Hepatopancreatic contributions of lipids and carotenoids to vitellogenesis in the intertidal anomuran crab, Emerita asiatica (Milne Edwards)

ABSTRACT

In decapod crustaceans, lipids and the associated carotenoid pigments form an integral part of yolk to serve as nutrientsduring embryogenesis. This study reports on the analysis of different lipid classes and the major carotenoids in the ovary,hepatopancreas and hemolymph and their fluctuation during different phases of ovarian maturation in an anomuran crab, Emerita asiatica. Neutral lipids including triglycerides (TG) and free fatty acids (FFA) formed the bulk of ovarian lipids. Important fatty acids are Saturated fatty acids (SFA) 160 and 180, Monounsaturated fatty acids (MUFA) 161n7 and181n9, and Polyunsaturated fatty acids (PUFA) 205n3 and 226n3. While phospholipids increased during maturation, glycolipids decreased. Cholesterol level in ovary increased initially, but declined during later stages. Dominant pigments, ?-carotene and astaxanthin, steadily increased during ovarian maturation within the ovary, although canthaxanthin declineddrastically towards last stage. In hepatopancreas, however, TG and FFA showed gradual decrease during maturation. Palmitic acid, palmitoleic acid and eicosapentaenoic acid are the predominant fatty acids in hepatopancreas, showing asteady decline during ovarian maturation. Other lipid classes such as glycolipids also showed a decline in hepatopancreas. Both ?-carotene and astaxanthin in hepatopancreas declined from the first stage of ovarian development, suggestingtranslocation to ovary. The overall metabolic changes of lipids and carotenoids in hepatopancreas, hemolymph and ovary areindicative of their accumulation within developing eggs to provide metabolic energy and substrates for membrane formation, and to serve as precursors for pigment formation respectively, during embryogenesis.