Field study on immune response and performance of commercial broiler chickens with maternal immunity to live Newcastle and infectious bronchitis disease vaccines

In this study, 8000 Hubbard broiler chicks having maternal antibodies to Newcastle disease (ND) and infectious bronchitis disease (IB) were reared on deep litter in a poultry farm. The chicks were received Gumbopest (IBD + Newcastle Inactivated vaccines) and Avinew (ND live vaccine –VG/GA strain) with Bioral H120 strain (IB live vaccine) via spray and drinking water to investigate its immunogenicity and its effect on broiler performance. Neither IB nor ND related clinical signs or mortalities or lesions were observed after vaccination till the end of the breeding period (7 weeks). The result of serological response to ND vaccines showed that the maternal antibody titer to NDV in 1day old chicks was 10655.5 ± 3420.9 and weaned 3516 ± 3784.4 at 2 weeks. At the 3rd and 4th weeks after vaccination ND ELISA titres were increased to 1181.5 ± 1126.4 and 2326 ± 2.117 ; respectively. On the
other hand the maternal antibody titer to IB Vaccine in the used day old chicks was 8271.5 ± 10642.7; this titer waned to reach 9142.5 ± 4323.2 at 1 week of age and 92 ± 130.11 at 2 weeks after vaccination. At the 3rd and 4th weeks after vaccination IB ELISA titres were reached to 0 ± 0 and 2657 ± 3757.6 respectively. This result revealed that the used live ND and IBV vaccines were able to induce antibody levels in chickens with maternal ND and IBV antibodies. The best weekly feed conversion rate (FCR) was recorded at the 4th week (1.31) and the 6th (1.71) with total FCR of 1.89. Mortality rate in the susceptible age (2-6 week) was the lowest (0.4-.73%) with total mortality of 3.27 at the end of the 7th
week. These findings pointed out that live ND Avinew vaccine and live IB Bioral H120 vaccine were safe, immunogenic to maternally immune chicks and has no dverse effect on performance