Immune Effect Of Combination Vaccine Of ND-IBD On Layers And Differential Diagnosis Of Velogenic And Mesogenic IBDV

Infectious Bursal Disease(IBD)is an immunosuppressive,highly contagious disease.It predominantly infectes broilers.IBD is caused by Infectious Bursal Disease Virus(IBDV)that is the double-stranded RNA virus family.Newcastle disease(ND)is an acute,highly contagious and fatal disease.It is caused by Newcastle Disease Virus(NDV)of Paramyxoviridae.Chickens of different ages,breeds and sex can be infected with ND.But the broilers’s morbidity and mortality were significantly higher.The study found that the domestic development of ND-IBD inactivated vaccine and its immunized effect on the layers were less.Therefore,in view of this situation,immunized effect research of the ND-IBD inactivated vaccine on the layers still needs be further studied.Meanwhile,in the production of clinical practice or scientific research,serological tests to monitor the level of broilers often caused broilers’ stress and affect its growth performance and economical benefits.By extracting egg yolk antibodies of ND and IBD from eggs can indirectly predict serum antibodies of ND and IBD.obtaining samples is convenient and reducing repeated stress in broilers.In view of the relation between egg yolk antibodies of ND and IBD with serum antibodies of ND and IBD was not clear.So correlation analysis between egg yolk antibodies of ND and IBD with serum antibodies of ND and IBD was studied by measuring egg yolk antibodies and serum antibodies.In addition,studies shown that organism existed to IBDV wild strain and IBDV vaccine strain in clinical practice.It caused bursal lesion and immunity failure.So,it is important to establish an efficient and simple method for differential diagnosis of IBDV wild strain and IBDV vaccine strain.In this study,100-day-old layers was to be subcutaneously injected ND-IBD inactivated vaccine and then measure its ND and IBD antibodies to observe the immune effects of layers and their offspring.In addition,the correlation between egg yolk antibody level of ND and IBD and serum antibodies level in offspring broilers were analyzed.At last,an efficient and simple method was to be established for differential diagnosis of IBDV wild strain and IBDV vaccine strain.1.Immunized effect research of the ND-IBD inactivated vaccine on the layers.In this test,100-day-old layers was subcutaneously injected ND-IBD inactivated vaccine.Blood was collected and separated before and after immunization every 15 days.Their ND and IBD antibodies level were measured by serological method and was analyzed.The results shown that layers were obtained immune protection well by being subcutaneously injected ND-IBD inactivated vaccine and produced higher antibodies level of ND and IBD.What is more,its immune protection can last 120 days.So,after they were subcutaneously injected ND-IBD inactivated vaccine,they were effectively improved the level of antibody to the layers and also increased the level of maternal antibodies to the offspring.2.Correlation analysis between egg yolk antibodies of ND and IBD and offspring’s serum antibodies of ND and IBD were analyzed.The optimal equations of immunized group for the relationship between egg yolk antibody of ND and IBD and offspring’s serum antibody level of ND and IBD was acquired by measuring their ND and IBD antibodies and analyzing with SPSS 18.0 software.The optimal equations are respectively y=0.923+0.701xand y=2.3 65+0.7x.3.The differential diagnosis method’s establishment of velogenic and mesogenic IBDV.Two primers(Fragment length:856 bp and 1356bp)were designed to RT-PCR amplifying by according to the Comparison and analysis of different strains’ VP2 conservative section sequence.And restriction endonuclease BamH Ⅰ and Pst Ⅰ were selected to digested 856 bp fragment length’s glue recycling products.And finally,its specificity,sensitivity and repeatability were verified.The differential diagnosis method of velogenic and mesogenic IBDV was established.Layers and their offspring were obtained immune protection well by being subcutaneously injected ND-IBD inactivated vaccine and produced higher antibodies level of ND and IBD.In addition,correlation analysis between egg yolk antibodies of ND and IBD and offspring’s serum antibodies of ND and IBD were analyzed to acquire the optimal equations of immunized group.At last,this study established an efficient and simple method for differential diagnosis of IBDV wild strain and IBDV vaccine strain.This test provides scientific basis for the development of scientific immunization procedures and provides an efficient and simple means of monitoring for clinical and production practice.At the same time,it provides a new method for IBD epidemiology and diagnosis and treatment research.