Immune responses upon in ovo HVT-IBD vaccination vary between different chicken lines

Abstract The genotype of chickens is assumed to be associated with variable immune responses. In this study a modern, moderate performing dual-purpose chicken line (DT) was compared with a high-performing layer-type (LT) as well as a broiler-type (BT) chicken line. One group of each genotype was vaccinated in ovowith a recombinant herpesvirus of turkeys expressing the virus protein VP2 of the infectious bursal diseasevirus (HVT-IBD) while one group of each genotype was left HVT-IBD unvaccinated (control group). Genotype associated differences in innate and adapted immune responses between the groups were determined over five weeks post hatch. HVT-IBD vaccination significantly enhanced humoral immune responses against subsequently applied live vaccines compared to non-HVT-IBD vaccinated groups at some of the investigated time points ( P + T-cell numbers ( P ex vivo stimulated spleen cells was independent of HVT-IBD vaccination. The results of our study suggest considering a genotype specific vaccination regime in the field.