LIPID-COMPOSITION OF TISSUE AND PLASMA IN 2 MEDITERRANEAN FISHES, THEGILT HEAD SEA BREAM (CHRYSOPHYRYS-AURATUS) AND THE EUROPEAN SEA-BASS (DICENTRARCHUS-LABRAX)

The fatty acid (FA) composition of phospholipid (PL), triacylglycerol (TAG), and total lipid (TL) fractions was determined for liver, adipos e tissue, white muscle, and plasma of European seabass (Dicentrarchus labrax) and gilt-head sea bream (Chrysophyrys auratus) fed on the same diet. FA composition of plasma nonesterified fatty acids (NEFA) and T AG as well as tissue TAG and TL correlates with that of the diet. FA c omposition of PL in tissues and plasma was different from that of the diet and different in the two species. Contribution to tissue wet weig ht of the different lipid fractions showed that both species store lip id primarily outside of muscle (only 3% in both species) as TAG in adi pose tissue (about 80% lipid . wet weight(-1)). Seabass store 33% wet weight of lipid in liver, while sea bream store only 5% wet weight. Th e plasma concentration of NEFA and TAG is 2223 and 12 260 nmol . ml(-1 ) for seabass and 2790 and 9670 nmol . ml(-1) for sea bream. The data show that these two fishes with similar lifestyle store lipid in the s ame fashion and that dietary FA composition affects the FA composition of TL and TAG fractions but not PL in tissue and plasma.