New study could revolutionize salmon farming

Study will measure potential benefits of using customized feed based on GM camelina to improve omega-3 levels in farmed salmon.

Photo: Fish farm in Scotland/University of Stirling

Scientists believe a new feed solution for Atlantic farmed salmon — created from a genetically modified (GM) plant — could help relieve pressure on stressed marine resources.

The University of Stirling, in collaboration with Rothamsted Research, is conducting a study into the potential benefits of using the customized feed to improve access to omega-3 fish oils, credited as being a key component of a balanced diet.

Wild fisheries, which currently provide the beneficial oils, are at their sustainable limits; therefore, existing stocks are not able to provide enough omega-3s for a global population.

In a bid to tackle the issue, current practice involves giving farmed fish a feed blended with both marine fish oil sourced from the sea and vegetable oil. However, the new study could revolutionize the industry — and return levels of omega-3 fatty acids in farmed fish to the levels of a decade ago.

The research is jointly led by plant scientist professor Johnathan Napier from Rothamsted Research and fish nutritionist professor Douglas Tocher with the University of Stirling’s Institute of Aquaculture.

“The joint project allows us to culture salmon to market size in sea pens while extracting data to ensure new feeds support good growth, feed use and product quality,” Tocher said.

Napier added, “This is the largest feeding trial to validate the efficacy of the project. It’s extremely significant because it will demonstrate the ability to use omega-3 fish oils from plants across the whole production cycle of salmon.”

For the study, non-GM farmed fish will be given a feed that includes oils pressed from GM camelina, an oilseed crop plant. The modified plant has high levels of the beneficial omega-3 fatty acids, proving to be a safe and cost-effective source of these for aquaculture feeds.

During the course of the trial, Dr. Monica Betancor, a research fellow at the University of Stirling, will play a crucial role by checking the salmon's health and collecting data.

“Collecting samples and analyzing the data are imperative to the project. To test the performance of the fish, I’ll be measuring the weight and growth of the fish but also looking at tissue and molecular samples, comparing results of fish fed the new fish feed to salmon fed a standard diet,” Betancor said.

The project will both serve as a proof of concept and a potential solution to the sustainability issue in supplying fish oils to farmed fish.

Napier has long been exploring how to develop a sustainable source of omega-3 using transgenic plants.

“It’s taken a decade to develop plants able to produce the oils and be used in aquaculture,” he said. “This GM technology shows great promise as a potential solution to help fish farming remain even more sustainable while continuing to grow as an industry.”

Omega-3 fish oils — also known as omega-3 long-chain polyunsaturated fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — have been shown to be beneficial to human health by reducing the risk of cardiovascular disease and other metabolic diseases, such as obesity and type-2 diabetes. Despite being crucial for optimal human nutrition, the wild fish stocks that provide these oils are at maximum levels of managed sustainability, meaning the current world fish stocks are not able to provide enough nutrition for a global population.

“A portion of farmed salmon today has about half the level of the omega-3 fatty acids EPA and DHA compared to 10 years ago,” Tocher said.

This research aims to return levels of omega-3 fatty oils in farmed fish to levels of a decade ago.

“This GM technology shows great promise as a potential solution to help fish farming remain even more sustainable while continuing to grow as an industry,” Napier added.

The new study is funded by the U.K.'s Biotechnology & Biological Sciences Research Council.