Sodium acetate alleviates adverse effects caused by the diet with high proportion of soybean meal in turbot (Scophthalmus maximus L.)

Short-chain fatty acids (SCFAs) mainly including acetate, propionate and butyrate are produced by the fermentation of indigestible polysaccharides through intestinal microorganisms, and play an important role in maintaining intestinal health of animals. The present study aimed to investigate the effects of acetate on turbot fed the diet with high proportion of soybean meal (SBM). Four experimental diets were designed: (1) fish meal (FM)-based diet (control group); (2) SBM protein replacing 45% FM protein in the diet (high SBM group); (3) 1.0% sodium acetate (NaAc) supplementation in the high SBM diet (1.0% NaAc group); (4) 2.0% NaAc supplementation in the high SBM diet (2.0% NaAc group). The turbots were fed different diets for 8 weeks. Our results showed that the addition of 1.0% NaAc in high SBM diet effectively promoted the fish growth. Meanwhile, dietary NaAc ameliorated the mucosal barrier and activities of digestive enzymes in the intestine of the turbot fed high SBM diet. Moreover, dietary supplementation of 1.0% or 2.0% NaAc relieved intestinal inflammation and oxidative stress caused by high SBM diet. In addition, the resistance of turbot to bacterial infection decreased in high SBM group, whereas dietary NaAc increased anti-infectious ability of turbot. In conclusion, the dietary supplementation of appropriate NaAc effectively alleviated high SBM diet-induced adverse effects on the growth and intestinal health of turbot, and improved the resistance of fish to bacterial infection. Our study provides a theoretical basis for the development of NaAc as a functional additive for fish feeds.