Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Malaysia.
Institute of Bioscience, Universiti Putra Malaysia, Serdang, Malaysia.
Open Vet J. 2022 Nov-Dec;12(6):839-850. doi: 10.5455/OVJ.2022.v12.i6.8. Epub 2022 Nov 14.
The studies about infection in newly hatched chicks were not extensive.
The objective of this study was to determine the pathogenicity of subspecies serovar (SE) phage type (PT) 1 in one-day-old specific pathogen-free (SPF) chicks.
Seventy, one-day-old SPF chicks, were divided into SE group (30 chicks), mortality group (10 chicks), both orally inoculated (1.0 ml) with SE PT1 (1 × 10 colony-forming unit per 1.0 ml), and one control group (30 chicks). The chicks were sacrificed at 6 and 12 hours, and days 1, 2, 3, 5, 7, 10, 14, and 21 post-inoculation (pi). Samples were collected for bacterial isolation, histological examination, and ultrastructural examination.
Starting from day 2 pi, the body weight in the SE group significantly ( < 0.05) decreased. The SE isolation percentages from the liver, spleen, mid-intestinal content, cecal content, cecal tonsil, blood, and cloacal swab were 0.73, 0.77, 0.33, 0.33, 0.36, 0.40, and 0.30, respectively. The isolation percentage in the liver was significantly ( < 0.05) higher than the blood and cloacal swab. The villi heights and crypt depths in the SE group were significantly ( < 0.05) greater and smaller, respectively. Ultrastructurally, erosion and necrosis were observed in the microvilli of the cecal tonsil. The bacteria were engulfed by macrophages at the interepithelial clefts of the M-like M cells.
It was concluded that the inoculation of SE PT 1 in one-day-old chicks caused a systemic infection with diarrhea, a decrease in the body weight and villi height in the duodenum, jejunum, and ileum, and high bacterial loading in the liver with mild gross and histological lesions of organs, erosion, and necrosis of microvilli and low mortality. The bacteria entered the body system from the intestinal tract through the interepithelial clefts of the M-like M cells of the cecal tonsil.
关于刚孵出小鸡感染的研究并不广泛。
本研究旨在确定 1 日龄 SPF 雏鸡亚种血清型（SE）噬菌体型（PT）1 的致病性。
将 70 只 1 日龄 SPF 雏鸡分为 SE 组（30 只）、死亡率组（10 只），两组均经口接种 SE PT1（1.0ml 中含 1×10 个集落形成单位），对照组（30 只）。接种后 6 小时和 12 小时，以及 1、2、3、5、7、10、14 和 21 天处死小鸡。采集样本进行细菌分离、组织学检查和超微结构检查。
从接种后第 2 天开始，SE 组的体重显著下降（<0.05）。肝脏、脾脏、中肠内容物、盲肠内容物、盲肠扁桃体、血液和泄殖腔拭子中 SE 的分离率分别为 0.73%、0.77%、0.33%、0.33%、0.36%、0.40%和 0.30%。肝脏的分离率显著高于血液和泄殖腔拭子（<0.05）。SE 组绒毛高度和隐窝深度显著增大和减小（<0.05）。超微结构观察发现，盲肠扁桃体微绒毛有侵蚀和坏死。细菌被 M 样 M 细胞的上皮间裂隙中的巨噬细胞吞噬。
接种 1 日龄雏鸡 SE PT1 可引起全身感染，导致腹泻、十二指肠、空肠和回肠绒毛高度和体重下降，肝脏细菌负荷增加，器官大体和组织学病变轻微，微绒毛侵蚀和坏死，死亡率低。细菌从肠道通过盲肠扁桃体的 M 样 M 细胞的上皮间裂隙进入机体系统。
