Variations in digestive enzyme activity and tissue biochemical composition of Penaeus chinensis broodstock during reproductive cycle

Using the tissue biochemical analysis method, the variations of digestive enzyme activity (in hepatopancreas and midgut) and biochemical composition (in ovary, hepatopancreas and haemolymph) for wild-caught and pond-reared Penaeus chinensis during the ovarian maturation stages were studied. Females had higher activities of protease and lipase with the ovarian development until IV stage, but had a significant decrease just before spawning (V stage). About these variations, there were no significant differences between wild-caught and pond-reared shrimps. The total protein in these tissues increased with ovarian development and reached the highest in stage IV (hepatopancreas) and stage V (ovary and haemolymph). Both the total lipids and acylglycerides in ovary increased regularly with the ovarian development. As to the fat level in hepatopancreas, there were no significant differences from stage Ⅰ to stage Ⅱ, and later it decreased with ovary development, and reached its lowest in stage V, as the fat level in ovary reached its climax. These data indicated that the changes of digestive enzyme activities affected significantly the digestion and absorption in female in different stage of sexual maturation, and the biochemical composition of the ovary reflected the nutrient accumulation associated with maturation.