Biochemical composition dynamics of the ovaries and hepatopancreas at different physiological stages of the female marine crab, Charybdis japonica

Abstract

The present study investigated the biochemical composition, including the amino acids and fatty acids profiles of the ovaries and hepatopancreas of the female marine crab, Charybdis japonica (A. Milne-Edwards, 1861), at different physiological stages (immature, mature, spawning and abortion), together with the dynamic changes of the Gonadosomatic Index (GSI) and Hepatosomatic Index (HSI) during gonad development. A significant inverse relationship between GSI and HSI (R=−0.82; P<0.05) was recorded. The protein, total amino-acid (TAA), essential amino acid (EAA) and polyunsaturated fatty acid (PUFA) content and the ratio of n-3/n-6 in the ovaries were significantly higher than those in the hepatopancreas, while the content of moisture and saturated fatty acid (SFA) were lower. From immature to mature, the content of proteins and lipids in ovaries increased, and the content of carbohydrates decreased noticeably, while these tendencies in hepatopancreas were in the reverse order. A significant increase in the total amount of TAA and EAA in ovaries of mature stages was measured; the content of all amino acids increased, except for arginine, which decreased slightly. The content of PUFA in the ovaries increased with maturation, while the content of monounsaturated fatty acid (MUFA) decreased. Abundant threonine, methionine, leucine and C22:6n-3 (docosahexaenoic acid, DHA) were observed in the hepatopancreas of spawning crabs. Compared to spawning crabs, the content of protein and ash in the hepatopancreas of aborting crabs decreased significantly, while the carbohydrates content rose, and that the content of TAA, EAA and PUFA in the ovaries and hepatopancreas of aborting crabs were all lower, especially the amount of n-3 fatty acids in hepatopancreas, which decreased substantially, including DHA from 9.02% to 3.25%, and eicosapentaenoic acid (EPA) from 0.93% to 0.44%.