Young, female nutrias (n ¼ 13) were fed a diet supplemented with 0.36 mg/kg selenium in seleniumenriched yeast (SeY; Sel-Plex; Alltech, Inc., Nicholasville, KY) for 60 days (total Se concentration in the basal diet was $0.1 mg/kg). Concentrations of fatty acids (FA) in the liver were compared to those of nutrias on a control diet (n ¼ 11). Animals were sacrificed at 8 months of age and liver samples (approximately 30 g) were collected. The gas-chromatographic analysis of tissue samples from the experimental group revealed a significant decrease in saturated fatty acids ( p < 0.001), monounsaturated fatty acid ( p ¼ 0.006), and polyunsaturated fatty acid (PUFA) ( p ¼ 0.02) compared to controls. The linoleic and linolenic acids, which are precursors of n-6 and n-3 PUFA, respectively, were significantly lower ( p ¼ 0.01 and p < 0.001, respectively) in the supplemented group. The n-6 to n-3 PUFA ratio was significantly affected ( p ¼ 0.001) by the SeY dietary supplement (13.17 vs. 8.93, respectively).