research further showed that the omega-3-rich canola oil reduced the prevalence and severity of dark melanin spots in salmon fillets.
In order to document the properties of the oil in salmon, scientists have had to carry out trials in fresh water, in closed tanks and finally in net-pens at sea. All the while, they have had to ensure that nothing is discharged into the surrounding nature. As a result, they carried out trials in all phases of the fish’s life cycle.
“It is now approved for use. Whether the industry uses it is another matter. But I think it will force its way in,” said Ruyter.