show Abstracthide AbstractBackground: Acute liver failure is a severe liver disorder and poses a huge global challenge. Researches have shown that probiotics may improve acute liver injury. Previous studies regarding Bifidobacterium longum R0175 mainly focused on its psychic function. The current research focused on the protective efficacy of B. longum R0175 on acute liver failure caused by D-Galactosamine (GalN) in rats and further tested the hypothesis that B. longum R0175 achieved its central effects of liver protection through intestinal microbiota, fecal metabolites, and inflammation inhibiting.Results: We found that oral gavage of B. longum R0175 remarkably reduced the severity of liver injury in D-GalN-treated rats, evidenced by decreased serum levels of AST and TBAs (P<0.05). Moreover, plasma concentrations of pro-inflammatory cytokines (IL-1b, TNF-a) and chemokines (GM-CSF, MCP-1, GRO/KC, RANTES, MIP-1a, and MCP-1) were also markedly attenuated (P<0.05). Probiotic treatment partially reversed gut microflora dysbiosis in rats with liver injury by increasing the presentation of potentially beneficial bacterium, for example, Alloprevotella, and decreasing the abundance of potentially harmful bacteria, such as Acetafactor muris, Butyricimonas and Oscillibacter. Furthermore, B.longum R0175 administration partially improved the metabolic function of intestinal flora as indicated by the enrichment of L-methionine, and the decreased levels of lithocholic acid and L-5-oxoproline in the feces.Discussion: Overall, our results illustrated that B.longum R0175 exhibited protective effects on rats with acute liver failure and it has greater clinical application prospects to be explored.