Gut Microbiome Modulation by Probiotics: Implications for Livestock Growth Performance and Health—Narrative Review

Abstract

Probiotics have emerged as gut modulators, capable of restructuring microbial communities to enhance animal health and performance. This review synthesizes peer-reviewed studies published between 2015 and 2025, retrieved from Scopus, Web of Science, and Google Scholar. It encompasses both ruminant and monogastric species to evaluate the effects of probiotic supplementation under diverse production environments. Evidence indicates that diet, age, host genetics, and management practices strongly influence gut microbiome composition and function, explaining the context-dependent nature of probiotic efficacy. These interventions improve growth performance, feed efficiency, gut morphology, pathogen resistance, and systemic immune parameters, supporting their potential as sustainable alternatives to antibiotic growth promoters. However, responses vary and are context-dependent, based on differences in strain specificity, dosage, host physiology, and environmental stress. By explaining how probiotic-mediated modulation translates into improved productivity, reduced antimicrobial dependence, and greater resilience in real-world farming systems, this review highlights their practical value for modern livestock production. Future research should focus on field-based validation, multi-omics approaches to resolve host–microbiota–probiotic interactions, and long-term assessments of animal health, productivity, and environmental impacts. Strategic deployment of probiotics, combined with scalable delivery technologies and regulatory alignment, can enhance resilience, sustainability, and efficiency in livestock production systems.