Effects of dietary digestible carbohydrate level on postprandial metabolism of Jade perch Scortum barcoo

Jade perches (Scortum barcoo) were fed with iso-protein and iso-lipid experimental diets at digestible carbohydrate levels of 0% (control group), 6% (groupⅠ), 23% (groupⅡ) and 40% (group Ⅲ) for 6 weeks. After 36-hour fasting, the blood biochemical indices andcontents of liver and muscle glycogens were examined at 0, 3, 6, 12, 24 and 36 h, respectively. The results showed that the growth performance and feed utilization of group Ⅱ(23%) were the best. Contents of plasma glucose, triglyceride and total cholesterol all increased firstly and then decreased after feeding; plasma glucose and triglyceride increased significantly fast (P0.05) with increasing digestible carbohydrate level in diets, while total cholesterol decreased gradually; total amino did not change obviously. Liver glycogen content (except for group Ⅲ) increased firstly and then decreased after feeding; muscle glycogen decreased firstly, then increased gradually and finally remained stable. Contents of liver and muscle glycogens increased faster with increasing level of digestible carbohydrate. The results indicated that the growth performance and feed utilization of Jade perch at 23% digestible carbohydrate achieved the best effect. Exorbitant digestible carbohydrate could cause physiological load and stress for the organism, which would be harmful to the growth and metabolismof the fish.