Comparison of Lysophospholipids and Bile Acids on the Growth Performance, Lipid Deposition, and Intestinal Health of Largemouth Bass (Micropterus salmoides)

Lysophospholipids (LPLs) and bile acids (BA) are commonly used as emulsifiers in aquaculture. This study investigated the effects of dietary supplementation of LPLs or BA on the growth performance, lipid deposition, and intestinal health of largemouth juveniles. Fish were randomly allotted into three groups in quadruplicate and fed with a basal diet (CON) or diets containing 300 mg/kg LPLs (LPLs), or 300 mg/kg commercially available BA product (BA) for 8 weeks. The results showed that compared with the control group, LPLs and BA supplemented groups showed a higher weight gain trend, and LPLs supplementation promoted the protein deposition in fish body. Both BA and LPLs supplementations helped to maintain liver health by decreasing the activities of aspartate aminotransferase and alanine aminotransferase in serum. Besides, LPLs supplementation decreased overall lipid deposition in terms of mesenteric fat index and liver lipid content. Furthermore, LPLs supplementation showed unique advantage in improving intestinal barrier, as characterized by the increased villus length and higher expression of the tight junction protein zo-1 expression. LPLs supplementation also increased the alpha diversity index and the abundances of Proteobacteria in the intestinal microbiota which is positively correlated with the abundance of SCFA in the gut. These findings will promote the application of novel feed additives and especially provide a basis for the rational selection of emulsifiers in the aquaculture industry.