It was recently shown that variations in the ratio of dietary fermentable
carbohydrates (fCHO) and fermentable protein (fCP) differentially affect large
intestinal microbial ecology and the mucosal response. Here we investigated
the use of mass spectrometry to profile changes in metabolite composition in
colon and urine associated with variation in dietary fCHO and fCP composition
and mucosal physiology. Thirty-two weaned pigletswere fed 4 diets in a 2 × 2
factorial design with low fCP and low fCHO, low fCP and high fCHO, high fCP
and low fCHO, and high fCP and high fCHO. After 21 to 23 d, all pigs were
euthanized and colon digesta and urine metabolite profiles were obtained by
mass spectrometry. Analysis of mass spectra by partial least squares approach
indicated a clustering of both colonic and urinary profiles for each pig by
feeding group. Metabolite identification and annotation using the Kyoto
Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed increased
abundance of metabolites associated with arachidonic acid metabolism in colon
of pigs fed a high concentration of fCP irrespective of dietary fCHO. Urinary
metabolites did not show as clear patterns. Mass spectrometry can effectively
differentiate metabolite profiles in colon contents and urine associated with
changes in dietary composition. Whether metabolite profiling is an effective
tool to identify specific metabolites (biomarkers) or metabolite profiles
associated with gut function and integrity needs further elucidation