Enhancement of EPA and DHA biosynthesis by over-expression of fatty acid metabolic enzymes in marine fish

n-3多不饱和脂肪酸，特别是二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）对人体具有重要的营养价值。养殖鱼类可以作为EPA/DHA的有希望的来源，但它们需要这些脂肪酸或其前体在它们的饮食中。我们将马苏鲑鱼Δ6-desaturase-like基因转移到斑马鱼体内，以提高其合成EPA和DHA的能力。该基因在转基因鱼中的表达使其EPA含量提高了1.4倍，DHA含量提高了2.1倍。α-亚麻酸含量下降，为Δ6-desaturase的底物，而总脂质保持不变。这一成果表明，转基因技术可以改变鱼类的脂肪酸代谢途径，也许这可以应用于定制养殖鱼类，使其成为有价值的人类食物的更好来源。

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 Δ6-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 α-linolenic acid content decreased, it being a substrate of Δ6-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.