Lack of Effect of Selenium Supplementation on the Response of the Equine Erythrocyte Glutathione System and Plasma Enzymes to Exercise

Abstract

Two experiments with mature horses were conducted to determine 1) if exercise resulted in increased peroxidation and 2) if selenium (Se) could alleviate this response. An initial study using six horses yielded increased erythrocyte (RBC) malondialdehyde, a product of peroxidation, immediately after exercise. Plasma glutamic-oxalacetic transaminase was also elevated. These findings are suggestive of increased peroxidation with exercise. In the second study, eight horses were assigned to one of two Se treatments. One-half the horses received the equivalent of .15 ppm supplemental Se in trace mineral salt (TMS). The others received TMS without Se. Animals were maintained on these regimes for 4 weeks. Blood was taken biweekly, before and after exercise. Both groups showed similar plasma Se (.15 ppm) and RBC glutathione peroxidase (about 20 U/mg hemoglobin). Again, increased malondialdehyde and plasma enzymes were seen subsequent to exercise, regardless of Se supplementation or time on diet.