Enhancement of EPA and DHA biosynthesis by over-expression of masu salmon 6-desaturase-like gene in zebrafish

The n - 3 polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have important nutritional benefits in humans. Farmed fish could serve as promising sources of EPA/DHA, but they need these fatty acids or their precursors in their diets. Here we transferred masu salmon 6-desaturase-like gene in zebrafish to increase its ability for synthesizing EPA and DHA. Expression of this gene in transgenic fish elevated their EPA content by 1.4-fold and DHA by 2.1-fold. On the other hand, the -linolenic acid (ALA) content decreased, it being a substrate of 6-desaturase, while the total lipid remained constant. This achievement demonstrates that fatty acid metabolic pathway in fish can be modified by the transgenic technique, and perhaps this could be applied to tailor farmed fish as even better sources of valuable human food.