“Major breakthrough”: Researchers uncover alternative sources of omega 3 fatty acids

08 May 2018 --- Research led by the University of Stirling has found that omega 3 fatty acids can be created by many invertebrates inhabiting marine ecosystems, including corals, worms and mollusks. The discovery runs contrary to the generally held principle that marine microbes, such as microalgae and bacteria, are responsible for virtually all primary production of omega 3. The researchers note that their findings could “revolutionize our understanding of omega 3 long chain polyunsaturated fatty acids (PUFAs) production on a global scale,” potentially paving the way for the production of alternative and sustainable omega 3 products.

Lead scientist Dr. Oscar Monroig, of the Institute of Aquaculture, says that the findings strongly suggest that aquatic invertebrates may make “a very significant contribution to global omega 3 production.”

“Our study provides a significant paradigm shift, as it demonstrates that a large variety of invertebrate animals, including corals, rotifers, mollusks, 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. Monroig explains.

“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,” says the lead author of the study, Dr. Naoki Kabeya, of Tokyo University of Marine Science and Technology.

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.

“Supply does not satisfy demand, and this has prompted considerable activity around the globe to develop transgenic oilseed crops producing omega 3s that will alleviate the pressure on fish stocks supplying omega 3 rich materials,” Monroig tells NutritionInsight.

“One of the possible impacts derived from this study is to uncover genes/enzymes with novel activities that can be used for the biotechnological production of omega 3 rich in oilseed crops or other organisms, a resource that will be highly precious in satisfying an increasing demand. Clearly, marine invertebrates represent an interesting and barely explored source of these genetic resources, potentially with novel functionalities amenable for biotechnological production of omega 3 oils,” Monroig says.

Moreover, Monroig notes, the results of this study are important for the aquaculture sector. 

“Marine ingredients including fishmeal and fish oil are still an essential part of many feeds for farmed fish species and shrimp. The vast majority of fishmeal and fish oil are sourced from reduction (forage) fisheries, which are currently exploited at or beyond their sustainable limit, and heavily influenced by global climate events such as El Niño. An increasing proportion of fishmeal and, to a lesser extent, fish oil, is derived from seafood and aquaculture by-products but, despite such a recycling effort, the reality is that these are still limited sources that can restrict the expansion expected for aquaculture and consequently its key role in food security,” Monroig says. 

On top of the potential impacts on the industries involved in the production of omega 3, this research could have an impact on the environment as a whole, by contributing to the reduction of potential adverse environmental impacts of fish farming. 

“More specifically, feed for the aquaculture industry is dependent on the supply of marine ingredients (e.g., fishmeal and fish oil) derived from wild stocks of feed-grade fisheries. Increasing these fisheries is environmentally unsustainable, and global competition is driving prices to economically non-viable levels,” Monroig notes. “The results of this study can help to alleviate the increasing pressure on fish stocks by enabling innovative and rationalized strategies to produce alternative omega 3 rich ingredients from marine invertebrates.”

Monroig tells NutritionInsight that further studies will aim to provide an estimation of the actual production of omega 3 PUFA by invertebrate animals found to have this novel and unknown capacity. 

“For that purpose, we first need to have an estimation of how much biomass the invertebrates reported in our study to possess omega 3 producing enzymes (desaturases) represent. This is challenging since it involves to assess the diversity and abundance of the invertebrate communities inhabiting ecosystems such as coral reefs, abyssal plains, thermal vents, etc.,” he notes. 

“Previous studies have been able to estimate the production of omega 3 PUFA by microalgae by using satellite technology, but this technology is not useful for invertebrates and other methodological approaches will be needed,” he says.

Estimating the production of omega 3 PUFAs by invertebrates will require understanding not only about how active the omega 3 producing genes/enzymes uncovered in the study are in each organism, but also how this activity varies during their life cycles, Monroig concludes.

By Lucy Gunn