Study On Heat Stress Damages And Heat Shock Protein 70 Expression In Broiler Tissues

Heat shock proteins (HSPs) are several families of proteins which organisms synthesize by inducing of stressors. HSPs are highly conserved, and play a important role in the survival of stressed cells and stabilization of internal environment. HSPs may perform a series of biological functions, such as molecular chaperone, assisting immune response, anti-apoptosis and enhancing tolerance to stressors, and so on. While, the basic biological function of HSPs is molecular chaperone. As universal cytoprotection proteins, HSPs may enhance tolerance to stress, and increase the survival rate of stressed cells. In term of the size of molecular weight, HSPs are usually identified six classes, namely the small HSPs family, the HSP40 family, the HSP60 family, the HSP70 family, the HSP90 family and the big HSPs family. In HSPs, the HSP70 family is the most conserved and the most important family. Because its quantity is the most in most organisms, and its synthesis is the most remarkable after being stressed. The relationship of heat stress damages and heat shock protein 70 expression in broiler tissues is discussed in the paper through the heat stress damages of broilers, changes of HSP70 (HSC70) mRNA and HSP70.One hundred and twenty AA broilers of thirty day were randomly divided into six groups, namely control group, 6 h heat stress group, 12 h heat stress group, 18 h heat stress group, 24 h heat stress group and 48h heat stress group. After 30-days fed adjustably, the broilers of control group were fed at room temperature (25±1℃) , and the heat stressed broilers were treated with high temperature of 40±1℃. According to the groups, these broilers were killed respectively, and these heart, liver, lung, kidney, spleen, thymus and bursa of Fabricius were divided two parts. One part was dipped into 10% neutral formalin to fix, and the other was frozen with liquid nitrogen and stored at -70℃.By measuring the activity of creatine kinase (CK) and glutamic-pyruvic transaminase(GPT), the histopathological lesions of heat stressed broilers were studied. The resultsshowed that the activity of CK and GPT was fluctuant during the persistent heat stress. Thehigh level of CK and GPT at 12 h heat stress suggests that the damages of heart and liverare sharp, and the low level of CK and GPT at 24 h heat stress suggests that the damages of...