Effects of Homofermentative and Heterofermentative Lactobacillus on Fermentation and Bacterial Communities of Sweet Corn By-Product Silage

To investigate the effects of different lactic acid bacteria additives on the bacterial community structure of silage prepared from fresh corn processing by-products, three treatment groups, including a non-inoculated control group (C), a Lactiplantibacillus plantarum-supplemented group (P), and a Lentilactobacillus buchneri-supplemented group (B), were set up in this study. Fermentation quality and bacterial community dynamics were measured on days 1, 3, 7, 15, and 45 of ensiling, while nutritional components, in vitro digestibility, and aerobic stability of the silage were systematically analyzed at the end of the 45-day ensiling period. The results showed that pH and ammonia nitrogen (NH3-N) contents in all groups gradually decreased with the prolongation of ensiling duration. Lactic acid (LA) and acetic acid (AA) contents increased progressively over the ensiling period, and their responses were significantly influenced by additives × day interactions (p < 0.05), with group P showing higher levels than group B on days 15 and 45. Propionic acid (PA) and butyric acid (BA) were not detected in any group. After 45 days of ensiling, the organic matter (OM) content in group B was significantly higher than that in the other two groups (p < 0.05). Compared with group C, the acid detergent lignin (ADL) content was significantly lower in both groups P and B (p < 0.05). Group P presented significantly higher in vitro organic matter digestibility (IVOMD), in vitro crude protein digestibility (IVCPD), and in vitro neutral detergent fiber digestibility (IVNDFD) than groups C and B (p < 0.05). In contrast, group B showed greater in vitro dry matter digestibility (IVDMD) than group P (p < 0.05). All experimental groups maintained silage aerobic stability exceeding 72 h, with no significant differences detected among treatments. The bacterial community of sweet corn by-product silage changed substantially after ensiling. Bacterial community diversity gradually decreased as ensiling proceeded. At 45 days of ensiling, the dominant bacterial genera shifted from Weissella, Levilactobacillus, and Pediococcus to Levilactobacillus and Lentilactobacillus. On days 1, 7, and 15 of ensiling, differences in the relative abundances of specific bacterial taxa were observed among the three groups. At specific ensiling time points, inoculation with L. plantarum was associated with higher relative abundances of most dominant bacterial taxa in sweet corn by-product silage than inoculation with L. buchneri.