title: Effect of 3-nitrooxypropanol on methane and hydrogen emissions, methane isotopic signature, and ruminal fermentation in dairy cows.
abstract: The objective of this crossover experiment was to investigate the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission, methane isotopic composition, and rumen fermentation and microbial profile in lactating dairy cows. The experiment involved 6 ruminally cannulated late-lactation Holstein cows assigned to 2 treatments: control and 3NOP (60 mg/kg of feed dry matter). Compared with the control, 3NOP decreased methane emission by 31% and increased hydrogen emission from undetectable to 1.33 g/d. Methane emissions per kilogram of dry matter intake and milk yield were also decreased 34% by 3NOP. Milk production and composition were not affected by 3NOP, except milk fat concentration was increased compared with the control. Concentrations of total VFA and propionate in ruminal fluid were not affected by treatment, but acetate concentration tended to be lower and acetate-to-propionate ratio was lower for 3NOP compared with the control. The 3NOP decreased the molar proportion of acetate and increase those of propionate, butyrate, valerate, and isovalerate. Deuterium-to-hydrogen ratios of methane and the abundance of (13)CH3D were similar between treatments. Compared with the control, minor (4‰) depletion in the (13)C/(12)C ratio was observed for 3NOP. Genus composition of methanogenic archaea (Methanobrevibacter, Methanosphaera, and Methanomicrobium) was not affected by 3NOP, but the proportion of methanogens in the total cell counts tended to be decreased by 3NOP. Prevotella spp., the predominant bacterial genus in ruminal contents in this experiment, was also not affected by 3NOP. Compared with the control, Ruminococcus and Clostridium spp. were decreased and Butyrivibrio spp. was increased by 3NOP. This experiment demonstrated that a substantial inhibition of enteric methane emission by 3NOP in dairy cows was accompanied with increased hydrogen emission and decreased acetate-to-propionate ratio; however, neither an effect on rumen archaeal community composition nor a significant change in the isotope composition of methane was observed.
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802.
authors.forename: J C
authors.initials: JC
authors.lastname: Lopes
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802.
authors.forename: L F
authors.initials: LF
authors.lastname: de Matos
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802.
authors.forename: M T
authors.initials: MT
authors.lastname: Harper
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802.
authors.forename: F
authors.initials: F
authors.lastname: Giallongo
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802.
authors.forename: J
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: D
authors.initials: D
authors.lastname: Gruen
authors.affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: S
authors.initials: S
authors.lastname: Ono
authors.affiliation: DSM Nutritional Products, Animal Nutrition and Health, Basel, Switzerland CH-4002.
authors.forename: M
authors.initials: M
authors.lastname: Kindermann
authors.affiliation: DSM Nutritional Products France, Research Centre for Animal Nutrition and Health, Saint Louis Cedex, France 68305.
authors.forename: S
authors.initials: S
authors.lastname: Duval
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802. Electronic address: anh13@psu.edu.
authors.forename: A N
authors.initials: AN
authors.lastname: Hristov
mesh_terms: D000818:Animals; D001105:Archaea / Q000187:drug effects / Q000502:physiology*; D002247:Carbon Isotopes / Q000032:analysis; D002417:Cattle / Q000502:physiology*; D018592:Cross-Over Studies; D003903:Deuterium / Q000032:analysis; D005260:Female; D005285:Fermentation / Q000187:drug effects*; D005766:Gastrointestinal Contents / Q000737:chemistry* / Q000187:drug effects; D007774:Lactation; D008697:Methane / Q000378:metabolism*; D008892:Milk / Q000378:metabolism; D020005:Propanols / Q000494:pharmacology*; D012417:Rumen / Q000378:metabolism / Q000382:microbiology
chemical_list: C000603069:3-nitrooxypropanol; D002247:Carbon Isotopes; D020005:Propanols; D003903:Deuterium; D008697:Methane
keywords: 3-nitrooxypropanol; dairy cow; methane; rumen fermentation