Impacts of diets fed after weaning on gut microbiota and susceptibility to DSS-induced colitis in mice

Abstract Background Living in a sanitary environment and taking Western-style diet in early life are both risk factors for inflammatory bowel disease and important factors for shaping host gut microbiota. Here, we aimed to establish whether different dietary composition fed during the early period after weaning would associate the susceptibility to DSS-induced colitis with different gut microbiota shifts. Methods Eighty weaned Balb/c mice were fed with high sugar, fat, protein, fiber, and standard diet for 8weeks respectively. Inflammation was induced by administration of 2.5% (wt/vol) dextran sulfate sodium (DSS) in drinking water for 7 days, and the microbiota characterized by 16s rRNA based pyrosequencing. Analyzed the inflammatory factors and toll-like receptors by Real-time PCR Results The high protein and high fiber+protein group exacerbated severity of DSS-induced colitis, the high fiber and high protein+fiber groups had the effect of reducing colitis, and the high sugar, fat and standard group show the similar disease phenotype of colitis. The diversity and richness of the microflora were significantly decreased in the high fiber group, while only decreased richness of flora was observed in the high protein group. The abundance of Firmicutes was decreased and the abundance of Bacteroides was increased in the high fat, high sugar, high protein and high fiber groups, especially in the high protein and high fiber group. The microbial community structure was slightly different at the species/genus level. The microbial community structure of high protein-fiber group and high fiber-protein group was still similar. Conclusions Mice were fed with different dietary compositions of high sugar, fat, protein and fiber diets since weaning, and similar gut microbiota of high-abundance Bacteroides and low-abundance Firmicutes are formed in adult mice. These microbiota do not cause colonic mucosal damage directly. Only high protein diet aggravated DSS-induced colitis, while high fiber diet alleviated the colitis.