title: Protein synthesis in splanchnic tissues of sheep offered two levels of intake.
abstract: Protein synthesis rates were measured in liver and gastrointestinal tract (GIT) sections of fattening sheep offered lucerne (Medicago sativa) pellets at either 1.25 or 2 times energy maintenance. The measurement technique involved a large dose of [1-13C]valine over 60 min. Animals on the higher intake had a larger mass of liver protein (143 v. 100 g, P = 0.02), similar fractional synthesis rates (ks; 22.5 v. 22.1%/d, not significant) and greater absolute amounts of protein synthesis (32 v. 23 g/d; P = 0.016) compared with those on the smaller amount of ration. The ks values and RNA: protein in the GIT sections also tended to increase with food intake. Estimated total GIT protein synthesis was approximately three-fold that in liver and probably constituted 25-35% of whole body synthesis. All splanchnic tissues measured had lower translational efficiencies (g protein synthesized/d per g total RNA) than reported for milk-fed and newly-weaned lambs and this may relate to the decline in the rate of protein deposition as lambs progress to the fattening condition.
authors.affiliation: Rowett Research Institute, Bucksburn, Aberdeen.
authors.forename: G E
authors.initials: GE
authors.lastname: Lobley
authors.forename: A
authors.initials: A
authors.lastname: Connell
authors.forename: E
authors.initials: E
authors.lastname: Milne
authors.forename: A M
authors.initials: AM
authors.lastname: Newman
authors.forename: T A
authors.initials: TA
authors.lastname: Ewing
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage*; D000818:Animals; D002247:Carbon Isotopes; D004064:Digestive System / Q000378:metabolism*; D007553:Isotope Labeling; D008099:Liver / Q000378:metabolism*; D008297:Male; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012756:Sheep / Q000378:metabolism*; D014633:Valine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D012313:RNA; D014633:Valine