Effects of selenium form on blood and milk selenium concentrations, milk component and milk fatty acid composition in dairy cows

Abstract

Human health may be improved if milk with a favorable fatty acid composition and Se concentration is ingested. The present study is to determine how a basal diet supplemented with daily 5 mg Se as Se-enriched yeast (SY) or sodium selenite (SS) affects the fatty acid composition and Se concentration of bovine milk. The effects of Se form on blood Se concentration, erythrocyte glutathione peroxidase 1 (GPx1) activity, serum GPx3 activity and milk yield and component were also studied. Both Se forms, when compared to control group, increased Se concentrations of blood (P < 0.01) and milk (P < 0.01), erythrocyte GPx1 activity (P < 0.05) and milk percentages of polyunsaturated fatty acids (PUFA) (P < 0.05) and cis-9,cis-12 linoleic acid (P < 0.05). Cows supplemented with SY had higher Se levels in blood (P < 0.01) and milk (P < 0.01) and percentage of PUFA in milk (P < 0.05) when compared with those supplemented with SS. Milk yield, milk component and serum GPx3 activity were not significantly affected by Se form. Supplementation of diet with SY appears to be of more benefit than SS in producing favorable milk with high PUFA and Se concentrations.