الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This work aimed to study serological immune response of some NDV
vaccines and their efficacy against challenge with recently circulating velogenic
NDv strain in Egypt.
These studies revaled the following results:
1. Serological response of broiler chickens vaccinated with Newcastle disease
inactivated oil emulsion vaccine at 7 days of age and live Newcastle disease
vaccine at 7and 15-days of age was higher than serological response of broiler
chickens vaccinated with HVT-ND vector vaccine at 1-day of age and live
Newcastle disease vaccine at 15 days of age .
2- Results of Challenge with Velogenic Newcastle disease virus
(genotype VII) at 25 and 31 days of age:
A) Sever clinical signs and post-mortem lesions were observed in non vaccinated
challenged chickens at 25 and 31 days of age varried between respiratory and
neurolgical manifistation, while less severe clinical signs and P-M were observed
in broiler chickens vaccinated with oil emulsion Newcastle disease inactivated
vaccine at 7 days of age and live Newcastle disease vaccine at 7&15-days and
broiler chickens vaccinated with HVT-ND vector vaccine at 1-day of age and live
Newcastle vaccine at 15 days and challenged at 25 and 31 days of age .
B) Partial protection against mortality (20%) were observed in broiler chickens
vaccinated with HVT-ND and live ND vaccines or vaccinated with inactivated oil
emulsion and live ND vaccines versus 80% in non vaccinated chickens
challenged at 25 days of age, while challenge at 31 days of age revealed complet
protection (0% mortality) in both vaccinated challanged groups and 80%
mortality in non vaccinated challenge group.
C) Detection of challanged virus by RT-PCR in trachea: all examined trachea of dead
and survived non vaccinated challenged chickens at 25 and 31 days of age were
Summary.
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positive for velogenic ND virus, while in both vaccinated challenged chickens at
25 and 31- days of age only trachea of dead chickens was positive for velogenic
ND virus.
D) The serological response of broiler chickens vaccinated with HVT-ND and live
ND vaccines or vaccinated with inactivated ND and live vaccines, then
challenged at 25 and 31 days of age were higher in comparison with serological
response of broiler chickens vaccinated with HVT-ND and live ND vaccines or
vaccinated with inactivated ND and live vaccines non challenged at 25 and 31
days of age