FATTY-ACID COMPOSITION OF EARLY NONFEEDING LARVAE OF THE EUROPEAN FLAT OYSTER, OSTREA-EDULIS

A total of 113 broods of Ostrea edulis L. larvae from a closely-controlled hatchery conditioning regime, from specific broodstock treatments, and from brooding oysters taken from a wild population in Poole Harbour, was analysed for fatty acid composition. Major differences in polyunsaturated fatty acids (PUFAs) were detected as the year proceeded, with increased levels of 20:5 (n-3) and 22:6 (n-3) from late June. Significant decreases in the PUFA content of both phospholipids and neutral lipids accompanied development from fertilized eggs to immediately pre-liberation larvae, but there was some evidence that the 20:4 (n-6) and 22:6 (n-3) content of phospholipids was protected. Fatty acid composition and content of newly liberated larvae were influenced by conditions during broodstock fattening and early gametogenesis (phospholipids) and by conditions during the later stages of oocyte development (neutral lipids).