Gut health in poultry and considerations of additives as alternatives to antibiotics.

Abstract

Abstract Gut health' is currently a hot topic in animal production but lacks precise definition or definitive assessment. Antibiotics have been used for many years to manage gut health issues but are under pressure in many parts of the world to help protect their long-term effectiveness. The intestine is composed of numerous components, including a microbiome, nutrients and host factors (e.g. cells, secretions, mediators, etc.) that are continually interacting. The gut microbiome governs the development and functionality of the immune system and strongly influences 'gut health'. Features of the innate gut immune system are largely present and functionally mature at hatch and may represent a particular focus for exogenous interventions. Inflammation is a key innate response and, although often viewed only as a negative response, evidence indicates an enhanced or less regulated acute inflammatory response capability is beneficial. Unresolved, sterile or metabolic inflammation, resulting from innate immune system stimulation by non-infectious cellular components and metabolites, are, however, generally recognized as undesirable and are a focus for intervention. Antibiotic growth promoters were effective at preventing and/or controlling intestinal disorders and although most evidence suggests benefits from microbiome modification there is still debate over the precise mode of action. The clear protective effects of the gut microbiome and influences on immunity make for potential interventions that have largely focused on the application of various microbiome (e.g. probiotics) and/or immune (e.g. cytokines) modulators. A better understanding of key microbiome-immune interactions, and thus how these can be appropriately modulated, is essential for significant progress in promoting gut and animal health.