He Wanwei, Goes Emanuele C, Wakaruk Jeremy, Barreda Daniel R, Korver Douglas R
Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
Front Physiol. 2022 Jun 8;13:788592. doi: 10.3389/fphys.2022.788592. eCollection 2022.
Necrotic enteritis (NE) in poultry is an opportunistic infection caused by . Well-known as a multifactorial disease, NE development is under the influence of a wide range of environmental risk factors that promote the proliferation of pathogenic at the expense of nonpathogenic strains. Current NE challenge models typically incorporate pre-exposure to disease risk factors, in combination with exogenous inoculation. Our goal was to enhance current models using a natural uptake of from the barn environment to produce a subclinical infection. We incorporated access to litter, coccidial exposure (either 10× or 15× of the manufacturer-recommended Coccivac B52 vaccine challenge; provided unspecified doses of , and two strains of ), feed composition, and feed withdrawal stress, and achieved the commonly observed NE infection peak at 3 weeks post-hatch. NE severity was evaluated based on gut lesion pathology, clinical signs, and mortality rate. Under cage-reared conditions, 15× coccidial vaccine-challenged birds showed overall NE lesion prevalence that was 8-fold higher than 10× coccidial vaccine-challenged birds. NE-associated mortality was observed only in a floor-reared flock after a 15× coccidial vaccine challenge.
家禽坏死性肠炎（NE）是由……引起的一种机会性感染。作为一种多因素疾病，NE的发生受到多种环境风险因素的影响，这些因素以非致病性菌株为代价促进病原菌的增殖。当前的NE攻毒模型通常包括预先暴露于疾病风险因素，并结合外源性……接种。我们的目标是通过让家禽自然摄取禽舍环境中的……以产生亚临床感染来改进当前模型。我们纳入了接触垫料、球虫暴露（制造商推荐的Coccivac B52疫苗攻毒剂量的10倍或15倍；提供未指明剂量的……以及两种……菌株）、饲料组成和禁食应激等因素，并在孵化后3周达到了常见的NE感染高峰。基于肠道病变病理学、临床症状和死亡率对NE的严重程度进行评估。在笼养条件下，接受15倍球虫疫苗攻毒的家禽总体NE病变发生率比接受10倍球虫疫苗攻毒的家禽高8倍。仅在地面饲养的鸡群中，接受15倍球虫疫苗攻毒后观察到了与NE相关的死亡情况。
