γ-aminobutyric acid improves the growth performance, food intake and glucose homeostasis of Micropterus salmoides fed high-carbohydrate diets

Abstract

This study aimed to assess the function of γ-aminobutyric acid (GABA) on growth performance, food intake and glucose homeostasis of Micropterus salmoides fed carbohydrate (CHO)-enriched diets. The intracerebroventricular glucose + GABA co-injected fish had higher cumulative food intake, and expression of orexigenic genes (ghrelin and neuropeptide y (npy)) in the brain than those of the single glucose-injected group. In the feeding trial, M. salmoides (10.35 ± 0.05 g) were fed four feeds containing a control feed (10 % CHO, C) and three GABA contents [0 (HC), 50 (HC-G1), and 100 (HC-G2) mg kg−1, respectively] of high-CHO feed (20 % CHO) for 12 weeks. High CHO prominently (P < 0.05) decreased WGR, SGR, FI, p-Ampk protein content, and expression of ghrelin, npy, fbpase, pparα, cpt1α and aco1 compared with the control group, but the opposite was true for plasma glucose and triglyceride levels, tissue glycogen and lipid contents, and expression of proopiomelanocortin, leptin a, gk, pk, gs, chrebp, srebp1, fas and acc1. HC-G2 diets prominently (P < 0.05) up-regulated WGR, SGR, FI, p-Ampk protein content, and expression of ghrelin, npy, gk, pk, chrebp, srebp1, fas and acc1 compared with the HC group. Also, HC-G2 diets increased glucose tolerance of M. salmoides fed high-CHO diets after glucose loading. Overall, GABA improved the growth performance, food intake and glucose homeostasis of high-CHO-fed fish by the increase of appetite, glycolysis, glycogenesis and lipolysis, as well as the inhibition of gluconeogenesis and lipid synthesis.

Keywords

• Food intake
• Carbohydrate utilization
• Fish culture
• γ-aminobutyric acid