Impact of sustainable feeds on omega-3 long-chain fatty acid levels in farmed Atlantic salmon, 2006–2015

TLDR

Aquaculture is expanding to meet global seafood demand, and farmed Atlantic salmon, a major source of omega‑3 fatty acids EPA and DHA, faces a challenge as terrestrial feed alternatives lacking these nutrients replace traditional fishmeal and fish oil. The study aims to assess the global shortfall of EPA and DHA in salmon and explore microalgae and genetically modified crops as potential future sources. The authors compared fatty‑acid profiles of over 3,000 Scottish Atlantic salmon harvested between 2006 and 2015 to evaluate changes in EPA and DHA content. The analysis revealed that terrestrial fatty acids rose while EPA and DHA fell, reducing the salmon’s nutritional value to the point that double portions are needed to meet recommended intakes, yet it still provides more EPA + DHA than most other fish species and terrestrial livestock.

Abstract

Abstract As the global population and its demand for seafood increases more of our fish will come from aquaculture. Farmed Atlantic salmon are a global commodity and, as an oily fish, contain a rich source of the health promoting long-chain omega-3 fatty acids, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Replacing the traditional finite marine ingredients, fishmeal and fish oil, in farmed salmon diets with sustainable alternatives of terrestrial origin, devoid of EPA and DHA, presents a significant challenge for the aquaculture industry. By comparing the fatty acid composition of over 3,000 Scottish Atlantic salmon farmed between 2006 and 2015, we find that terrestrial fatty acids have significantly increased alongside a decrease in EPA and DHA levels. Consequently, the nutritional value of the final product is compromised requiring double portion sizes, as compared to 2006, in order to satisfy recommended EPA + DHA intake levels endorsed by health advisory organisations. Nevertheless, farmed Scottish salmon still delivers more EPA + DHA than most other fish species and all terrestrial livestock. Our findings highlight the global shortfall of EPA and DHA and the implications this has for the human consumer and examines the potential of microalgae and genetically modified crops as future sources of these important fatty acids.