EFFECTS OF DIETARY DOCOSAHEXAENOIC ACID (DHA 22 6N-3) ON LIPID AND FATTY-ACID COMPOSITIONS AND GROWTH IN GILTHEAD SEA BREAM (SPARUS-AURATA L) LARVAE DURING 1ST FEEDING/

The effects of dietary DHA levels on lipid class compositions, total l ipid and phosphoglyceride fatty acid compositions and growth were inve stigated in gilthead sea bream, Sparus aurata, larvae during the first 2 weeks after hatching. Different dietary levels of DHA were supplied to the larvae in the rotifer, Brachionus plicatilis, previously enric hed with (a) Nannochloropsis gaditana, (b) a mixture of N. gaditana, I sochrysis galbana and Rhodomonas sp. or, (c) Protein Selco (Artemia Sy stems). The results showed that growth performance of gilthead sea bre am larvae at first feeding was influenced by both total n-3HUFA and DH A contents of the diet, the best growth rate being achieved with a hig h n-3HUFA content and a high DHA: EPA ratio. Lipid contents, nutrition al status, and total lipid and phosphoglyceride DHA levels of the larv ae were directly correlated with dietary DHA levels. The fatty acid co mpositional data suggested that dietary EPA could not contribute signi ficantly to tissue DHA levels in larval gilthead sea bream, presumably due to low DELTA4 desaturase activity.