title: Effect of ruminal administration of Escherichia coli wild type or a genetically modified strain with enhanced high nitrite reductase activity on methane emission and nitrate toxicity in nitrate-infused sheep.
abstract: The effects of two kinds of Escherichia coli (E. coli) strain, wild-type E. coli W3110 and E. coli nir-Ptac, which has enhanced NO(2) reduction activity, on oral CH(4) emission and NO(3) toxicity in NO(3)-treated sheep were assessed in a respiratory hood system in a 4 x 6 Youden square design. NO(3) (1.3 g NaNO(3)/kg(0.75) body weight) and/or E. coli strains were delivered into the rumen through a fistula as a single dose 30 min after the morning meal. Escherichia coli cells were inoculated for sheep to provide an initial E. coli cell density of optical density at 660 nm of 2, which corresponded to 2 x 10(10) cells/ml. The six treatments consisted of saline, E. coli W3110, E. coli nir-Ptac, NO(3), NO(3) plus E. coli W3110, and NO(3) plus E. coli nir-Ptac. CH(4) emission from sheep was reduced by the inoculation of E. coli W3110 or E. coli nir-Ptac by 6 % and 12 %, respectively. NO(3) markedly inhibited CH(4) emission from sheep. Compared with sheep given NO(3) alone, the inoculation of E. coli W3110 to NO(3)-infused sheep lessened ruminal and plasma toxic NO(2) accumulation and blood methaemoglobin production, while keeping ruminal methanogenesis low. Ruminal and plasma toxic NO(2) accumulation and blood methaemoglobin production in sheep were unaffected by the inoculation of E. coli nir-Ptac. These results suggest that ruminal methanogenesis may be reduced by the inoculation of E. coli W3110 or E. coli nir-Ptac. The inoculation of E. coli W3110 may abate NO(3) toxicity when NO(3) is used to inhibit CH(4) emission from ruminants.
authors.affiliation: Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Sar
authors.forename: B
authors.initials: B
authors.lastname: Mwenya
authors.forename: B
authors.initials: B
authors.lastname: Pen
authors.forename: K
authors.initials: K
authors.lastname: Takaura
authors.forename: R
authors.initials: R
authors.lastname: Morikawa
authors.forename: A
authors.initials: A
authors.lastname: Tsujimoto
authors.forename: K
authors.initials: K
authors.lastname: Kuwaki
authors.forename: N
authors.initials: N
authors.lastname: Isogai
authors.forename: I
authors.initials: I
authors.lastname: Shinzato
authors.forename: Y
authors.initials: Y
authors.lastname: Asakura
authors.forename: Y
authors.initials: Y
authors.lastname: Toride
authors.forename: J
authors.initials: J
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D005285:Fermentation; D007263:Infusions, Parenteral / Q000379:methods; D008297:Male; D008657:Metabolic Clearance Rate; D008697:Methane / Q000378:metabolism*; D008706:Methemoglobin / Q000032:analysis; D050901:Nitrate Reductase / Q000378:metabolism*; D009566:Nitrates / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics; D009573:Nitrites / Q000097:blood / Q000493:pharmacokinetics; D010101:Oxygen Consumption / Q000502:physiology; D012417:Rumen / Q000382:microbiology*; D012756:Sheep
chemical_list: D009566:Nitrates; D009573:Nitrites; D002245:Carbon Dioxide; C031618:sodium nitrate; D008706:Methemoglobin; D050901:Nitrate Reductase; D008697:Methane