Effect of probiotic treatment on the host gut metabolic profiles via gas-chromatography-mass spectrometry-solid phase microextraction and 1H nuclear magnetic resonance spectroscopy

The capacity of human Lactobacilli and Bifidobacteria to produce metabolites under conditions that may prevail in the human intestine has been studied in vitro. However the effect of systematic probiotics consumption on human metabolic phenotype has not been investigated in feces. This paper shows the potential for the use of 1H-Nuclear Magnetic Resonance (1H-NMR) spectroscopy for studying the changes of the metabolic profiles of human fecal slurries. Feces of 16 subjects characterized by natural different level of Lactobacilli and Bifidobacteria before and after 1 month of supplementation with a symbiotic food based on Lactobacillus acidophilus, Bifidobacterium longum and fructooligosaccharides have been analyzed with 1H NMR. Multivariate statistical approach has been applied to the data obtained and particularly Canonical Discriminant Analysis of Principal Coordinates (CAP). More than 150 molecules belonging to the short chain fatty acids, organic acids, esters, alcohols and amino acids were detected and quantified in the samples considered. The number and the extent of these molecules in fecal slurries were strongly affected by the symbiotic food consumption and gave rise to characteristic metabolic signature. In particular, the short chain fatty acids concentrations significantly increased while the amino acids contents decreased. The comparison of the data indicated that the intake of the symbiotic food taken into consideration alters the metabolism of hosts in a measure dependent on the natural initial level of Lactobacilli and Bifidobacteria in the host fecal slurries. 1H NMR profiles combined with CAP allowed a separation of fecal slurries of the subjects considered on the basis of the thirty days supplementation or not with symbiotic food. The analytical system and the multivariate statistical approach used demonstrate the potential of metabolic profiling of the gut microbial activity related to dietary supplementation of probiotics.