Immunosuppressive Properties of Infectious Bronchitis Vaccine4/91 strain against different programs and method of vaccination against Newcastle disease in Broilers

[摘要] Infectious bronchitis virus (IBV) primarily induces a respiratory disease in broilers causing important economic losses in poultry industry. The aim of this study was to investigate the immunosuppressive properties of live IB vaccine on the different programs and method of vaccination against Newcastle disease (ND) in broilers. A total of 125 one-day-old broiler chicks were assigned into five equal groups. At day one G1 and G2groupswere vaccinated with a live (ND, IB)vaccine by dipping the head in the vaccine and intra-cloacae method respectively. Afterward, G3and G4 groups were vaccinated with a live ND vaccine alone by the same method of G1 and G2. At the same time all these4 groups were vaccinated by subcutaneous injection (S/C) with inactivated oil based vaccine ND. The G5 group was left without vaccination as a control group. After that, all treated groups were vaccinated with a live ND by spray method at day 10 of the age. The immunosuppressive effects of this IB virus was evaluated by Haemagglutination inhibition test (HI), and challenged by virulent ND virus. Bursa and Spleen indices were estimated in all groups. The results showed that the antibody titers against ND was higher (P<0.05) in G3and G4 in compared with G1, G2 and control groups at 20 and 30 days of age. However, there was no significant difference of bursa index and spleen index in all groups. Challenge test showed no mortality in the 3rd group while 10% in the 4th group, 85% in the 1st group and 90% in the 2nd group. In conclusion it’s revealed that the best method and program of vaccination which can protect against ND was applied in the 3 rd group.

[学科分类] 土木及结构工程学