糖胁迫对牙鲆肝脏代谢和肠道消化相关酶活性的影响

The Effects of Glucose Stress on the Activities of Metabolism and Digestive Enzymes in Liver and Intestine of Japanese Flounder Paralichthys olivaceus

牙鲆是海水养殖肉食性鱼类。本研究以灌喂葡萄糖的方式,研究糖胁迫对牙鲆(初始体重225±50g)肝脏蛋白质和脂肪代谢酶和消化酶活性的影响,为解析肉食性鱼类糖耐受能力弱的机制提供基础数据。共设计2个实验组,第1组为糖胁迫组,将葡萄糖溶液(500mg/ml)按照1.67g葡萄糖/kg体重的剂量灌喂给牙鲆;第2组为对照组,按第1组同等剂量灌喂牙鲆磷酸缓冲盐溶液(PBS,0.01mol/L)。分别在灌喂前(0h),灌喂后1、3、5、7、12、24和48h取样。结果表明,肝脏谷丙转氨酶活性在灌喂葡萄糖后表现出先下降后升高的趋势,在7h达到最低且显著低于灌喂前水平(P<0.05),谷草转氨酶活性与0h差异不显著(P>0.05)。葡萄糖-6-磷酸脱氢酶活性先升高后下降,在7h显著高于灌喂前水平(P<0.05)。脂蛋白脂酶、肝脂酶活性变化不显著(P>0.05)。肠道脂肪酶和胰蛋白酶活性先升高后下降,分别在5h和7h达到最高且显著高于灌喂前水平(P<0.05)。肠道淀粉酶和胃蛋白酶活性没有显著变化(P>0.05)。在对照组中,上述酶活性在不同取样时间点之间没有显著差异(P>0.05)。总的来说,糖胁迫影响了牙鲆肝脏的转氨酶活性,在一定程度上减弱了肝脏的氨基酸代谢强度,促进了肝脏脂肪酸的合成,增强了脂肪酶和胰蛋白酶的活性。

In the present study,the oral administration of glucose was used to investigate the effects of glucose stress on the temporal changes of liver aminotransferase,lipid metabolism and digestive enzymes activities in Japanese flounder Paralichthys olivaceus（body weight：225±50g）.The experiment included a group of oral administration of glucose（500mg/ml,1.67g/kg body weight）and a control group of oral administration of PBS（0.01mol/L）.Samples were collected just before（time 0h）and1h,3h,5h,7h,12 h,24hand 48 hafter oral administration of glucose or PBS.The results showed that the activity of the liver glutamic-pyruvic transaminase reduced to the lowest level at 7hafter oral administration of glucose.It was significantly lower than the activity at 0h（P〈0.05）,and then it restored to the normal level gradually.The activity of glutamic oxalacetic transaminase showed no significant difference（P〉0.05）.The activity of glucose-6-phosphate dehydrogenase peaked at 7h（P〈0.05）.The activities of lipoprotein lipase and hepatic lipase showed no significant difference after oral administration of glucose（P〉0.05）.The activities of lipase and trypsase in the intestine both showed a first increasing then decreasing tendency,and peaked at 5hand 7h（P〈0.05）,respectively.The activities of amylase in the intestine and pepsase were not significantly influenced after oral administration of glucose（P〉0.05）.The enzymes activities mentioned above showed no significant difference at the designed time points in the control group（P〉0.05）.In conclusion,the oral administration of glucose influenced the amino acid metabolism in Japanese flounder and promoted lipid synthesis and its intestinal digestive function in a degree.