Taurine supplements in high-fat diets improve survival of juvenile Monopterus albus by reducing lipid deposition and intestinal damage

A 8-week feeding trial was conducted to investigate the effects of the addition of taurine to a high-fat diet on growth performance, lipid deposition, antioxidant ability, and intestinal health in juvenile rice field eel (Monopterus albus). Four diets were designed: a normal fat diet (6.51% lipid, Control), high-fat diet (12.67% lipid, HFD), and high-fat diets supplemented with 0.2 and 0.5% taurine (HFD + T-0.2 and HFD + T-0.5, respectively). The results showed that (1) the survival rate was significantly lower in fish fed a high-fat diet than in those fed other diets. The feed conversion rate in the HFD + T0.5 group was markedly lower than that in the HFD group. (2) HFD-feeding significantly increased lipid deposition compared to that in the Control group. The addition of 0.2 or 0.5% taurine both ameliorated the HFD-induced increase in lipid droplets in the liver, significantly increased the hepatic lipase and lipoprotein lipase activities in serum, and decreased total cholesterol and triacylglycerol contents. (3) HFD-feeding significantly reduced serum immunity and antioxidant capacity. The HFD + T-0.2 and HFD + T-0.5 groups remarkably increased the levels of serum complement, lysozyme, alkaline phosphatase, glutathione, catalase, and superoxide dismutase. (4) The expression of pro-inflammatory cytokine (il-1 beta, il-12 beta, il-15, tlr-3, tlr-7, tlr-8, and nf-kappa b) in the HFD + T-0.2 and HFD + T-0.5 groups were significantly downregulated, while the expression of anti-inflammatory cytokines (il-10) and intestinal tight junction proteins (occludin and zo-2) were significantly upregulated. Beside, taurine supplementation at 0.2 or 0.5% both significantly decreased the nuclear NF-kappa B p65 protein level. In conclusion, high-fat diets induced negative effects in rice field eels, and dietary supplementation with 0.2 or 0.5% taurine can improve growth performance, decrease lipid deposition, enhance antioxidant ability, and maintain intestinal health. The best growth performance was seen in fish supplemented with 0.5% taurine.