Dynamic fermentation quality and bacterial community structure of paper mulberry silage from three regions of China

Abstract

Abstract Background Paper mulberry has been regarded as a potential protein resource for relieving the forage supply crisis, and ensiling has become the most important method for preserving it. An in-depth analysis of the fermentation characteristics of paper mulberry silage could provide a theoretical basis for producing high-quality silage. In this study, we aimed to investigate the dynamic fermentation quality and bacterial community of paper mulberry silages harvested from different regions in China. Results The results showed an increased trend in ammonia nitrogen (NH3-N) concentration, despite a decrease in pH with prolonged ensiling days. Furthermore, fermentation patterns varied among paper mulberry silages from three regions. Paper mulberry from Zhuozhou, Hebei (HZ) showed the highest dry matter (DM) content and a slight decrease in pH during ensiling. While the lowest DM content was observed in Hechi, Guangxi (GH), which exhibited abnormal fermentation in the silage. In particular, silage from Lankao, Henan (HL) exhibited the best fermentation quality, with lower pH and NH3-N concentration, and higher lactic acid concentration than others (P < 0.05). The bacterial richness and evenness also declined with prolonged ensiling. Among all samples, Enterobacter was the most abundant in all silages, with a trend of increasing and then decreasing during the fermentation process. Pseudocitrobacter dominated in GH silage with abnormal fermentation. Although the bacteria community during ensiling varied widely among silages from different regions, Enterobacter cloacae and Lactobacillus plantarum were the main differential bacteria in silage quality of paper mulberry. Conclusion Ensiling days and regions had significant effects on the fermentation patterns and bacterial community of paper mulberry silage which might be due to the differences in DM content. Notably, silage quality showed a close relationship with Enterobacter cloacae and Lactobacillus plantarum. Inhibiting the proliferation of Enterobacter and Pseudocitrobacter could be critical for improving the fermentation quality of paper mulberry silage. Graphical Abstract