Abstract: Effect of different carbohydrate levels of dietary on growth, glucokinase (GK)activities and GK mRNA levels in topmouthculter.540 topmouth culter (average weight (40.73 ±0.44)g)were allotted into 3 groups randomly for 8 weeks, triplicationof every group were fed with the diets containing high carbohydrate level,middle carbohydrate level, and low carbohydratelevel, respectively.Growth of fish 、plasma biochemical indices and GK and GK mRNA levels were determined.The results showedspecific growth rate and mortality rates were decreasing and feed coefficient is on the contrary with the increasing of carbohydratelevels.After diet intake, the general trend of plasma glucose were appeared increasing before becoming smooth, the higher relativelyin the high-carbohydrate group, and the lower in no carbohydrate group.Plasma concentrations of triglycerides were increasingbefore decreasing, and decreasing of which high-carbohydrate group was the higher relatively and middle-carbohydrategroup was the lower relatively.Therewere relatively lower in plasma concentrations of cholesterol of carbohydrate-free group, hexokinaseactivities of middle-carbohydrate group and glucose dehydrogenase activities of high-carbohydrate group.And the othersshowed the trend increasing before decreasing.GK activities after diet intake generally appeared increase while no GK activitieswere measured out for the fasting of various group.With the increase of dietary carbohydrate level,GK activities were improving,but GK mRNA levels did not correlate with different carbohydrate levels of dietary.Ingestion of the high-carbohydrate dietary maybring out plasma glycemia in topmouth culter and induce GK activities and GK mRNA, however, it may be negative effects of fishgrowth.