title: Key bacterial families (Clostridiaceae, Erysipelotrichaceae and Bacteroidaceae) are related to the digestion of protein and energy in dogs.
abstract: BACKGROUND
  Much of the recent research in companion animal nutrition has focussed on understanding the role of diet on faecal microbiota composition. To date, diet-induced changes in faecal microbiota observed in humans and rodents have been extrapolated to pets in spite of their very different dietary and metabolic requirements. This lack of direct evidence means that the mechanisms by which microbiota influences health in dogs are poorly understood. We hypothesised that changes in faecal microbiota correlate with physiological parameters including apparent macronutrient digestibility.
  
  
  METHODS
  Fifteen adult dogs were assigned to two diet groups, exclusively fed either a premium kibbled diet (kibble;K;n= 8) or a raw red meat diet (meat;M;n= 7) for nine weeks. Apparent digestibility of macronutrients (protein, fat, gross energy and dry matter), faecal weight, faecal health scores, faecal VFA concentrations and faecal microbial composition were determined. Datasets were integrated using mixOmics in R.
  
  
  RESULTS
  Faecal weight and VFA levels were lower and the apparent digestibility of protein and energy were higher in dogs on the meat diet. Diet significantly affected 27 microbial families and 53 genera in the faeces. In particular, the abundances ofBacteriodes,Prevotella,PeptostreptococcusandFaecalibacteriumwere lower in dogs fed the meat diet, whereasFusobacterium,LactobacillusandClostridiumwere all more abundant.
  
  
  CONCLUSIONS
  Our results show clear associations of specific microbial taxa with diet composition. For example, Clostridiaceae, Erysipelotrichaceae and Bacteroidaceae were highly correlated to parameters such as protein and fat digestibility in the dog. By understanding the relationship between faecal microbiota and physiological parameters we will gain better insights into the effects of diet on the nutrition of our pets.
authors.affiliation: AgResearch Ltd., Food Nutrition & Health Team , Palmerston North , New Zealand.
authors.forename: Emma N
authors.initials: EN
authors.lastname: Bermingham
authors.affiliation: AgResearch Ltd., Bioinformatics & Statistics Team , Lincoln , New Zealand.
authors.forename: Paul
authors.initials: P
authors.lastname: Maclean
authors.affiliation: Massey University, Institute of Veterinary, Animal & Biomedical Sciences , Palmerston North , New Zealand.
authors.forename: David G
authors.initials: DG
authors.lastname: Thomas
authors.affiliation: Massey University, Institute of Veterinary, Animal & Biomedical Sciences , Palmerston North , New Zealand.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Cave
authors.affiliation: AgResearch Ltd., Food Nutrition & Health Team , Palmerston North , New Zealand.
authors.forename: Wayne
authors.initials: W
authors.lastname: Young
keywords: Dog; Faecal microbiota; Nutrient digestibility