Dynamics of fermentation, bacterial community, and nutritional value in alfalfa-sunflower mixed silage with different additives

This study investigated the effects of Lactobacillaceae and sucrose on microbial diversity and fermentation quality in alfalfa-sunflower mixed silage (1:1 wet weight ratio). The experimental treatments included non-additive groups with unadulterated silage and a mixed silage group and groups supplemented with Lactiplantibacillus plantarum (LP), Lentilactobacillus buchneri (LB), or sucrose(SUG), all vacuum-sealed and fermented for 60 days. Results demonstrated that all additive treatments successfully reduced pH below 4.5, with LP showing the most pronounced acidification. The mixed silage strategy significantly improved nutritional quality by increasing crude protein content while reducing fiber components (ADF and NDF), particularly in LP and LB groups. Microbial analysis revealed Bacillota as the dominant phylum across all treatments. Although LB group maintained higher microbial diversity, all additive groups shared similar operational taxonomic units dominated by beneficial bacteria. Specifically, Lentilactobacillus dominated in LB group while Lactiplantibacillus prevailed in other additive groups, with both LP and LB treatments exhibiting simplified bacterial communities without detectable harmful microorganisms. These findings indicate that LP and LB additions effectively enhance lactic acid bacteria abundance and significantly improve fermentation quality in mixed alfalfa-sunflower silage.