Investigation On The Relationship Among Thyroid Hormone, Selenium And Glutathione Peroxidase Of Poll Dorset And Mongolian Sheep

Two breeds of sheep, Poll Dorsetl and Mongolian Sheep were used in this study in autumn and spring. Each kind of sheep was divided into three groups that were lamb group, young group and adult group, 30 sheep per group. Thyroid hormone, thyroid-stimulating hormone, Selenium and Glutathione peroxidase were determined by using Radioimmunoassay (RIA) and visible spectrophotofluorometry respectively from the serum samples and wool samples. The results showed that: In autumn,The levels of thyroid hormone and thyroid-stimulating hormone in serum samples of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05). The levels of selenium in serum and wool samples of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05). The activities of Glutathione peroxidase (GSH-Px) in serum samples of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05). In spring, The level of thyroid-stimulating hormone in serum samples of Poll Dorset Sheep was little higher than that of Mongolian sheep(P>0.05). The level of thyroid hormone in serum samples of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05). The levels of selenium in serum and wool samples of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05). The activities of Glutathione peroxidase (GSH-Px) in serum samples of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05). The levels of thyroid hormone , thyroid-stimulating hormone and GSH-Px in serum samples and selenium in wool samples of Mongolian and Poll Dorset Sheep were significantly higher in spring than in autumn(P<0.05). The levels of selenium in serum samples of Mongolian and Poll Dorset Sheep were significantly higher in autumn than in spring(P<0.05). The experiment proved that all the levels of selenium in wool and serum,thyroid hormone, thyroid-stimulating hormone and GSH-Px in serum of Mongolian Sheep were significantly higher than that of Poll Dorset sheep(P<0.05) under the same conditions and this is maybe one of the reasons that the disease resisitivity of Poll Dorset is lower than that of Mongolian Sheep. It is important to perfect element of the nutrition and management of the feeding.