Comparative effects of selenium supplementation on the plasma selenium concentration and erythrocyte glutathione peroxidase activity in cattle and camels

At an experimental farm, five camels and five cows were each given a simila r basal diet for 6 months. They received oral trace element supplementation for 3 months (day 22 to 112) which included zinc, copper, selenium, mangan ese, iodine and cobalt and corresponded to twice the daily requirement gene rally recommended for cows. Plasma selenium concentrations were significant ly lower in the camels (20 (s.e. 2) mg/l) compared with the cows (33 (s.e. 2) mu g/l). The mineral supplementation induced a large increase in the pla sma selenium concentration in the camels which reached 200 (s.e. 35) mu g/l . In the cows, the increase was much smaller and did not go beyond 65 (s.e. 8) mu g/l. Before supplementation the red blood cell glutathione peroxidas e activity was similar in the camel and the cow varying between 4000 and 60 00 IU per 100 g haemoglobin. In both species, this activity increased with mineral supplementation and remained very high even when mineral supplement ation was stopped. The results suggested that selenium metabolism in camels is different from that in the cows.