Monitoring Of Decrease Of IBD Maternal Antibodies In Progeny Born To Two Different Broiler Breeder Genetics At The End Of The Laying Period (> 40 Weeks Of Lay) And Vaccinated With VAXXITEK® HTV+IBD In Ovo

Delvecchio A., Gauthier J.C., & Lemiere S

 

Monitoring of ‘IBD classic’ ELISA serology was performed at day-old, then kinetics was established at D10, D18, and D31 of age. Serological results were interpreted as maternally-derived antibodies, as post-vaccination seroconversion, and/or as IBD virus spread, live IBD vaccine or field virus. Monitoring of ‘IBD plus’ ELISA serology was performed at day-old, then kinetics was established at D10, D18, and D31 of age. Serological results were interpreted as maternally-derived antibodies, as post-vaccination sero-conversion, and/or as IBD virus spread, live IBD vaccine or field virus. Low IBD ELISA titres in progeny (between 4000 and 8000) of ‘IBD plus’ increased affinity to the viral VP2 protein expressed on the HVT-IBD vector vaccine maternal antibodies led to significantly lower post-HVT-IBD vector vaccine seroconversion, as compared to high titres (between 14000 and 16000). No negative interaction between the antibodies and the vaccine intake was shown, and in opposite, it seemed that these high titres were ‘favorable’ to HVT-IBD vector vaccine injected in ovo intake. Levels of IBD maternal antibodies were still high (between 2000 and 4000 with the ‘IBD classic’ kit and between 14000 and 16000 with the ‘IBD plus’ kit), displaying expected results, in birds not born to breeders vaccinated with the IBD inactivated vaccine alone, having received at least one VAXXITEK HVT+IBD, despite the late laying period, superior to 40 weeks in both genetics. The interest of priming with the HVT-IBD vector vaccine prior to IBD inactivated vaccine re-vaccination of future breeders, in order to get high levels of IBD maternal antibodies and to prepare the embryos to be themselves stimulated immunologically by the HVT-IBD vector vaccine VAXXITEK HVT+IBD, was demonstrated using late laying period serological data.

 

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