Effects of wilting and additives on fermentation characteristics, microbial composition, metabolome, and ruminal degradation properties of mulberry silage

Background Optimizing the processing technology of mulberry silage is a prerequisite for enhancing the utilization efficiency of mulberry resources. This study examined effects of wilting pretreatment and silage additives on mulberry silage fermentation, microbiota, metabolites, and ruminal degradation. Lactobacillus plantarum (LP), organic acids (OA), and a control treatment without additives were applied to unwilted (73% moisture) or wilted (62% moisture) mulberry forage. Results Wilting significantly enhanced lactic acid and crude protein (CP) contents, and lowered pH (P < 0.05). Adding OA or LP additives reduced pH and increased CP content (P < 0.05). LP treatment further reduced ammonia nitrogen and pH, improved lactic acid content (P < 0.05). Pre-wilted mulberry inoculated with LP showed further reductions in acetic acid and neutral detergent fiber contents (P < 0.05). LP treatment enriched Lactiplantibacillus and suppressed Enterococcus (P < 0.05). Lactiplantibacillus was strongly correlated with lactic acid, CP, and beneficial metabolites L-arginine and salicin (P < 0.05). These metabolites were enriched in the phosphotransferase system and arginine biosynthesis pathways (P < 0.05). Wilting improved DM digestibility while reducing methane and ammonia nitrogen level. LP treatment reduced ruminal ammonia nitrogen level (P < 0.05). Pre-wilted mulberry inoculated with LP further increased microbial protein content (P < 0.05). Conclusion In conclusion, combining wilting pretreatment and LP inoculant offers an effective strategy to enhance silage quality.