Leymus Chinensis Silage

The purpose of this study was to investigate the effect of different additives on the microbial composition, fermentation quality and bacterial community structure of big-bale Leymus chinensis silage. The experiment was set up with three treatment groups and three replications in each group, which were control (C) group, Lactobacillus rhamnosus (L) group, molasses (M) group and Lactobacillus rhamnosus + molasses (LM) group, respectively, and Leymus chinensis silages were fermented for 20 and 40 days. Lactic acid, acetic acid, 1,2-propanediol and propionic acid contents increased and pH, butyric acid, 1-propanol and ethanol contents decreased in the L, M and LM groups compared to the C group. Lactic acid bacteria number in the LM group was highest, while the pH was lowest. Enterobacter and Paucibacter were the main dominant genera in C group. The addition of Lactobacillus rhamnosus and molasses increased the relative abundance of Lactobacillus, Weissella and Enterococcus. Lactobacillus abundance correlated positively (P < 0.01) with Lactococcus, Enterococcus, and Weissella, and negatively with Enterobacter and Paucibacter. Conversely, Enterobacter and Paucibacter showed a strong positive correlation (P < 0.01, R = 0.55) during fermentation. Lactobacillus, Enterococcus, and Weissella were positively associated (P < 0.01) with acetic and lactic acid levels, while Enterobacter abundance correlated positively (P < 0.05, R = 0.43) with 1,2-propanediol content. In summary, both Lactobacillus rhamnosus and molasses additions improved the fermentation quality and bacterial community structure of big-bale Leymus chinensis silage. Moreover, the effect of combination addition in big-bale Leymus chinensis silage is even better, which not only inhibited harmful microorganisms but also improved the fermentation products of big-bale Leymus chinensis silage through microbial regulation.