title: [Nitrogen metabolism in the large intestine of ruminants. 6. Metabolism of intracecally administered 14C and 15N urea in sheep with simultaneous intracecal doses of heat-damaged hay].
abstract: Two wethers (28 kg and 33 kg) were supplied with ileocaecal re-entrance cannulae and received a straw pellet ration rich in crude fibre (70.5% straw, 12% chopped sugar beet, 10% cereals, 2% urea, 3% NH4HCO3 and 2.5% of a mineral mixture). In a preliminary period 50% of the digesta flow was collected on 6 successive days for 18 h each. An amount of digesta sufficient for 24 h was apportioned for hourly application and stored at a temperature of -20 degrees C for the main trial. In the main trial the two animals received intracaecally the collected digesta with a supplement of ca. 6 g hay damaged by heat/kg LW(0.75) in hourly portions over 24 h (hay made up ca. 15 and 20% resp. of the DM amount). In addition, each digesta sample was supplemented with 14C and 15N labelled urea (19.7.10(6) Bq 14C urea and 364 mg 15N excess from 15N urea). About 9% of the applied 15N amount was microbially utilized; the utilization quota was thus lower than after the application of partly hydrolyzed straw meal (16% in a previous trial). The 14C activity from 14C urea was quickly eliminated in the form of CO2 in the respiratory gases (at the 18th hour after the end of the infusion 70% excreted as CO2). The half-lives for the urea resulting from the semi-logarithmic decrease of the atom-% 15N excess in the blood plasma were 7.9 and 7.7 resp. 23% and 34% resp. of the applied 15N excess were excreted in urine. The excretion of radioactive carbon in urine, however, was at 2.8% and 4.3% resp. of the applied amount very low 120 h after the beginning of the trial (96 h after the end of the infusion). On the whole one can conclude from this trial that hay damaged by heat has only a low stimulating effect on microbial activity in the large intestine.
authors.affiliation: Sektion Tierproduktion und Veterinärmedizin, Humboldt-Universität zu Berlin.
authors.forename: C
authors.initials: C
authors.lastname: Kijora
authors.forename: J
authors.initials: J
authors.lastname: Bartelt
authors.forename: H
authors.initials: H
authors.lastname: Bergner
mesh_terms: D000821:Animal Feed; D000818:Animals; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D006358:Hot Temperature; D007420:Intestine, Large / Q000378:metabolism* / Q000382:microbiology; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D012756:Sheep / Q000378:metabolism*; D014508:Urea / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D014508:Urea; D009584:Nitrogen
vernacular_title: Untersuchungen zum Stickstoffumsatz im Dickdarm von Wiederkäuern. 6. Mitteilung. Umsatz von intrazäkal verabreichtem 14C- und 15N-Harnstoff bei Schafen bei gleichzeitiger intrazäkaler Gabe von hitzegeschädigtem Heu.