LIPID-COMPOSITION IN TURBOT LARVAE FED LIVE FEED CULTURED BY EMULSIONS OF DIFFERENT LIPID CLASSES

Fatty acid and lipid class compositions were determined in eggs and la rvae of turbot (Scophthalmus maximus L.). The larvae were fed on rotif ers and Artemia fed on various lipid emulsions. Starving larvae were a lso studied. The lipid class compositions of the emulsions affect the fatty acid composition of the rotifers. Ethyl ester-based emulsion exh ibited the highest assimilation by the rotifers and Artemia and were p ossibly incorporated in their triacylglycerol fraction. During larval starvation docosahexaenoic acid and arachidonic acid levels tended to be conserved whereas eicosapentaenoic acid was highly reduced. Moreove r, the relative proportion of phosphatidylethanolamine increased where as that of phosphatidylcholine decreased in starved larvae. Increasing the n-3 highly unsaturated fatty acid levels in rotifers and Artemia did not influence the survival and growth of the turbot larvae. A posi tive correlation was found between pigmentation success and the ratios of docosahexaenoic/ eicosapentaenoic acids in the total and polar lip id fractions of the turbot larvae. Furthermore, the amounts of these p olyunsaturated fatty acids in the phosphatidylethanolamine fraction of the larvae are suggested to be of particular importance in turbot pig mentation.