From Gut to Gain: The Microbiome's Contribution to Broiler Health and Productivity.

The gut microbiome plays a central role in regulating nutrient utilization, immune function, and disease resistance, thereby directly influencing growth performance and feed efficiency. Existing microbiome modulation strategies, including probiotics, prebiotics, dietary interventions, and antibiotic alternatives, are critically evaluated. Despite their reported benefits, the effectiveness of these approaches often remains inconsistent across production systems. Evidence suggests that this variability is largely driven by complex interactions among microbial communities, host factors, and environmental and management conditions, which are frequently overlooked in conventional intervention-based approaches. To address this gap, this review proposes an integrated microbiome-host-environment framework that links microbial ecology with host physiology and production conditions. The framework provides a systems-level perspective for understanding the factors governing microbiome stability and production responses, offering a basis for more targeted and reliable microbiome management strategies. Finally, current challenges and future research priorities are discussed, including the integration of multi-omics technologies, precision nutrition, and data-driven approaches to support next-generation poultry production systems. By emphasizing the interconnected nature of microbiome regulation, this review contributes a conceptual foundation for improving broiler productivity and sustainability through more consistent and effective microbiome optimization.