Comparison of the lipid class and fatty acid composition between a reproductive cycle in nature and a standard hatchery conditioning of the Pacific Oyster Crassostrea gigas

The lipid composition of Crassostrea gigas was analyzed during the reproduc tive phase in natural as well as under artificial conditions. The lipid con tent increased and accumulated in the gonads, but to a higher extend in the naturally conditioned animals. The percentage of neutral lipid in total li pid of the gonad plus mantle was stable, high (> 70%) and equal under both conditions, underscoring that the lipid reserves were preferentially locate d in that organ. The composition of the polar lipid classes was stable with little variations. The fatty acid (FA) composition of the neutral lipids i n all organs is influenced by diet. However, there is a different response according to organs. A high dietary impact occured in the digestive gland w hereas the muscle was less affected. The polyunsaturated fatty acid (PUFA) level of the neutral and polar lipids in the gonads changed little despite the dietary conditions but the respective proportions of (n-3) and (n-6) PU FA differed drastically as a result of diet composition. There was clear ev idence in all organs for a specific accumulation of 22:6(n-3) and 20:5(n-3) in the polar lipids under both conditioning diets. The proportions of 22:6 (n-3) and 20:5(n-3) from neutral and polar lipids of oysters conditioned ar tificially were significantly lower than of those that were naturally condi tioned. (C) 1999 Elsevier Science Inc. All rights reserved.