鸡球虫病三价四株活疫苗实验室效力试验

Research on the Laboratory Efficacy of Trivalent Live Vaccine with Four Strains against Avian Coccidiosis

为了确定鸡球虫病三价四株活疫苗的免疫效果,对鸡球虫病三价四株活疫苗进行了最小免疫剂量、最小首免日龄、最小二免间隔期、免疫产生期和持续期以及网上平养和地面平养试验。结果显示,当鸡球虫病三价四株活疫苗一免/二免剂量分别≥1600和3200个孢子化卵囊/只时,可达到良好免疫效果,符合疫苗效力检验标准;首免日龄≥4日龄的免疫攻毒组鸡至少9只雏鸡3个肠段的病变记分均≤1.0,死亡率≤10.0%,符合效力检验标准;二免间隔在7~11 d时均能够获得良好的免疫效果;鸡只在二免后第6~56天可产生足够免疫保护;网上和地面平养对免疫鸡群的生长性能与疫苗的免疫效果并无显著差异,均符合疫苗效力检验标准。表明鸡球虫病三价四株活疫苗的最小免疫剂量:一免剂量为1600个孢子化卵囊/只,二免剂量为3200孢子化卵囊/只;最小首免日龄为4日龄;最小二免间隔为7 d;免疫产生期为二免后的第6天,免疫持续期可至二免后第56天;该疫苗可用于网上和地面平养鸡的免疫。

In order to determine the immune effect of the trivalent live vaccine with four strains against avian coccidiosis,the experiments of the minimum immune dose,the minimum age of first immunization,the minimum interval of second immunization,the period of immune production and duration,and the experiments of cage-rearing and floor-rearing were studied.The data showed that,when the first immunizing dose was at least 1600 oocysts/per,and the second immunizing dose was at least 3200 oocysts/per,the good immune effect was achieved and the efficacy of the vaccine was met.When first immunizing age was higher than 4 day-old,the average lesion score in 3 intestinal segments of at least 9 chicks was at most 1.0 and mortality was at least 10.00%.All indexes were up to the efficacy test standards.When the interval between the two immunizations was 7~11 days,good immune effect was obtained.The chickens produced enough immune protection from the 6th to the 56th day after the second immunization.Growth performance of immunized chickens and immune effect of vaccines had no significant difference between cage and floor rearing chicks,and both feeding methods met the testing criteria for vaccine efficacy.The results showed that each chicken of the first immunizing dose of the trivalent live vaccine with four strains against avian coccidiosis was 1600 sporidized oocysts and the second immunizing dose was 3200 sporidized oocysts.Age of 4 days was the minimum age for the first immunization.The minimum interval of second immunization was 7 days.The period of immune production was the 6th day after the second immunization and the immune duration can reach 56th day after the second immunization.The vaccine can be used to immunize cage and floor rearing chicks.