Omega 3s – polyunsaturated fats found in oily fish, nuts, seeds and green vegetables – are well-known for their benefits to human cardiovascular and general health.
Naturally, Omega 3s are found in marine microalgae, eaten by tiny fish and crustaceans. Omega 3s move up the food chain by bioaccumulation: building up in the tissues of larger and larger fish as they eat each other. Top-of-the-food-chain predators, like sharks, are rich in accumulated Omega 3s.
These beneficial Omega 3s are not a sustainable product, however. Tonnes of wild sea fish, including 90% of the anchovy catch, are harvested and turned into fishmeal and oil supplements for fattening farmed salmon and trout, which in turn are harvested for their accumulated Omega 3 fish oil. This clearly puts pressure on wild fish stocks.
British scientists at Rothamsted Research and the University of Stirling have engineered a sustainable way to produce the Omega 3 oils found in fish – in genetically modified glasshouse plants.
Returning to the primary producer of Omega 3s – microalgae – researchers moved DNA from the microalgae into Camelina plants (a relative of oilseed rape) using agrobacteria as the carrier.
When the Camelina plants set seed, the proportion of the seeds containing Omega 3s was identified by fluorescent markers, extracted and crushed to yield oil. The resulting Omega 3-rich oil contained all the benefits of fish oil, without the fishy smell.
The oil extracted from the GM Camelina plants was then fed to farmed Atlantic salmon, and compared with farmed Atlantic salmon fed on fish oil derived from wild stocks.
The study showed that there was no difference in the nutritional quality of the Omega 3 fish oil extracted from the Atlantic salmon fed on Camelina fish oil, and that from Atlantic salmon fed on wild fish oil. Both fish colonies grew and fed with equal efficiency.
Professor Douglas Tocher, leading the study at the University of Stirling, said: “The development of these novel plant oils, tailored to human requirements, represent a sustainable way to farm fish with high levels of omega-3 fish oils that maintain their high nutritional value to the human consumer while preserving wild fish stocks.”