Impact of the gut microbiota on the immune system

Authors: Kogut, Michael - Mike

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/22/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The intestinal microbiota, a diverse population of bacteria, archaea, and fungi, flourishes within the gastrointestinal tract of the avian host in a population density of around 10**11 microbes/g tissue. This microbial population contributes to host physiology through inter-kingdom signaling and by providing nutrients that have both local and systemic effects. In a homeostatic state, the overall host-microbial interaction is symbiotic; however, a growing number of physiological issues have been associated with a dysregulated microbiota. To avoid these effects, the host applies considerable efforts to maintain proper regulation of the microbiota with respect to localization and composition. The host immune response is important for maintaining microbial balance but can also be the cause of a disrupted microbiota (dysbiosis), contributing to disease issues. The intestine performs the key roles of nutrient absorption and tolerance of innocuous/beneficial microbiota, while retaining the ability to respond appropriately to undesirable microbes or microbial products and preventing their translocation to sterile body compartments. Beyond its effects on metabolism and tissue development, the microbiota has multiple overlapping roles in modulating host immunity. A healthy microbiota is a critical barrier against the outgrowth of opportunistic infections as is evident by the incidence of opportunistic enteric infections after the use of broad-spectrum antibiotics. This function of the microbiota in preventing the bloom of aggressive organisms is termed colonization resistance. In a state of homeostasis (intestinal tolerance), the immune system acts as an active vigilant by preventing or modulating the response to a known or innocuous antigen. The plasticity of the avian microbiome allows defined interventions as a means of enhancing poultry health and productivity. The ability to intentionally manipulate the microbiota by providing nutrients, modulating host immunity, inhibiting/preventing pathogen intestinal colonization, or improving intestinal barrier function has led to a number of novel methods to prevent disease, but also led to improved body weight, feed conversion, and carcass yield.