Diseases of the Reproductive System
(M214) EPIDIDYMAL STONE FORMATION AND DECREASED SPERM PRODUCTION IN ROOSTERS VACCINATED WITH A KILLED STRAIN OF AVIAN INFECTIOUS BRONCHITIS VIRUS.
Boltz, David1, Zimmerman, Claire1, Bahr, Janice1, 1 Universirty of Illinois Urbana-Champaign, Urbana, IL
ABSTRACT- Avian infectious bronchitis virus (AIBV), a respiratory virus, has a tropism for the rooster reproductive tract and is capable of infecting the epididymal region of the rooster. Vaccination of roosters with live attenuated AIBV causes stones and reduces fertility. Our objective was to determine if vaccinating with killed AIBV would cause stones and reduced fertility. Killed AIBV, unlike live attenuated AIBV, is inactivated and unable to cause infection. Specific Pathogen Free (SPF) roosters were divided into three groups: a non-vaccinated group (SPF), a live attenuated AIBV vaccinated group (LVAC), a killed AIBV vaccinated group (KVAC). Roosters were vaccinated at 2, 6, 10, and 14 wks. At 28 wks the reproductive tract was removed and examined for stones and prepared for histology, testis weight and daily sperm production were determined. Stones were present in one (1/8) SPF birds, whereas 50% (5/10) of the KVAC and 64% (7/11) of LVAC roosters had stones. Testes weights were not different among the three groups. Daily sperm production (sperm/testis/day) was reduced in KVAC (4.4 ± 0.7 x 108) and in LVAC (3.9 ± 0.3 x 108, p<0.05) when compared to SPF roosters (4.9 ± 0.4 x 108). When comparing roosters within groups: LVAC with stones had an increased testis weight (11.3 ± 1.0 g) when compared to LVAC without stones (10.9 ± 1.9 g). Daily sperm production was reduced in LVAC roosters with stones (3.8 ± 0.4 x 108) when compared to LVAC without stones (4.2 ± 0.7 x 108). Testis weight was reduced in KVAC with stones (9.9 ± 0.9 g, p<0.05) when compared to KVAC without stones (13.3 ± 1.8 g). Daily sperm production was reduced in KVAC with stones (3.4 ± 0.4 x 108, p<0.05) when compared to KVAC without stones (6.3 ± 1.0 x 108). Histologically, seminiferous tubules were normal in KVAC and LVAC when compared to SPF controls. Efferent ductules (ED) from roosters without stones were normal. ED from roosters with stones were infiltrated with immune cells surrounding the area where a stone was present. We conclude that the use of a killed vaccine does not reduce the incidence of epididymal stones. It is possible AIBV proteins resemble those of the rooster resulting in an autoimmune response. Supported by NIH PHS T32 HD07028, NIH PHS 2 T32 GM07283 & USDA-NRI Grant 2004-35203-14770.
KEY WORDS: reduced fertility, epididymal stones, aibv, killed vaccine