Bacteroides-derived isovaleric acid enhances mucosal immunity by facilitating intestinal IgA response in broilers

Area of Science:

• Poultry immunology
• Gut microbiota research
• Animal nutrition

Background:

• Nutrition significantly impacts poultry immunity, digestion, and metabolism.
• Gut microbiota are crucial for developing intestinal mucosal immunity, but regulatory mechanisms are unclear.

Purpose of the Study:

• To elucidate the mechanisms by which gut microbes regulate intestinal mucosal immunity in broilers.
• To identify key microbes and their metabolites influencing immunoglobulin A (IgA) production and immune cell function.

Main Methods:

• Comparative analysis of intestinal immunity and microbiota in two broiler breeds (AA and WLMB) using 16S rDNA sequencing, transcriptomics, and IgA repertoire sequencing.
• Microbial transplantation experiments and in vitro validation of microbial metabolites' effects on immune cells.

Main Results:

• WLMB chickens exhibited superior mucosal immunity, with higher IgA levels and bacterial affinity compared to AA broilers.
• Bacteroides were identified as key microbes promoting IgA production by enhancing gene expression (IgA, PIgR, BAFF, AID).
• Bacteroides-derived isovaleric acid promoted M2 macrophage polarization and cytokine production (IL-10, IL-4, BAFF, TGF-β), enhancing IgA synthesis.

Conclusions:

• Bacteroides effectively modulate the intestinal IgA response and maintain gut health in broilers.
• Bacteroides represent a promising microbial agent for developing next-generation probiotics in poultry production.