Transgenic modification of the n-3 HUFA biosynthetic pathway in nibe croaker larvae: improved DPA (docosapentaenoic acid; 22:5n-3) production

Abstract

Marine fish are generally unable to produce sufficient quantities of n-3 highly unsaturated fatty acid (n-3 HUFA) such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). Consequently, the seed production of marine fish requires careful nutritional enrichment of live feeds such as rotifers and brine shrimp Artemia to meet n-3 HUFA requirements for normal growth. Another strategy for improving n-3 HUFA availability is modifying the biosynthetic pathway of marine fish using transgenic technology. In this study, we conducted a feeding trial with non-transgenic and transgenic nibe croaker Nibea mitsukurii carrying the elongation of very long-chain fatty acids protein 2 (Elovl2) gene isolated from masu salmon Oncorhynchus masou and three groups of Artemia (non-enriched and enriched with two products). For all Artemia groups, docosapentaenoic acid (DPA, 22:5n-3), which is a direct product of Elovl2, was significantly higher in the transgenic fish than that in non-transgenic fish, despite the absence of DPA in all diets. Thus, applying transgenic techniques to marine fish at the larval stage are a powerful strategy for modifying n-3 HUFA biosynthetic pathways.