Omega-3 fatty acids have for the first time been found in invertebrates inhabiting marine ecosystems, including corals, worms and molluscs.

The major discovery that could revolutionise the understanding of omega-3 production in the ocean was made by an international team of scientists led by the University of Stirling.

The breakthrough challenges the generally held principle that marine microbes – such as microalgae and bacteria – are responsible for virtually all primary production of omega-3.

Paradigm shift

Dr Oscar Monroig, from the Institute of Aquaculture, was the lead scientist on the report and said that the findings strongly suggest that aquatic invertebrates may make “a very significant contribution to global omega-3 production”.

He added: “Our study provides a significant paradigm shift, as it demonstrates that a large variety of invertebrate animals, including corals, rotifers, molluscs, polychaetes and crustaceans, possess enzymes called ‘desaturases’ of a type that enable them to produce omega-3, an ability thought to exist almost exclusively in marine microbes.”

Dr Naoki Kabeya, from Tokyo University of Marine Science and Technology and the first author of the study, said: “Since invertebrates represent a major component of the biomass in aquatic ecosystems such as coral reefs, abyssal plains and hydrothermal vents, their contribution to the overall omega-3 production is likely to be remarkable.”

Professor Douglas Tocher from Stirling University also took part in the research. He said: “It was very surprising to us to see just how widespread these genes were, particularly in animals that are so common and abundant in the sea.

Horizontal gene transfer

“It is also intriguing that these genes seem to be jumping between very different organisms, such as from plants or fungi into an insect and a spring-tail, by a process of horizontal gene transfer.

“This has been a controversial idea, that genes can move around in this way, but our data looks rather convincing that these genes have done this in at least some of these species.”

Certain omega-3 fatty acids are considered essential for human health, particularly in western countries with high prevalence of cardiovascular and inflammatory diseases for which omega-3 oil supplements are commonly prescribed.

Therefore, the new research is not only likely to impact the scientific community, but also the general public and various industries involved in the production of supplements.

Dr Monroe added: “These findings can revolutionise our understanding of omega-3 long-chain polyunsaturated fatty acids production on a global scale.”

This Author

Catherine Harte is a contributing editor of The Ecologist. This story is based on a news release from The University of Stirling.