Effects of Cellulase and Lactobacillus plantarum Supplementation on Fermentation Characteristics, In Situ Degradability, and Microbial Community Dynamics of Apple Pomace Silage

This study aimed to investigate the effects of cellulase and Lactobacillus plantarum on the fermentation characteristics, in situ digestibility, and microbial communities of apple pomace (AP) silage. Fresh AP was selected as the silage raw material, and four treatments were designed: no additive (CON), cellulase supplementation (CE), Lactobacillus plantarum inoculation (LP), and their combination (LPCE). Silage samples were collected on days 20, 40, and 80 during fermentation to analyze relevant indices. The results showed that during the ensiling of AP, cellulase supplementation reduced the pH, neutral detergent fiber (NDF), and acid detergent fiber (ADF) contents, while increasing the rumen effective degradability of dry matter (DM) ( p  < 0.05). Lactobacillus plantarum inoculation enhanced lactic acid (LA) production, lowered the pH, reduced DM loss, and improved the antioxidant activity and rumen effective degradability of NDF and ADF ( p  < 0.05). The combined addition of Lactobacillus plantarum and cellulase increased LA and acetic acid production, further reduced the pH, decreased NDF and ADF content, as well as increased antioxidant activity and effective degradability of DM, NDF and ADF ( p  < 0.05). The linear discriminant analysis effect size coupled with linear discriminant analysis showed that compared with the CON treatment, there was a higher relative abundance of Pseudomonadales in the CE treatment. Compared with the CON treatment, the LP treatment showed higher abundance of Lactiplantibacillus, etc., but lower abundance of Peptostreptococcales_Tissierellales , etc. In conclusion, the combined supplementation of cellulase and Lactobacillus plantarum in AP silage improved fermentation quality, reduced DM loss, and enhanced rumen utilization efficiency. This synergistic strategy provides a promising approach for valorizing AP through silage technology.