title: Methane production by two non-ruminant foregut-fermenting herbivores: The collared peccary (Pecari tajacu) and the pygmy hippopotamus (Hexaprotodon liberiensis).
abstract: Methane (CH4) production varies between herbivore species, but reasons for this variation remain to be elucidated. Here, we report open-circuit chamber respiration measurements of CH4 production in four specimens each of two non-ruminant mammalian herbivores with a complex forestomach but largely differing in body size, the collared peccary (Pecari tajacu, mean body mass 17kg) and the pygmy hippopotamus (Hexaprotodon liberiensis, 229kg) fed lucerne-based diets. In addition, food intake, digestibility and mean retention times were measured in the same experiments. CH4 production averaged 8 and 72L/d, 18 and 19L/kg dry matter intake, and 4.0 and 4.2% of gross energy intake for the two species, respectively. When compared with previously reported data on CH4 production in other non-ruminant and ruminant foregut-fermenting as well as hindgut-fermenting species, it is evident that neither the question whether a species is a foregut fermenter or not, or whether it ruminates or not, is of the relevance previously suggested to explain variation in CH4 production between species. Rather, differences in CH4 production between species on similar diets appear related to species-specific differences in food intake and digesta retention kinetics.
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, 8057 Zurich, Switzerland.
authors.forename: Catharina
authors.initials: C
authors.lastname: Vendl
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, 8057 Zurich, Switzerland.
authors.forename: Samuel
authors.initials: S
authors.lastname: Frei
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, 8057 Zurich, Switzerland; Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland.
authors.forename: Marie Theres
authors.initials: MT
authors.lastname: Dittmann
authors.affiliation: Zoo Zurich, Zürichbergstrasse 221, 8044 Zürich, Switzerland.
authors.forename: Samuel
authors.initials: S
authors.lastname: Furrer
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Ortmann
authors.affiliation: Zoological Gardens Wuppertal, Hubertusallee 30, 42117 Wuppertal, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Lawrenz
authors.affiliation: Jaderpark, Tiergartenstr. 69, 26349 Jaderberg, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Lange
authors.affiliation: School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia.
authors.forename: Adam
authors.initials: A
authors.lastname: Munn
authors.affiliation: Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Kreuzer
authors.affiliation: Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, 8057 Zurich, Switzerland. Electronic address: mclauss@vetclinics.uzh.ch.
authors.forename: Marcus
authors.initials: M
authors.lastname: Clauss
mesh_terms: D000818:Animals; D001188:Artiodactyla / Q000378:metabolism*; D001835:Body Weight; D002245:Carbon Dioxide / Q000378:metabolism; D004032:Diet; D004063:Digestion / Q000502:physiology; D005285:Fermentation; D041981:Gastrointestinal Tract / Q000378:metabolism*; D060434:Herbivory / Q000502:physiology*; D008697:Methane / Q000378:metabolism*; D010101:Oxygen Consumption; D012418:Ruminants / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D008697:Methane
keywords: Artiodactyla; Hippopotamidae; Mean retention time; Methane; Methanogen; Rumination; Tayassuidae