Lactiplantibacillus plantarum and cellulase synergistically improve the fermentation quality, chemical compositions, and bacterial community structure of Leymus chinensis silage

Leymus chinensis (Trin.) Tzvel is a high-quality perennial native grass species in China, boasting a host of desirable traits such as high biomass yield, superior forage quality and excellent palatability for livestock. The purpose of this study was to explore Lactiplantibacillus plantarum (LP), 5 × 10⁶ CFU/g of fresh weight (FW); cellulase (CE, xylanase and cellulase activities of 100,000 and 10,000 μ/g, 1% FW), and their combinations (LPCE, 5 × 10⁶ CFU/g FW). Silage fermentation quality and bacterial community of L. chinensis were analyzed after 60 days of fermentation. The chopped material (500 g) was mixed well and then packaged into individual polyethylene bags (dimensions 22 cm × 35 cm) with three replications. Following a 60-day ensiling period, all additives significantly decreased the pH compared with the control group (CK, p < .05). The lactic acid (LA) and water-soluble carbohydrate (WSC) contents accumulated (p < .05), whereas acidic detergent fiber (ADF) and neutral detergent fiber (NDF) contents decreased (p < .05) in LPCE group on Day 60, and LPCE group exhibited superior fermentation quality, as indicated by large amounts of LA (~18.75 g/kg dry matter [DM]), relatively low pH (~4.01), acceptable levels of ammonia nitrogen (~5.38 g/kg total nitrogen) and trace amounts of butyric acid (<2 g/kg DM). Lactiplantibacillus was dominant in all treated groups, whereas Enterobacter was predominant in CK. The LP and LPCE groups inhibited the reproduction threats posed by harmful microorganisms and decreased the growth and reproduction of Enterobacter, Pseudomonas and Pantoea during ensiling. Overall, LPCE can be used as a strategy to improve the fermentation quality, chemical composition and microbial community composition of Leymus chinensis silage.