Immunological and histopathological evaluation of the seventh day Intermediate Plus Tissue Culture live attenuated IBD vaccine in commercial broiler chickens

Abstract

Infectious Bursal Disease (IBD) causes significant challenges to the poultry industry, particularly with the emergence of novel variant Infectious Bursal Disease virus (IBDV) strains. Effective vaccination program is required for controlling this disease, but the impact of such vaccines on the bursa of Fabricius, the main immune organ, remains a concern. This study had been conducted for immunological evaluation of early vaccination with Intermediate plus tissue culture (INP-TC) IBD vaccine (Bursipharm®) and to assess the impact of this vaccine on the bursa of Fabricius in broiler chickens. No significant differences were observed in body weight and feed conversion ratio between the vaccinated and control groups. The relative weight of the bursa and spleen did not differ significantly, and the bursa/body index indicated no significant atrophy on the bursa of Fabricius in vaccinated birds. Immunologically, IBDV antibody titers were significantly higher in the vaccinated group, whereas Newcastle disease virus (NDV) antibody levels showed no significant differences. Histopathological lesion score in bursa of Fabricius showed mild to moderate lesions in the vaccinated group without causing any pathological atrophy throughout the experiment. Using the intermediate plus IBDV tissue culture origin vaccine (Bursipharm®) at 7 days and the second dose at 14 days induced an effective immune response against Gumboro disease with controllable effects on the bursa of Fabricius. The vaccine can overcome maternal derived antibodies (MDA) and initiate an immune response as early as possible, which becomes beneficial in combating novel variant strain of IBDV and preventing the replication of this strain in the bursa of Fabricius at an early age.