title: Initial studies on leucine metabolism in the rumen of sheep.
abstract: 1. [3H]leucine infused directly into the rumen of sheep labelled microbial protein and, when compared with the specific activity of the rumen free-leucine pool, indicated that 50% of the bacterial protein leucine originated from the rumen free-leucine pool. 2. The lower limit for bacterial protein turnover in the rumen was 0.37/d when calculated as the difference between the specific rate of disappearances of labelled bacteria from the rumen and the liquid-phase dilution rate. 3. Intravenously infused leucine also labelled the rumen bacteria. The build-up of specific activity in the rumen bacteria was sigmoidal and did not resemble that of the salivary protein which suggested that the rumen epithelium was a major endogenous protein input to the rumen. Additionally, bacteria isolated from the rumen epithelium had high radioactivity indicating that they were ingesting the rumen epithelial cells.
authors.affiliation: Department of Applied Biochemistry and Food Science, University of Nottingham School of Agriculture, Loughborough, Leics.
authors.forename: M
authors.initials: M
authors.lastname: Marsden
authors.forename: C I
authors.initials: CI
authors.lastname: Bruce
authors.forename: C G
authors.initials: CG
authors.lastname: Bartram
authors.forename: P J
authors.initials: PJ
authors.lastname: Buttery
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D007930:Leucine / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D012417:Rumen / Q000378:metabolism*; D012756:Sheep
chemical_list: D001426:Bacterial Proteins; D007930:Leucine