Complex interaction among nutrition, gut microbiota, and immunity, and their modulation strategies for improved health of poultry

SUMMARYPoultry production is vital to global protein supply, and modern poultry productivity and health are governed by the integrated effects of nutrition, gut microbiota, and immunity. Growing consumer demand for sustainable and antibiotic-free poultry production has intensified efforts to optimise nutrition, gut microbiota, and immunity, yet the molecular mechanisms underlying these interactions in poultry remain poorly understood. Nutrition influences the gut microbiota, which also provides the building blocks for immunity. Beyond maintaining gastrointestinal health, the gut microbiota ferments dietary fibres and protects against pathogenic microorganisms. Immunity maintains the equilibrium of the gut microbiota and modulates the host’s physiological response to disease. These components are so intricately interconnected that, under certain conditions, they can dynamically modulate one another. In addition to influencing growth performance and gut health, this triangular mechanism also affects overall metabolism, host–pathogen interactions, and disease progression. Many poultry studies have focused on nutrition and its potential to modulate the microbiome and immunity. Key cellular and molecular mechanisms remain inadequately understood at multiple levels, including microbial metabolite signalling, immune cell – nutrient interactions, and host – microbiome regulatory pathways governing immune homoeostasis and nutrient utilisation in poultry. This review aims to comprehensively summarise the available information and analyse the interrelationships among these three components. This information will help both poultry science research and industry practices by guiding feed formulation, precision nutrition strategies, and immune-supportive interventions, ultimately improving bird health, production efficiency, and the sustainability of safe poultry food systems.