Effects of Lactobacillus buchneri on fermentation quality and microbial diversity in space-mutagenesis Arundo donax silage

Background This study investigated the effects of fermentation duration on silage quality, microbial composition, and in vitro rumen fermentation parameters of Space-mutagenesis Arundo donax (SA) inoculated with Lactobacillus buchneri . Two treatments were established: control group (CK) and Lactobacillus buchneri - added group (LB). Samples were stored at room temperature (25 ± 5 °C) in the dark. Fermentation durations were set at 3, 7, 15, 30, 45, and 60 days. Results Results indicate that the interaction between additives and fermentation duration significantly influenced the pH, acetic acid (AA), propionic acid (PA), and lactic acid (LA) levels in SA silage ( P < 0.05). Across different treatment groups at the same time, the LB group exhibited significantly higher AA content than the CK group across all time points. For LA, the LB group was significantly higher than the CK group at 3 days( P < 0.05), whereas LA in the CK group were significantly higher than those in the LB group at all other time points ( P < 0.05). At day 30, the CK group was approximately 53.4% higher than the LB group. pH in the CK group was higher than that in the LB group at 3, 7, and 60 days. Within the same treatment group at different time points, pH decreased as fermentation progressed, NH₃-N and LA first increased then decreased, and AA increased. At the phylum level, Bacillota was the dominant phylum, with higher relative abundance in the LB group compared to the CK group. Within the same treatment group, its relative abundance initially decreased and subsequently increased over the fermentation period. At the genus level, Lactiplantibacillus and Lentilactobacillus were the dominant genera, with the relative abundance of Lentilactobacillus increasing as fermentation time progressed. After in vitro fermentation, pH, AA, and PA were lower in the LB group, while ruminal NH₃-N concentration was higher, indicating enhanced microbial nitrogen metabolism. As fermentation time increased, NH₃-N, AA, and PA first decreased and then increased, while pH rose. Conclusion These results highlight the possibility of supplemented with Lactobacillus buchneri significantly improves the fermentation quality of SA.