Objective

Keeping in view, the constraints faced by the Indian broiler industry with lack of a suitable vaccine against Necrotic Enteritis (NE), a study has been proposed to explore the prevalence and detail characterization of C. perfringens type G in NE suspected broiler chicken in the process of suitable vaccine development.

Methods

Intestinal scrapings/faecal contents of NE suspected broiler chickens were screened to establish the prevalence of C.perfringens type G in broiler birds. A most pathogenic, highly resistant type G isolate of C. perfringens, bearing both tpeL and gapC gene was selected for preparation of three different vaccine formulations, and to evaluate their immunogenic potential in broiler birds.

Results

Screening of clinical samples of NE suspected broiler birds revealed C. perfringens type G, bearing gapC gene in 51.22% samples, of which 47.62% revealed tpeL gene. Seven of the tpeL ^pos type G isolates were comparatively more pathogenic for mice, of which, one exhibited multidrug resistance towards ciprofloxacin, norfloxacin, tetracycline and levofloxacin. The sonicated supernatant (SS) prepared from the selected tpeL and gapC positive isolate could maintain a significantly higher protective IgG response than toxoid and bacterin preparation from the 21st to 28^thday of age in immunized birds.

Conclusion

The additional TpeL toxin in C. perfringens type G has been proved to be an additional key biological factor in the pathogenesis of NE in broiler chickens. Considering the release of more immunogenic proteins, the SS proved to be a better immunogenic preparation against NE with a multiple immunization dose.

中文翻译：

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使用新型产气荚膜梭菌 G 型菌株评价肉鸡坏死性肠炎的不同抗原制剂

客观的

考虑到印度肉鸡行业面临缺乏针对坏死性肠炎 (NE) 的合适疫苗的限制，已提出一项研究，以探讨NE 疑似肉鸡中产气荚膜梭菌G 型的流行情况和详细特征。合适的疫苗开发过程。

方法

对 NE 疑似肉鸡的肠道刮屑/粪便内容物进行筛选，以确定肉鸡中产气荚膜杆菌G 型的流行率。选择具有tpeL和gapC基因的最具致病性、高度抗性的 G 型产气荚膜梭菌分离物用于制备三种不同的疫苗制剂，并评估它们在肉鸡中的免疫原性潜力。

结果

NE 疑似肉鸡的临床样本筛查显示产气荚膜梭菌G 型，51.22% 的样本中带有gapC基因，其中 47.62% 的样本带有 tpeL基因。tpeL ^pos G 型分离株中有7株对小鼠的致病性相对较强，其中1 株对环丙沙星、诺氟沙星、四环素和左氧氟沙星表现出多药耐药性。由选定的tpe L 和gap C 阳性分离物制备的超声处理上清液 (SS)可以在免疫鸟类中从第 21天到^第28天保持比类毒素和菌苗制备物显着更高的保护性 IgG 反应。

结论

产气荚膜梭菌G 型中的额外 TpeL 毒素已被证明是肉鸡 NE 发病机制中的额外关键生物学因素。考虑到更多免疫原性蛋白质的释放，SS 被证明是针对 NE 的更好的免疫原性制剂，具有多重免疫剂量。