Detection of maternally derived antibodies (mda) titer and comparison of intermediate and intermediate plus (gm-97 strain) vaccines of infectious bursal disease virus

Anotace: The Infectious Bursal disease (IBD) is an important devastating disease among the infectious diseases of poultry in Bangladesh. Hence, this study was designed to determine the MDA titer and compare the two commercially available vaccines strains of IBDV (“GM-97 strain Intermediate plus” and “Intermediate type strain”). In this study, a total of 1500 layer birds were equally allocated into three groups (group-A, group-B and control). The Group-A and Group-B were vaccinated by “GM-97 strain Intermediate plus” and “Intermediate type strain” of IBD vaccine, respectively and control was unvaccinated. Blood samples were collected prior to vaccination (1- and 7-days old birds), as well as 7, 14, and 21 days after vaccination. The antibody titer was measured by iELISA test. The highest MDA mean titer was 6227.69±327.63 in day-old birds. The group-A birds had the significantly (p<0.01) higher antibody mean titer than group-B and control. The highest antibody mean titer was 9121.94±657.05 at the age of 39 days in group-A. The MDA titer at 1 days-old had the higher effect size (4.10; CI:4675.36-6072.01; n=16). In group-A, the highest effect size (4.49, CI:5953.80-7556.08; n=16) was in 32 days-old (14 d.p.v.) and the group-B had the highest effect size (3.35; CI:4861.04-6702.59; n=16) was in 32 days-old (14 d.p.v.). Significantly (p<0.01) higher histopathological-lesion scores were 4.75±0.25 and 3.5±0.65 in 32- and 39-days-old respectively in group-A. In brief, the protective level of IBDV MDA titer may remain up to 1 week of post-hatching and the Intermediate plus vaccine can generate higher antibody titer than the intermediate type.