Ulcerative colitis is a globally prevalent chronic disease that continues to attract significant attention. 5-aminosalicylicacid (5-ASA) is the primary treatment for mild to moderate colitis, but its use may be compromised by side effects and dependency. Lactiplantibacillus (L.) plantarum has shown promise as a remission strategy for alleviating colitis. Our previous study demonstrated that supplementation with L. plantarum LP-315 (LP-315) effectively alleviated dextran sulfate sodium (DSS)-induced colitis in mice, though its effects on the gut microbiota and metabolism remained unexplored. In this follow-up study, we analyzed the fecal metagenome, gut metabolic modules (GMMs), and bioactive metabolites in four groups of mice (n = 8 per group): normal control group, DSS group, LP group (LP-315 intervention), and ME group (5-ASA intervention). A correlation network analysis was performed to investigate the associations between key differential gut microbial species, GMMs, metabolites, and the significantly improved phenotypic indicators identified in previous study. The results revealed that LP-315 ameliorated colitis symptoms by modulating the gut microbiota (increasing Duncaniella newyorkensis), bioactive metabolites (reducing serotonin, while increasing indole-3-acetic acid, xanthurenic acid, and indole-3-carboxylic acid), and the inflammation-associated Glutamine degradation pathway. Compared to 5-ASA, which primarily reduced the abundance of the harmful bacterium Parasutterella excrementihominis, LP-315 exhibited superior efficacy in ameliorating DSS-induced colitis symptoms. Besides, 25 bacterial species and 14 GMMs, closely linked to colitis but unchanged by the intervention, were identified as worthy of further targeted investigation. These findings provide rigorous preclinical evidence supporting the potential and feasibility of L. plantarum in colitis amelioration.

This work was undertaken in order to study the microbial diversity in dairy products from ethnic minority habitats in Xilin Gol. Six fresh cow milk samples from Sunit Left Banner and East Ujimqin Banner (n = 3 for each region) were selected for metagenomic sequencing, and lactic acid bacteria (LAB) from these samples were isolated and identified by the traditional culture method. There results showed that a total of 165 microbial species were identified in the six milk samples, the dominant ones being Lactococcus lactis and Leuconostoc mesenteroides. Many microbial species were common to the two groups, and there was no significant difference in α- or β-diversity, but there were still significantly differential species identified between these groups. Fresh milk from Sunit Left Banner was dominated by Lactococcu phage BM13, while that from East Ujimqin Banner was dominated by Enterobacter sp. MGH8. A total of 1408048 genes and 412 metabolic pathways were annotated using the Uniprot database, whose functions were concentrated on amino acid metabolism and glycolic acid metabolism. A total of 47 strains were isolated from the six fresh milk samples, and L. lactis was the dominant strain, which was consistent with the metagenomic results. This study is expected to provide a theoretical basis for the safe production of fermented dairy products and the development of starter cultures.