Diet alters probiotic Lactobacillus persistence and function in the intestine

We investigated the effects of host diet on the intestinal persistence and gene expression of Lactobacillus plantarum WCFS1 in healthy and health‐compromised, 2,4,6‐trinitrobenzene sulfonic acid (TNBS)‐treated mice. Mice fed either a low‐fat chow diet (CD) or high fat and sucrose Western diet (WD) received 10⁹ L. plantarum WCFS1 cells for five consecutive days. Lactobacillus plantarum persistence was 10‐ to 100‐fold greater in the intestines of WD‐fed compared with CD‐fed mice. TNBS, an intestinal irritant that induces the development of inflammatory bowel disease‐like symptoms, resulted in up to a 10⁴‐fold increase in L. plantarum survival in the digestive tract relative to healthy animals. Expression levels of 12 metabolic and gut‐inducible L. plantarum genes were differentially affected by diet and TNBS administration. Pyrosequencing of 16S rRNA transcripts from the indigenous intestinal microbiota showed that WD resulted in significant reductions in proportions of metabolically active indigenous Lactobacillus species and increases in the Desulfovibrionaceae family. Feeding L. plantarum WCFS1 resulted in lower levels of colitis and higher concentrations of colonic IL‐10 and IL‐12 in WD and not CD‐fed mice. Interactions between probiotics, nutritional components and the intestinal bacteria should be considered when examining for probiotic‐mediated effects and elucidating mechanisms of probiotic function in the mammalian gut.