title: Dietary linoleic acid elevates endogenous 2-arachidonoylglycerol and anandamide in Atlantic salmon (Salmo salar L.) and mice, and induces weight gain and inflammation in mice.
abstract: Dietary intake of linoleic acid (LA) has increased dramatically during the twentieth century and is associated with a greater prevalence of obesity. Vegetable oils are recognised as suitable alternatives to fish oil (FO) in feed for Atlantic salmon (Salmo salar L.) but introduce high amounts of LA in the salmon fillet. The effect on fish consumers of such a replacement remains to be elucidated. Here, we investigate the effect of excessive dietary LA from soyabean oil (SO) on endocannabinoid levels in Atlantic salmon and mice, and study the metabolic effects in mice when SO replaces FO in feed for Atlantic salmon. Atlantic salmon were fed FO and SO for 6 months, and the salmon fillet was used to produce feed for mice. Male C57BL/6J mice were fed diets of 35% of energy as fat based on FO- and SO-enriched salmon for 16 weeks. We found that replacing FO with SO in feed for Atlantic salmon increased LA, arachidonic acid (AA), decreased EPA and DHA, elevated the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA), and increased TAG accumulation in the salmon liver. In mice, the SO salmon diet increased LA and AA and decreased EPA and DHA in the liver and erythrocyte phospholipids, and elevated 2-AG and AEA associated with increased feed efficiency, weight gain and adipose tissue inflammation compared with mice fed the FO salmon diet. In conclusion, excessive dietary LA elevates endocannabinoids in the liver of salmon and mice, and increases weight gain and counteracts the anti-inflammatory properties of EPA and DHA in mice.
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), PO Box 2029, Nordnes, 5817 Bergen, Norway.
authors.forename: Anita R
authors.initials: AR
authors.lastname: Alvheim
authors.forename: Bente E
authors.initials: BE
authors.lastname: Torstensen
authors.forename: Yu Hong
authors.initials: YH
authors.lastname: Lin
authors.forename: Haldis H
authors.initials: HH
authors.lastname: Lillefosse
authors.forename: Erik-Jan
authors.initials: EJ
authors.lastname: Lock
authors.forename: Lise
authors.initials: L
authors.lastname: Madsen
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Hibbeln
authors.forename: Marian K
authors.initials: MK
authors.lastname: Malde
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000704:Analysis of Variance; D000821:Animal Feed; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D004041:Dietary Fats / Q000009:adverse effects / Q000378:metabolism*; D063388:Endocannabinoids / Q000378:metabolism*; D005395:Fish Oils; D007249:Inflammation / Q000209:etiology* / Q000503:physiopathology; D019787:Linoleic Acid / Q000009:adverse effects / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020317:Salmo salar / Q000378:metabolism; D013024:Soybean Oil; D015430:Weight Gain
chemical_list: D001095:Arachidonic Acids; D004041:Dietary Fats; D063388:Endocannabinoids; D005395:Fish Oils; D013024:Soybean Oil; D019787:Linoleic Acid