Erythrocyte resistance to oxidative damage and leucocyte capacity to reduce nitroblue tetrazolium in selenium-deficient cattle.

Simmental x Red Holstein steers which were fed roughage with a low selenium (Se) content received either a Se-delivering bolus orally (group Se+) or no Se supplement (group Se-). Weight gain was not influenced by Se supplementation. When blood for the in-vitro assays was drawn 8 weeks after bolus administration, erythrocyte glutathione peroxidase (GSH-Px) activity was much higher in the Se+ than in Se- animals (P < 0.01). The addition of acetylphenylhydrazine to the blood samples induced significantly fewer Heinz bodies in erythrocytes of Se+ animals (P < 0.01). It was shown that H2O induced the formation of identical amounts of thiobarbituric acid reactive substances (TBARS) in the erythrocytes of Se+ and Se- animals. Thus, GSH-Px seems to be more important for the protection of haemoglobin than for the protection of erythrocyte lipids from oxidative damage. After addition of endotoxin and nitroblue tetrazolium to blood samples, leucocytes of Se+ and of Se- animals reduced the same amount of nitroblue tetrazolium. Thus, selenium deficiency apparently had no negative effect on the oxidative burst of leucocytes.