Studies on infectious bronchitis in broiler chickens in EL Menia Governorate

A total of 986 serum samples were collected from IB non vaccinated 26 broiler farms in El- Menia; A total population of 135500 bird. All tested farms were ELISA positive for IBV antibodies. The percent of positivity were 42.86, 33.04, 48.37, 31.01, 43.09, 34.01 and 33.68 in samples from Abo- Korkas, Bani- Mazar, Dear-Mawas, EI-Menia, Malawy, Mtay and Smaloot; respectively. IB virus was successfully isolated by 4 blind passages in SPF chicken embryos, which showed curling and dwarfing and were positive to Dot-ELISA against reference antibodies IBV. Pathogenicity of the obtained virus isolate was studied in both broiler and layer chicken. In broiler chick, pathogenicity was performed in groups aged 1, 7, and 14 days. No mortality was seen in group infected at 14 day of age, while it was 8/2 chicks in both 1 and 7 days. Examined tissue sections of trachea, lung and kidney of birds at 4 and 14 days post infection in different age groups revealed severe histopathological changes especially in birds inoculated at 1 and 7 days old as compared with birds inoculated at 14 day old. In layer chicken the isolate resulted in mild respiratory manifestations [sneezing, coughing], decline of egg quantity and quality [rough shell and shell less eggs] 2 weeks after challenge as well as mortality reached 20%. Postmortem examination of succumbed broiler and layer birds revealed severe renal congestion and mild congestion in trachea and larynx

Studies on some parameters of immune response of chickens vaccinated against ILT by different routes

The immune response against ILT vaccination using different routes [intraocular, spray, dipping and drinking water] was evaluated. The criteria of evaluation depended on quantitative agar gel precipitation test [QAGPT], counter immunoelectrophoresis [QCIE], lymphocyte transformation [LT] test and protection against challenge of vaccinated and control groups. The results indicated no significant difference between different vaccinated groups either by QAGPT or QCIE, while revealed significant difference between different vaccinated groups on the following descending order: Intraocular, spray, drinking water and dipping route. Results of challenge revealed maximum protection [90%] in ocular instillation and spray procedures [in spite of adverse post-vaccination reaction was recorded in spray vaccination] followed by drinking water route [80%], while dipping and non-vaccinated groups gave 40% and 20%, respectively

Evaluation of emergency vaccination against infectious bursal disease [IBD] with or without some non-specific immunostimulants

A trial for emergency vaccination against lBDV 48-hour post experimental infection of 29-day old immunostimualnts, namely; Pind-Avi [Fowl pox virus inactivated by gamma rays], Ultracorn[R] [Corynebacterium cutis lysate], Levamisole hydrochloride [R] and transferrin. The results revealed that emergency vaccination of infected chicks was useless in controlling mortality or bursal damage [which was evidenced by bursal lesion score and bursal lymphoid tissue lesions]. The use of these immunostmulants alone improved the protection% but had not restored the bursal damage with varying degree of stimulation of non-specific immune response in the following order: Transferrin, ultracorn [R], Pind-Avi finally levamisole. The combination of emergency vaccine with immunostimulant didn't show a significant control point

Laboratory investigations on the use of an inactivated IBDV-oil emulsion vaccine in commercial layer chicks. I-protectiveness of partial doses in maternally immune chicks

Three simultaneous experiments were carried out to investigate the efficacy of partial doses [1/5 and 2/5 field doses] of an oil emulsion vaccine [OEV], given either alone or in combination with live vaccine at 1 and 7 days, in protecting experimental chicks against very virulent infectious bursal disease virus [vvlBDV]. Variable protection results were obtained and attributed not only to vaccination scheme but also to the high levels of maternal antibodies but OEV seems to play a role in their depletion rate as measured by Elisa. Work is in progress to investigate the efficacy of full dose of OEV on the immune response and depletion rate of maternal antibodies

Studies on the effect of specific immunostimulant on the immune response of chickens I Evaluation of the immunopotentiates of New Castle Disease virus-specific transfer factor [NDV-S-TF] in chicken

Efficacy of the administration of Newcastle disease virus-specific-transfer factor [NDV-S.TF] either orally or intramuscular injection in chickens was evaluated. The results revealed that NDV-S-TF potentiated the lymphocyte blastogenesis response against PHA mitogen and NDV antigen; as well as induced extraordinary potentiation of the haemagglutinating antibody production against NDV in treated chickens than non-treated one. Chickens immunized with NDV-S-TF and challenged showed good protection percentage than non-immunized birds