Effect of selenium supplementation on glutathione peroxidase synthesis and element accumulation in sheep erythrocytes

For three months four groups of sheep were fed either a basal diet (group A) containing 0.082 ppm selenium (Se), or this diet plus mineral mixture with Se (as selenite) so that the total diet contained 0.25, 0.41 and 0.58 ppm Se (groups B, C, and D, respectively). The Se concentration and GSH-Px activity in red cells were determined at the commencement of the study and at monthly intervals. While in the control group the Se level and GSH-Px activity did not differ throughout the study, in the experimental groups both Se accumulation and GSH-Px activity were elevated. In group B the increase in Se concentration was linear throughout, while in groups C and D great accumulation was observed in the first month and lower in the subsequent period. In all Se-supplemented groups, the red cell GSH-Px increased linearly throughout the study, but no significant differences were found between groups B, C and D. The mean elevations of the enzyme activities were: 58 +/- 8%, 142 +/- 5% and 192 +/- 7% of the initial values after 1, 2 and 3 months of the study, respectively. These data show that the amount of 0.25 ppm Se in the sheep diet satisfy the requirement of the erythropoietic systems to synthesize the enzyme.