中文摘要：

在实验条件下观察自主研制的四价鸡球虫苗（LCV）对平养鸡的安全性和免疫保护效果。试验设空白对照组（NC）、攻虫对照组（PC）和免疫组（VC）3个试验组，每组30只鸡。试验结果：空白对照组、攻虫对照组和免疫组的相对增重率依次为100％、84．77％和94．97％；免疫后（免疫后攻虫前）排卵囊高峰期间（免疫后5d～10d），免疫组平均OPG（即每克粪便中的卵囊数）为2．70×10^4，攻虫后排卵囊高峰期间（攻虫后6d～13d）攻虫对照组组平均OPG为2．32×10^4，高于免疫组（2．69×10^5）（p〈0．01）；攻虫后各组死亡率依次为0、10％和0；3个组的ACIf抗球虫指数1分别为200．0、154．77和184．97，免疫组试验效果最佳。结果表明，LCV安全性高、免疫保护效果理想，接种该疫苗后的鸡对较大剂量攻虫具有较强的抵抗力。

英文摘要：

The protective efficacy of a vaccine against coccidiosis was examined in Lingnanhuang female broilers kept in floor-pens. Three trail groups, including negative group （NC）, positive group （PC） and vaccinated group （VC） was tested, and each group comprised 30 broilers. The results showed that the average relative ratio of weight gain of 3 groups were 100 %, 84.77 % and 94.97 %, respectively. The OPG of PC group （2.32× 10^6） was significantly higher （p〈0.01） than vaccinated group （2.69×10^5） after challenge infection. The mortality rate of 3 groups were 0, 10 % and 0, respectively. Furthermore, higher ACI were detected in NC （200） and VC birds （184.97）, which were significantly higher than that of PC birds （154.77）.