Multi-omics exploration of rumen microbiota-mediated liver and adipose metabolic adaptations in high-concentrate fed lambs

Abstract High-concentrate diets are commonly used to enhance lamb growth performance; however, their long-term impacts on metabolic health, particularly fat deposition and liver function, remain a challenge. This study utilized an integrative multi-omics approach to explore the role of keystone rumen microbiota in modulating the rumen-liver-tail adipose axis under high-concentrate diets. Keystone rumen bacterial taxa, including Ruminococcus_gauvreauii, Syntrophococcus, Solobacterium, Bifidobacterium , and Ruminococcaceae_UCG-010 , were identified as critical mediators linking dietary changes to tail fat deposition. Liver transcriptomic analysis revealed disrupted folate biosynthesis, regulated by key members of the AKR1C3 family ( AKR1C23, AKR1C1 , and PGFS ), which played a pivotal role in glucose and fatty acid metabolism through the action of tetrahydrobiopterin. In tail adipose tissue, pathways associated with vitamin B6 metabolism and fatty acid elongation were significantly enriched, with pyridoxal 5’-phosphate and elongation-related genes ( ELOVL3, HSD17B12 , and FADS2 ) contributing to lipid biosynthesis and deposition. These findings establish a mechanistic framework for the rumen-liver-tail adipose axis, highlighting the influence of keystone rumen microbiota on host metabolism. This study offers novel insights into dietary interventions and microbial strategies to improve ruminant healthy production efficiency and meat quality.