Department of Poultry Science, University of Georgia, Athens, GA, USA.
Animal Bioscience and Biotechnology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, MD, USA.
Poult Sci. 2023 Oct;102(10):102841. doi: 10.1016/j.psj.2023.102841. Epub 2023 Jun 7.
Necrotic enteritis (NE) is a widespread infectious disease caused by Clostridium perfringens that inflicts major economic losses on the global poultry industry. Due to regulations on antibiotic use in poultry production, there is an urgent need for alternative strategies to mitigate the negative effects of NE. This paper presents a passive immunization technology that utilizes hyperimmune egg yolk immunoglobulin Y (IgY) specific to the major immunodominant antigens of C. perfringens. Egg yolk IgYs were generated by immunizing hens with 4 different recombinant C. perfringens antigens, and their protective effects against NE were evaluated in commercial broilers. Six different spray-dried egg powders were produced using recombinant C. perfringens antigens: α-toxin, NE B-like toxin (NetB; EB), elongation factor-Tu (ET), pyruvate:ferredoxin oxidoreductase, a mixture of 4 antigens (EM-1), and a nonimmunized control (EC). The challenged groups were either provided with different egg powders at a 1% level or no egg powders (EN). The NE challenge model based on Eimeria maxima and C. perfringens dual infection was used. In Experiments 1 and 2, the EB and ET groups exhibited increased body weight gain (BWG; P < 0.01), decreased NE lesion scores (P < 0.001), and reduced serum NetB levels (P < 0.01) compared to the EN and EC groups. IgY against NetB significantly reduced Leghorn male hepatocellular cytotoxicity in an in vitro test (P < 0.01). In Experiment 3, the protective effect of the IgYs mixture (EM-2) against C. perfringens antigens (NetB and EFTu) and Eimeria antigens (elongation factor-1-alpha: EF1α and Eimeria profilin: 3-1E) was tested. The EM-2 group showed similar body weight, BWG, and feed intake from d 7 to 22 compared to the NC group (P < 0.05). On d 20, the EM-2 group showed comparable intestinal permeability, NE lesion scores, and jejunal NetB and collagen adhesion protein levels to the NC group (P < 0.05). In conclusion, dietary mixture containing antibodies to NetB and EFTu provides protection against experimental NE in chickens through passive immunization.
坏死性肠炎（NE）是一种由产气荚膜梭菌引起的广泛传染病，给全球家禽业造成了重大经济损失。由于家禽生产中对抗生素使用的规定，急需替代策略来减轻 NE 的负面影响。本文介绍了一种利用针对产气荚膜梭菌主要免疫优势抗原的高免卵黄免疫球蛋白 Y（IgY）的被动免疫技术。通过用 4 种不同的重组产气荚膜梭菌抗原免疫母鸡来产生卵黄 IgY，并在商业肉鸡中评估其对 NE 的保护作用。使用重组产气荚膜梭菌抗原生产了 6 种不同的喷雾干燥卵黄粉：α-毒素、NE B 样毒素（NetB；EB）、延伸因子-Tu（ET）、丙酮酸：铁氧还蛋白氧化还原酶、4 种抗原的混合物（EM-1）和非免疫对照（EC）。用不同的卵黄粉处理组的添加水平为 1%或不添加卵黄粉（EN）。采用基于最大艾美耳球虫和产气荚膜梭菌双重感染的 NE 挑战模型。在实验 1 和实验 2 中，与 EN 和 EC 组相比，EB 和 ET 组的体重增加（BWG；P < 0.01）增加，NE 病变评分（P < 0.001）降低，血清 NetB 水平（P < 0.01）降低。针对 NetB 的 IgY 显著降低了体外莱航雄性鸡肝细胞的细胞毒性（P < 0.01）。在实验 3 中，测试了 IgY 混合物（EM-2）对产气荚膜梭菌抗原（NetB 和 EFTu）和艾美耳球虫抗原（延伸因子-1-α：EF1α和艾美耳原肌球蛋白：3-1E）的保护作用。与 NC 组相比，EM-2 组在第 7 至 22 天的体重、BWG 和采食量相似（P < 0.05）。在第 20 天，EM-2 组的肠道通透性、NE 病变评分以及空肠 NetB 和胶原蛋白黏附蛋白水平与 NC 组相似（P < 0.05）。总之，含有针对 NetB 和 EFTu 的抗体的饮食混合物通过被动免疫为鸡提供了对实验性 NE 的保护。
