Le microbiote intestinal: composition et fonctions

Hundreds of species compose the human gut microbiota, which reaches its highest density in the large bowel (10¹¹ bacteria per gram). If this species profile is specific to a given individual, three phyla (Firmicutes, Bacteroidetes, Actinobacteria) invariably dominate the adult human gut microbiota. This microbiota is globally stable in time and return to its initial status following a perturbation. It also exerts various functions, in particular metabolic functions, which are essential for maintaining host??s health. This microbial community is indeed able to convert a large variety of substrates (including sugars, proteins, and lipids) leading to the production of a diversity of metabolites. Most of these metabolites could beneficially affect host??s health. In addition, comparisons between germfree and conventional animals revealed the influence of the gut microbiota on the development and maturation of the immune system, the intestinal physiology, or the regulation of fat storage.