Effects of Different Dry Matter Levels and Additives on the Fermentation Quality and In Vitro Digestibility of Legume-Cereal Forage Crop Mixture Silage

This study aimed to evaluate the effects of different dry matter (DM) levels and additive applications on the fermentation characteristics, chemical composition, microbiological profile, aerobic stability, and in vitro digestibility of silages prepared from a mixture of legume and cereal forage crops. The forage material, consisting of a legume-cereal mixture, was divided into two portions after harvest. One half was directly ensiled with the addition of various additives, while the other half was artificially wilted at 30 °C for 3 hours prior to additive application and ensiling. The additives tested in this study included: (1) Control (no additive), (2) Homofermentative lactic acid bacteria (3) Heterofermentative lactic acid bacteria (4) Sodium diacetate and (5) Resin. The treated silages were vacuum-sealed in plastic bags (seven replicates per group) and incubated for 60 days under laboratory conditions. After fermentation, a 7-day aerobic stability test was performed. Chemical, microbiological, and in vitro evaluations were carried out on both fresh and fermented silage samples.The results demonstrated that additive applications significantly improved silage quality by increasing DM, pH, and water-soluble carbohydrate (WSC) contents, while reducing NH₃-N/TN ratio and dry matter lost (DML) (P<0.05). Similar positive effects were observed with wilting. Additives did not significantly influence the organic acid profile (lactic, acetic, propionic, and butyric acids) (P>0.05). In terms of chemical composition, additives increased crude protein (CP) and neutral detergent fiber (NDF) contents while decreasing crude fiber (CF), acid detergent fiber (ADF), and hemicellulose (HCEL) (P<0.05). Microbiological analysis showed that additives reduced yeast populations and enhanced lactic acid bacteria (LAB) counts (P<0.05). Aerobic stability was also improved, particularly through reduced pH increases during air exposure. However, neither additives nor wilting had significant effects on in vitro gas production, metabolic energy (ME), or organic matter digestibility (OMD) (P>0.05). In conclusion, additives and the drying process had a positive effect on silage quality. In particular, resin and heterofermentative LAB additives stood out in terms of increasing microbial stability, inhibiting yeast growth, and delaying aerobic spoilage.