The synergistic effect between sodium selenite and Pediococcus acidilactici on fermentation quality and aerobic stability of alfalfa silage.

Selenium, an essential micronutrient that cannot be endogenously synthesized by mammals, requires exogenous dietary supplementation. Lactic acid bacteria can biotransform sodium selenite (Na₂SeO₃) into bioavailable selenium nanoparticles (SeNPs), creating multifunctional selenium-enriched forages. This study systematically assessed the synergy of SeNPs and Pediococcus acidilactici in alfalfa silage through four treatments: control (CK), P. acidilactici alone (LP), Na₂SeO₃ alone (Se), and combined treatment (LPSe). After 30 days of ensiling, fermentation quality, microbial community, and aerobic stability were determined. The results revealed that LPSe silage exhibited decreased pH, butyric acid, and binding protein contents compared with CK, while its organic selenium content (1.64 mg/kg DM) was Significantly higher than that of LP Silage. 16S rRNA sequencing showed increased abundance of Pediococcus and Lactobacillus in LPSe Silage with Simplified bacterial community structure. After 7 days of aerobic exposure, CK Silage showed rapid pH and ammonia Nitrogen increase, whereas LPSe Silage had 28.24% longer aerobic stability than CK and 11.50% longer than LP. These results demonstrate LPSe as the optimal treatment for alfalfa silage.