Effects of Two Supplements on Rate of Infectious Bursal Disease Virus Antibody Decay and Response to a Very Virulent Strain of the Virus in Pullet Chicks

This study evaluated the effects of two supplements on the rate of infectious bursal disease virus (IBDV) antibody decay and response to a very virulent strain of the virus (vvIBDV) in pullet chicks. Two hundred ISA Brown 1-day-old chicks were divided into four groups (AD), each containing 50 birds. Chicks in group A were given supplement A, and B supplement B, from 1-day-old to 42 days of age, while C (positive control) and D (negative control) were not given any supplement. Groups A, B and C were challenged with vvIBDV at 28-days-old. Blood was collected from each bird, serum was obtained and analysed for antibodies against IBDV. The rate of antibody decay and response to vvIBDV were determined. There was significantly higher (p<0.05) antibody titre in chicks of groups A and B than in C and D at days 28, 35 and 42. The rate of antibody decay was lower in chicks of groups A (-57.7%) and B (-65.4%) than in C (-72.1%) and D (-74.2%) at 28-days-old. The antibody response rate was higher in groups A (+76.4%) and B (+71.1%) at 35-days-old. There was lower antibody decline rate in groups A (-22.4%) and B (-29.0%) compared to C (-38.6%) and D (-51.4%) at 42-days-old. These supplements decreased IBD antibody decay, enhanced antibody response to vvIBDV infection and decreased antibody decline by vvIBDV. Therefore, the use of these supplements in IBD outbreaks to enhance immune responses is recommended.