Montgomery R D, Boyle C R, Maslin W R, Magee D L
College of Veterinary Medicine, Mississippi State University 39762-9825, USA.
Avian Dis. 1997 Jan-Mar;41(1):80-92.
Various organisms, including 12 aerobic and 2 anaerobic bacteria, an infectious bronchitis virus (IBV), a reovirus, and 2 bacteriophages, were isolated from intestinal tracts of commercial broiler chicks undergoing a runting/stunting-type condition. In a series of trials, these agents were given alone and in combination to 1-day-old chicks in an attempt to reproduce the field condition. Because the agents were isolated and evaluated over time, an augmented designs variation of the analysis of variance proved particularly useful in analyzing the data collected and minimizing bird usage. Chicks inoculated with tryptose phosphate broth served as negative controls, and those inoculated with the original intestinal tract material were positive controls. Relative to the negative control chicks, body weights of the positive control chicks and of chicks inoculated with several of the agent combinations were depressed at 7, 14, and 21 days postinoculation. Common to combinations that most consistently caused weight depression were reovirus + IBV + others of the agents isolated. However, because none of the agent combinations reproduced the lethargy or dry feces seen in the positive controls, none was considered to be the ultimate cause of this particular runting/stunting-type condition. Further characterization of the disease syndrome was based on the positive control chicks. These chicks consistently had lowered body weights and transient lethargy and dry fecal pellets. Microscopic lesions consisted of lymphocytic renal and pancreatic interstitial infiltrates, dilated or cystic duodenal and jejunal crypts of Lieberkühn, increased crypt depth, and increased cellularity in the intestinal lamina propria. Electron microscopy revealed regular arrays of 26-nm viral particles, usually in association with membrane debris, in intestinal epithelial cells and crypt lumens and in intestinal and renal mesenchymal cells. These viral particles were theorized to be essential to reproduction of the complete malady seen.
从患有发育迟缓/生长受阻型病症的商品肉鸡肠道中分离出了多种生物体，包括12种需氧菌和2种厌氧菌、一种传染性支气管炎病毒（IBV）、一种呼肠孤病毒以及2种噬菌体。在一系列试验中，将这些病原体单独或组合接种给1日龄雏鸡，试图重现田间病症情况。由于这些病原体是随着时间推移分离和评估的，方差分析的增广设计变体在分析所收集的数据以及尽量减少雏鸡使用量方面被证明特别有用。接种胰蛋白胨磷酸盐肉汤的雏鸡作为阴性对照，接种原始肠道物质的雏鸡作为阳性对照。与阴性对照雏鸡相比，阳性对照雏鸡以及接种几种病原体组合的雏鸡在接种后第7、14和21天体重下降。最一致导致体重下降的组合共同特点是呼肠孤病毒+传染性支气管炎病毒+其他分离出的病原体。然而，由于没有一种病原体组合能重现阳性对照中出现的嗜睡或粪便干结症状，因此没有一种被认为是这种特定发育迟缓/生长受阻型病症的根本原因。对疾病综合征的进一步特征描述基于阳性对照雏鸡。这些雏鸡体重持续降低，有短暂的嗜睡和干结粪便颗粒。显微镜下病变包括淋巴细胞性肾和胰腺间质浸润、十二指肠和空肠的利伯kühn隐窝扩张或呈囊状、隐窝深度增加以及肠固有层细胞增多。电子显微镜显示，在肠道上皮细胞、隐窝腔以及肠道和肾间质细胞中存在规则排列的26纳米病毒颗粒，通常与膜碎片相关。据推测，这些病毒颗粒对于所观察到的完整病症的发生至关重要。
