Effectiveness Evaluation Of Co-vaccination With Avian Infectious Bronchitis Virus Vaccine And Newcastle Disease Virus Vaccine

Intensification of the poultry production had increased the prevalence of the respiratory diseases in poultry.NDV and IBV are two major respiratory pathogens of the infectious diseases in the poultry industry.To control these two respiratory infectious diseases,currently vaccination is commonly practiced,but the disease often occurs after immunization of chickens.At present,there are different reports on the interaction and promotion between IBV and NDV vaccines after co-immunization.To understand the interaction between chicken infectious bronchitis and newcastle disease vaccine co-immunity,we designed the experiment for the following study.(1)The co-immunity model of H52 type IBV attenuated vaccine and La sota type NDV attenuated vaccine were established in adult chickens,and the results are as follows:According to the results of antibody level:the antibody level of IBV vaccine strain H52 in the co-immunization group was significantly higher than that in the single immunization group after 10 days immunization;the positive detection rate from co-immunization group was earlier than that in the single immunization group,it was detected at 3 days after immunization.According to the results of peripheral blood lymphocytes:H52 in the single immunization group was significantly higher than that in the co-immunization group(P<0.05),at the same time,the La sota alone immunized group was significantly higher than the co-immunized group(P<0.01)after 8 days of immunization.The ratioin of CD4+/CD8+ in the co-immunization group was significantly higher than that in the H52 alone immunization group(P<0.01)and La sota immunization group(P<0.001)after 16 days of immunization,respectively;Observation of lung histology,the inflammatory cell infiltration was more serious in the co-immunized group than in the co-immunized group and in the single immunized group;The results of detoxification from the throat and cloacal cavity showed that:after 7 days of immunization,the amount of detoxification of H52 in the pharyngeal immunization group was significantly higher than that in the immunization group alone(P<0.001).the amount of La-sota detoxification in the La-sota co-immunized group of pharynx and clocal were significantly higher than that in the single immunized group(P<0.05)On 7 days,10 days of immunization,respectively;The results of viral load in the lungs of adult chickens showed that:the viral load of H52 in the co-immunized group was significantly higher than that in the immunized group alone(P<0.01)after 7 days of immunization.From the results of cytokine immunity level:after 7 days of immunization,the gene expression of 1FN-β in the single immunization group(La Sota)was significantly higher than that in the co-immunization group(P<0.001),and the single immunization group(La Sota)the gene expression of IFN-γ was significantly higher than that of the co-immunization group(P<0.0001).After 14 days of immunization,the level of expression of IL-1β in the co-immunization group was significantly higher than that in the immunization group alone(P<0.001).After 14 days of immunization,the expression of IL-2 in the co-immunization group was significantly higher than that in the H52 type IBV single immunization group(P<0.0001),and the co-immunization group was significantly higher than the La Sota type NDV single immunization group(P<0.01).(2)Chicks are used as experimental objects to establish a co-immunization model H120 of IBV and La Sota of NDV attenuated vaccines.the results are as follows:From the results of antibody level,it shows that the antibody detection rate of H120 group was earlier than that in the co-immunization,and there is no significant difference between the single and co-immunized groups;The results of peripheral blood lymphocyte immunity shows that the percentage of CD4+/CD8+in the co-immunization group gradually increased,and the co-immunization group was significantly higher than that of H120 alone group(P<0.05);The results of histological observation of the lungs show that the infiltration of inflammatory cells was much more serious in the co-immunized group than in the single immunized group;The results of detoxification from the thorat shows that was no significant difference in the level of H120 detoxification between the co-immunized group and the single immunized group.There was no significant difference in the detoxification level of La sota between in the co-immunized pharynx group and the single immunized group;The results of viral load in the lungs of chicks shows that after 7 days of immunization,the viral load of H120 in the lungs of the co-immunized group was significantly higher than that of the immunized group alone(P<0.001);From the cytokine immunity level results:after 3 days of immunization,the expression levels of IFN-β and IFN-γ in the co-immunization group were significantly higher than those in the immunization alone group(P<0.0001);After 14 days of immunization,the inflammatory factors IL-1β and IL-2 in the lungs of the individual immunization group were significantly higher than those of the co-immunization group(P<0.001).In summary,infectious bronchitis vaccine and newcastle disease vacine were immunized in both chicks and adult chickens.the high expression of cytokines can induce cell immune response and humoral immune response,it shows that there is an immune promotion effect after co-immunization of the attenuated strains of infectious bronchitis virus and newcastle disease virus,therefore,the immunization program should be carefully selected according to the actual situation.