Long-term administration of benfotiamine benefits the glucose homeostasis of juvenile blunt snout bream Megalobrama amblycephala fed a high-carbohydrate diet

Abstract

This study aimed to investigate the effects of benfotiamine on growth performance, glucose homeostasis and intermediary glucose metabolism of blunt snout bream (Megalobrama amblycephala). A total of 240 fish (average body weight: 24.24±0.05g) were randomly distributed into 12 tanks and fed three diets (control, diet with 30% carbohydrate; HC, diet with 43% carbohydrate; HCB, HC diet supplemented with 2.85mg/kg benfotiamine) for 12weeks. The results indicated that fish fed the HCB diet had a lower specific growth rate and feed conversion ratio compared to those fed the control and HC diets, whereas protein efficiency ratio, nitrogen retention efficiency and energy retention efficiency showed an opposite trend. Additionally, fish offered HCB diet showed relatively high values of whole-body lipid contents, tissue glycogen and lipid contents and plasma insulin levels, whereas plasma levels of glucose, advanced glycation end products and glycated serum protein significantly decreased compared with other treatments. Furthermore, benfotiamine improved the glucose tolerance of fish fed HC diet after a glucose load. High carbohydrate intake significantly up-regulated the mRNA levels of glucokinase, pyruvate kinase, glucose transporter 2, glycogen synthase, fatty acid synthetase and glucose-6-phosphate dehydrogenase, whereas the opposite was true for phosphoenolpyruvate carboxykinase, fructose-1,6-biphosphatase, glucose-6-phosphatase, carnitine palmitoyl transferase I and acyl-CoA oxidase. This also held true for fish fed HCB diet except for fatty acid oxidation process which was further enhanced. Overall, these findings suggested that benfotiamine benefited the glucose metabolism of Megalobrama amblycephala fed high-carbohydrate diet through the stimulation of glycolysis, glycogenesis, lipogenesis and fatty acid oxidation coupled with the depression of gluconeogenesis.Statement of relevanceThis study investigated the effects of dietary benfotiamine supplementation on growth performance, glucose homeostasis and intermediary metabolism of blunt snout bream. The data obtained here will facilitate our understanding of the potential mechanisms concerning the beneficial effects of benfotiamine on the carbohydrate metabolism of fish. It is also helpful for the development of low-protein and high-energy feed for fish.