Effects of Lactic Acid Bacteria on Fermentation Quality and Microbiome of Leymus chinensis Silage

This study investigated the distinct effects of Lentilactobacillus buchneri (LB) and Lactiplantibacillus plantarum (LP) inoculants on the fermentation characteristics and bacterial community succession of Leymus chinensis silage. Treatments included distilled water (CON), LB, and LP, applied at a concentration of 1 × 10⁶ cfu/g of fresh matter (FM). Compared with the CON group, the fermentation quality was improved by the inoculations, the markedly (p < 0.05) lower pH and NH₃-N were found in the LB and LP treatments. The significantly (p < 0.05) highest LA and AA contents were detected in the LP and LB treatments, respectively. The bacterial diversity, reflected by Shannon and Chao1 indices, decreased throughout the ensiling process, with the LP group exhibiting the most pronounced reduction. Furthermore, beta-diversity analysis revealed distinct microbial community structures among the treatments. While fresh L. chinensis was dominated by Proteobacteria (48.03%), Firmicutes (26.23%), and Actinobacteriota (23.72%), the microbiome shifted dramatically after 60 days of ensiling to be predominantly Firmicutes (94.96%-99.79%), the genus Rhodococcus, Microbacterium, Enterococcus and Leuconostoc, Weissella, and Enterococcus were markedly (p < 0.05) enriched in the CK treatment during fermentation from 3 to 14 days, while from 30 days, the genus Lactobacillus as the dominant genus, especially in the LB and LP treatments. In conclusion, both additives facilitate L. chinensis ensiling by regulating the microbiome, yet L. plantarum demonstrates superior efficacy in optimizing fermentation quality.