title: Colonic Transit Time Is a Driven Force of the Gut Microbiota Composition and Metabolism: In Vitro Evidence.
abstract: OBJECTIVE
  Human gut microbiota harbors numerous metabolic properties essential for the host's health. Increased intestinal transit time affects a part of the population and is notably observed with human aging, which also corresponds to modifications of the gut microbiota. Thus we tested the metabolic and compositional changes of a human gut microbiota induced by an increased transit time simulated in vitro.
  
  
  METHODS
  The in vitro system, Environmental Control System for Intestinal Microbiota, was used to simulate the environmental conditions of 3 different anatomical parts of the human colon in a continuous process. The retention times of the chemostat conditions were established to correspond to a typical transit time of 48 hours next increased to 96 hours. The bacterial communities, short chain fatty acids and metabolite fingerprints were determined.
  
  
  RESULTS
  Increase of transit time resulted in a decrease of biomass and of diversity in the more distal compartments. Short chain fatty acid analyses and metabolite fingerprinting revealed increased activity corresponding to carbohydrate fermentation in the proximal compartments while protein fermentations were increased in the lower parts.
  
  
  CONCLUSIONS
  This study provides the evidence that the increase of transit time, independently of other factors, affects the composition and metabolism of the gut microbiota. The transit time is one of the factors that explain some of the modifications seen in the gut microbiota of the elderly, as well as patients with slow transit time.
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: William
authors.initials: W
authors.lastname: Tottey
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: David
authors.initials: D
authors.lastname: Feria-Gervasio
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: Nadia
authors.initials: N
authors.lastname: Gaci
authors.affiliation: INRA, UMR 1019, Plateforme d'Exploration du Métabolisme, Nutrition Humaine, Saint-Genès Champanelle, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Laillet
authors.affiliation: INRA, UMR 1019, Plateforme d'Exploration du Métabolisme, Nutrition Humaine, Saint-Genès Champanelle, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Pujos
authors.affiliation: INRA, UMR 1019, Plateforme d'Exploration du Métabolisme, Nutrition Humaine, Saint-Genès Champanelle, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Martin
authors.affiliation: INRA, UMR 1019, Plateforme d'Exploration du Métabolisme, Nutrition Humaine, Saint-Genès Champanelle, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Sebedio
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Sion
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Jarrige
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Alric
authors.affiliation: EA 4678 CIDAM, Clermont Université, Université d'Auvergne, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Brugère
keywords: Aging; Colon; Constipation; Gut microbiome; Microbiological techniques