高糖饲料对草鱼葡萄糖耐受的影响

HIGH CARBOHYDRATE FEED ON GLUCOSE TOLERANCE IN GRASS CARP(CTENOPHARYNGODON IDELLA)

为探究高糖饲料对草鱼葡萄糖耐受量的影响,研究选取饲喂高糖饲料140d,平均体重374 g的草鱼为高糖组,以及饲喂普通饲料,体重接近高糖组的草鱼为对照组进行葡萄糖腹腔注射试验。高糖组和对照组分别包含48尾草鱼,每组3个重复,注射前断食48h。葡萄糖注射量按每千克体重注射1.5 g计算,采用1 mL PBS缓冲液溶解后注入草鱼腹腔,同时选取体重接近一致的48尾草鱼作为阴性对照组(PBS组),腹腔注射1mL PBS缓冲液。在注射完成后0、1h、3h、6h和12h测定其血浆血糖和胰岛素含量,并采集草鱼肝脏组织,利用RTqPCR技术检测肝脏糖代谢关键基因表达水平。血浆检测结果显示,初始时(0h)高糖组含量最低;1h时高糖组和对照组草鱼血糖含量达到峰值,且高糖组血糖峰值显著低于对照组;12h时两组草鱼血糖恢复至初始水平。高糖组和对照组草鱼腹腔注射葡萄糖后胰岛素水平都略有升高,但是差异不显著。RT-qPCR显示,初始时高糖组葡萄糖转运蛋白2基因(glut2)、葡萄糖-6-磷酸酶基因(g6pase)和糖原合成酶2基因(gys2)相对表达量比对照组高;1—3h时高糖组gk和gys2基因相对表达量显著高于对照组。综上,饲喂高糖饲料的草鱼能够快速清除过剩血糖,具有更高的葡萄糖耐受能力,增加糖原合成是高糖组草鱼快速清除血糖的主要方式。

To investigate the impact of a high-carbohydrate diet on glucose tolerance in grass carp,a total of 48 common grass carp and 48 grass carp fed with high carbohydrate diet,with an average weight of 374 g,were selected for a glucose tolerance test.The experimental fish were divided into two groups:a control group and a high carbohy-drate group.The injection dosage was determined as 1.5 grams per kilogram of body weight,dissolved in 1 mL of PBS buffer.Additionally,48 grass carp with similar body weight were chosen as the negative control group(PBS group)and injected with 1 mL of PBS buffer.Following the injection,blood glucose and insulin levels were measured at 0,1h,3h,6h,and 12h,and liver samples were collected at the corresponding times to detect the expression of glucose-metabolism related genes.The blood tests showed that the high carbohydrate group exhibited the lowest blood glucose levels at the 0 hour.At the 1st hour,both groups reached peak blood glucose levels,with the high carbohydrate group demonstrat-ing significantly lower levels than the control group.At the 12th hour,blood glucose levels in both groups returned to the normal range.Although insulin levels showed a slight increase post-glucose injection,the difference was not signifi-cant.RT-qPCR results showed that the expression levels of glut2(glucose transporter),g6pase(glucose-6-phosphatase G-6-pase),and gys2(glycogen synthase 2)genes were higher in the carbohydrate group compared to the control group at the 0h mark.Between the 1st and 3rd hours,expression of the gk(glucokinase)and gys2 gene in the high carbohy-drate group was significantly higher than that in the control group.In summary,grass carp fed a high carbohydrate diet exhibited enhanced blood glucose clearance ability and improved glucose tolerance.The primary mechanism underly-ing rapid blood sugar clearance in the high-carbohydrate group grass carp appears to be the enhancement of glycogen synthesis.