Dynamics of gas and greenhouse gases of ensiling barley with lactic acid bacteria during fermentation

Abstract Greenhouse gases (GHG) are generated in silage, especially in barley silage, during fermentation. However, little is known regarding the dynamics of GHG productions in silage during fermentation. The GHG accumulation and reduction were assessed in barley silage in the study. Barley was harvested at milk stage and ensiled without (CK) and with commercial lactic acid bacterial additives (L1 or L2). Gas and GHG productions, fermentation quality, fermentation weight loss (FWL), and bacterial communities were analyzed at d 0, d 1, d 3, d 6, d 15, d 35, and d 90 after ensiling. The gas and GHG productions rapidly increased in all silages during early fermentation phase and then decreased (P < 0.05). The gas and GHG productions in CK were higher than those in L1 and L2 from d 1 to d 35 (P < 0.05) and the peak productions of gas and GHG were observed at d 6 in CK and at d 3 in L1 and L2. The gas and GHG had positive correlation with Coliforms, Enterobacter, Klebsiella, and Atlantibacter from d 0 to d 6 (P < 0.05), but had negative correlation with Lentilactobacillus, Lactiplantibacillus, and Lacticaseibacillus from d 1 to d 35 (P < 0.05). The L1 and L2 had increasing pH and decreasing LA after d 15 (P < 0.05). Lentilactobacillus in L1 and L2 dominated the bacterial communities from d 35 to d 90 and correlated positively with pH and AA and negatively with LA from d 6 to d 90 (P < 0.05). The FWL had positive correlation with gas and GHG from d 1 to d 35 (P < 0.05). The ensiling fermentation process was divided into gas accumulation and reduction phases. Inoculating LAB reduces the gas and GHG productions. The activities of enterobacteria majorly contributes to the gas and GHG accumulations. The gas and GHG might participate in LAB metabolism during gas reduction phase. Lentilactobacillus activity causes mainly fermentation quality deterioration during late fermentation phase. The gas and GHG generated in silage contribute to the FWL during fermentation.