title: Fibre digestibility, abundance of faecal bacteria and plasma acetate concentrations in overweight adult mares.
abstract: The purpose of the present study was to compare digestibility of grass hay, faecal and plasma volatile fatty acid (VFA) concentrations, and faecal bacterial abundance in overweight and moderate-condition mares. Five overweight adult mixed-breed mares and five adult mixed-breed mares in moderate condition were housed individually and limit-fed orchard grass (Dactylis glomerata) hay at 20 g/kg body weight (as fed) daily for 14 d. Forage DM and fibre digestibility were determined using AOAC methods; digestible energy was measured using bomb calorimetry; plasma and faecal VFA concentrations were determined by use of GC and MS; faecal Firmicutes, Bacteroidetes, Fibrobacter succinogenes, Ruminococcus flavefaciens and total bacteria abundance was determined by quantitative real-time PCR using previously designed phylum-specific 16S ribosomal RNA gene primers. No differences in hay digestibility, faecal VFA concentrations or faecal bacterial abundance were detected between overweight and moderate-condition mares. Mean plasma acetate concentrations were higher (P = 0·03) in overweight (1·55 (range 1·43-1·65) mmol/l) v. moderate-condition (1·39 (range 1·22-1·47) mmol/l) mares. We conclude that the higher plasma acetate in overweight mares should be further investigated as a potential link between gut microbes and obesity in horses.
authors.affiliation: Department of Large Animal Clinical Sciences , Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech , Duck Pond Drive (0442), Blacksburg, VA 24061 , USA.
authors.forename: Megan L
authors.initials: ML
authors.lastname: Shepherd
authors.affiliation: Department of Food Science and Technology , Virginia Tech , Blacksburg, VA 24061 , USA.
authors.forename: Monica A
authors.initials: MA
authors.lastname: Ponder
authors.affiliation: Department of Animal and Avian Sciences , University of Maryland , College Park, MD 20742 , USA.
authors.forename: Amy O
authors.initials: AO
authors.lastname: Burk
authors.affiliation: Department of Large Animal Clinical Sciences , Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech , Duck Pond Drive (0442), Blacksburg, VA 24061 , USA.
authors.forename: Stewart C
authors.initials: SC
authors.lastname: Milton
authors.affiliation: Department of Large Animal Clinical Sciences , Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech , Duck Pond Drive (0442), Blacksburg, VA 24061 , USA.
authors.forename: William S
authors.initials: WS
authors.lastname: Swecker
keywords: ADF, acid-detergent fibre; BCS, body condition score; Body condition score; DE, digestible energy; DMI, DM intake; Digestible energy; Faecal bacteria; Horses; NDF, neutral-detergent fibre; OG, orchard grass; VFA, volatile fatty acid; rDNA, ribosomal DNA; rRNA, ribosomal RNA