Effect of dietary selenium on antioxidant status of cows

Abstract

Influence of supplementation of cows diet with 0,2 or 0,5 ppm (as elementary selenium) of sodium selenite and selenium methionine on blood antioxidant status are presented. Dose depended increasing of glutathione peroxidase activity in the cows blood has been found thus selenium methionine affected more effectively. Glutathione peroxidase activity in erythrocytes were increased independently selenium chemical form and quantity. Both doses of sodium selenite have decreased concentrations of thiobarbituric acid reactive substances in blood plasma at approximately equal levels. Effect of 0,5 ppm selenium methionine supplementation was more expressed. Supplementation of cows diet with 0,2 ppm of sodium selenite didn't change the milk yields but increasing of dose to 0.5 ppm has lowered the milk yields for 8 %. Both doses of sodium selenite decreased protein content in the milk. Addition to diet the 0,2 ppm of selenium methionine increased milk yields for 5 % and milk fat content - for 0,31 %. When the selenium methionine dose has risen to 0,5 ppm the cows milk yields and milk protein and fat contents have stayed at the control group cows level. So the effective decreasing element of peroxidation products concentration in blood plasma is selenium-methionine in the amount of 0.5 mg/kg, when 0.2 mg/kg has a positive effect on milk productivity.