Pathology and immunoprotection of hyperimmune yolk in IBD in layer chicks

Infectious bursal disease (IBD) is major problem for poultry industry, which is causing heavy economic losses. To control the disease, a vaccine was prepared from bursa of Fabricious collected from field out break of IBD. Chicken layers when primed with self prepared vaccine at 40 week of age and boosted with the same vaccine after 8 days showed high titer of yolk agar gel precipitating (AGPT) antibodies against IBD virus. Day old chicks (n=125) were vaccinated against IB, ND and HPS on the day 4, 7 and 16 respectively. At the age of day 20 group A (1 ml) and B (1.5 ml) were injected hyperimmune yolk before infection and groups C (1 ml) and D (1.5 ml) were injected hyperimmune yolk after infection and group E served infected and untreated. Results showed hyper immune yolk has positive effect on IHA titre against IBD as compared to control group. IBD lesions exhibited by the birds were swollen bursar, hypertrophy of spleen, swollen kidney hemorrhages of muscles and thigh. Histopathologically. Thigh and chest muscles were showing congestion and oedema of muscle fibers. In some cases, hyaline degeneration was also observed. In the central group, birds even showed necrosis of the muscles fibers and there was infiltration of hetrophils. The prominent histopathological feature of IBD infected kidneys was necrosis of renal tubules and cellular infiltration of hetrophils. Glumeruli in most of the cases seethed to be showing no pathological changes. In control group birds showed extensive hetrophilis infiltration and also necrosis of renal tubules. In these cases, fibroplasias replacing the necroses area was also observed. Bursa showed extensive congestion. Blood vessels in the bursal follicles and even outside these follicles were encouraged with blood. This congestion was also present in the adjacent area of the bursal follicles. Inter follicular spaces were also showing congested areas and proliferation of fibrous connective tissue. The hyperimmune yolk has good effect on tile recovery of IBD infected chicks. The 1.5 ml S/C injection of hyperimmune yolk after production of IBD showed 83% recovery in-group D. It anticipated that the hyperimmune yolk might be used as treatment of the IBD infected birds.