Sero-prevalence of infectious bursal disease virus (IBDV) specific antibody in chicken

In the present experiment, Enzyme linked immunosorbent assay (ELISA) was applied on a total of 49 samples collected from 4 breeds of chicken (BV-300, Broiler Kasile, LBM and Hisex) at different age (day 1, day 5, day 10 and day 15) to determine the level of maternally derived antibody (MDA) against infectious bursal disease (IBD). All the chickens were the progeny from the parent stock that had the history of vaccination. A total number of 10 broilers were used to determine the level of IBDV specific antibody in vaccinated and in non-vaccinated chickens following infection with field virus suspension. As these chickens attained the age of 14 days, 6 chickens were vaccinated with Gumboro D78 live vaccine while remaining 4 chickens were kept without vaccination. All the chickens were infected with field virus suspension on day 19 and blood samples collected on day 29 were subjected to ELISA. Slight variation in the antibody titer was observed among 4 breeds of chickens. An average antibody titer of 5320.79, 5877.15, 3676.24 and 5581.55 was found in day old BV-300, Broiler Kasile, LBM and Hisex respectively. Day old BV-300 contained high level of MDA (average of 5320.79) and the level gradually declined and persisted up to 15- 20 days. Five days old, 10 days old and 15 days old BV-300 contained an average antibody titer of 3848.57, 2615.53 and 580.88, respectively. On day 29, there was a significant level of antibody (1489.50), much above minimum protection level, in vaccinated chicken whereas nil antibody level was observed in non-vaccinated chickens. Therefore, the chicks should be vaccinated at around day 14, at which time the antibody level reaches nearly to minimum protection level. Antibody level must be carefully monitored at proper interval of time in order to make the vaccination program more effective, to keep the chickens disease free, to increase the production and to prevent the economic loss.