Dietary conjugated linoleic acid isomers and selenite or selenized yeast affect fatty acid concentration in the kidneys of rats

Abstract

The influence of diets enriched in a mixture of conjugated linoleic acid (CLA) isomers (CLAmix) and/or selenium as Na 2 SeO 3 (SeIV) or selenized yeast (SeY) on feed intake, kidneys' weight and the concentrations of fatty acids (FA) in the kidneys of rats was investigated. The study was performed on 80 female Wistar rats (Hsd Brl Han: WIST), 8 weeks of age with an initial body weight of 195.7±0.8 g. Each group numbered 8 rats. During the 7-day preliminary period the rats were fed a standard Labofeed H diet at a sub-maintenance level. Next, for 6 weeks the rats were fed ad libitum on the experimental diets supplemented with CLAmix, 0.2 ppm Se or 0.5 ppm Se as SeIV ( L SeIV or H SeIV, respectively) and SeY ( L SeY or H SeY, respectively). The rats were sacrificed at the end of the six-week experimental period. The diets enriched in CLAmix or Se (as SeIV or SeY) showed a negligible effect on kidneys' weight, although the diets containing simultaneously CLAmix and Se numerically increased kidneys' weight compared with the control animals. The addition of CLAmix to the diet, regardless of the higher level of SeY, showed a tendency to decrease in feed intake and decreased the concentrations of saturated (SFA), mono-(MUFA) and polyunsaturated (PUFA) fatty acids in comparison with the control rats. Dietary SeIV or SeY, irrespective of the concentration of extra Se, decreased the concentration of unsaturated fatty acids (UFA) and the sum of all assayed fatty acids (ΣFA) in the kidneys. The diet containing CLAmix and Se as H SeIV or L SeY decreased the concentrations of SFA, MUFA and PUFA in the kidneys compared with the control rats. On the other hand, the addition of L SeIV or, especially, H SeY to the diet enriched in CLAmix resulted in an increasing in the concentrations of SFA, MUFA and PUFA in the kidneys compared with the control group and rats fed the diets containing CLAmix, SeIV or SeY. The diet enriched in CLAmix and HSeY most effectively stimulated the accumulation of CLA isomers with the exception of cis11trans13CLA in the kidneys in comparison with other diets. Dietary CLAmix decreased the