Nephropathogenic infectious bronchitis virus can induce duodenum inflammation and barrier defect in Hy-Line brown...

Area of Science:

• Poultry Health
• Virology
• Immunology

Background:

• Nephropathogenic infectious bronchitis virus (NIBV) commonly affects poultry, causing kidney, respiratory, and intestinal damage.
• Intestinal damage from NIBV is under-researched, despite the intestine being a major immune organ.
• Understanding NIBV's impact on the duodenal barrier is crucial for poultry health management.

Purpose of the Study:

• To investigate the effects of NIBV infection on the duodenal intestinal barrier function in chickens.
• To analyze histopathological changes and cytokine expression in the duodenum following NIBV inoculation.

Main Methods:

• Hy-Line brown chickens were divided into control and NIBV-infected groups.
• NIBV SX9 was inoculated into 28-day-old pullets in the disease group.
• Duodenal tissues were analyzed for histopathology, SIgA content, and expression of barrier-associated cytokines.

Main Results:

• NIBV infection caused duodenal bleeding spots and increased secretory IgA (SIgA) levels.
• Histopathology revealed decreased villus height, increased crypt depth, and reduced goblet cells.
• NIBV downregulated physical (ZO-1, Occludin, Claudin-1) and chemical (MUC2, TFF3) barrier genes, while upregulating immune-related cytokines (IL-2, IL-4, IL-17, TGF-β, TNF-α, CCR7).

Conclusions:

• NIBV replicates in the chicken duodenum, inducing inflammation and damaging intestinal barrier functions.
• The physical, chemical, and immune barriers of the duodenum are compromised by NIBV infection.
• NIBV infection significantly affects normal duodenal function in poultry.