Abstract

Pig production is a major contributor to global animal protein supply but faces challenges of high feed costs, disease risks, and restrictions on antibiotic growth promoters. Recent advances highlight the gut microbiome as a key regulator of nutrient utilization, immune function, and overall health in pigs. This review summarizes the development and composition of the gut microbiota across life stages and its roles in digestion, energy harvest, barrier protection, and immune modulation. Nutritional interventions such as prebiotics, probiotics, synbiotics, phytogenic compounds, organic acids, functional amino acids, enzymes, and unconventional feed resources are discussed for their ability to beneficially modulate the microbiome and enhance pig performance. In addition, emerging strategies including precision feeding, microbiome-informed biomarkers, multiomics integration, and next-generation approaches such as phage therapy, fecal microbiota transplantation, and engineered probiotics are explored. While these developments are promising, challenges remain in terms of mechanistic understanding, cost-effectiveness, regional adaptability, and standardization of microbiome-based interventions. The integration of host genetics, microbial ecology, and digital technologies holds future potential for precision and sustainable pig nutrition. Overall, feeding the microbiome represents a paradigm shift in swine production, offering avenues to improve productivity, animal welfare, and environmental sustainability in the post-antibiotic era.

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