Effects of glimepiride on growth, glucose metabolism and expression of p38MAPK, JNK in skeletal muscles of GIFT tilapia

Abstract

This study aimed to investigate the effects of glimepiride on the growth, glucose metabolism and the expressions of p38 mitogen-activated protein kinases (p38MAPK), C-JUN N-terminal kinase (JNK) in skeletal muscle of genetically improved farmed tilapia (GIFT). The tilapia were categorized into five feed groups: normal starch group (32%, LS), high starch group (53%, HS), HS+ glimepiride group 1 (10 mg/kg, G1), HS+ glimepiride group 2 (20 mg/kg, G2), and HS+ glimepiride group 3 (30 mg/kg, G3). The results showed that the final body weight and specific growth rate of the G2 group increased (P > 0.05), and the protein efficiency ratio of groups G1 and G2 was significantly higher than that of the HS group (P < 0.05). The blood glucose content of groups G2 and G3 decreased, compared to that of the HS group. An increase in the glimepiride concentration led to the decreased serum glucose content of the G1 and G2 groups. Compared with the HS group, the insulin content of the G1, G2, and G3 groups significantly decreased, and the hepatic and muscle glycogen content in these three groups increased gradually with an increase in the glimepiride concentration (P > 0.05). The expression of p38MAPK and JNK mRNAs in the G1 and G2 groups were significantly lower than those in the HS groups (P < 0.05). In the G2 and G3 groups, p-p38MAPK and p-JNK protein expression were significantly lower than that in the HS group (P < 0.05); meanwhile, the p-JNK protein expression in G1 and G2 groups was lower than that in the HS group (P > 0.05). Thus, GIFT tilapia can tolerate a high amount of starch, and the addition of glimepiride at an optimal dosage of 10–20 mg/kg does not significantly impact the growth index. However, it can improve glucose metabolism by promoting insulin secretion and liver/muscle glycogen synthesis.