Investigation Of Respiratory Disease Pathogens And Early Warning Of Inflammatory Factors About Broilers

In recent years, the morbidity of respiratory diseases caused by many pathogenic factors had become higher and higher with the rapid development of intensive, large-scale breeding,resulting in seriously frustration of the poultry’s growth, high mortality and sound development of poultry breeding industry. Researching on pathogenic factors of respiratory diseases, pathogenic mechanism, pathological changes, the change of inflammation factors and serum antibody in sick chickens to early warn, diagnose and prevent of chicken respiratory diseases will have an important guiding significance.The Avian flu, Newcastle disease and Chicken infectious bronchitis single or mixed with the infection were the the most common cause of avian respiratory infection. They could cause the common features of acute inflammation of respiratory tract mucous membrane with different degrees of systemic infection. This study tracking sampled for twice on diseased chicken group to understand pathogen source of respiratory disease, infection status and pathological changes.The first time, 210 lung samples of dead or weak broiler embryo and 50 lung and liver samples of broilers with respiratory symptoms(5d、12d、19d、26d、33d)were collected from a large-scale broiler farm. The second time, 30 lung samples of dead or weak broiler embryo and 75 lung and liver samples of broilers with respirator y symptoms(5d、12d、19d、26d、33d) were collected, and then RT-PCR was used to detect H9N2 subtype of Avian influenza virus(H9N2 AIV), Newcastle disease virus(NDV) and infectious bronchitis virus(IBV). Observing pathological changes of respira tory tract mucous membrane under light microscope. The results show that the sample s of dead or weak broiler embryo and broilers with respiratory symptoms were all pic ked out the three pathogens, while the co-infection of the three virus were not detecte d. One of the isolated strains of infectious bronchitis virus(IBV) was discussed in det ailed classification identification. This strains has a distant relationship with H120 vacc ine strains(78.1%), was similar to LX4 genotype with only 95.4% of similarity so as a popular wild strain. The chicken embryos were easier to die during incubation with respiratory viral, but if not die the chicks developed to a certain period(the maternalantibody failure) while the virus could proliferation then respiratory diseases would h appen and spread rapidly in chicken flocks with bacterial infection resulted in a large number of death, which is an important cause of late respiratory illness increasingly s erious in broiler chickens. Under light microscope, tracheas of the sick avian in respira tory tract mucous membrane could be clearly observed catarrhal or hemorrhagic catarr hal inflammation.Investigate the changes of inflammatory cytokines(interleukin 1, interleukin 6, inter leukin 8, tumor necrosis factor alpha) and serum antibody(Newcastle disease、Influenz a) by double antibody sandwich ELISA and HA-HI methods to analyze the inner relat ionship between the quantity changes and respiratory diseases. The results show that inflammation mediums and serum antibody became roughly same with the respiratory disease occurrence. By ELASA method to detect the changes of inflammatory factors with high sensitivity, simple operation, that can quantitatively reflect the changes of in flammation and the changes of inflammation factors were long before early clinical m anifestations, pathological changes and serum antibody production, which were an imp ortant index for determining respiratory inflammation. But this method also had disadv antages: 1) the inflammation factors were not specific for determining which kind of pathogen causing inflammation; 2) the serum inflammatory factor were comprehensive manifestation of systemic inflammation, that cannot locate in inflammatory site.The dynamic test of serum antibody accurately reflected the correlation of disease conditions so it was necessary to dynamically monitor serum antibody(ND, AI) that to evaluate effect of vaccine, early warn the outbreak, prevent and control disease dia gnosis as important direction.Through investigation and analysis of five bartons to know in the process of bree ding chicks the inner temperature and humidity was directly related to the respiratory diseases and had a considerable effect on the survival rate of the middle and later per iod. A large-scale broiler farm cannot only depend on the automatic temperature and h umidity control device, should also refer to the breeding season and the performance of the chickens to manual intervention.