Utilization and Metabolism of α-Starch by Black Carp (Mylopharyngodon piceus) Juveniles

Abstract

The ability of black Carp Mylopharyngodon piceus, to utilize high levels of dietary carbohydrate was assessed using artificial purified feed, containing normal (20%, NS group) and high (40%, HS group) levels of digestible carbohydrate. After a 10 week feeding trial, specific growth rate, weight gain rate, and protein efficiency ratio of the HS group were significantly lower (P<0.05). The 40% carbohydrate diet significantly influenced the crude protein and crude fat levels in the muscle tissue (P<0.05). Plasma cortisol of the HS group was significantly lower (P<0.05), and levels of plasma triglycerides and total cholesterol were highly significantly lower (P<0.01). Hepatic superoxide dismutase concentrations of the HS group were lower (P<0.05), and contents of the carbohydrate metabolic enzyme, hepatic pyruvate kinase were highly significantly lower (P<0.01). Hepatic ultrastructure results show that the high carbohydrate diet induced sedimentation of glucose and fat in the hepatic cells, and ultrastructural damage was observed. Although Mylopharyngodon piceus are able to tolerate long-term feeding of the 40% carbohydrate diet, effects on growth and immunity were negative resulting in ultrastructural damage of the hepatic cells.