Effects of wilting and additives on fermentation characteristics, microbial composition, metabolome, and ruminal degradation properties of mulberry silage
摘要
Optimizing the silage processing technology for mulberry is essential to improve the utilization efficiency of this feed resource. This study investigated the effects of a wilting pretreatment and silage additives on fermentation dynamics, microbial community structure, metabolites, and in situ ruminal degradation characteristics of whole-plant mulberry silage. A 2 × 3 factorial arrangement with two conditions (62% vs. 73% moisture content) and three silage additives (control, Lactiplantibacillus plantarum (LP), and organic acids (OA)) was applied in a completely randomized design with 6 replications. All samples were ensiled for 60 days before analysis.
ResultsThe wilting procedure increased lactic acid and crude protein (CP) contents while lowering pH (P < 0.05). Both OA and LP additive treatments reduced pH and increased CP content in mulberry silage (P < 0.05). The LP treatment specifically reduced ammonia nitrogen and pH and improved lactic acid content (P < 0.05). The interaction between wilting and additive led to decreases in acetic acid and neutral detergent fiber contents (P < 0.05). 16S rRNA sequence revealed that LP inoculation enriched the relative abundance of Lactiplantibacillus while suppressing that of Enterococcus (P < 0.05). Lactiplantibacillus abundance was positively correlated with contents of lactic acid, CP, and beneficial metabolites L-arginine and salicin (P < 0.05). These two differential metabolites were enriched in phosphotransferase system and arginine biosynthesis pathways (P < 0.05). The in situ ruminal study further confirmed that wilting improved DM digestibility while reducing methane and ammonia nitrogen concentration. The LP treatment also reduced ruminal ammonia nitrogen level (P < 0.05).
ConclusionThe combined application of a wilting pretreatment and LP inoculant presents a validated and effective approach to comprehensively improve the fermentation quality and nutritive value of mulberry silage.