The Study Of Synthetic Co-infection Of The Major Bacterium Pathogens Of Avian Embryo

The disease of avian embryo is a synthetical disease which can cause the increase of embryo death and decrease of incubation rate and is fatal to economy. In most condition, it is very common occurrence that the avians coinfect with two or more pathogens. The manner in which multiple pathogens interact is not always straightforward, however the disease of avian embryo is a synthetical disease which can cause the increase of embryo death and decrease of incubation rate and is fatal to economy. There are many species of the disease of avian embryo, and most is conditional pathogenic bacteria. Mycoplasma gallisepricum, Salmonella Avium and Bordetella Avium are three disease of avian embryo. Liu Hong-qin reported that a kind of disease appeared in one large-scale AA broiler breeder farm in Shandong province with the symptom of embryo death, increase of weak chicken, ineffective immunity, stunted growth of 30 days chicken since June, 2004. Antibody in serum was tested to the broiler breeder, 1d chicken and the commercial chicken, it was showed that the average positive rate of bordetella avium, salmonella avium, E.coli, mycoplasma were 13.59%,12.69%,8.10%,19.62% and 37.14%, respectively. Sun Qing reported that this kind of disease appeared on three parental generation branch farms in 2007. It was showed that the co-infection of bordetella avium, salmonella avium and mycoplasma was the major cause of the disease. These pathogens spread vertically from the eggs to the embryos. Thus, the study and detection aims directly at the co-infection of these three diseases of avian embryo. The pathogenic study of synthetic co-infection of bordetella avium, salmonella avium and mycoplasma was had done. And the study of the establishment of detection methods for the co-infection with IFA and PCR was had done.The research subject aims at imitation the similar problems that usually emergent in production. The discussion on the harmfulness of pathogens interact and the pathogenesis, supplying the theoretical foundation to the prevention of avian embryo in breeder farm.The research divides two parts: Part One: The pathogenic study of synthetic co-infection of three major bacterium pathogens of avian embryoIn an initial experiment, the effect of coinfection of Mycoplasma gallisepricum, Salmonella Avium and Bordetella Avium was examined in seventy , 1-day-old chicken (10 chicken /group) and seventy, 11-day-old embryos (10 mbryos/group) that were infected with the three pathogens or two pathogens or only one pathogens . An additional 10 chicken and 10 embryo served as sham infected controls. Observe the growth and death of the chicken (once every 6 hours) and embryo (once every 8 hours). When they die, dissect the dead bodies. Make the tissue paraffin section with the fresh tissue. The results: The thesis aims at observing the appearance and the tissue paraffin section of the co-infection.The symptom of the coinfection of the three pathogens is the most serious, the death time is the most early (the chicken is 6h, the embryo is 8h), the death rate is highest (the chicken is60%, the embryo is 100%), and the next in order is the dually infected chicken and embryo.The grous which were co-infected by MG, Bordetella avium and Bordetella avium, Salmonella have the same death time (12h) and death rate (50).Thus, the avians coinfect with two or more pathogens can cause the increase of embryo death and decrease of incubation rate and is fatal to breeding industry. In most condition, it is a synthetical disease.It usually causes atypical pathological changes.Part Two: The study of detection methods for synthetic co-infection of three major bacterium pathogens of avian embryoThe recent years, it is very common occurrence that the avians coinfect with two or more pathogens. In this case, It usually causes atypical pathological changes.Thus, it is difficult to do clinical diagnosis when the co-infection is emergent. In order to investigate the potential trend in disease severity after co-infection, a second experiment was performed to examine the pathogens by IFA and PCR in tissues from single and dually infection and triplicate infection. The results: the content of MG is highist in aerocyst, Salmonella Avium and Bordetella Avium is in Liver and bursa. When it is 36h, the content of pathogens is highest in chicken and ahout 24h in emobryo. Then it will reduce slowly.The establishment of detection technique of labelled for the co-infection with IFA and PCR are simple, rapid and strong specificity.The exeperiment provides essential essay datas for collecting samples and controlling technology for the co-infection of three bacterium pathogens of avian embryo.