Effects Of Cold Stress On Neuroendocrine And Antioxidative Function In Chicken

There are various stress factors. Animals'reaction to them is different. Cold stress is a universal stress factor to animals, especially newborn animals in cold region. This has become the main reason that restricts the advance of the stock farming. Cold stress often evokes the functional disorder of animals'neuroendocrine and immune systems, and induces and aggravates many diseases. So it is positive significance for prevention and treatment of various clinical diseases to relieve and eliminate the adverse reaction of cold stress. As the experimental materials, chickens were treated with acute and chronic cold stress (12±1℃) in order to reveal the mechanism of the effect of cold stress on the organism. Some items about the expression level of CRH, TRH and iNOS mRNA in hypothalamus, NO metabolism and antioxidative function in hypothalamus, gastrocnemius and serum, hormone, glucose and FFA in blood were detected. The results showed as follows:1. NO contents and NOS activities increased in serum and decreased in hypothalamus and gastrocnemius, and the expression level of iNOS mRNA decreased in hypothalamus during acute cold stress. NO contents and NOS activities increased in serum, hypothalamus and gastrocnemius, and the expression level of iNOS mRNA in hypothalamus increased during chronic cold stress. It is demonstrated that cold stress can play a role in the orgnism regulation and toxicity through the alteration of NO metabolism in serum, hypothalamus and gastrocnemius and the expression level of iNOS mRNA in hypothalamus.2. Through the detection of antioxidative function in hypothalamus, gastrocnemius and serum, it is demonstrated that cold stress can change antioxidative function, induce oxidative stress, increase the content of free radicals, finally result in the body damage.3. The content of ACTH, CORT, ALD, TSH, FT₃ and INS first increased and then decreased, the content of FT₄ and GLU increased in blood, the expression level of CRH mRNA decreased and the expression level of TRH mRNA increased in hypothalamus during acute cold stress. The content of CORT, ALD, INS and GLU increased, the content of ACTH, TSH, FT₃ and FT₄ decreased in blood, the expression level of CRH mRNA increased and the expression level of TRH mRNA decreased in hypothalamus during chronic cold stress.It is demonstrated that cold stress could change the secretion of CRH and TRH in hypothalamus from the transcriptional level. Further cold stress could make the hornone secreted by hypothalamus-hypophysis-adrenal cortex axis, hypothalamus- hypophysis-thyreoid axis and pancreatic island change, finally carry out general regulation and make all organs coordinate to commonly resist the adverse effect of cold stress on the body.