title: Butter naturally enriched in cis-9, trans-11 CLA prevents hyperinsulinemia and increases both serum HDL cholesterol and triacylglycerol levels in rats.
abstract: BACKGROUND
  Evidence from in vitro and animal studies indicates that conjugated linoleic acid (CLA) possesses anti-diabetic properties, which appear to be attributed to cis-9, trans-11 CLA, the major CLA isomer in ruminant fat. However, there is a shortage of studies addressing CLA from natural source. The present study aimed to evaluate the effects of butter naturally enriched in cis-9, trans-11 CLA on parameters related to glucose tolerance, insulin sensitivity and dyslipidemia in rats.
  
  
  METHODS
  Forty male Wistar rats were randomly assigned to the following dietary treatments (n=10/group), for 60 days: 1) Normal fat-Soybean oil (NF-So): diet containing 4.0% soybean oil (SO); 2) High Fat-Control Butter (HF-Cb): diet containing 21.7% control butter and 2.3% SO; 3) High Fat-CLA enriched Butter (HF-CLAb): diet containing 21.7% cis-9, trans-11 CLA-enriched butter and 2.3% SO; and 4) High fat-Soybean oil (HF-So): diet containing 24.0% SO. HF-Cb and HF-CLAb diets contained 0.075% and 0.235% of cis-9, trans-11 CLA, respectively.
  
  
  RESULTS
  HF-CLAb-fed rats had lower serum insulin levels at fasting than those fed with the HF-Cb diet, while the PPARγ protein levels in adipose tissue was increased in HF-CLAb-fed rats compared to HF-Cb-fed rats. Furthermore, R-QUICK was lower in HF-Cb than in NF-So group, while no differences in R-QUICK were observed among NF-So, HF-CLAb and HF-So groups. Serum HDL cholesterol levels were higher in HF-CLAb-fed rats than in those fed NF-So, HF-Cb and HF-So diets, as well as higher in NF-So-fed rats than in HF-Cb and HF-So-fed rats. HF-CLAb, HF-Cb and HF-So diets reduced serum LDL cholesterol levels when compared to NF-So, whereas serum triacylglycerol levels were increased in HF-CLAb.
  
  
  CONCLUSIONS
  Feeding rats on a high-fat diet containing butter naturally enriched in cis-9, trans-11 CLA prevented hyperinsulinemia and increased HDL cholesterol, which could be associated with higher levels of cis-9, trans-11 CLA, vaccenic acid, oleic acid and lower levels of short and medium-chain saturated fatty acids from butter naturally modified compared to control butter. On the other hand CLA-enriched butter also increased serum triacylglycerol levels, which could be associated with concomitant increases in the content of trans-9 and trans-10 C18:1 isomers in the CLA-enriched butter.
authors.forename: Mariana Macedo
authors.initials: MM
authors.lastname: de Almeida
authors.forename: Sheila Cristina Potente Dutra
authors.initials: SC
authors.lastname: Luquetti
authors.forename: Céphora Maria
authors.initials: CM
authors.lastname: Sabarense
authors.forename: José Otávio
authors.initials: JO
authors.lastname: do Amaral Corrêa
authors.forename: Larissa Gomes
authors.initials: LG
authors.lastname: dos Reis
authors.forename: Ellen Paula
authors.initials: EP
authors.lastname: Santos da Conceição
authors.forename: Patrícia Cristina
authors.initials: PC
authors.lastname: Lisboa
authors.forename: Egberto Gaspar
authors.initials: EG
authors.lastname: de Moura
authors.forename: Jacy
authors.initials: J
authors.lastname: Gameiro
authors.forename: Marco Antônio Sundfeld
authors.initials: MA
authors.lastname: da Gama
authors.forename: Fernando César Ferraz
authors.initials: FC
authors.lastname: Lopes
authors.affiliation: Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil. raul.garcia@ufjf.edu.br.
authors.forename: Raúl Marcel González
authors.initials: RM
authors.lastname: Garcia
mesh_terms: D000818:Animals; D002079:Butter; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood; D004353:Drug Evaluation, Preclinical; D006946:Hyperinsulinism / Q000517:prevention & control*; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D050152:Intra-Abdominal Fat / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000008:administration & dosage*; D008297:Male; D047495:PPAR gamma / Q000378:metabolism; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood*
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D007004:Hypoglycemic Agents; D044243:Linoleic Acids, Conjugated; D047495:PPAR gamma; D014280:Triglycerides; D002079:Butter