Chew P H, Wakenell P S, Farver T B
School of Veterinary Medicine, Department of Population Health and Reproduction, University of California, Davis 95616, USA.
Avian Dis. 1997 Jul-Sep;41(3):598-603.
A fixed effects, completely randomized factorial design was used to study the effect of infectious bronchitis virus (IBV) inoculation at two different exposure ages and three postinoculation (PI) durations on chick oviduct pathology. Maternal antibody-positive chicken embryos at 18 days of embryonation (ED) and newly hatched chicks were inoculated with an IBV vaccine (V-IBV) or with an IBV vaccine that had been serially passaged 21 times in chick kidney tissue culture (P-IBV). Hatchability of eggs inoculated with V-IBV at 18 ED was significantly lower (27%) than eggs that were not inoculated with IBV or were inoculated with P-IBV (45-58%, P < 0.01). Chicks from all treatment groups survived to 5 days after hatch. Pathologic changes in the oviduct were evaluated at 9, 18, and 27 days PI by light microscopy. Inoculation of V-IBV and P-IBV in the presence of maternal antibodies did not result in any oviduct pathology at 9, 18, and 27 days PI. Respiratory clinical signs, however, were observed in 61% and 5% of chicks inoculated with V-IBV at 18 ED and at hatch, respectively. Respiratory clinical signs were not observed in control birds, birds inoculated with P-IBV at 18 ED, or birds inoculated with P-IBV at hatch.
采用固定效应完全随机析因设计，研究两种不同暴露年龄接种传染性支气管炎病毒（IBV）以及接种后（PI）三个不同时间段对雏鸡输卵管病理学的影响。对18日胚龄（ED）的母源抗体阳性鸡胚和新孵出的雏鸡接种IBV疫苗（V-IBV）或在鸡肾组织培养中连续传代21次的IBV疫苗（P-IBV）。18日胚龄接种V-IBV的种蛋孵化率（27%）显著低于未接种IBV或接种P-IBV的种蛋（45 - 58%，P < 0.01）。所有处理组的雏鸡均存活至出壳后5天。在接种后9、18和27天，通过光学显微镜评估输卵管的病理变化。在母源抗体存在的情况下接种V-IBV和P-IBV，在接种后9、18和27天未导致任何输卵管病变。然而，分别在18日胚龄和出壳时接种V-IBV的雏鸡中，观察到61%和5%出现呼吸道临床症状。在对照鸡、18日胚龄接种P-IBV的鸡或出壳时接种P-IBV的鸡中未观察到呼吸道临床症状。
