Functional role of the enteric nervous system in poultry intestinal health and production

Like mammals, the avian intestinal epithelium is innervated by three neuronal pathways: vagal and sympathetic terminals, which originate from ganglia outside the gut wall and send information to the brain to modulate visceral sensitivity, appetite, and gut homeostasis; and the enteric nervous system (ENS), a complex network embedded within the gut wall that functions independently from the brain. The ENS coordinates essential GI physiological functions, such as intestinal motility, peristalsis, digestion, and absorption of nutrients and water. Recent studies conducted in mammals have shown that enteric neurons can orchestrate the intestinal immune response and reduce Salmonella colonization in the GI tract. However, such neuronal-mediates defense mechanisms have not yet been explored in the poultry gut. This review will provide a comprehensive overview of the avian ENS, highlighting similarities and differences with the well-known mammalian ENS. Additionally, particular focus will be given on ENS-dependent neuroimmune interactions that could reveal novel biomolecular mechanisms to mediate health, disease susceptibility, behavior, and other aspects as affected by the chicken GI tract.