Variations saisonnières de la composition en acides gras chez Penaeus japonicus (Crustacea: Decapoda)

The lipid and fatty acid composition of male and female Penaeus japonicus Bate was investigated over a period of 11 months to determine the effects of environmental and nutritional factors such as temperature and starvation. The lipid content of the prawns increases from May to November, whereas water content decreases. We observed a time-lag between the highest lipid rate of males (in November) and that of females (in October); this is probably related to ovarian metabolism. From September to March, the high lipid content of the females coincided with a high percentage of monounsaturated fatty acids (especially 16:1 and 18:1). Winter starvation induces a decrease in palmitic acid content. As temperature decreases, the monounsaturated (16:1, 18:1) and polyunsaturated (20:4, 20:5, 22:6) fatty acids increase at the expense of the saturated fatty acids (16:0, 18:0) in the adult prawn. However, in post-larvae and juveniles, this increased rate of polyunsaturated fatty acids would be related to their particular lipid metabolism.