Description:Feeding LAB-inoculated silage modulates rumen microbiota composition and metabolites, thereby improving ruminant production performance. The goal of the project is to explore how LAB inoculants affect the rumen metabolic profile. Results showed that inoculation with homofermentative Lactiplantibacillus plantarum BX62 improved the alfalfa flavonoid content. Feeding flavonoid-rich BX62 silage reshaped the rumen microbiota, which resulted in the increase in flavonoid metabolites, the growth of flavonoid-metabolizing microorganisms, and the upregulation of the flavonoid and carbohydrate metabolic pathways in the rumen. These results demonstrate that silage-derived flavonoids can reprogram rumen microbiota and metabolic profile.