Determining the association between gut microbiota and its metabolites with higher intestinal Immunoglobulin A response

Immunoglobulin A (IgA) is one of the important and most abundant immunoglobulins which neutralize invading pathogens at mucosal sites. Gut microbial community and their metabolites which are responsible for higher IgA are poorly known. The current study was carried out to determine those microbial community and their metabolites. Twenty-two healthy, 26 days wean piglets were used in the study. After 10 days of weaning, piglets were divided into two groups. Group 1 with significantly higher fecal IgA while group 2 with significantly lower IgA concentrations from each other. Both groups were analyzed for the fecal inflammatory cytokine, fecal microbial community using 16S ribosomal sequencing, and microbial metabolites using GC–MS. Results showed that Firmicutes and Bacteroidetes constituted 90.56% of the microbiome population in the fecal matter of pigs with higher IgA concentration while pigs with lower fecal IgA had Firmicutes and Bacteroidetes abundance as of 95.56%. Pigs with higher IgA had significantly higher Bacteroidota and Desulfobacterota populations, while significantly lower Firmicutes and Firmicutes/ Bacteroidota ratio (p <0.05). Roughly at the species level, animals with higher fecal IgA concentration had significantly higher bacteria which are associated with gut inflammation and infectious such Prevotella spp and Lachnospiraceae AC2044. Pigs with higher IgA had comparatively lower short-chain fatty acid (SCFA) such as acetic acid, butyric, formic acid, isovaleric acid, and propionic acid which has been associated with gut immune tolerance and immune homeostasis.