Abstract

Salmonella is a pathogen normally found in the gastrointestinal tract of poultry. The objective of this study was to determine changes in avian β-defensin (AvBD) and liver-enriched antimicrobial peptide 2 (LEAP2) mRNA following Salmonella challenge. Day of hatch chicks were challenged with 10⁶, 10⁷ or 10⁸ colony-forming units (cfu) of Salmonella typhimurium. There were dose-, tissue- and age-specific changes in AvBD and LEAP2 mRNA. At 1-day post-infection (dpi) there was a transient upregulation of AvBD1, 8, 10 and 12 mRNA in the 10⁸ cfu group. At 5 dpi, all seven AvBD mRNA were downregulated in the ileum, while only AvBD1, 6, 10 and 11 mRNA were downregulated in the jejunum and AvBD6, 8, 10, 12 and 13 were downregulated in the cecum. At 7 dpi, there was downregulation of all seven AvBD mRNA in the duodenum and downregulation of selected AvBD in the jejunum, ileum and cecum. LEAP2 mRNA was downregulated at all doses of Salmonella in the cecum at 1 dpi and in the ileum at 5 dpi. In summary, Salmonella infection caused an initial upregulation followed by a downregulation of AvBD mRNA.

摘要

沙门氏菌是一种通常存在于家禽胃肠道中的病原体。本研究的目的是确定沙门氏菌攻击后禽类 β-防御素 (AvBD) 和富含肝脏的抗菌肽 2 (LEAP2) mRNA 的变化。用10 ⁶、10 ⁷或10 ⁸鼠伤寒沙门氏菌菌落形成单位(cfu)攻击孵化日雏鸡。AvBD 和 LEAP2 mRNA 存在剂量、组织和年龄特异性变化。在感染后 1 天 (dpi)，AvBD1、8、10 和 12 mRNA 在 10 ⁸cfu组。在 5 dpi，所有 7 种 AvBD mRNA 在回肠中均下调，而只有 AvBD1、6、10 和 11 mRNA 在空肠中下调，而 AvBD6、8、10、12 和 13 在盲肠中下调。在 7 dpi，十二指肠中所有 7 个 AvBD mRNA 都下调，空肠、回肠和盲肠中选定的 AvBD 下调。LEAP2 mRNA在第 1 天盲肠和第 5 天回肠中所有沙门氏菌剂量下均下调。总之，沙门氏菌感染引起了 AvBD mRNA 的初始上调，然后是下调。