Early Fermentation Dynamics and Aerobic Stability of Maize Silage Improved by Dual-Strain Lactic Acid Bacteria Inoculation

This study aimed to provide deeper insights into fermentation dynamics, aerobic stability, and bacterial community composition during the short-term ensiling of maize forage with lactic acid bacteria-based inoculants. A 50:50 combination of <i>Lentilactobacillus buchneri</i> DSM2250 and <i>Lactococcus lactis</i> DSM11037 (LBL target application: 150,000 CFU per 1 g forage) was tested alongside an untreated control (C) over fermentation periods of 2, 4, 8, 16, and 32 days. A total of 50 3 L mini-silos were filled with 2 kg of fresh maize each and stored at 20 °C. The pH, dry matter, nutrient profiles, volatile fatty acids, lactic acid, alcohols, ammonia-N, microbiological counts (yeast and mold), and aerobic stability of all samples were analyzed after seven days of air exposure. LBL silage showed higher average dry matter content (DMc) and crude protein (CP) levels by 1.5%, <i>p</i> < 0.001, and 10.8%, <i>p</i> < 0.001, respectively, as well as reduced average dry matter (DM) losses by half (<i>p</i> < 0.001) compared to pure silage. The beneficial effects of inoculation became more pronounced with prolonged storage, particularly by day 32 of fermentation. LBL silage showed increased production of lactic and acetic acids by an average of 55.5% and 5.0%, respectively, (<i>p</i> < 0.01) and significantly reduced butyric acid formation by approximately 14 times. Ethanol and ammonia-N concentrations were also reduced by 55.4% and 25.6%, respectively (<i>p</i> < 0.001), while the pH value remained 0.17 units lower (<i>p</i> < 0.001) compared to the control. The combination of the two strains improved silage aerobic stability by 2.4 days (<i>p</i> < 0.001) and extended shelf life by reducing yeast counts (8.02 vs. 7.35 log₁₀CFU g⁻¹ FM, <i>p</i> < 0.001), while maintaining the pH value close to its initial level. Therefore, compared to the untreated control, the inoculated silage exhibited higher nutritional value, reduced fermentation losses, and suppressed undesirable microbial activity. The positive effects of inoculation became increasingly evident over time, particularly by day 32, highlighting the synergistic benefits of using mixed-strain lactic acid bacteria. These findings support the use of LBL inoculants as an effective strategy to enhance short-term silage quality and stability.