高碳水化合物日粮对翘嘴红鲌生长、GK及GK mRNA表达的影响

EFFECT OF HIGH CARBOHYDRATE LEVELS OF DIETARY ON GROWTH,GK ACTIVITIES AND GK mRNA LEVELS IN TOPMOUTH CULTER (ERYTHROCULTER ILISHAEFORMIS BLEEKER)

探讨不同碳水化合物(CHO)水平对翘嘴红鲌生长、葡萄糖激酶(GK)及GK基因表达的影响。选用540尾(40.73±0.44)g翘嘴红鲌,随机分成为高CHO组、中CHO组、无CHO组,每组设三个重复,饲养8周,测定鱼体生长、血液指标、GK活性及GK mRNA水平等指标。结果显示,随着CHO添加量的增加,鱼体特定生长率与死亡率呈下降趋势,饵料系数刚好相反。摄食后,血糖先上升后趋于平缓,其中高CHO组相对高,无糖组低;血浆甘油三酯先上升后下降再上升又下降,其中高CHO组相对高,中CHO组最低;无CHO组血浆胆固醇、中CHO组HK活性、高CHO组GDH相对较低,其他各组在投喂后都呈先上升后下降。GK活性总体呈上升趋势,各组在禁食时,检测不到GK活性,饲料CHO含量越高,GK活性也越高,但是GK mRNA的水平与CHO含量并不呈线性关系。血糖、GK活性与GK mRNA的水平之间有一定的相关性,摄食高CHO饲料可诱导GK酶活性及基因的表达,造成持续高血糖,这可能不利于生长。

Effect of different carbohydrate levels of dietary on growth,glucokinase （GK） activities and GK mRNA levels in topmouth culter.540 topmouth culter （average weight （40.73±0.44） g） were allotted into 3 groups randomly for 8 weeks,triplication of every group were fed with the diets containing high carbohydrate level,middle carbohydrate level,and low carbohydrate level,respectively.Growth of fish、plasma biochemical indices and GK and GK mRNA levels were determined.The results showed specific growth rate and mortality rates were decreasing and feed coefficient is on the contrary with the increasing of carbohydrate levels.After diet intake,the general trend of plasma glucose were appeared increasing before becoming smooth, the higher relatively in the high-carbohydrate group, and the lower in no carbohydrate group.Plasma concentrations of triglycerides were increasing before decreasing, and decreasing of which high-carbohydrate group was the higher relatively and middle-carbohydrate group was the lower relatively.Therewere relatively lower in plasma concentrations of cholesterol of carbohydrate-free group,hexokinase activities of middle-carbohydrate group and glucose dehydrogenase activities of high-carbohydrate group.And the others showed the trend increasing before decreasing.GK activities after diet intake generally appeared increase while no GK activities were 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 may bring out plasma glycemia in topmouth culter and induce GK activities and GK mRNA,however,it may be negative effects of fish growth.