Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1993-12-21
pubmed:abstractText
Texel wethers (68 +/- 2.5 kg BW) fitted with catheters in the ruminal veins and a mesenteric artery, blood flow probes on ruminal arteries, and a ruminal cannula were fed 500 g of orchardgrass hay every 12 h. During the last third of the feeding cycle, intraruminal injections were performed to evaluate the effect of urease activity, osmolality, and concentrations of NH3, butyrate, and CO2 in the rumen on urea and NH3 fluxes across the rumen wall. At pH 6.7, NH3 absorption increased with NH3 and butyrate concentrations in the rumen, and to a lesser extent with CO2 concentration. The increase in ruminal blood flow associated with CO2 and butyrate increase was always greater than the increase in NH3 absorption. Increasing ruminal osmolality slightly decreased NH3 absorption. Ruminal NH3 concentration and ruminal blood flow seemed to be the main determinant of NH3 absorption. Decreasing urease activity in the rumen decreased urea net transfer. The net transfer of urea to the rumen was stimulated by CO2. High concentrations of NH3 (330 mg of N/L) and butyrate (25 mM) in the rumen decreased urea net uptake, whereas osmolality (up to 420 mOsmol/L) did not affect it. Modifications in ruminal blood flow or water net movement across the ruminal wall did not seem to account for the effect of CO2, NH3, and butyrate on urea net uptake.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-8812
pubmed:author
pubmed:issnType
Print
pubmed:volume
71
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2785-92
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Net transfer of urea and ammonia across the ruminal wall of sheep.
pubmed:affiliation
Station de Recherche sur la Nutrition des Herbivores, Institut National de la Recherche Agronomique de Clermont-Ferrand, St Genès-Champanelle, France.
pubmed:publicationType
Journal Article