Avian infectious bronchitis virus: A tropism for the rooster reproductive tract and effects on reproductive performance.

摘要

The epididymal region of the rooster consists of the rete testes, the efferent ductules and the epididymal duct. In the epididymal region, the spermatozoa gain the ability to move and acquire surface proteins. The specialized microenvironment of the epididymal region is vital for these developments to occur. A dysfunction of the epididymal region, epididymal stones, has been shown to affect fertility in the rooster. The cause of these epididymal stones was investigated and avian infectious bronchitis virus (AIBV) has been identified as a cause. AIBV is a highly contagious respiratory disease in chickens. The pathogenesis of AIBV in the female reproductive tract has been well studied; however, there have been few studies concerning the effects of AIBV on the rooster reproductive tract. Therefore this investigation was undertaken to identify the role of AIBV in epididymal stone formation and to characterize changes in seminal plasma composition. Specific objectives were: (1) to determine if AIBV can infect the epididymal region; (2) to investigate if vaccination with killed AIBV would result in epididymal stone formation; (3) to determine if AIBV affects fertility by altering composition of seminal plasma; and (4) to characterize protein changes in seminal plasma in response to AIBV vaccination with two dimensional gel electrophoresis. There were four major findings; First, replication of AIBV in the epididymal region of the rooster reproductive tract was detected using 3' RACE indicating the epididymal region is a target for the virus in vitro. Second, vaccination with killed AIBV did not reduce the incidence of epididymal stones; therefore, entrance and replication of AIBV in the reproductive tract is not required for stone formation. Third, seminal plasma protein patterns and free amino acid levels are altered in vaccinated roosters when compared to non-vaccinated roosters. Fourth, differentially expressed seminal plasma proteins were identified in vaccinated roosters when compared to non-vaccinated roosters. These data provide further evidence that the proper function of the efferent ductules is necessary for normal fertility and exposure to AIBV disrupts fertility.