Effects of low temperature silage on microbial community and free amino acids of oat silage quality

BACKGROUND: This study evaluated the effects of different temperatures (5 °C, 10 °C, 15 °C, and 25 °C) on the fermentation characteristics, microbial communities, and free amino acids (FAAs) dynamics of oat (Avena sativa) silage. RESULTS: Fermentation was significantly inhibited at 5 °C, characterized by a slower pH decline, lower lactic acid production, and a reduced lactic acid to acetic acid (LA/AA) ratio. Under low-temperature conditions, microbial diversity was higher, with Pseudomonas, Enterobacter, and Proteobacteria becoming more abundant. At low temperatures, several free amino acids (FAAs), particularly lysine, histidine, and arginine, accumulated. Correlation analysis revealed that Enterobacter and Pseudomonas were positively correlated with many FAAs, suggesting their involvement in protein degradation and amino acid transformation under low-temperature conditions. CONCLUSIONS: These findings contribute to a deeper understanding of the microbial and biochemical mechanisms of low-temperature silage fermentation and provide a theoretical basis and strategic support for optimizing silage quality in cold regions.