Effects Of Rosiglitazone On Growth And Muscle Glucose Metabolism Of Gift Tilapia Based On PI3K/Akt Signaling Pathway

Aquaculture feed costs account for more than 60-70% of total costs,and protein sources accounts for a major portion of feed costs.Therefore,it has become an important subject in the field of fish nutrition to reduce the feed cost,save protein source and improve the utilization of feed sugar.But because of the "diabetic constitution" of fish,it will adversely affect the production and health of fish when the sugar level in the feed is too high.As a human insulin sensitizer,rosiglitazone(RSG)can improve the ability of insulin to bind to receptors and increase the utilization of sugar.However,there are few reports on rosiglitazone picolinate in regulating sugar metabolism on fish.This paper aimed to study the effects of different concentrations of rosiglitazone picolinate on growth indexes,blood biochemical indicators,whole fish nutritional components,and insulin and liver muscle glycogen levels of Gifu tilapia,to explore rosiglitazone on the expression of IRS-1,PI3 K,GLUT-4,Akt and GSK3 in fish skeletal muscles,and also to explore the regulatory mechanisms of related molecules in the sugar metabolism pathway of fish.In this experiment,720 Gift tilapia with an average weight of about 80.33 ± 0.68 g were randomly allocated to 24 aquariums.The experiment was divided into 5 treatment groups: normal starch group(32%,LC),high starch group(52%,HC),high starch + rosiglitazone 1 group(10mg / kg,R1),high starch + Rog prostaglandin 2 group(20mg/kg,R2),high starch + rosiglitazone 3 group(30mg / kg,R3).There were 3 replicates in each group,with 30 tilapia each.After raising for 50 days,the results are as follows:1.The growth experiment results showed that when 10-20 mg / kg RSG was added to feed,the relative growth rate,protein efficiency,and viscera-to-body ratio all reached good levels,which was beneficial to the growth of Gifu tilapia.2.Analysis of nutritional composition of whole fish showed that the addition of rosiglitazone had no significant effect on whole fish body composition(P>0.05).3.Analysis of blood biochemical indicators showed that triglyceride was significantly higher in the HC group than in the LC group,and total cholesterol in the R1,R2 and R3 groups was significantly lower than that in the HC group(P <0.05).Globulin(GLB)was significantly higher in R2 and R3 groups than that in HC group(P <0.05).Aspartate aminotransferase in R2 group was significantly lower than that in HC group(P<0.05).Glutamate in R1 and R2 groups was significantly lower than that in HC and LC groups(P<0.05).4.Analysis of blood glucose and insulin levels showed that blood glucose in R3 group was significantly lower than that of HC group.Adding rosiglitazone can significantly reduce insulin levels(P <0.05),and insulin levels in the R1,R2,and R3 groups are significantly lower than those in the HC and LC groups(P <0.05).5.Analysis of liver muscle glycogen showed that the content of liver glycogen in the LC group was significantly lower than that in the HC group(P <0.05).The glycogen content in the R3 group was significantly higher than that in the HC group(P <0.05).6.The expression of IRS-1,PI3 K,GLUT-4,Akt,and GSK3 mRNA in skeletal muscle showed that the expression of IRS-1 mRNA in the R1,R2,and R3 groups was significantly higher than that in the HC group(P <0.05).The expression of PI3 KmRNA in R1 group was significantly lower than that in LC group(P <0.05).The expression of GLUT-4 mRNA in R2 group was significantly higher than that in HC group,and the expression of Akt mRNA in R1 group was significantly higher than that in HC group(P <0.05).The expression of GSK3 mRNA in R2 group was significantly higher than that in LC group(P <0.05).7.Analysis of Akt,p-Akt and p-GSK protein expression in skeletal muscle showed that the expression of Akt protein in R1,R3 and group was significantly higher than that in HC group(P<0.05).The expression of p-Akt protein in R1 and R3 groups was significantly higher than that in R2 group.The expression of p-GSKβ protein was significantly higher in the R2 group than in the R1 and R3 groups(P <0.05).In summary,the proper amount of carbohydrates in the diet is beneficial to fish growth,but excessive dietary carbohydrate level will cause liver fat accumulation,which will adversely affect the growth of the fish body.Adding a certain amount of rosiglitazone can reduce liver glycogen content,alleviate damage to fish liver caused by high sugar,and improve the growth performance of Gifu tilapia.When the amount of rosiglitazone is 10-20 mg / kg,the final weight and protein efficiency of tilapia reached the optimal levels in the gradient experiment.In addition,adding rosiglitazone can also reduce blood sugar and insulin levels,reduce triglycerides and total cholesterol levels,and improve the fish’s utilization of sugar.What’s more,adding an appropriate amount of rosiglitazone to the diet can significantly increase the phosphorylation of Akt and GSK-3β,cause inactivation of GSK-3β,thereby improving insulin resistance,up-regulatingIRS-1,GLUT-4 and PI3 KmRNA levels,and increasing insulin sensitivity.