title: Comparison of microbial populations in the small intestine, large intestine and feces of healthy horses using terminal restriction fragment length polymorphism.
abstract: BACKGROUND
  The composition of the microbiota of the equine intestinal tract is complex. Determining whether the microbial composition of fecal samples is representative of proximal compartments of the digestive tract could greatly simplify future studies. The objectives of this study were to compare the microbial populations of the duodenum, ileum, cecum, colon and rectum (feces) within and between healthy horses, and to determine whether rectal (fecal) samples are representative of proximal segments of the gastrointestinal tract. Intestinal samples were collected from ten euthanized horses. 16S rRNA gene PCR-based TRFLP was used to investigate microbiota richness in various segments of the gastrointestinal tract, and dice similarity indices were calculated to compare the samples.
  
  
  RESULTS
  Within horses large variations of microbial populations along the gastrointestinal tract were seen. The microbiota in rectal samples was only partially representative of other intestinal compartments. The highest similarity was obtained when feces were compared to the cecum. Large compartmental variations were also seen when microbial populations were compared between six horses with similar dietary and housing management.
  
  
  CONCLUSIONS
  Rectal samples were not entirely representative of intestinal compartments in the small or large intestine. This should be taken into account when designing studies using fecal sampling to assess other intestinal compartments. Similarity between horses with similar dietary and husbandry management was also limited, suggesting that parts of the intestinal microbiota were unique to each animal in this study.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Canada. aschoste@uoguelph.ca
authors.forename: Angelika
authors.initials: A
authors.lastname: Schoster
authors.forename: Luis Guillermo
authors.initials: LG
authors.lastname: Arroyo
authors.forename: Henry Rolf
authors.initials: HR
authors.lastname: Staempfli
authors.forename: Jeffrey Scott
authors.initials: JS
authors.lastname: Weese
mesh_terms: D000821:Animal Feed; D000818:Animals; D005243:Feces / Q000382:microbiology*; D005260:Female; D006736:Horses; D007420:Intestine, Large / Q000382:microbiology*; D007421:Intestine, Small / Q000382:microbiology*; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000378:metabolism
chemical_list: D012336:RNA, Ribosomal, 16S