D型氨基酸的营养生理功能研究进展OA

Amino acids are chiral molecules that exist as L-and D-enantiomers.Diets for poultry and livestock are predominantly composed of L-amino acids;however,intestinal microbiota exhibit amino acid racemase activity,which catalyzes the racemization of certain L-amino acids into their respective D-counterparts.Although D-amino acids are not incorporated into host proteins,they serve as neurotransmitters or neuromodulators,participating in the regulation of immune function,inflammatory responses,and microbial homeostasis in animals.This review systematically summarizes the sources,biosynthetic pathways,metabolism,and tissue distribution of D-amino acids,with emphasis on their roles in modulating gut microbiota and immune function,as well as their implications in diseases.Furthermore,we preliminarily discuss the potential mechanisms by which D-amino acid oxidase and the N-methyl-D-aspartate receptor mediate the antibacterial,immunoregulatory,and disease-modulating effects of D-amino acids,aiming to provide a theoretical reference for the rational application of D-amino acids in poultry and livestock production to regulate growth performance and intestinal health.