title: Effect of α-linolenic acid and DHA intake on lipogenesis and gene expression involved in fatty acid metabolism in growing-finishing pigs.
abstract: The regulation of lipogenesis mechanisms related to consumption of n-3 PUFA is poorly understood. The aim of the present study was to find out whether α-linolenic acid (ALA) or DHA uptake can have an effect on activities and gene expressions of enzymes involved in lipid metabolism in the liver, subcutaneous adipose tissue and longissimus dorsi (LD) muscle of growing-finishing pigs. Six groups of ten pigs received one of six experimental diets supplemented with rapeseed oil in the control diet, extruded linseed, microalgae or a mixture of both to implement different levels of ALA and DHA with the same content in total n-3. Results were analysed for linear and quadratic effects of DHA intake. The results showed that activities of malic enzyme (ME) and fatty acid synthase (FAS) decreased linearly in the liver with dietary DHA. Although the expression of the genes of these enzymes and their activities were poorly correlated, ME and FAS expressions also decreased linearly with DHA intake. The intake of DHA down-regulates the expressions of other genes involved in fatty acid (FA) metabolism in some tissues of pigs, such as fatty acid desaturase 2 and sterol-regulatory element binding transcription factor 1 in the liver and 2,4-dienoyl CoA reductase 2 in the LD muscle. FA oxidation in the LD muscle and FA synthesis decreased in the liver with increasing amount of dietary DHA, whereas a retroconversion of DHA into EPA seems to be set up in this last tissue.
authors.affiliation: 1INRA,UMR1348 PEGASE,35590 Saint-Gilles,France.
authors.forename: A
authors.initials: A
authors.lastname: De Tonnac
authors.affiliation: 1INRA,UMR1348 PEGASE,35590 Saint-Gilles,France.
authors.forename: E
authors.initials: E
authors.lastname: Labussière
authors.affiliation: 1INRA,UMR1348 PEGASE,35590 Saint-Gilles,France.
authors.forename: A
authors.initials: A
authors.lastname: Vincent
authors.affiliation: 1INRA,UMR1348 PEGASE,35590 Saint-Gilles,France.
authors.forename: J
authors.initials: J
authors.lastname: Mourot
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D064429:Fatty Acid Synthases / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D050356:Lipid Metabolism / Q000187:drug effects*; D050155:Lipogenesis / Q000187:drug effects*; D008297:Male; D013552:Swine / Q000502:physiology*; D017962:alpha-Linolenic Acid / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D064429:Fatty Acid Synthases
keywords: 4-dienoyl CoA reductase 2; ALA 
                    α-linolenic acid; CON control diet; DECR2 2; DHA; ELOVL elongation of very long chain fatty acid 5; FA fatty acid; FADS2 fatty acid desaturase 2; FAS fatty acid synthase; G6PDH glucose-6-phosphate dehydrogenase; LD 
                    longissimus dorsi; LPL lipoprotein lipase; Linolenic acid; Lipogenic enzymes; ME malic enzyme; Pigs; RXRα
                  retinoid X receptor alpha; SCAT subcutaneous adipose tissue; SREBP1 sterol-regulatory element binding transcription factor 1