title: The effect of the source of nitrogen supplementation on nitrogen balance, rates of plasma leucine turnover, protein synthesis and degradation in sheep.
abstract: Combined experiments of the isotope dilution method of [1-(13)C]leucine, open-circuit calorimetry and nitrogen (N) balance test were used to determine the effect of the source of N supplementation on N balance, whole body protein synthesis (WBPS) and degradation (WBPD) in sheep. The experiment was performed in a replicated 3 × 3 Latin square design. The control diet consisted of timothy hay, ground maize and soybean meal. The urea diet was the control diet supplemented with 1.5% urea. The SBM diet contained the same N and metabolisable energy as the urea diet, which was reached by changing ground maize and soybean meal weights of the control diet. Nitrogen retention was greater (p < 0.05) for the urea diet than the control and SBM diets. Plasma urea concentrations were highest for the SBM diet, followed by the urea diet, and the control diet was lowest. The WBPS and WBPD did not differ between diets, but were numerically lower for the urea and SBM diets. These results suggest that in sheep, urea supplementation influenced N retention without clear changes in WBPS and WBPD.
authors.affiliation: a Department of Animal Sciences , Faculty of Agriculture, Iwate University , Morioka , Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sano
authors.affiliation: a Department of Animal Sciences , Faculty of Agriculture, Iwate University , Morioka , Japan.
authors.forename: Sachi
authors.initials: S
authors.lastname: Shibasaki
authors.affiliation: a Department of Animal Sciences , Faculty of Agriculture, Iwate University , Morioka , Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sawada
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects; D000818:Animals; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis; D005260:Female; D007930:Leucine / Q000097:blood*; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction; D014176:Protein Biosynthesis / Q000502:physiology*; D034561:Sheep, Domestic / Q000378:metabolism*; D013024:Soybean Oil / Q000008:administration & dosage; D014508:Urea / Q000008:administration & dosage
chemical_list: D013024:Soybean Oil; D014508:Urea; D007930:Leucine; D009584:Nitrogen
keywords: amino acid metabolism; feed supplements; protein degradation; protein synthesis; sheep; soybean oil meal; urea