title: Effects of soybean oil and dietary copper on ruminal and tissue lipid metabolism in finishing steers.
abstract: An experiment was conducted to determine the effects of Cu and soybean oil (SBO) supplementation on ruminal and tissue lipid metabolism and carcass characteristics in finishing steers. Sixty Angus steers (369.0 +/- 10.1 kg) were stratified by weight and randomly assigned to treatments in a 2 x 2 factorial arrangement, with factors being 0 or 20 mg of supplemental Cu/kg DM from Cu sulfate and 0 or 4% SBO. Steers were fed a high-concentrate basal diet that contained 5.3 mg Cu/kg DM. Average daily gain and feed intake were reduced (P < 0.01) by SBO but were not affected by Cu. Gain:feed ratio was not affected by treatment. Liver Cu concentrations were higher (P < 0.01) in steers receiving supplemental Cu and lower (P < 0.04) in SBO-supplemented steers. Copper supplementation tended to reduce (P < 0.12) and SBO supplementation tended to increase (P < 0.11) serum cholesterol concentrations. Backfat depth was reduced (P < 0.10) by Cu and SBO supplementation. Marbling scores and longissimus muscle lipid content were not affected by Cu supplementation; however, SBO supplementation reduced (P < 0.01) marbling scores. Longissimus muscle polyunsaturated fatty acids tended to be increased (P < 0.14) in Cu-supplemented steers. Longissimus muscle C18-conjugated dienes and the 18:1 trans isomer were increased (P < 0.05) in SBO-supplemented steers. Ruminal fluid 18:3 was increased (P < 0.05) and the 18:1 trans isomer was decreased (P < 0.05) in Cu-supplemented steers. These results indicate that as little as 20 mg of supplemental Cu/kg DM can reduce backfat and may alter lipid metabolism in steers fed high-concentrate diets.
authors.affiliation: Department of Animal Science and Interdepartmental Nutrition Program, North Carolina State University, Raleigh 27695-7621, USA.
authors.forename: T E
authors.initials: TE
authors.lastname: Engle
authors.forename: J W
authors.initials: JW
authors.lastname: Spears
authors.forename: V
authors.initials: V
authors.lastname: Fellner
authors.forename: J
authors.initials: J
authors.lastname: Odle
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism; D003300:Copper / Q000494:pharmacology*; D004032:Diet; D019587:Dietary Supplements; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism; D012417:Rumen / Q000187:drug effects* / Q000378:metabolism; D013024:Soybean Oil / Q000494:pharmacology*
chemical_list: D005231:Fatty Acids, Unsaturated; D003300:Copper; D013024:Soybean Oil; D002784:Cholesterol