Ruminants would suffer from gastric distension (bloat) when feeding on alfalfa (Medicago sativa L.; Alf), while tannins can relieve this problem. Thus, this study aimed to evaluate the effect of Alf mixed with paper mulberry (Broussonetia papyrifera) leaves (PML) or condensed tannins (CT) extracted from PML on in vitro fermentation performance. Seven experimental treatments based on the mass ratios of Alf and PML were set up: Alf, PML, 3A1P (Alf:PML = 3:1), 1A1P (Alf:PML = 1:1), 1A3P (Alf:PML = 1:3), A1P (Alf with 1% CT extracted from PML), A2P (Alf with 2% CT extracted from PML), and a blank. The results after fermentation were as follows. (1) The degradable dry matter (DDM) and degradable organic matter (DOM) contents increased simultaneously with the increase in the proportion of PML (p < .05). However, the DDM and DOM contents decreased with the increase in PML CT concentration. Moreover, mixing PML with ALF improved (p <.05) the concentrations of acetic (except in 3A1P, p > .05), propionic, and butyric acids compared to Alf alone. Adding CT improved the concentrations of propionic and butyric acids over the Alf treatment (p < .05). (2) The 1A1P, 1A3P, and PML treatments showed the maximum rate of gas production during fermentation when compared with the other treatments (p < .05). The asymptotic gas volumes of the treatments with added CT were less than the Alf treatment (p < .05). It can be concluded that a mixture of Alf and PML after in vitro fermentation for 96 h could improve the DDM and DOM contents, reduce gas production, and produce more short-chain fatty acids.

The aim of this study is to investigate the dynamic changes in nutritional components, fermentation parameters, and microbial communities of mulberry leaves during silage fermentation with exogenous and epiphytic Pediococcus pentosaceus (P. pentosaceus). P. pentosaceus P (Pp) and P. pentosaceus M (Pm), isolated from the epiphytic microbiota of paper mulberry and mulberry leaves, respectively, were used as fermentation inoculants (OD₆₀₀ = 0.6). Fresh mulberry leaves were treated with the inoculants at 1% (mL/g) of leaf weight and ensiled for 60 days. Three groups were established: T1 (exogenous Pp), T2 (epiphytic Pm), and CK (control, sterile water). Samples were collected on days 1, 3, 5, 7, 15, 30, and 60 to analyze chemical composition, fermentation characteristics, and bacterial communities. Redundancy analysis was conducted to explore relationships between fermentation characteristics and bacterial communities. The results showed that T2 had significantly higher dry matter content from day 30 (p < 0.05) and lower neutral detergent fiber content from day 3 (p < 0.05) compared to T1. Additionally, T2 exhibited faster water-soluble carbohydrate consumption and more rapid pH decline during the early fermentation phase (days 1–7). Lactic acid (LA) content in T2 was significantly higher during days 1–7 (p < 0.05), while acetic acid (AA) content was significantly lower from day 3 (p < 0.05). T2 consistently showed higher crude protein and lower ammonia nitrogen (NH₃-N) levels than T1 throughout fermentation. Microbial analysis revealed higher abundance of Firmicutes in T2 during days 1–15 and greater relative abundance of Pediococcus from day 1 to 30. Kosakonia was more abundant in T2, whereas Escherichia-Shigella was less abundant. During days 3–15, bacterial communities in T1 and T2 correlated positively with LA, with stronger effects in T2, driven by Pediococcus. In the later stages (days 30 and 60), bacterial communities were influenced by AA, NH₃-N, and propionic acid, with Enterobacter, Lactobacillus, and Enterococcus as key contributors. This study demonstrates that supplementing epiphytic P. pentosaceus improves fermentation efficiency and nutritional quality of mulberry leaf silage compared to exogenous P. pentosaceus.