Abstract
Agricultural wastes such as sugar beet byproducts and corncobs face challenges including high fiber content and low microbe-substrate interaction efficiency during their storage and conversion into animal feed resources. This study evaluated the effects of Lentilactobacillus buchneri and cellulase supplementation on fermentation quality, microbial community structure, and the in vitro fermentation rate of mixed silage containing sugar beet tops and corncobs (air-dried). Sugar beet tops and corncobs were mixed at a fresh weight ratio of 9:1 and divided into three treatments-no additives (CK), Lentilactobacillus buchneri (LB, 1 × 10(6) CFU·g(-1)Lentilactobacillus buchneri), Lentilactobacillus buchneri and cellulase (LBC, 1 × 10(6) CFU·g(-1)Lentilactobacillus buchneri and 0.1 g kg(-1) cellulase)-and subjected to anaerobic fermentation for 60 days. The results showed that LB and LBC treatments reduced the losses of crude protein (CP) and water-soluble carbohydrate (WSC) (p < 0.05) and decreased the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) (p < 0.05). Furthermore, LB and LBC treatments significantly increased the yields of lactic acid (by 31% and 46%, respectively) and acetic acid (by 60% and 78%, respectively) after anaerobic fermentation. Microbial community analysis revealed that Lactiplantibacillus (79~85%) was the dominant genus in both LB and LBC treatments, followed by Levilactobacillus (9~15%); however, principal coordinate analysis (PcoA) showed significant differences in bacterial communities between the LB and LBC treatment. The LBC treatment significantly enriched Levilactobacillus, which exhibited significant positive or negative correlations with multiple fermentation indicators. In addition, in vitro fermentation trial demonstrated that the silage treated with LBC showed higher in vitro dry matter digestibility (IVDMD) and better fermentation characteristics during in vitro fermentation (p < 0.05), with significantly increased total volatile fatty acids (TVFA) and butyric acid (BA) contents, and a decreased acetic acid content (p < 0.05). During in vitro fermentation, the LBC treatment had higher total gas production, as well as lower methane and carbon dioxide emissions (p < 0.05). Under the synergistic effect of Lentilactobacillus buchneri and cellulase, the fermentation quality and microbial community of sugar beet top-corncob silage are improved, thereby enhancing in vitro fermentation characteristics and providing insights for the recycling of agricultural wastes.