Effect of Storage Time on the Fermentation Quality, Bacterial Community Structure, and Metabolic Profiles of Jinmu...

This study aimed to investigate the effect of storage time on the fermentation quality, bacterial community structure, and metabolic profiles of Jinmu grain grass silage. It was ensiled in vacuum bags for 60 days. Samples were collected after 0, 3, 7, 15, 30, and 60 days of ensiling. Nutritional analysis revealed no significant differences in dry matter (DM), ether extract (EE), crude protein (CP), neutral detergent fiber (NDF), or acid detergent fiber (ADF) across storage periods (p > 0.05), but relative feeding value (RFV) significantly increased at 30 and 60 days (p < 0.05). Fermentation quality improved with prolonged storage, pH values declined to 4.01 at 60 days, while lactic acid (LA) and acetic acid (AA) increased significantly (p < 0.05). Butyric acid(BA) was undetected. 16S rDNA sequencing showed bacterial diversity (Chao1, Simpson, and Shannon indices) increased significantly at 30 and 60 days (p < 0.01); The relative abundance of Lacticaseibacillus, and Amylolactobacillus at 30 days were significantly higher than 0 and 60 days (p < 0.05); The relative abundance of Stenotrophomonas, Serratia, Comamonas, GKS98_freshwater_group, and Sphingobium at 60 days were significantly higher than 0 and 30 days (p < 0.05). Comprehensive targeted metabolomics identified 2958 metabolites. There were 256 differential metabolites shared by the comparison groups at 0, 30, and 60 days. The pathways for enrichment of differential metabolites mainly include plant hormone signal transduction, Histidine metabolism, arginine biosynthesis, etc. In conclusion, the storage time of Jinmu grain grass silage can enhance its fermentation quality by influencing microbial communities and metabolic pathways.