INTERFERING OF INFECTIOUS BRONCHITIS VACCINE (MA5 AND 4/91) STRAINS ON THE IMMUNE RESPONSE OF NEWCASTLE AND AVIAN INFLUENZA VACCINES IN MALE LAYERS

Abstract

The aim of this study was to investigate the immunological interference of Infectious Bronchitis vaccine (IBV) MA5 and 4/91 strains on immune response to Newcastle (ND) and Avian Influenza (AI) vaccines by studying the humeral immunity in layers. A total of 90-day-old male layer chicks were assigned into three equal treatment groups as follow: G1 chicks were vaccinated against AI at 2nd days and against ND at 2, 10, 20 and 30 days of age. G2: chicks were vaccinated as in G1 and vaccinated against IB at 10 and 30 days of age. G3: chicks in this group were left without vaccination as a control group. the result showed that the antibodies titers against ND and AI were high in G1 in contrast with G2 and control group at 20 and 45 days of age. A key finding from these results revealed that vaccination of chicken by using of live attenuated IBV leading to immunological interference and immune stress which negatively affect on the immune response against ND and AI vaccines