Abstract
This study was conducted on 100 one-day-old broiler chicks to evaluate the effect of Poulvac
E. coli
vaccine in reduction of clinical signs and complications after concurrent infectious bronchitis virus (variant 02) and virulent
E. coli
O78 challenges. The birds were evaluated for clinical signs, mortality for 7 days post-infection, PM lesion score, average body weight and serological evaluation. Re-isolation and RT-PCR for the challenging infectious bronchitis virus (IBV) variant 02 were conducted thereafter. The results showed that the Poulvac
E. coli
at one-day old chicks in the presence of co-infection with virulent
E. coli
and IBV variant 02 provides better body weight gain at 35 days than the other groups. The challenge with IBV variant 02 alone in non-vaccinated birds doesn’t give any mortality; this indicated that the severity of IBV variant 02 increased by the presence of co-infection with Avian Pathogenic
E. coli
(APEc). The mortality percentage associated with both
E. coli
and IBV variant 02 infections in the none vaccinated group by Poulvac
E. coli
was 25% while this percentage was 10% of the vaccinated group. The Poulvac
E. coli
is not negatively affecting the immune response against different concurrent viral vaccines like Infectious bursal disease (IBD), and moreover, it improves the immune response against some others like Newcastle disease virus (NDV), Avian Influenza (AI) H5 and IBV.