DECREASED 20 4N-6/20/5N-3 RATIO IN SPERM FROM CULTURED SEA BASS, DICENTRARCHUS-LABRAX, BROODSTOCK COMPARED WITH WILD FISH/

The fatty acid composition of the four main phospholipid classes, phos phatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserin e (PS) and phosphatidylinositol (PI), from the sperm of broodstock sea bass fed either a commercial pelleted diet or fed 'trash fish' were c ompared with sperm from wild fish. The phospholipids were very unsatur ated, with total polyunsaturated fatty acids (PUFA) accounting for 35% of PC, 60% of PE, 85% of PS and 43-51% of PI. Docosahexaenoic acid wa s the major PUFA in PC, PE and PS, and arachidonic acid in PI. The fat ty acids from the wild fish and broodstock fed 'trash fish' were gener ally very similar, but the fish fed a commercial diet had elevated 20: 5n - 3 and decreased 20;4n - 6 reflecting the fish oil component of th e diet. Consequently, ratios of 20:4n - 6/20:5n - 3 were greatly decre ased in the phospholipids of fish reared on the commercial diet, espec ially in PI, where the ratio fell from 7.2 to 1.2. The possible functi onal consequences of these changes are discussed in relation to prosta glandin formation and egg and larval viability.