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

Abstract 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, with a slower pH decline, lower lactic acid production, and a reduced lactic acid to acetic acid (LA/AA) ratio. Microbial diversity was higher under low-temperature conditions, with Pseudomonas, Enterobacter, and Proteobacteria dominating. Most FAAs, particularly lysine, histidine, and arginine, accumulated at low temperatures. Correlation analysis revealed that Enterobacter and Pseudomonas were positively correlated with many FAAs, indicating their key roles in proteolysis. 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.