title: Effects of dietary n-3 fatty acids on Toll-like receptor activation in primary leucocytes from Atlantic salmon (Salmo salar).
abstract: The shortage of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the international markets has led to increasing substitution of fish oil by plant oils in Atlantic salmon (Salmo salar) feed and thereby reducing the EPA and DHA content in salmon. However, the minimum required levels of these fatty acids in fish diets for securing fish health are unknown. Fish were fed with 0, 1 or 2% EPA or DHA alone or in combination of both over a period, growing from 50 to 400 g. Primary head kidney leucocytes were isolated and stimulated with Toll-like receptor (TLR) ligands to determine if EPA and DHA deficiency can affect expression of important immune genes and eicosanoid production. Several genes related to viral immune response did not vary between groups. However, there was a tendency that the high-level EPA and DHA groups expressed lower levels of IL-1β in non-stimulated leucocytes. These leucocytes were also more responsive to the TLR ligands, inducing higher expression levels of IL-1β and Mx1 after stimulation. The levels of prostaglandin E2 and leukotriene B4 in serum and media from stimulated leucocytes were lower in both low and high EPA and DHA groups. In conclusion, leucocytes from low EPA and DHA groups seemed to be less responsive towards immunostimulants, like TLR ligands, indicating that low levels or absence of dietary EPA and DHA may have immunosuppressive effects.
authors.affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068, Blindern, 0316, Oslo, Norway.
authors.forename: Marianne
authors.initials: M
authors.lastname: Arnemo
authors.affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068, Blindern, 0316, Oslo, Norway.
authors.forename: Arturas
authors.initials: A
authors.lastname: Kavaliauskis
authors.affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068, Blindern, 0316, Oslo, Norway.
authors.forename: Adriana Magalhaes Santos
authors.initials: AMS
authors.lastname: Andresen
authors.affiliation: Nofima, P. O. Box 210, 1431, Ås, Norway.
authors.forename: Marta
authors.initials: M
authors.lastname: Bou
authors.affiliation: Nofima, P. O. Box 210, 1431, Ås, Norway.
authors.forename: Gerd Marit
authors.initials: GM
authors.lastname: Berge
authors.affiliation: Nofima, P. O. Box 210, 1431, Ås, Norway.
authors.forename: Bente
authors.initials: B
authors.lastname: Ruyter
authors.affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068, Blindern, 0316, Oslo, Norway. tor.gjoen@farmasi.uio.no.
authors.forename: Tor
authors.identifier: http://orcid.org/0000-0003-4040-5793
authors.initials: T
authors.lastname: Gjøen
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3 / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D060226:Head Kidney / Q000737:chemistry / Q000378:metabolism; D007962:Leukocytes / Q000187:drug effects* / Q000378:metabolism*; D020317:Salmo salar / Q000502:physiology*; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D051193:Toll-Like Receptors
keywords: Atlantic salmon; Docosahexaenoic acid; Eicosapentaenoic acid; Fish oil; Omega-3; Toll-like receptor