Effects of infectious bronchitis virus on the oviduct of laying hens

Abstract

The research described in this thesis was conducted to study the pathogenesis of Australian strains of infectious bronchitis virus (IBV) on the oviduct of laying hens and also to the study whether the Australian strains of IBV have negative effects on egg production and quality. All the trials were conducted using two strains of IBV, T and N1/88. The two strains have been placed in different groups, based on their genotypic variation of which T is highly nephropathogenic and N1/88 is a respiratory strain. A range of experiments has been conducted. In the preliminary trial, the histopathology of IBV was studied in unvaccinated White Leghorn hens and cockerels. IBV appeared to be pathogenic for all parts of the oviduct of White Leghorn hens at 65 weeks of age and hens were more severely affected than cockerels. Both the strains of IBV can induce pathology in the trachea and kidney of hens and cockerels. Based on the histopathological findings, it was concluded that rearing phase vaccine offers limited protection in HyLine Grey hens of 110 weeks of age.