Organic and Inorganic Selenium Compounds Affected Lipidomic Profile of Spleen of Lambs Fed with Diets Enriched in Carnosic Acid and Fish Oil

The purpose of our study was to investigate the effect of 0.35 mg Se/kg basal diet (BD) (Se as sodium selenate (Se⁶) and yeast rich in seleno-methionine (Se^Ye)) and 0.1% carnosic acid (CA) supplementation to the diet containing 1% fish oil (F-O) and 2% rapeseed oil (R-O) on the contents of fatty acids (FA), malondialdehyde (MDA), tocopherols (Ts), and total cholesterol (TCh) in lambs’ spleens. A total of 24 male lambs (4 groups per 6 animals) have been fed: the control diet—the basal diet (BD) enriched in F-O and R-O; the CA diet—BD enriched in F-O, R-O, and CA; the Se^YeCA diet—BD enriched in F-O, R-O, CA, and Se^Ye; the Se⁶CA diet—BD enriched in F-O, R-O, CA, and Se⁶. Dietary modifications affected the profiles of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids in spleens. The Se^YeCA and Se⁶CA diets increased the docosapentaenoic acid preference in Δ4-desaturase; hence, a higher content of docosahexaenoic acid was found in the spleens of Se^Ye- or Se⁶-treated lambs than in spleens of animals receiving the CA and control diets. The Se^YeCA and Se⁶CA diets increased the concentration ratio of n-3long-chain PUFA (n-3LPUFA) to FA (n-3LPUFA/FA) in spleens compared to the control and CA diets. The content of n-3PUFA was higher in the spleens of Se⁶ treated lambs than in spleens of animals receiving the Se^YeCA, CA, and control diets. The Se⁶CA diet increased the content of c9t11CLA in the spleen compared to the control, CA, and Se^YeCA diets. Experimental diets reduced the level of atherogenic FA, the content ratios of n-6PUFA/n-3PUFA and n-6LPUFA/n-3LPUFA, and improved the content ratio of MUFA/FA and the value of the hypocholesterolemic/hypercholesterolemic FA ratio in the spleen in comparison with the control diet. The experimental diets supplemented with Se^Ye or Se⁶ increased levels of TCh and Ts in spleens in comparison with the CA and control CA diets. The present studies documented that Se⁶, Se^Ye, and CA influenced the metabolism of FA, Ts, and cholesterol in spleens.