Studies On Effect Of Selenium On Chicken's Resistance To Marek's Disease And Its Mechanism

Marek's disease (MD) caused by a herpesvirus is the most common of the neoplastic diseases of chickens. The activities of total superoxide dismutase (T —SOD), Mn—SOD, CuZn—SOD, catalase (CAT) and glutathione peroxi-dase (GSH—Px) and the level of malondialdehyde (MDA) in the serum, blood or tissues of 36 chickens suffering from MD tumors were determined in the paper. The results showed that the activities of T—SOD (152. 45±11. 67u/ml), Mn—SOD (64. 45±6. 07u/ml) and CuZn—SOD (88. 01±8.71u/ml) in the serum and the activities of T—SOD (286. 01 ±68. 07 u/g) in the tumor tissues of chickens with MD respectivly were high significantly lower than those of the normal (p<0. 01), the activity of CAT (19. 3±3. 22U/gHb) in red blood cell and the selenium level (0. 077±0. 021μg/ml) in blood of chickens with MD were respectively significantly lower than those of the normal (p<0. 05), the activity of GSH—Px of blood didn't difference significantly between MD chickens and healthy (p<0. 05), in contrast, the level of MDA (4. 09±0. 76n mol/ ml) in serum of chickens with MD tumors were significantly higher (p<0. 01) than those of the normal. The present paper suggests that free radicals are involved in the developing process of MD tumor and there is a relation between selenium and MD tumors.