title: Changes in faecal bacteria associated with concentrate and forage-only diets fed to horses in training.
abstract: BACKGROUND
  Diets rich in readily fermentable carbohydrates, fed traditionally to meet the increased energy requirements of the performance horse, are associated with a number of gastrointestinal disorders that involve disturbances in the intestinal microbiota, however, these changes are poorly understood.
  
  
  OBJECTIVE
  With the long-term objective of improving intestinal health and to increase understanding of the relationship between diet and microbiota, the effect of feeding Standardbred horses a high-energy forage-only (F) diet was studied compared to a more traditional forage-concentrate (C) diet on faecal microbiota.
  
  
  METHODS
  Diets were fed in a cross-over design to 6 mature geldings on a scheduled training regime, both periods consisting of 29 days. DNA was extracted from faecal samples collected at 4 time points from each period, bacterial 16S rRNA genes were amplified and community composition assessed by terminal-restriction fragment length polymorphism, cloning and sequencing. Faecal pH and cultivable lactic acid bacteria (LAB) and enterobacteria were also assessed on the final collection day of each period.
  
  
  RESULTS
  Diet F resulted in a microbial composition that was more stable between sampling periods and had lower counts (P < 0.05) of cultivable LAB and specifically members of the Streptococcus bovislequinus complex. Motile and swarming Lactobacillus ruminis was present in all horses on diet C and not in horses on diet F. Diet C also resulted in the increase (P < 0.05) in members of Clostridiaceae cluster III and a concomitant reduction (P < 0.05) in an unknown group of Bacteroidales.
  
  
  CONCLUSIONS
  The greater microbial stability and reduction in LAB and members of the Streptococcus bovis/equinus complex on diet F indicate an opportunity to develop feeding strategies that support equine health and welfare. Novel changes identified in the faecal microbiota that resulted from carbohydrate inclusion merit further investigation.
authors.affiliation: Department of Microbiology, P.O. Box 7025, Swedish University of Agricultural Science, 75007 Uppsala, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Willing
authors.forename: A
authors.initials: A
authors.lastname: Vörös
authors.forename: S
authors.initials: S
authors.lastname: Roos
authors.forename: C
authors.initials: C
authors.lastname: Jones
authors.forename: A
authors.initials: A
authors.lastname: Jansson
authors.forename: J E
authors.initials: JE
authors.lastname: Lindberg
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D018592:Cross-Over Studies; D004032:Diet / Q000662:veterinary*; D005243:Feces / Q000382:microbiology*; D006736:Horses; D006863:Hydrogen-Ion Concentration; D008297:Male; D010802:Phylogeny; D010805:Physical Conditioning, Animal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S