Dynamic Changes in Nutritional Composition, Fermentation Quality, and Microbiota during the Ensiling of Miscanthus with Different Additive Treatments

Miscanthus cultivated in saline-alkaline regions exhibits high nutritional levels at the vegetative growth stage, which makes it suitable for ensiling and serves as good fodder resource for ruminants. This study investigated the dynamic changes in the quality of miscanthus silage under different additive treatments. The experiment included the following treatments: CK (no additive), LP1 (Lactiplantibacillus plantarum LW8 and K3 at a bacterial concentration ratio of 1:2), LP2 (Lactiplantibacillus plantarum LW8 and K3 at a ratio of 2:1), and CB (commercial lactic acid bacteria inoculant). The silages were sampled at 0, 20, 30, and 40 days of ensiling. The results showed that all lactic acid bacterial additives improved the sensory quality of miscanthus during the mid to late fermentation stages. At the end of ensiling, the LP2 and CB groups exhibited higher contents of dry matter, crude protein, and lactic acid compared to the other groups. Moreover, throughout the entire ensiling period, the LP1 and LP2 groups demonstrated lower ratios of ammonia-nitrogen/total nitrogen, lower acetic acid contents, and higher LA/AA ratios. 16S rDNA sequencing revealed that during the mid and late fermentation stages, the LP1 and LP2 groups maintained higher microbial diversity, greater relative abundance of beneficial bacteria, and higher expression levels of genes related to microbial metabolism and biosynthesis pathways of secondary metabolites. In conclusion, using Lactiplantibacillus plantarum LW8 and K3 at a 2:1 ratio as a miscanthus silage additive achieved the optimal silage quality.