Aynı Yaşta ve Aynı Aşı Programları ile Yetiştirilen Damızlık Ebeveynlerinden, Etlik Civcivlerine Aktarılan Maternal Antikor Seviyesinin Karşılaştırılması

Abstract

Maternal antibody transfer represents the primary protection mechanism for chicks during the early days of life, before their immune system reaches full maturity. The genetic makeup of breeder hens is recognized as a critical determinant of transfer efficiency, yet its influence on local poultry lines remains insufficiently characterized. This study compares maternal antibody levels transferred to offspring between two meat-type breeder genotypes, the commercial Cobb 500 line and the local Turkish line Anadolu-T against four pathogens: NDV, IBV, IBDV, and CAV. Both genotypes were subjected to identical rearing conditions and vaccination protocols. Blood samples were collected from a total of 96 animals: 48 breeder hens aged 62 weeks (24 per genotype) and 48 one-day-old chicks derived from these breeders. Serum antibody levels were measured by ELISA, and geometric mean titre (GMT), seroprotection rate, and maternal transfer rate were calculated. Results showed a 100% seroprotection rate for NDV, IBV, and IBDV in both genotypes. No significant difference was observed between genotypes for NDV. For IBV, Anadolu-T breeders exhibited significantly higher titres (p = 0.04), although this advantage was not significantly reflected in chicks. The most marked difference was observed for IBDV: Anadolu-T displayed substantially higher titres at all physiological stages (p < 0.001) with a higher maternal transfer rate (66.5% vs. 55.4%). Conversely, for CAV, Cobb 500 chicks showed significantly higher titres (p = 0.004) and a markedly superior maternal transfer rate (68.4% vs. 41.6%), despite comparable maternal titre levels. Significant positive correlations between titres against different pathogens suggest the existence of a general maternally transferable immune competence. Kinetic modelling of anti-IBDV antibody decay reveals a three-day shift in optimal vaccination windows between the two genotypes, directly attributable to the higher initial titres of Anadolu-T. These findings demonstrate that breeder genotype constitutes a determining parameter not only for the establishment of passive immunity, but also for the planning of active vaccination programmes.