title: Lipid metabolism in pigs fed supplemental conjugated linoleic acid and/or dietary arginine.
abstract: We proposed that the combination of conjugated linoleic acid (CLA) and arginine would decrease adiposity by depressing lipid synthesis in liver and adipose tissues of growing pigs. Pigs were allotted to treatments in a 2 × 2 factorial design with two lipids (CLA or canola oil) and two amino acids [L-arginine or L-alanine (isonitrogenous control)]; supplements were provided from 80 to 110 kg body weight (approximately 4 weeks). Treatment groups (n = 4) were: control (2.05% L-alanine plus 1% canola oil); CLA (2.05% L-alanine plus 1% CLA); arginine (1.0% L-arginine plus 1.0% canola oil); arginine plus CLA (1.0% arginine plus 1.0% CLA). Arginine increased backfat thickness (P = 0.07) in the absence or presence of CLA, and arginine supplementation increased subcutaneous and retroperitoneal adipocyte volume, especially in combination with dietary CLA (interaction P = 0.001). Arginine increased palmitate incorporation into total lipids by over 60% in liver (P = 0.07). Dietary CLA increased palmitate incorporation into lipids in longissimus muscle by over 100% (P = 0.01), and CLA increased longissimus muscle lipid by nearly 20%. CLA increased glucose oxidation to CO(2) by over 80% in retroperitoneal and subcutaneous adipose tissues (P = 0.04), and doubled palmitate oxidation to CO(2) in intestinal duodenal mucosal cells (P = 0.07). Arginine supplementation decreased muscle pH at 45 min postmortem (P = 0.001), indicating elevated early postmortem glycolysis, and CLA and arginine independently increased PGC-1α gene expression in longissimus muscle. CLA but not arginine depressed mTOR gene expression in intestinal duodenal mucosal cells. CLA decreased serum insulin by 50% (P = 0.02) but increased serum triacylglycerols by over 40%. CLA supplementation increased (P ≤ 0.01) total saturated fatty acids in liver and adipose tissue. In conclusion, neither CLA nor arginine depressed tissue lipid synthesis in growing/finishing pigs, and in fact dietary CLA promoted elevated intramuscular lipid and arginine increased carcass adiposity.
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, TX 2471, USA.
authors.forename: Gwangwoong
authors.initials: G
authors.lastname: Go
authors.forename: Guoyao
authors.initials: G
authors.lastname: Wu
authors.forename: David T
authors.initials: DT
authors.lastname: Silvey
authors.forename: Seongho
authors.initials: S
authors.lastname: Choi
authors.forename: Xilong
authors.initials: X
authors.lastname: Li
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Smith
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D050154:Adiposity / Q000187:drug effects; D000409:Alanine / Q000008:administration & dosage; D000821:Animal Feed; D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D001823:Body Composition / Q000187:drug effects; D019587:Dietary Supplements; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D044243:Linoleic Acids, Conjugated / Q000008:administration & dosage*; D050356:Lipid Metabolism / Q000187:drug effects*; D008460:Meat; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000378:metabolism; D000074262:Rapeseed Oil; D013552:Swine; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
chemical_list: D005229:Fatty Acids, Monounsaturated; D006360:Heat-Shock Proteins; D044243:Linoleic Acids, Conjugated; D000074262:Rapeseed Oil; D014280:Triglycerides; D019308:Palmitic Acid; D001120:Arginine; D058570:TOR Serine-Threonine Kinases; D005947:Glucose; D000409:Alanine