Effects of selenium supplementation on polyunsaturated fatty acid concentrations and antioxidant status in plasma and liver of lambs fed linseed oil or sunflower oil diets

Thirty-two, 17 weeks old, wether lambs (Chinese Poll Dorset × Small Tailed Han × Charolais), weighing 26.3 ± 1.2 kg, were used to evaluate effects of different Se levels and polyunsaturated fatty acid (PUFA) sources in the diet on fatty acid composition and antioxidant status in plasma and liver. Lambs were divided into four groups and each was fed one of the following diets: 950 g basal diet/kg DM and 50 g linseed oil/kg DM (LO); LO plus 2 mg Se/kg DM (as sodium selenite) (LOSe); 950 g basal diet/kg DM and 50 g sunflower oil/kg DM (SO); SO plus 2 mg Se/kg DM (SOSe). The experiment lasted 50 days and lambs were slaughtered at the end of it. Concentrations of C18:2trans-10, cis-12 in liver, and C18:1trans-11 in plasma, increased with Se supplementation, which also increased concentrations of C20:4 in lambs fed the sunflower oil diet, but not in those fed the linseed oil diet, in both plasma and liver. Fatty acid composition in plasma and liver reflected the dietary fatty acid source. Lambs fed the linseed oil diet had higher concentrations of C18:3n-3, C20:5n-3 and C22:6n-3. In contrast, lambs fed the sunflower oil diet had higher concentrations of conjugated linoleic fatty acid, C18:2n-6 and C20:4n-6. Antioxidant status increased with Se supplementation, but was not affected by PUFA source in the diets. Results indicate the possibility of increasing the PUFA deposition by combining Se with PUFA in lamb diets, and that Se increased concentrations of C20:4n-6 more efficiently when combined with the sunflower oil diet versus the linseed oil diet.