Combined application of Pediococcus pentosaceus and cellulase improves silage quality and in vitro digestibility of Krascheninnikovia arborescens

Combined use of microbial inoculants and enzymes can improve highly lignified silage, but their effects on Krascheninnikovia arborescens remain unclear. This study combined microstructural characterization with absolute microbial quantification to assess the impact of Pediococcus pentosaceus (PP) and cellulase (CE) on fermentation characteristics, fiber structure, in vitro digestibility, and bacterial succession. This work aims to clarify the mechanisms underlying fiber degradation, thereby providing a theoretical basis for utilizing unconventional woody forages. Combined inoculation (PPCE) reduced the contents of structural fibers, with neutral detergent fiber (NDF) and acid detergent fiber (ADF) decreasing continuously to 52.32%DM and 40.01%DM, respectively, after 60 days of fermentation. Meanwhile, PPCE increased the accumulation of lactic acid and acetic acid, with the lactic acid content reaching 5.14%DM on day 60. PPCE treatment significantly disrupted the fiber surface structure and resulted in the greatest reduction in the intensity of characteristic peaks, including those associated with C-O-C glycosidic bonds. As a consequence of these structural alterations, the in vitro degradability of dry matter, crude protein, and detergent fibers was significantly enhanced, with the in vitro crude protein digestibility reaching 68%. Absolute quantitative sequencing revealed that PPCE treatment reduced microbial diversity and drove a targeted shift in community structure. Lactiplantibacillus plantarum and P. pentosaceus dominated the early fermentation phase, whereas Lentilactobacillus buchneri had the highest absolute abundance in the late stage. KEGG-based functional prediction suggested a higher predicted representation of the phosphotransferase system under PPCE treatment and a lower predicted representation of pathways annotated as penicillin and cephalosporin biosynthesis. These results indicate differences in inferred functional potential rather than measured pathway activity or metabolic regulation. The combined application of P. pentosaceus and cellulase alleviated lignification-related constraints in K. arborescens. The superior performance of PPCE was associated with greater fiber disruption, favorable bacterial succession, and increased predicted representation of carbohydrate transport functions such as the phosphotransferase system. These findings offer a conceptual framework and actionable approach for valorizing unconventional woody forages in desert steppe ecosystems. The woody forage Krascheninnikovia arborescens serves as a promising unconventional feed for ruminants. Combined use of Pediococcus pentosaceus and cellulase altered silage fiber surface morphology. The combined treatment improves in vitro digestibility of dry matter and fibers. The co-additive reshapes bacterial succession and predicted functional potential, including the PTS.