BIOCHEMICAL-COMPOSITION AND FATTY-ACID CONTENT OF FERTILIZED-EGGS, YOLK-SAC STAGE LARVAE AND FIRST-FEEDING LARVAE OF THE SENEGAL SOLE (SOLEA-SENEGALENSIS KAUP)

Changes in biochemical composition and fatty acid content were investigated during the early development of the Senegal sole (Solea senegalensis Kaup). The pattern of lipid utilization in this rapidly developing marine flatfish species favored neutral lipids, particularly triacylglycerol and sterol ester fractions. Fertilized eggs and yolk sac larvae were richer in neutral lipids, which decreased during development. In contrast, a significant increase occurred to proportions of phospholipids, mainly due to significant increases in minor classes such as phosphatidylserine, phosphatidylinositol and phosphatidic acid/cardiolipin, whereas major phospholipid classes such as phosphatidylcholine and phosphatidylethanolamine remained constant during development. Saturated and monounsaturated fatty acids such as 16:0, 16:1 n-7, 18:1 n-9 and 18:1 n-7 were utilized to a greater extent than polyunsaturated fatty acids as energy substrates. A requirement for long-chain polyunsaturated fatty acids such as eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) is likely since no evidence of bioconversion from their precursors was found. A requirement for arachidonic acid (20:4n-6) is also suggested as it is specifically retained throughout development.