Effects of rosiglitazone on growth and skeletal muscle glucose metabolism of GIFT tilapia based on PI3K/Akt signaling pathway

Abstract

This study aimed to investigate the effects of rosiglitazone on glucose metabolism of GIFT tilapia based on the PI3K/Akt signalling pathway. The experiment was divided into five groups: normal starch group (32%, LC), high starch group (53%, HC), HC + rosiglitazone group 1 (10 mg/kg, R1), HC + rosiglitazone group 2 (20 mg/kg, R2) and HC + rosiglitazone group 3 (30 mg/kg, R3). The results showed that a high starch diet added with 10–20 mg/kg rosiglitazone had a better specific growth rate and protein efficiency that was beneficial for the growth of the tilapia. With an increase in the rosiglitazone concentration, the contents of serum glucose, insulin and hepatic glycogen in the R1, R2 and R3 groups decreased gradually. Meanwhile, the muscle glycogen content in the R1, R2 and R3 groups increased gradually. The mRNA expression of the IRS-1, PI3K, GLUT-4 and Akt proteins in the R1, R2 and R3 groups was significantly higher than that in the HC group (p < 0.05). Compared with the HC group, the expression of the GSK-3 mRNA in the R1, R2 and R3 groups was significantly reduced (p < 0.05). The protein expression of p-GSK-3β (phosphorylated GSK-3β) in the R1 and R2 groups was significantly higher than that in the HC group (p < 0.05). In conclusion, a high starch diet supplemented with rosiglitazone can improve growth, enhanced the serum biochemical indices and increase the muscle glycogen content in the GIFT tilapia. It benefits in upregulating the IRS-1, PI3K and GLUT-4 mRNA in the skeletal muscle and promotes glucose uptake. Meanwhile, the phosphorylation of Akt and GSK-3β increased significantly and resulted in the inactivation of GSK-3β and alleviation of insulin resistance. Under these experimental conditions, the optimal dosage of rosiglitazone on tilapia was 10–20 mg/kg diet.