3Rs	Replacement, Reduction, and Refinement (ethical principle for animal use)
AhR	Aryl hydrocarbon receptor
AMP	Antimicrobial peptide
APC	Antigen-presenting cell
BA	Bile acid
BSH	Bile salt hydrolase
CA	Cholic acid
CD	Crohn’s disease
CDCA	Chenodeoxycholic acid
DC	Dendritic cell
DCA	Deoxycholic acid
DKD	Diabetic kidney disease
EECs	Enteroendocrine cells
F/B ratio	Firmicutes/Bacteroidetes ratio
FMT	Fecal microbiota transplantation
FXR	Farnesoid X receptor
GALT	Gut-associated lymphoid tissue
GI	Gastrointestinal
GIT	Gastrointestinal tract
GPCR	G-protein-coupled receptor
HDAC	Histone deacetylase
IAA	indole-3-acetic acid
ILA	indole-3-lactic acid
IPA	indole-3-propionic acid
IEL	Intraepithelial lymphocyte
IgA	Immunoglobulin A
IgY	Immunoglobulin Y (Avian antibody)
ILC	Innate lymphoid cell
IL	Interleukin
IBD	Inflammatory bowel disease
JAK	Janus kinase
LCA	Lithocholic acid
MAIT	Mucosal-associated invariant T cell
MAMP	Microbe-associated molecular pattern
MR1	Major histocompatibility complex class I-related molecule
MyD88	Myeloid differentiation primary response protein 88
NF-κB	Nuclear factor kappa-light-chain-enhancer of activated B cells
NGS	Next generation sequencing
NLR	NOD-like receptor
NOD2	Nucleotide-binding oligomerization domain-containing protein 2
PAMP	Pathogen-associated molecular pattern
pIgR	Polymeric immunoglobulin receptor
PRR	Pattern-recognition receptor
PSA	Polysaccharide A
RA	Retinoic acid
RORγt	Retinoic acid related orphan receptor γt
SCFA	Short-chain fatty acid
sIgA	Secretory immunoglobulin A
TGF-β	Transforming growth factor beta
Th	Helper T cell
TLR	Toll-like receptor
TNF	Tumor necrosis factor
Treg	Regulatory T cell
UC	Ulcerative colitis
Wnt	Wingless/Integrated signaling pathway