Taurine supplements in high-carbohydrate diets increase growth performance of Monopterus albus by improving carbohydrate and lipid metabolism, reducing liver damage, and regulating intestinal microbiota

An 8-week feeding trial was performed to investigate the effects of the addition of taurine to high-carbohydrate diets on growth performance, carbohydrate metabolism, lipid deposition, antioxidant ability, inflammation, and intestinal microbiota in juvenile Monopterus albus. Four diets were designed: a control diet (0% corn starch, CON), high-carbohydrate (40% corn starch, HC), and high-carbohydrate diets supplemented with 0.2 and 0.5% taurine (HCT0.2 and HCT0.5, respectively). Each treatment group had 3 replicates. The results showed that the HC feeding significantly decreased growth performance and gluconeogenesis, increased lipid deposition, glycolysis and liver inflammation, and disrupted the intestinal microbiota compared with the CON group. However, compared with the HC group, the addition of taurine to HC diets significantly increased growth performance and the activities of glycolysis and antioxidative enzymes, whereas the opposite occurred in the levels of triglyceride, low-density lipoprotein cholesterol, total cholesterol, and gluconeogenesis enzymes. Additionally, the addition of taurine to HC diets remarkably increased the mRNA expression levels of glycolysis, lipolysis, anti-inflammatory cytokine compared with the HC group, whereas the opposite occurred in the mRNA expression levels of antioxidative enzymes, gluconeogenesis, lipid accumulation, and pro-inflammatory cytokine genes. Besides, the relative abundance of Lactococcus in the HC group remarkably higher than those in the CON group, whereas the opposite occurred in the relative abundance of Clostridium sensu stricto 1. Compared with the CON group, 0.5% taurine supplementation in HC diets showed no significant different on the composition and diversity of intestinal microbiota. Based on the findings, HC diets induced negative effects on rice field eel, and dietary taurine supplementation can improve the growth performance, decrease lipid deposition, enhance antioxidant ability, reduce liver damage, and regulate the homeostasis of intestinal microbiota. And the optimum supplemental level of taurine was 0.5%.