title: Fermentable soluble fibres spare amino acids in healthy dogs fed a low-protein diet.
abstract: BACKGROUND
  Research in cats has shown that increased fermentation-derived propionic acid and its metabolites can be used as alternative substrates for gluconeogenesis, thus sparing amino acids for other purposes. This amino acid sparing effect could be of particular interest in patients with kidney or liver disease, where this could reduce the kidneys'/liver's burden of N-waste removal. Since dogs are known to have a different metabolism than the obligatory carnivorous cat, the main objective of this study was to assess the possibility of altering amino acid metabolism through intestinal fermentation in healthy dogs. This was studied by supplementing a low-protein diet with fermentable fibres, hereby providing an initial model for future studies in dogs suffering from renal/liver disease.
  
  
  RESULTS
  Eight healthy dogs were randomly assigned to one of two treatment groups: sugar beet pulp and guar gum mix (SF: soluble fibre, estimated to mainly stimulate propionic acid production) or cellulose (IF: insoluble fibre). Treatments were incorporated into a low-protein (17 %) extruded dry diet in amounts to obtain similar total dietary fibre (TDF) contents for both diets (9.4 % and 8.2 % for the SF and IF diet, respectively) and were tested in a 4-week crossover feeding trial. Apparent faecal nitrogen digestibility and post-prandial fermentation metabolites in faeces and plasma were evaluated. Dogs fed the SF diet showed significantly higher faecal excretion of acetic and propionic acid, resulting in a higher total SCFA excretion compared to IF. SF affected the three to six-hour postprandial plasma acylcarnitine profile by significantly increasing AUC of acetyl-, propionyl-, butyryl- + isobutyryl-, 3-OH-butyryl-, 3-OH-isovaleryl- and malonyl-L-carnitine. Moreover, the amino acid plasma profile at that time was modified as leucine + isoleucine concentrations were significantly increased by SF, and a similar trend for phenylalanine and tyrosine's AUC was found.
  
  
  CONCLUSIONS
  These results indicate that guar gum and sugar beet pulp supplementation diminishes postprandial use of amino acids favoring instead the use of short-chain fatty acids as substrate for the tricarboxylic acid (TCA) cycle. Further research is warranted to investigate the amino acid sparing effect of fermentable fibres in dogs with kidney/liver disease.
authors.affiliation: Laboratory of Animal Nutrition, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820, Merelbeke, Belgium.
authors.forename: Wendy
authors.identifier: http://orcid.org/0000-0002-4990-5703
authors.initials: W
authors.lastname: Wambacq
authors.affiliation: Laboratory of Animal Nutrition, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820, Merelbeke, Belgium.
authors.forename: Galena
authors.initials: G
authors.lastname: Rybachuk
authors.affiliation: Department of Research and Development, Affinity Petcare SA, Sant Cugat Nord Office Park, Xavier Cugat Square, Building D, 08174, Sant Cugat del Valles, Barcelona, Spain.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Jeusette
authors.affiliation: Laboratory of Animal Nutrition, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820, Merelbeke, Belgium.
authors.forename: Kristel
authors.initials: K
authors.lastname: Rochus
authors.affiliation: Laboratory of Metabolic Disorders, Department of Clinical Chemistry, Microbiology and Immunology; Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Wuyts
authors.affiliation: Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Faculty of Bioscience Engineering, Ghent University, Proefhoevestraat 10, 9090, Melle, Belgium.
authors.forename: Veerle
authors.initials: V
authors.lastname: Fievez
authors.affiliation: Nutrition and Endocrinology Unit, Nantes-Atlantic National College of Veterinary Medicine, UNAM Université, Food Science and Engineering-ONIRIS, Site de la Chantrerie, BP 40706, 44307, Nantes Cedex 3, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Nguyen
authors.affiliation: Laboratory of Animal Nutrition, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, B-9820, Merelbeke, Belgium. Myriam.Hesta@UGent.be.
authors.forename: Myriam
authors.initials: M
authors.lastname: Hesta
mesh_terms: D019342:Acetic Acid / Q000032:analysis; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood; D018592:Cross-Over Studies; D004032:Diet / Q000662:veterinary*; D004043:Dietary Fiber / Q000378:metabolism*; D004285:Dogs / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D011422:Propionates / Q000032:analysis; D011897:Random Allocation
chemical_list: D000596:Amino Acids; D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D011422:Propionates; C116917:acylcarnitine; C029658:propionic acid; D019342:Acetic Acid; D002331:Carnitine
keywords: Acylcarnitine; Apparent protein digestibility; Canine renal diet; Dietary fibre; Guar gum