title: Conjugated linoleic acid depresses the delta9 desaturase index and stearoyl coenzyme A desaturase enzyme activity in porcine subcutaneous adipose tissue.
abstract: Conjugated linoleic acid (CLA) has been shown to have an effect on subcutaneous fatty acid composition and has been reported to decrease stearoyl coenzyme A desaturase (SCD) activity by decreasing mRNA expression and(or) catalytic activity in rodents and rodent cell lines. This investigation was designed to study the effects of CLA, corn oil, or beef tallow supplementation on s.c. adipose tissue fatty acid composition, adiposity, SCD enzyme activity, and the delta9 desaturase index in piglets. Eighteen crossbred barrows 16 to 18 d of age were adapted to diet for 1 wk and then assigned randomly to one of three treatments: 1.5% added CLA, 1.5% added corn oil, or 1.5% added beef tallow. Barrows were penned individually and fed the supplemental oils for 35 d (to 25.6 +/- 0.6 kg BW). Subcutaneous adipose tissue samples were obtained after slaughter. Fatty acid composition of the s.c. adipose tissue differed for each fatty acid measured due to diet with the exception of 18:3. The concentrations of CLA trans-10, cis-12 and cis-9, trans-11 were elevated from nondetectable to 1.62 and 2.52 g/100 g lipid, respectively (P < 0.001 for both isomers). Conjugated linoleic acid decreased the delta9 desaturase index (P < 0.01) and SCD enzyme activity, expressed as nanomoles of palmitate converted to palmitoleate/(7 min x g of tissue) (P = 0.075) and nanomoles of palmitate converted to palmitoleate/(7 min 105 cells) (P= 0.056). Tallow-fed pigs had a greater proportion of large adipocytes (> 700 pL) and the greatest SCD activity. These data provide the first direct evidence that dietary CLA depresses SCD enzyme activity in porcine adipose tissue, which may in part be responsible for the depression of adiposity by CLA observed by others in market weight pigs.
authors.affiliation: Department of Animal Science, Texas Agricultural Experiment Station, Texas A&M University, College Station 77843, USA. sbsmith@tamu.edu
authors.forename: S B
authors.initials: SB
authors.lastname: Smith
authors.forename: T S
authors.initials: TS
authors.lastname: Hively
authors.forename: G M
authors.initials: GM
authors.lastname: Cortese
authors.forename: J J
authors.initials: JJ
authors.lastname: Han
authors.forename: K Y
authors.initials: KY
authors.lastname: Chung
authors.forename: P
authors.initials: P
authors.lastname: Casteñada
authors.forename: C D
authors.initials: CD
authors.lastname: Gilbert
authors.forename: V L
authors.initials: VL
authors.lastname: Adams
authors.forename: H J
authors.initials: HJ
authors.lastname: Mersmann
mesh_terms: D017667:Adipocytes; D000273:Adipose Tissue / Q000737:chemistry* / Q000201:enzymology*; D000821:Animal Feed; D000818:Animals; D003314:Corn Oil; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology; D005223:Fats; D005227:Fatty Acids / Q000032:analysis*; D019787:Linoleic Acid / Q000494:pharmacology*; D008297:Male; D011897:Random Allocation; D013230:Stearoyl-CoA Desaturase / Q000378:metabolism*; D013552:Swine / Q000378:metabolism*
chemical_list: D004041:Dietary Fats; D005223:Fats; D005227:Fatty Acids; D003314:Corn Oil; C013698:tallow; D019787:Linoleic Acid; D013230:Stearoyl-CoA Desaturase