Exploring the Effects of Different Bacteria Additives on Fermentation Quality, Microbial Community and In Vitro Gas Production of Forage Oat Silage

SIMPLE SUMMARY: Forage oat is an important feed resource in the world. Few studies on the application of different bacterial additives in forage oat silage have been found, which limits the utilization and promotion of oat silage in animal husbandry. In this study, we compared the fermentation quality and in vitro gas production of oat silage treated with four additives (Lactiplantibacillus plantarum F1,LP; Lacticaseibacillus rhamnosus XJJ01, LR; Lacticaseibacillus paracasei XJJ02, LC; and Propionibacterium acidipropionici 1.1161, PP). The results show that compared to the CK group (without additives), the LR group had a higher dry matter content, while the LP group showed an improvement in fermentation quality. At the same time, the bacterial community in the LR group was also different from that in other groups. The treatments of PP and LC had no significant effects on fermentation quality, but the in vitro gas production was significantly reduced in the treated oat silage. These results could help us to optimize the utilization of forage oat silage in balanced ruminant diets. ABSTRACT: Bacterial inoculants are considered as a good choice for successful ensiling, playing a key role in improving the silage quality. However, the potential of different bacteria, especially the propionic acid bacteria, in forage oat ensiling is yet to be explored. Therefore, the purpose of this study was to investigate the regulation effects of different bacterial additives on the fermentation quality of forage oat silage. Four additives (Lactiplantibacillus plantarum F1, LP; Lacticaseibacillus 0rhamnosus XJJ01, LR; Lacticaseibacillus paracasei XJJ02, LC; and Propionibacterium acidipropionici 1.1161, PP; without additives, CK) were inoculated in forage oat silage, and the fermentation quality and organic compounds were determined after 60 days of ensiling. Notably, LR showed higher dry matter preservation compared to other additives and CK. In addition, LP and LR showed strong lactic acid synthesis capacity, resulting in lower pH compared to other additives and CK. The treatments of PP and LC increased the bacterial diversity in silage, while the bacterial community in the LR group was different from that in other groups. In addition, the PP- and LC-treated oat silage showed significantly lower total in vitro gas production and a lower methane content. These results suggest that LP is more favorable for producing high-quality oat silage than LR, LC, or PP. Both the PP- and LC- treated oat silage may reduce rumen greenhouse gas emissions.