Revisiting Oxidative Stress and the Use of Organic Selenium in Dairy Cow Nutrition

Among feed-derived antioxidants, selenium (Se) was shown to have a special place as an essential part of 25 selenoproteins identified in animals. Organic Se, in the form of selenomethionine (SeMet), has been reported to be a much more effective Se source when compared with mineral forms such as sodium selenite or selenate. There is a growing body of evidence that demonstrates that organic Se has a number of benefits, particularly in dairy and beef animals; these include improved selenium and antioxidant status, and better Se transfer via the placenta, colostrum, and milk to the newborn. However, there is a paucity in the data concerning molecular mechanisms of SeMet assimilation, metabolism and selenoprotein synthesis regulation in ruminant animals, and as such, further investigation is required