不同剂量和免疫次数对鸡毒害艾美耳球虫免疫保护力的影响

Effects of Vaccinating Times and Dosages with Oocysts of E.necatrix on the Specific Immunity

以相对增重率(RBWG)、饲料转化率(FCR)和盲肠相对卵囊产量(ROP)为指标,评价了1次或2次分别以1×103个或3×103个毒害艾美耳球虫(E.necatrix)孢子化卵囊(SO)/鸡剂量免疫接种后特异性免疫力的产生和持续时间。笼养岭南黄肉雏鸡于3日龄1次或3日龄和10日龄2次分别接种不同剂量的E.necatrix SO后,于17日龄(2次免疫组为24日龄)、34日龄和50日龄时以14×104SO/鸡剂量的同源卵囊攻虫,结果表明,免疫后2周卵囊接种鸡已产生坚强免疫力,1次免疫接种者(17日龄)高、低2个不同剂量组的RBWG、FCR和ROP分别为95.5%、2.32、24.54%和101.4%、2.32、21.1%;而2次免疫组(24日龄)的上述指标则分别为106.5%、2.44、9.3%和98.2%、2.38、7.48%。至34日龄和50日龄攻虫时,这些指标均有不同程度的下降,且随着时间延长,下降更为明显,但2次免疫处理组的这些指标均明显优于1次免疫者;同一次处理的不同剂量组间无明显差异。结果揭示,雏鸡口服免疫接种一定剂量的E.necatrix孢子化卵囊后可迅速诱导鸡体特异性免疫力的产生,但免疫保护力在笼养条件下持续时间较短。

The immunoprotection induced by the sporulated oocysts of Eimeria necatrix vaccination in the single dose of 1 （low） or 3（high） × 10^3 at 3 day-old or dual doses of 1 or 3×10^3 at 3 and 10-day-old were evaluated with the parameter of relative body weight gain （RBWG）, feed conversation rate （FCR） and relative cecal oocyst product ion （ROP）. The caged vaccinated chickens were challenged using E. necatrix sporulated oocysts with a dose of 14 × 10^4 at 17（single dose）- or 24（dual dose）-dayold, 34- and 50-day-old ,respectively. The results showed that the specific immunity to the challenged E. necatrix could be produced 2 weeks post immunization. The parameters of RBWG,FCR and ROP in the single dose treatment with low vaccinated dose were 95.5%,2.32 and 24.545,vs. 101.4% ,2.32 and 21.1% in high immunized dose group challenged at 17-day-old. The better immunoprotection could be found in the treatment with dual vaccination at low or high dose. The parameters were 106.5% ,2.44 and 9.3% in low dose treatment and 98.2% ,2.38 and 7.48% in high dose treatment when challenged at 24-day-old,respectively. All the parameters reduced as the challenged day-old was postponed,but higher immunoprotection was ob- served in the groups with dual doses vaccination.