New study could revolutionise salmon farming

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Salmon farm, Scotland
Fish farm in Scotland

Scientists believe a new feed solution for Atlantic farmed salmon – created from a genetically modified 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 customised 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 and, therefore, existing stocks are not able to provide enough of the beneficial omega-3 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 revolutionise 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, 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”, Professor Tocher said.

Professor 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.”

The study will see the farmed fish – which are not genetically modified (GM) – being given a feed which includes oils pressed from a GM oilseed crop plant, Camelina. 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 Stirling, will play a crucial role by checking on the salmons’ health and collecting data.

“Collecting samples and analysing 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,” said Dr Betancor.

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.

Professor 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.”

Studies have suggested a link between omega-3 fish oils – also known as omega-3 long chain polyunsaturated fatty acids such as EPA and DHA- and benefits to human health.

The new study is funded by the Biotechnology and Biological Sciences Research Council.

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