title: Low fish oil intake improves insulin sensitivity, lipid profile and muscle metabolism on insulin resistant MSG-obese rats.
abstract: BACKGROUND
  Obesity is commonly associated with diabetes, cardiovascular diseases and cancer. The purpose of this study was to determinate the effect of a lower dose of fish oil supplementation on insulin sensitivity, lipid profile, and muscle metabolism in obese rats.
  
  
  METHODS
  Monosodium glutamate (MSG) (4 mg/g body weight) was injected in neonatal Wistar male rats. Three-month-old rats were divided in normal-weight control group (C), coconut fat-treated normal weight group (CO), fish oil-treated normal weight group (FO), obese control group (Ob), coconut fat-treated obese group (ObCO) and fish oil-treated obese group (ObFO). Obese insulin-resistant rats were supplemented with fish oil or coconut fat (1 g/kg/day) for 4 weeks. Insulin sensitivity, fasting blood biochemicals parameters, and skeletal muscle glucose metabolism were analyzed.
  
  
  RESULTS
  Obese animals (Ob) presented higher Index Lee and 2.5 fold epididymal and retroperitoneal adipose tissue than C. Insulin sensitivity test (Kitt) showed that fish oil supplementation was able to maintain insulin sensitivity of obese rats (ObFO) similar to C. There were no changes in glucose and HDL-cholesterol levels amongst groups. Yet, ObFO revealed lower levels of total cholesterol (TC; 30%) and triacylglycerol (TG; 33%) compared to Ob. Finally, since exposed to insulin, ObFO skeletal muscle revealed an increase of 10% in lactate production, 38% in glycogen synthesis and 39% in oxidation of glucose compared to Ob.
  
  
  CONCLUSIONS
  Low dose of fish oil supplementation (1 g/kg/day) was able to reduce TC and TG levels, in addition to improved systemic and muscle insulin sensitivity. These results lend credence to the benefits of n-3 fatty acids upon the deleterious effects of insulin resistance mechanisms.
authors.affiliation: Department of Physiology, Biological Sciences Building, Federal University of Parana, Curitiba, PR, Brazil. rkyamazaki@hotmail.com
authors.forename: Ricardo K
authors.initials: RK
authors.lastname: Yamazaki
authors.forename: Gleisson A P
authors.initials: GA
authors.lastname: Brito
authors.forename: Isabela
authors.initials: I
authors.lastname: Coelho
authors.forename: Danielle C T
authors.initials: DC
authors.lastname: Pequitto
authors.forename: Adriana A
authors.initials: AA
authors.lastname: Yamaguchi
authors.forename: Gina
authors.initials: G
authors.lastname: Borghetti
authors.forename: Dalton Luiz
authors.initials: DL
authors.lastname: Schiessel
authors.forename: Marcelo
authors.initials: M
authors.lastname: Kryczyk
authors.forename: Juliano
authors.initials: J
authors.lastname: Machado
authors.forename: Ricelli E R
authors.initials: RE
authors.lastname: Rocha
authors.forename: Julia
authors.initials: J
authors.lastname: Aikawa
authors.forename: Fabiola
authors.initials: F
authors.lastname: Iagher
authors.forename: Katya
authors.initials: K
authors.lastname: Naliwaiko
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Tanhoffer
authors.forename: Everson A
authors.initials: EA
authors.lastname: Nunes
authors.forename: Luiz Claudio
authors.initials: LC
authors.lastname: Fernandes
mesh_terms: D000818:Animals; D004032:Diet; D005227:Fatty Acids / Q000032:analysis; D005247:Feeding Behavior / Q000187:drug effects*; D005395:Fish Oils / Q000008:administration & dosage* / Q000494:pharmacology*; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012970:Sodium Glutamate / Q000008:administration & dosage
chemical_list: D005227:Fatty Acids; D005395:Fish Oils; D007328:Insulin; D008055:Lipids; D012970:Sodium Glutamate