Effects of glucose and vitamin C on activities of lipoprotein lipase and hepatic lipase during yolk-sac larva development of Carassius auratus gibelio

In this study, we investigated how glucose and vitamin C regulated the activities of lipoprotein lipase and hepatic lipase during yolk-sac larva development of Carassius auratus gibelio (C. auratus gibelio). Glucose solutions and vitamin C solutions at different concentrations were added into the hatching water, and the treatments lasted until the yolk sac disappeared completely. The concentrations of glucose were 0, 5, 10, 15 and 20 g/L, and the concentrations of vitamin C were 0, 20, 25, 30 and 35 mg/L. We recorded the incubation time, the hatching rate and survival rate of larvae, and tested the activities of lipoprotein lipase and hepatic lipase after the treatments with the optimal glucose level, the optimal vitamin C level, and the control. The results showed that the specific activity and total activity of lipoprotein lipase displayed a down-up trend in the control group and the vitamin C group, while those of hepatic lipase maintained a pattern of increase during yolk-sac larva development of C. auratus gibelio. In the glucose group, the specific activity and total activity of lipoprotein lipase and hepatic lipase were increased and significantly higher than those in the control group during the mixed nutrient stage and exogenous nutrient stage (P0.05). In the vitamin C group, the specific activity and total activity of lipoprotein lipase and hepatic lipase were only slightly higher than those in the control group, but the total activity of hepatic lipase was significantly higher than that in the control group during the endogenous nutrient stage (P0.05). Our studies showed that glucose solution (15 g/L) could help regulate lipid metabolic enzyme activity thus maintain the dynamic balance of lipid metabolism, and vitamin C solution (30 mg/L) could improve lipid metabolism.