title: In vitro ouabain-sensitive respiration and protein synthesis in rumen epithelial papillae of Hereford steers fed either timothy hay or timothy hay supplemented with cracked corn once daily.
abstract: Rumen epithelial papillae samples, acquired from the Central sac of six adult Hereford steers (585 +/- 17 kg) fed either timothy hay plus soybean meal (T) or timothy hay plus cracked corn and soybean meal (TC) once daily (0900), were used in a crossover design to study the daily pattern of O2 consumption and protein synthesis. Tissue samples were acquired at 0900, 1200, 1800, and 2400 over a 10-d sampling period. Additionally, ruminal fermentation characteristics (pH, ammonia, VFA, and osmolality) were measured at 0430, 0900, 1030, 1200, 1500, 1800, 2100 and 2400. Total, ouabain-insensitive (OIO2), and cycloheximide-insensitive (CIO2) O2 consumption were greatest at 2400 (P < .01, P < .06, and P < .02 respectively). Additionally, steer fed TC had a greater CIO2 at 2400. In conjunction with a temporal effect on ruminal fermentation patterns, after an initial decline, there was an increase (P < .05) in total O2, ouabain-sensitive (OSO2), OIO2, and CIO2 consumption throughout the day. Fractional rates of protein synthesis were not different at any time point between diets. Rumen epithelial metabolism exhibits a temporal pattern in cattle fed once daily.
authors.affiliation: Department of Animal and Poultry Science, University of Guelph, ON, Canada.
authors.forename: J M
authors.initials: JM
authors.lastname: Kelly
authors.forename: A S
authors.initials: AS
authors.lastname: Vaage
authors.forename: L P
authors.initials: LP
authors.lastname: Milligan
authors.forename: B W
authors.initials: BW
authors.lastname: McBride
mesh_terms: D000641:Ammonia / Q000032:analysis; D000818:Animals; D002417:Cattle / Q000378:metabolism* / Q000502:physiology; D018592:Cross-Over Studies; D003513:Cycloheximide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004848:Epithelium / Q000378:metabolism / Q000502:physiology; D005232:Fatty Acids, Volatile / Q000032:analysis; D005285:Fermentation; D005527:Food, Fortified; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D008871:Microvilli / Q000378:metabolism / Q000502:physiology; D010042:Ouabain / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D006109:Poaceae; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012417:Rumen / Q000378:metabolism* / Q000502:physiology; D013025:Glycine max / Q000592:standards; D003313:Zea mays / Q000592:standards
chemical_list: D004791:Enzyme Inhibitors; D005232:Fatty Acids, Volatile; D011500:Protein Synthesis Inhibitors; D010042:Ouabain; D000641:Ammonia; D003513:Cycloheximide