Immunomodulation of Avian Dendritic Cells under the Induction of Prebiotics

SIMPLE SUMMARY: Dendritic cells recognize pathogen-associated molecular patterns in chicken intestines and are part of the initial immune response. The immunoregulatory properties of prebiotics acting in several ways in poultry have been known for many years. According to their function, dendritic cells should play an indispensable role in the proven effects of prebiotics on the intestinal immune system, such as through activation of T and B cells and cytokine production. Currently, there are no studies concerning direct interactions in poultry between non-digestible feed components and dendritic cells. Whereas most in vitro experiments with chicken dendritic cells have studied their interactions with pathogens, in vitro studies are now needed to determine the impacts of prebiotics on the gastrointestinal dendritic cells themselves. The present lack of information in this area limits the development of effective feed additives for poultry production. The main purpose of this review is to explore ideas regarding potential mechanisms by which dendritic cells might harmonize the immune response after prebiotic supplementation and thereby provide a basis for future studies. ABSTRACT: Although the immunomodulatory properties of prebiotics were demonstrated many years ago in poultry, not all mechanisms of action are yet clear. Dendritic cells (DCs) are the main antigen-presenting cells orchestrating the immune response in the chicken gastrointestinal tract, and they are the first line of defense in the immune response. Despite the crucial role of DCs in prebiotic immunomodulatory properties, information is lacking about interaction between prebiotics and DCs in an avian model. Mannan-oligosaccharides, β-glucans, fructooligosaccharides, and chitosan-oligosaccharides are the main groups of prebiotics having immunomodulatory properties. Because pathogen-associated molecular patterns on these prebiotics are recognized by many receptors of DCs, prebiotics can mimic activation of DCs by pathogens. Short-chain fatty acids are products of prebiotic fermentation by microbiota, and their anti-inflammatory properties have also been demonstrated in DCs. This review summarizes current knowledge about avian DCs in the gastrointestinal tract, and for the first-time, their role in the immunomodulatory properties of prebiotics within an avian model.