Intake of a cetoleic acid concentrate lowered concentrations of markers of inflammation and macrophage infiltration but did probably not increase EPA biosynthesis in male obese Zucker fa/fa rats

Obesity is characterised by chronic low-grade inflammation, which is a key factor in the development of obesity-related co-morbidities. Intake of <i>n</i>-3 long-chain PUFAs is associated with anti-inflammatory effects. Recent studies suggest that also <i>n</i>-11 long-chain MUFAs may reduce the concentrations of inflammatory markers, possibly by increasing the biosynthesis of EPA. The primary aim was to investigate if diets added herring oil containing cetoleic acid (CA, C22:1<i>n</i>-11) or a CA concentrate (CECO) affected the fatty acid composition in tissues from obese rats with chronic inflammation. Secondary aims included investigating the effects on inflammatory markers. Thirty male obese Zucker fa/fa rats were fed diets containing herring oil (HERO) or a CECO, containing 0·70 or 1·40 wt% CA, respectively, with a comparable content of EPA (0·17 and 0·20 wt%, respectively), or a control diet with soyabean oil for 5 weeks. Data were analysed using one-way ANOVA. CA from HERO and CECO diets were recovered in liver, adipose tissue, muscle and blood cells. The EPA concentration was similar between HERO and CECO groups in tissues, whereas the hepatic concentrations of fatty acid desaturases were lower or similar to Controls. The concentrations of TNF<i>α</i>, matrix metalloproteinase-3, IL6, monocyte chemotactic protein 1 and integrin <i>α</i> M in adipose tissue, and the hepatic concentration of CD68 were lower after CECO intake but were not affected by the HERO diet. To conclude, rats fed the CECO diet had lower concentrations of inflammatory and macrophage infiltration markers, but this effect was probably not mediated through increased EPA biosynthesis.