The dynamic changes of tissue structure in 4 days old ducklings which were infected with chicken embryo attenuatedstrain MY of duck hepatitis virus were observed.
对鸭肝炎鸡胚化弱毒株MY接种4日龄雏鸭后的组织变化进行了动态观察比较研究。
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Conclusion The JEV attenuatedstrain SA14-14-2 is genetic stability after passaged continuously on PHKC to 20 generations, and proved a good safety on molecular level.
The results showed that the numbers of IEL in tracheas was increased significantly (P<0.01) with PRRS attenuatedstrain immunization by nasal route contrast to muscle injection and control group;