title: Corn oil versus lard: Metabolic effects of omega-3 fatty acids in mice fed obesogenic diets with different fatty acid composition.
abstract: Mixed results have been obtained regarding the level of insulin resistance induced by high-fat diets rich in saturated fatty acids (SFA) when compared to those enriched by polyunsaturated fatty acids (PUFA), and how metabolic effects of marine PUFA of n-3 series, i.e. docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), depend on dietary lipid background. Here we compared two high-fat diets, in which the major lipid constituent was based either on SFA in the form of pork lard (LHF diet) or PUFA of n-6 series (Omega-6) as corn oil (cHF diet). Both cHF and LHF parental diets were also supplemented with EPA+DHA (∼30 g/kg diet) to produce cHF+F and LHF+F diet, respectively. Male C57BL/6N mice were fed the experimental diets for 8 weeks. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps in mice fed LHF and cHF diets, and then metabolic effects of cHF+F and LHF+F diets were assessed focusing on the liver and epididymal white adipose tissue (eWAT). Both LHF and cHF induced comparable weight gain and the level of insulin resistance, however LHF-fed mice showed increased hepatic steatosis associated with elevated activity of stearoyl-CoA desaturase-1 (SCD1), and lower plasma triacylglycerol levels when compared to cHF. Despite lowering hepatic SCD1 activity, which was concomitant with reduced hepatic steatosis reaching the level observed in cHF+F mice, LHF+F did not decrease adiposity and the weight of eWAT, and rather further impaired insulin sensitivity relative to cHF+F, that tended to improve it. In conclusion, high-fat diets containing as much as ∼35 weight% as lipids induce similar weight gain and impairment of insulin sensitivity irrespective whether they are based on SFA or Omega-6. Although the SFA-rich diet containing EPA+DHA efficiently reduced hepatic steatosis, it did so without a corresponding improvement in insulin sensitivity and in the absence of effect on adiposity.
authors.affiliation: Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Pavlisova
authors.affiliation: Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
authors.forename: Kristina
authors.initials: K
authors.lastname: Bardova
authors.affiliation: 4th Department of Internal Medicine, 1st Faculty of Medicine of Charles University and the General Teaching Hospital, Prague, Czech Republic.
authors.forename: Barbora
authors.initials: B
authors.lastname: Stankova
authors.affiliation: 4th Department of Internal Medicine, 1st Faculty of Medicine of Charles University and the General Teaching Hospital, Prague, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Tvrzicka
authors.affiliation: Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Kopecky
authors.affiliation: Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic. Electronic address: Martin.Rossmeisl@fgu.cas.cz.
authors.forename: Martin
authors.initials: M
authors.lastname: Rossmeisl
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D003314:Corn Oil / Q000032:analysis / Q000494:pharmacology; D004041:Dietary Fats / Q000032:analysis / Q000494:pharmacology; D015525:Fatty Acids, Omega-3 / Q000032:analysis / Q000494:pharmacology; D043371:Fatty Acids, Omega-6 / Q000032:analysis / Q000494:pharmacology; D005234:Fatty Liver / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D007333:Insulin Resistance; D008297:Male; D051379:Mice
chemical_list: D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D003314:Corn Oil; C029310:lard
keywords: Hepatic steatosis; Insulin resistance; Obesity; Omega-3 fatty acids; Stearoyl-CoA desaturase-1