Role of Microbiome Manipulation in Enhancing Ruminant Digestion and Productivity: A Review
The rumen microbiome is a diverse and dynamic consortium of bacteria, archaea, protozoa, fungi, and viruses that supports feed degradation, nutrient transformation, animal health, and productive performance in ruminants. Advances in microbial ecology, sequencing technologies, and systems biology have created opportunities to manage this microbial ecosystem to improve the efficiency and sustainability of livestock production. This review examines the composition, functions, and ecological interactions of the rumen microbiome, with emphasis on its contribution to fibre digestion, volatile fatty acid production, microbial protein synthesis, feed conversion efficiency, methane formation, and host physiological functions. Current strategies for microbiome modulation, including dietary modification, probiotics, direct-fed microbials, prebiotics, synbiotics, phytogenic compounds, exogenous enzymes, and rumen microbial transplantation, are evaluated in relation to digestive efficiency and animal performance. Emerging approaches, including metagenomics, metatranscriptomics, metabolomics, precision nutrition, synthetic microbial communities, genome-editing tools, and artificial intelligence-based predictive models, are also considered as developing pathways for targeted microbiome engineering. These approaches may support improved nutrient utilisation, milk and meat production, animal health, and mitigation of greenhouse gas emissions from ruminant systems. However, practical implementation remains constrained by microbial ecosystem complexity, inter-animal variability, limited persistence of introduced microorganisms, economic considerations, and regulatory challenges. The review highlights the need to integrate multi-omics datasets, computational modelling, and precision livestock technologies to develop robust, scalable, and economically viable microbiome management strategies. A deeper understanding of host-microbiome interactions and microbial functional dynamics remains essential for translating scientific advances into practical approaches that support sustainable livestock production, environmental stewardship, and overall global food security.