Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, NEA, ARS, USDA, Building 1040, BARC-EAST, Beltsville, MD 20705, USA.
Mountaire Farms, Inc., Millsboro, DE 19966, USA.
Poult Sci. 2019 Aug 1;98(8):3176-3180. doi: 10.3382/ps/pez147.
The purpose of this study was to determine if Eimeria oocysts recovered from litter at the time of chick placement in commercial broiler houses contained oocysts that were infectious for chickens. Over 100 litter samples were collected from 30 poultry farms representing a total of 60 different broiler houses with 9 houses sampled more than once over 1.5 yr. The samples were collected just before the placement of newly hatched chicks and after an anticoccidial drug (ACD) or Eimeria vaccine (VAC) program, and processed for counting oocysts followed by Eimeria species determination using ITS1 PCR. Broiler chicks were inoculated with recovered Eimeria oocysts to determine if the litter oocysts were viable and capable of causing patent infection. At placement, E. maxima (Emax) oocysts were detected in 70 of 75 houses after ACD program and 46 of 47 houses after VAC program. Eimeria acervulina, E. praecox, and/or E. tenella (Eapt) were detected in 75 of 75 houses after ACD program and 47 of 47 houses after VAC program. Viability testing revealed that 33.0% of broiler houses contained viable Emax oocysts, while 46.9% contained viable Eapt oocysts. During VAC programs, the concentration of Emax oocysts at placement and the total number of Emax oocysts shed by chickens in viability studies showed a very strong correlation (r = 0.83). Likewise, during ACD programs, the concentration of Eapt oocysts at placement and the total number of Eapt oocysts shed by chickens in the viability study showed a strong correlation (r = 0.62). In general, Eimeria oocyst levels at placement and number of viable oocysts shed by chickens in the viability study were similar among houses on the same farm. However, the number of Eimeria oocysts shed in the viability studies was considerably less than expected based on the number of oocysts given. These data suggest that nearly 100% of all poultry houses contain Emax and Eapt oocysts at placement with 30 to 50% of the houses containing viable Eimeria oocysts, thus possibly representing a source of the protozoa to newly hatched chicks.
本研究旨在确定在商业肉鸡舍放置雏鸡时从垫料中回收的艾美耳球虫卵囊是否含有对鸡具有感染力的卵囊。从 30 个家禽养殖场采集了超过 100 个垫料样本，这些养殖场共代表了 60 个不同的肉鸡舍，其中 9 个肉鸡舍在 1.5 年内被多次采样。这些样本是在刚孵化的雏鸡放置之前和抗球虫药（ACD）或艾美耳球虫疫苗（VAC）程序之后收集的，并进行了卵囊计数，然后使用 ITS1 PCR 确定艾美耳球虫种类。用回收的艾美耳球虫卵囊对肉鸡雏鸡进行接种，以确定垫料卵囊是否具有活力并能够引起显性感染。在 ACD 程序后，75 个肉鸡舍中有 70 个检测到最大艾美耳球虫（Emax）卵囊，47 个 VAC 程序后有 46 个检测到 Emax 卵囊。在 ACD 程序后，75 个肉鸡舍中有 75 个检测到柔嫩艾美耳球虫、毒害艾美耳球虫和/或堆型艾美耳球虫（Eapt）卵囊，47 个 VAC 程序后有 47 个检测到 Eapt 卵囊。活力测试显示，33.0%的肉鸡舍含有活的 Emax 卵囊，而 46.9%的肉鸡舍含有活的 Eapt 卵囊。在 VAC 程序期间，放置时 Emax 卵囊的浓度和活力研究中鸡排出的 Emax 卵囊总数之间存在很强的相关性（r=0.83）。同样，在 ACD 程序期间，放置时 Eapt 卵囊的浓度和活力研究中鸡排出的 Eapt 卵囊总数之间存在很强的相关性（r=0.62）。一般来说，同一养殖场的不同肉鸡舍之间，放置时的艾美耳球虫卵囊水平和活力研究中鸡排出的活卵囊数量相似。然而，根据给予的卵囊数量，活力研究中鸡排出的艾美耳球虫卵囊数量明显较少。这些数据表明，几乎 100%的家禽舍在放置时都含有 Emax 和 Eapt 卵囊，其中 30%至 50%的家禽舍含有活的艾美耳球虫卵囊，因此这些卵囊可能是刚孵化的雏鸡中这种原生动物的来源。
