الفهرس 
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Abstract
It was noticed that all the tested inactivated vaccines considered completely inactivated because there was no agglutination for the RBCs observed in HA test after 2 passages and less of 20% of embryo mortality occurred.
It was shown that all the sera collected from vaccinated chickens and tested by HI test using standard homologous H5 AI antigens, gave positive results. It means that the produced HA antibodies were identical to the used antigens and proved that the AI strains contained in the different type of inactivated vaccines were to be H5 subtype.
The challenged viruses were also tested for detection of the most effective challenge dose using pathogen test. It was found that 105 EID50 was the suitable to infect the chickens causing high mortalities up to 100% within 3 days post challenge.
It was observed that in case of imported inactivated H5N1, the HI antibody titers in serum of chickens was increased from 0 at pre-vaccination time till reached 7 log2 at the 4th WPV. While imported H5N2, local H5N1 and imported H5N3 gave titers of 10.3 log2, 9.3 log2 and 9.1 log2.
The results indicated that the protection percent of chickens vaccinated with one field dose of either imported H5N1 vaccine, imported H5N2, local H5N1 and imported H5N3 was 96%, 88 %, 56% and 88 %, respectively during 10 days against the local HPAI H5N1 isolate.
On day 2 post challenge (pc), in all control and vaccinated chickens, high titers of virus were recovered from the oropharynx and cloaca. There was reduction in local HPAI challenge virus replication either 10^2.9 or 10^0.5 EID50 from oropharyngeal swabs or 10^3.3 and 10^1.1 from cloacal swabs in case of checken groups vaccinated with one dose of imported H5N1 and local H5N1.
There was reduction in local HPAI challenge virus replication either 102.4 EID50 from oropharyngeal swabs 10^2.8 from cloacal swabs in case of chicken groups vaccinated with one dose of imported H5N2.
There was reduction in local HPAI challenge virus replication either 10^0.3 EID50 from oropharyngeal swabs or 10^1.3 from cloacal swabs in case of chicken groups vaccinated with one dose of imported H5N3.