Dietary supplementation of glycyrrhetinic acid (Ga) promoting lipid lipolysis from blunt snout bream megalobrama amblycephala by tnf-α and lpl expression

Abstract

Glycyrrhetinic acid (GA), which is a main active principal constituent of liquorice, is extensively used as a non-nutrition sweetener or anti-inflammatory in Chinese medicine. This study was carried out to evaluate the effects of different GA levels on growth, biometric parameters, plasma lipid metabolites, Tumor necrosis factor alpha (TNF-α) and Lipoprotein lipase (LPL) gene expression of Megalobrama amblycephala (average weight, 68.78 ± 1.13 g). Three diets were formulated to contain various levels of GA (0, 30 and 300 mg/kg). Fish were randomly distributed into 12 cages and fed three times daily for 8 weeks. Dietary GA levels have little significant effect on weight gain and feed conversion ratio. Intraperitoneal fat ratio and viscera/body ratio decreased significantly as dietary GA levels increased, and hepatosomatic index tended to decrease as dietary GA levels increased. Plasma triglycerides, cholesterol, and non-esterified free fatty acid levels also decreased as dietary GA concentrations increased. Adipose tissue and liver TNF-α expression increased significantly with increasing dietary GA levels; whereas, LPL expression showed an opposite trend. Results of this study indicate that dietary supplementation of 300 mg/kg GA had a positive effect in promoting lipid lipolysis in Megalobrama amblycephala without having a negative effect on growth through the regulation of TNF-α and LPL expression.