Determining the Net Growth Efficiency of Eicosapentaenoic Acid and Docosahexaenoic Acid in Atlantic Pollock (Pollachius virens) Using a Mass Balance Approach

Abstract

The essential fatty acids (EFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are required for the maintenance of good health in humans. Marine production of EPA and DHA is predicted to decrease as a result of warming seawater temperatures. With reduced production, it becomes critical to understand the efficiency with which these EFA are transferred through trophic systems. We employed a mass balance approach to determine the net growth efficiency (NGE) of EPA and DHA in Atlantic pollock (Pollachius virens) fed two low-lipid diets; one diet contained half the proportion of EPA and DHA as the other. NGEs for EPA and DHA were greater than 50% in fish fed diets that were rich in these EFA. However, in fish that received reduced dietary proportions of EPA and DHA, significantly lower NGEs were observed. This indicates that a limited ability to retain essential nutrients may exist when dietary supply is reduced.