高糖饲料对草鱼生长及肝脏糖代谢的影响

Effects on growth and hepatic glucose metabolism of grass carp fed with high dietary carbohydrates

为了从生长性状、器官健康和营养代谢水平方面探究草食性鱼类草鱼(Ctenopharyngodon idella)对高糖饲料的适应和利用能力,以初始体质量(132.01±16.43)g的草鱼为研究对象,分别配制正常糖水平(15%,对照组)和高糖水平(40%,高糖组)的等氮等能饲料分组投喂草鱼140 d,每组设3个重复,每个重复300尾鱼。结果显示,相较于对照组,第60、第80和第140天时高糖组草鱼的体质量显著增加(P<0.05),第140天时,高糖组草鱼的脏体比、肠系膜脂肪系数、中肠绒毛高度和肝糖原含量均显著提高且肝脏和中肠肠道组织出现损伤。随实验时间的延长,高糖组葡萄糖激酶(gk)、丙酮酸激酶(pk)、糖原合酶(gys2)、脂肪酸合成酶(fas)基因表达量呈下降趋势,磷酸烯醇式丙酮酸激酶(pepck)、葡萄糖-6-磷酸酶(g6pase)基因表达量呈上升趋势,对照组gys2、fas、pepck和g6pase基因表达量变化趋势与高糖组一致,但gk、pk基因表达量在各时间点均无显著性变化。第140天时,与对照组相比,高糖组pk基因表达量显著下调,g6pase、pepck和fas基因表达量显著上调。综上,采用高糖饲料投喂草鱼可促进其体质量增加,但长期饲喂会对其生理指标造成一定负面影响,肝脏糖代谢相关基因表达变化显著。

In order to explore the growth performance,organic health and nutritional metabolism level of Ctenopharyngodon idella,a fed herbivorous fish-grass carp,with high dietary carbohydrates,we divided 1800 individuals of(132.01±16.43)g into normal carbohydrate diet group(Control group)and high carbohydrate diet group(Group H),feeding them with 15%and 45%level carbohydrate diets for 140 d.Each group included three replications and each replication included 300 individuals.The re-sults show that compared with the control group,the body mass of Group H was higher significantly on 60^(th),80^(th) and 140^(th) day(P<0.05).The visceral body ratio,mesenteric fat coefficient,villus height and hepatic glycogen content of Group H increased sig-nificantly on 140^(th) day,and damage was observed in liver and intestinal tract.The expression of glucose kinase gene(gk),pyru-vate kinase gene(pk),glycogen synthase 2 gene(gys2)and fatty acid synthetase gene(fas)showed a decreasing trend in Group H along with time,while phosphoenolpyruvate carboxykinase gene(pepck)and glucose-6-phosphatase gene(g6pase)showed an increasing trend.The expressions of gys2,fas,pepck and g6pase had the same trend in Group L as that in Group H,while no sig-nificant variation trend was observed in gk and pk gene at each time.Compared with the control group,the expression of pk was significantly lower,while those of g6pase,pepck and fas were significantly higher in Group H.In conclusion,40%level dietary carbohydrate can improve the weight gain rate of grass carp,but high dietary carbohydrates have a negative impact on physiolo-gical indicators and significantly affect glucose metabolism at molecular level.