Seasonal variations in the biochemical composition and lipids of the digestive gland in the shrimp Pleoticus muelleri bate

1. 1. Seasonal variations in the biochemical composition, lipid classes and fatty acids in the digestive gland of the shrimp Pleoticus muelleri from San Jorge Gulf, Argentina, were studied during 1984–1985. 2. 2. The relative size of the digestive gland decreased significantly in fully mature shrimps of both sexes during the summer. 3. 3. Immature females and mature males gradually increased the level of total lipids from winter toward the autumn as a reflex of the annual cycle of feeding. 4. 4. Total lipids fell markedly during the ovary maturation in summer whilst protein increased. Free fatty acids, triacylglycerols and phospholipids were apparently transferred to the developing ovary; however, the immediate dietary supply of lipids and protein appeared to be preponderant from incipient maturation until the completion of ovary development. 5. 5. Total lipids decreased with the maturation of the male reproductive system in spring with the suggestion of their utilization during spermatogenesis. 6. 6. Maturing females appeared to use selectively fatty acids 16:0, 16:1 and 18:1 of neutral lipids during oogenesis in summer whereas males used the mentioned acids of polar lipids apparently due to metabolic stress. 7. 7. The results are discussed in terms of concentration and absolute amounts in relation to physiological and ecological factors.