EPA/DHA and linseed oil have different effects on liver and adipose tissue in rats fed with a high-fat diet

Effect of the high-fat diet on rats fed for 20 weeks without treatment and after treatments started on the 18th week in the LO, EPA, and DHA groups according to analyses in the adipose tissue, serum, and liver of the animals. Marking with * indicates metabolic effects caused by treatment with EPA; markings with indicate the metabolic effects caused by treatment with DHA and with # are the metabolic effects of treatment with linseed oil. ACC, acetyl-CoA carboxylase; CCL5, CC chemokine ligand 5; DHA, docosapentaenoic acid group; EPA, eicosapentaenoic acid group; FAS, fatty acid synthase; HF, high-fat diet group; LO, linseed oil group; MCP, monocyte chemoattractant protein; SREBP-1c, sterol regulatory element-binding protein; TAG, triacylglycerol; TNF-α, tumor necrosis factor-alpha. [Display omitted] •EPA and DHA, in both proportions, lead to remodeling of the adipose tissue.•Higher proportion of EPA was more efficient to improve liver steatosis.•EPA and DHA improved the expression of SREBP-1c and PPAR-α in liver.•Higher proportion of DHA was more efficient to reduce MCP1 in WAT.•EPA and DHA in both proportions reduced the ω6/ω3 ratio in liver and WAT. The incidence of cardiovascular diseases and metabolic disorders has increased worldwide. Clinical and experimental research has shown that the consumption of ω-3 FAs can be beneficial to metabolism in several ways, as they can act on metabolic pathways. Our objective was to evaluate the effect of treatment with linseed oil, a vegetable oil rich in alpha-linolenic acid, and EPA and DHA in different proportions (3:1 EPA:DHA, and 1:3 EPA:DHA), on the metabolic disorders induced by a high-fat diet (20 % lipids) in rats for 2 weeks, after 18 weeks of consumption of a high-fat diet. In 18 weeks, the high-fat diet increased blood glucose, systolic blood pressure, triglyceride concentration in the liver and adipose tissue, and impaired insulin sensibility without interfering in the weight of the animals. All treatments were effective in reducing the deposition of hepatic type III collagen, the proportion of ω-6/ω-3 in the liver and WAT (white adipose tissue), the proportion of area/number of adipocytes, and the gene expression of the ACC, FAS, and CPT1 enzymes. In addition, treatment with EPA and DHA reduced blood glucose, serum TNF-α concentration, amount of liver fat, degree of microsteatosis and type I collagen deposition in the liver, deposition of type I and III collagen in TA, gene expression of the transcriptio