The mechanism of action of a fat regulator: Glycyrrhetinic acid (GA) stimulating fatty acid transmembrane and intracellular transport in blunt snout bream (Megalobrama amblycephala).

High-fat diets are associated with fatty liver and aberrant hepatic lipid metabolism, and glycyrrhetinic acid (GA) has been shown to exert a beneficial effect on lipolysis and fat deposition in fish. In the present study, we evaluated the effect of GA on the growth performance and expression of hepatic lipid transport related genes in blunt snout bream (Megalobrama amblycephala) fed a high fat diet. Two hundred and sixteen fish (average body weight: 45.57 g ± 0.98 g) were fed three experimental diets (6% fat/L6 group, control, 11% fat/L11 group, and 11% fat with 0.3 mg kg-1 GA/L11GA group) for 8 weeks. Compared to the control group, the weight gain and specific growth rate of high-fat fed group at the end of the trialwere significantly improved (P < .05).However, GA showed no effect on animals' growth performance(P > .05). Dietary supplementation with 0.3 mg kg-1 GA significantly decreased the hepatosomatic index, viscera/body ratio, and intraperitoneal fat ratio (P < .05), and up-regulated the expression levels of fatty acids transport protein (FATP), fatty acids binding protein (FABP), fatty acid translocase (CD36), carnitine palmitoyl transferase I (CPT1) and peroxisome proliferators-activated receptors α (PPARα) compared to both the L6 group and L11 group (P < .05). However, no significant difference was observed in fatty acid synthetase (FAS), acetyl-CoA carboxylase α (ACCα), or lipoprotein lipase (LPL) between groups (P > .05). In conclusion, GA significantly rescued high-fat diet induced hepatic lipid accumulation and metabolism dysfunction in M. amblycephalaby stimulating hepatic fatty acid transport and β-oxidation. Dietary GA may be used as a promising supplement to alleviate high-fat diet induced side effects on M. amblycephala.