Phospholipid composition of common carp (Cyprinus carpio) larvae starved or fed different phospholipid classes

Following earlier experiments, which showed important differences in early development of common carp larvae dependent on the phospholipid (PL) class composition of the diet, the present study evaluated the hypothesis that th e manipulation of the dietary PL might have modified the PL composition of the larvae. For this purpose, we examined the fatty acid (FA) composition o f body phosphatidylcholine (PC), the body PL content and the PL class profi le in carp fed from first-feeding up to 28 days semi-purified diets contain ing different PL classes, Larvae kept for 1 to 7 days without food were ana lyzed for comparison. The FA distribution in the larval body PC between sat urated/monounsaturated/polyunsaturated FA (SAFA/ MUFA /PUFA) varied accordi ng to larval size and diet, being approximately 40/30/30 in unfed larvae an d 33-35/38-44/22-28 in fish after 28 days of feeding. The greatest modifica tion concerned the relative importance of n - 3 and n - 6 FA, with n - 3/n - 6 ratios changing from approximately eight in the start-feeding larvae to 0.04-0.11 in the final fed larvae, in accordance with the low dietary n - 3/n - 6 ratios (0.02-0.08). The total PL content (% dry matter) of the fed larvae fluctuated around 7%, irrespective of fish size or diet. Expressed a s a percentage of total FL, PC increased and phosphatidylserine (PS) decrea sed during growth, whereas phosphatidylethanolamine (PE), phosphatidylinosi tol (PI) and phosphatidic acid (PA) remained constant. No significant effec t of the PL class composition of the diet on that of the fish was found. Th e fixed PL class composition of the larvae, of a given size, implies the sy nthesis of the PL classes which are not provided by the diet. It is suggest ed that this synthesis is a limiting factor for the development of early la rvae fed PL-deficient diets. (C) 1999 Elsevier Science B.V. All rights rese rved.