Metabolic responses of hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus ) induced by different feeding modes: Effects on growth, serum biochemical indices, intestinal digestion and hepatic metabolism of glucose and lipid

Abstract

A 56-day feeding trial was conducted to investigate metabolic responses of hybrid grouper (Epinephelus fuscoguttatus × ♂ E. lanceolatus) induced by different feeding modes. The experimental groupers were divided into three feeding modes as follows: continuous feeding group (8 weeks, C group), prolonged starvation group (8 weeks, S group) and refeeding group (starving for 4 weeks + refeeding for 4 weeks, R group). The results show that prolonged starvation had negative effect on growth, yet refeeding caused compensatory growth (p < .05). Serum glucose, triglycerides, total cholesterol and glutamic oxalacetic transaminase activity decreased in S group; triglycerides and total cholesterol reduced in R group; insulin-like growth factor-1 and its gene expression both increased in S and R groups (p < .05). Both glycogen content and intestinal digestive enzymes activity decreased in S group (p < .05). Prolonged starvation caused decrease in hepatic enzymes activity of glycolysis and lipogenesis, while enhanced enzymes activity and genes expression of gluconeogenesis and lipolysis (p < .05). The glycolytic enzymes activity and genes expression improved in R group (p < .05), which may be a solution to compensatory growth. Thus, grouper performed more efficient and active glycolysis in the metabolism of hepatic glucose and lipid. Besides grouper obtained a certain ability to resist prolonged starvation.