Topographical variation in murine intestinal metabolic profiles in relation to microbiome speciation and functional ecological activity.

Symbiotic gut microbes can have a significant influence on host health and disease etiology. Here, we assessed the effects of inoculating germfree mice with human baby microbiota (HBM, n=17) on the biochemical composition of intact intestinal tissues (duodenum, jejunum, ileum, proximal and distal colon) using magic-angle-spinning 1H NMR spectroscopy. We compared the HBM tissue metabolite profiles with those from conventional (n=9) and conventionalized (n=10) mice. Each topographical intestinal region showed a specific metabolic profile that was altered differentially by the various microbiomes, especially for osmolytes. In each animal model, duodenum had higher ethanolamine and myo-inositol, and ileum higher taurine and betaine than other gut regions. HBM mice showed lower taurine and myo-inositol in the colon, and all ex-germfree animals had higher taurine, choline and ethanolamine in the jejunum. Interestingly, the jejunum of HBM mice was marked by a higher glutathione level and lower concentrations of its precursor methionine when compared to other groups. Proximal and distal colon tissues were differentiated in the different microbiome models by the concentrations of bacterial products (higher in conventional animals). These studies show the depth of gut microbiome modulations of the intestinal biochemistry.