Effect of reduced glutathione treatment on selenosis, blood selenium concentration and glutathione peroxidase activity after repeated short-term selenium exposure in buffalo calves.

Effects of repeated feeding of selenium, when given alone or along with reduced glutathione, on whole blood selenium levels, selenosis and glutathione peroxidase activity, was studied in buffalo calves. After feeding 2.5 mg/kg of BW sodium selenite, good correlation was found between the onset of selenosis and whole blood selenium concentrations. Adverse effects appeared when the whole blood selenium concentrations increased above 2 microg/ml and mortality occurred when they exceeded 3.4 microg/ml. Reduced glutathione, given i.v. at 5 mg/kg of BW arrested the progress of selenosis and prevented mortality which was 100% in the sodium selenite supplemented group; also a reduced whole blood selenium concentration was noted. Whole blood selenium concentrations were a better and more sensitive indicator of selenium status than glutathione peroxidase activity alone.

Blood selenium levels during different stages of selenosis in buffaloes and its evaluation as a diagnostic tool.

Selenium (SC) toxicity was experimentally induced in male buffalo calves following repeated oral administration of 0.3 mg selenourea/kg (providing 0.19 mg/Se kg) for 75 d. On the basis of the major toxic effects produced in the experimental animals, 10 additional clinical cases of selenosis were identified from field cases. In experimental selenosis blood Se increased from 0.70 +/- 0.08 microg/ml on day 0 to 3.12 +/- 0.01 microg/ml on day 75. Hair Se rose from 2.42 +/- 0.6 ppm on day 0 to 22.91 +/- 2.6 ppm by the 11th w. The erythrocyte glutathione peroxidase (GSH-Px) activity increased from 5.35 +/- 0.94 Eu/mg Hb (0 day) to 18.81 +/- 0.46 EU/mg Hb in the 11th week. Blood Se was of better diagnostic value than hair Se or erythrocytic GSH-Px activity. Signs occurred when Se levels were about 2.0 microg/ml and were prominent above 2.5-2.6 microg/ml: Se levels > or = 1.5-1.75 microg/ml were diagnostic of impending selenosis. The Se concentrations in blood from the field cases of Se toxicity in buffalo had excellent correlation with Se levels in the experimental cases.