Fig. 1

Pathway of Lactobacillus-mediated tryptophan metabolism was obviously inhibited in AP model. A Gut microbiota imbalance in rat feces of the AP group compared with the Ctrl group based on 16S rDNA sequencing (n = 10). B Alterations in the gut microbiota between the Ctrl and AP groups (n = 10). C The relative abundance of Lactobacillus species in rat feces was decreased in the AP group compared with the Ctrl group (n = 10). D Metabolite disorder was shown in the feces of the rats in the AP group compared with the Ctrl group based on untargeted metabolomics (n = 10). E The differentially abundant metabolites were enriched in various metabolic pathways. F The relative abundance of tryptophan was significantly reduced in feces of the AP group compared with the Ctrl group (n = 10). G Both endogenous and gut microbiota tryptophan metabolism were indeed inhibited in AP. H The abundance of Lactobacillus was positively correlated with the level of tryptophan (n = 10). Data are presented as the mean ± SEM; *P < 0.05 and **P < 0.01 vs. the Ctrl group