| In order to study the mechanism of carbohydrate metabolism,improve the effective utilizition of carbohydrates,and alleviate the pressure on protein feed resources in aquaculture,we set a high sugar model and added sugar metabolism regulators to aquafeed,and explored the effects of glimepiride on growth,sugar metabolism,and related gene expression of Gift tilapia.Seventy hundred and twenty fish with an average body weight of 80.33±0.68 g were selected.Eight test groups were set up,namely the normal group LC group,the high starch HC group,and the high starch+ glimepiride(10,20,30mg/kg),named G1,G2,G3 groups,high starch+chromium picolinate(1.2,2.4,3.6mg/kg),named Cr1,Cr2,Cr3 groups,respectively,for two months of feeding experiments.The results are as follows:1.Growth performance indicators: compared with the HC group of the control group,the LC group had no statistically significant differences in final body weight,special growth rate,and relative growth rate(P>0.05),but the HC group had final weight,special growth rate,and the growth rates were 6.21%,10.34%,and 12.96% lower than those in the LC group,respectively.After adding glimepiride and chromium picolinate,compared with the HC control group,there was no significant difference in final body weight,special growth rate and relative growth rate(P>0.05).After adding 2.4mg/kg chromium picolinate to the diet,the protein efficiency was significantly higher than that in the control group(P<0.05).2.Whole fish body composition: The content of crude protein in LC group was significantly lower than that in HC group(P<0.05).The addition of glimepiride and chromium picolinate had no significant effect on whole fish body composition(P>0.05).3.Blood biochemical indicators: The content of blood glucose in LC group was significantly lower than that in HC group(P<0.05).The content of blood glucose in fish fedadding 20 mg/kg of glimepiride and 2.4 mg/kg of chromium picolinate was significantly lower than that in HC group(P<0.05).After adding 20 mg/kg glimepiride and 2.4 mg/kg chromium picolinate to the diet,both TG and TC were decreased significantly(P <0.05).The insulin content in the HC group was significantly higher than that in the LC group(P<0.05).After the addition of 20 mg/kg glimepiride,the insulin content was significantly increased(P<0.05).After adding 2.4 mg/kg chromium picolinate,the insulin content also was significantly increased(P<0.05).4.The contents of insulin and liver/muscle glycogen: The content of liver glycogen in the LC group was significantly lower than that in HC group and control group(P<0.05).After the addition of glimepiride,the content of liver glycogen was significantly higher than that in HC group(P<0.05).There was no significant difference in the content of muscle glycogen among the treatment groups(P>0.05).5.Gene and protein expression of p38 MAPK and JNK in skeletal muscle::The relative expression level of p38 MAPK in LC group was significantly lower than that in HC group(P<0.05).Compared with HC group,p38 MAPK mRNA was significantly up-regulated after adding 20 mg/kg glimepiride and 2.4 mg/kg chromium picolinate(P<0.05).The relative expression of JNK in LC group was significantly lower than that in HC group(P<0.05).There was no significant difference in p-p38 MAPK protein expression between the LC group and the HC group(P>0.05).Compared with the HC group,the expression of p-p38 MAPK protein was significantly increased after the addition of 20 mg/kg of glimepiride(P<0.05).Compared with the HC group,the expression of p-p38 MAPK protein was significantly increased after the addition of chromium picolinate(P<0.05).The p-JNK protein was scarcely expressed in the LC group,and the expression of p-JNK protein was significantly up-regulated compared with the HC group after the addition of 10 mg/kg and 20 mg/kg of glimepiride(P<0.05).In summary,the Gift tilapia can tolerate a higher amount of starch and will not affect the growth performance.The addition of glimepiride will not have a significant impact on growth performance.The addition of chromium picolinate will increase the protein efficiency of Gift tilapia,which is optimal at 2.4 mg/kg.The addition of glimepiride and chromium picolinatewill reduce the total triglyceride and total cholesterol content of Gift tilapia,improve the blood lipid level of tilapia,and reach the best at 20mg/kg and 2.4mg/kg.Glimepiride will promote insulin secretion and promote glycogen synthesis in the liver,so improves the glucose metabolism of Gift tilapia,the optimal dose is 20 mg/kg.Under high glucose conditions,the p38 MAPK and JNK signaling pathways in skeletal muscle tissue are activated.After the addition of 20 mg/kg of glimepiride,insulin secretion was stimulated,then insulin activated the AMPK signaling pathway,and the p38 MAPK was activated as a downstream kinase of AMPK,which promoted skeletal muscle glucose transport by inducing GLUT4 translocation. |
PDF Full Text Request