الفهرس 
Cover Page Title in EnglishOnly 14 pages are availabe for public view
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Abstract
In this study, the efficacy of different vaccination programs including rHVT-H5 and inactivated H5N1 vaccines applied alone or in combination was evaluated in broiler chickensFirstly, the viral genome was extracted from vaccines and then the RT-PCR and PCR were conducted on them using primer pair specific for H5 gene of AI virus and gave positive results. It means that AIV type incorporated in the different types of vaccines were identical to be H5 subtypeSecondly, the maternally derived antibodies in the broiler chickens used in this study was waned up by HI test and it was no longer detectable at the age of 4 week Then, The potency of the three reassorted inactivated H5N1 vaccines (Re-5 vaccine (Merial), Re-5 vaccine (Qyh Biotech) and Egy-flu 1 vaccine ) in broiler chickens was evaluated following single dose vaccination by using HI test against either homologous or heterologous AI antigens and the results of humoral immune response of them against the homologous virus as antigen indicated that the mean HI titer was 243 , 367 and 356.4 respectively at 3rd WPV While the results of humoral immune response of Re-5 vaccine (Merial) and Re-5 vaccine (Qyh Biotech) using A/chicken/Egypt/18-H/09 (H5N1) as antigen were.1, 5.4, 8.2 and 0.6, 2, 8.8 respectively through the three weeks PV and the result of humoral immune response of Egy-flu 1 vaccine using A/duck/Anhui/1/2006 (H5N1) as antigen was 6.4, 17.6, 72.6<Also, The results of humoral immune response of Re-5 vaccine (Merial), Re-5 vaccine (Qyh Biotech) and Egy-flu 1 vaccine using the heterologous field isolate A/chicken/Egypt/9403NAMRU3-CLEVB214/ 2007(H5N1) as antigen indicated that the mean HI titer were 1.2, 4.8, 8.4 and 1, 4.4, 9.6 and 5, 56, 142.6 respectively at the three weeks PV. While By using the heterologous field isolate A/chicken/ Egypt/ 5612NAMRU3-S /2006 (H5N1) as antigen indicated that the mean HI titer were 3, 40, 146 and 5, 20, 267 and 10, 72, 320 respectively at the three weeks PVOn the other hand, the potency of rHVT–H5 vaccine by HI test following single dose vaccination using different types of antigens showed that the mean HI titer through the five weeks PV was 176, 22, 5, 88, 104 with A/duck/Anhui/1/06 as antigen and was 22.4, 3, 1.6, 9.8, 89.6 with A/chicken/Egypt/18-H/09 as antigen and was 3.8, 1, 1.8, 3.8, 32.6 with A/chicken/Egypt/9403NAMRU3-CLEVB214/07 as antigen and was 116, 15.8, 4, 32, 260 with A/chicken/ Egypt/ 5612NAMRU3-S /06 as antigenfrom the previous, it could be concluded that the inactivated vaccine which give the highest HI titers against either homologous or heterologous antigens was Egy-flu 1 vaccine. So, this observation suggests the usage of a combination between the live rHVT-H5 vaccine and the inactivated Egy-flu 1 vaccine in a vaccination programFinally, the potency of the combination between the live rHVT-H5 vaccine and the inactivated Egy-flu 1 vaccine by HI test using different types of antigens was evaluated and it indicated that the higher mean HI titer was measured against A/chicken/Egypt/18-H/09 as antigen , reaching 1186 followed by A/chicken/ Egypt/ 5612NAMRU3-S/2006 (H5N1) as antigen, reaching 1060, then followed by A/chicken/Egypt/9403NAMRU3-CLEVB214/07 as antigen, reaching 566 and finally followed by A/duck/Anhui/1/06 as antigen, reaching And at 3rd WPV And It Was Concluded That The Combination Between The Live RHVT-H5 Vaccine And The Inactivated Egy-flu 1 Vaccine In AVaccination Program Was The best Vaccination Program Compared To The Other Vaccination Programs Including The Reassorted Inactivated H5N1 Vaccine Alone.