Synergistic effects of fibrolytic enzymes and lactic acid bacteria on cassava leaf silage quality and microbial...

Cassava leaves are a valuable protein-rich feed resource, but their high fiber content and poor fermentation characteristics can reduce silage quality. To address these challenges, this study evaluated the synergistic effects of fiber-degrading enzymes and lactic acid bacteria (LAB) on the fermentation profiles, nutritional quality, and microbial community of cassava leaf silage. Silage was prepared using five treatments: CK (2% glucose), T1 (Lactobacillus plantarum + 2% glucose), T2 (glucanase + L. plantarum + 2% glucose), T3 (cellulase + L. plantarum + 2% glucose), and T4 (glucanase + cellulase + L. plantarum + 2% glucose), and ensiled for 0, 21, and 42 days. The findings demonstrated that additive treatments (T1-T4) rapidly decreased silage pH and increased lactic acid compared to the CK (P < 0.001). By day 42, the enzyme-inoculated groups (T2-T4) exhibited elevated crude protein alongside reduced fiber fractions compared to both CK and T1 (P < 0.001). Regarding the microbial community, Shannon and Simpson indices were lower in treated groups than in the CK group (P < 0.05). Beta diversity analysis revealed that the microbial community structure of the CK differed clearly from that of the additive-treated silages. At the phylum level, Bacillota dominated all other groups on day 42, with a relative abundance exceeding 92%. At the species level, Lactobacillus plantarum dominated enzyme-treated silages (relative abundance > 93%, P = 0.036), compared to only 13.1% in CK, which contained higher proportions of Pediococcus and Weissella species. Collectively, the synergistic application of fibrolytic enzymes and LAB improves cassava leaf silage quality by accelerating acidification, reducing fiber fractions, and establishing a highly favorable L. plantarum-dominated microbial community.