AUTHOR=Bai Rui , Li Haiping , Chen Shiyong , Yuan Xianjun , Chen Youjun , Huang Yanling , Zhou Qingping , Guan Hao 

TITLE=Microbiome and response surface methodology analyses reveal Acetobacter pasteurianus as the core bacteria responsible for aerobic spoilage of corn silage (Zea mays) in hot and humid areas

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1473238

DOI=10.3389/fmicb.2024.1473238

ISSN=1664-302X

ABSTRACT=<sec id="sec80"><title>Introduction</title><p>Weak aerobic stability is a notable challenge for whole-plant corn silage, particularly in hot and humid regions. <italic>Acetobacter</italic> is commonly regarded as an indicator of aerobic deterioration in silage, yet its precise role in fermentation and during aerobic exposure, as well as the factors that promote its growth, remain insufficiently understood.</p></sec><sec id="sec81"><title>Methods</title><p>In this study, whole-plant corn silage was prepared using a bagged method with controlled dry matter (DM) content at 20%, 25%, and 30%, and initial concentrations of <italic>A. pasteurianus</italic> at 40%, 50%, and 60%. The silage was stored for 60 days under varying temperatures (20°C, 30°C, and 40°C). Following the anaerobic storage phase, the silage was exposed to air at room temperature (20-25°C) for 7 days, both with and without <italic>A. pasteurianus</italic> inoculation.</p></sec><sec id="sec82"><title>Results</title><p>The results demonstrated that <italic>A. pasteurianus</italic> did not impact the nutritional value of the silage during anaerobic fermentation, maintaining a low pH (&lt; 3.80). However, during aerobic exposure, the presence of <italic>A. pasteurianus</italic> significantly reduced the aerobic stability of the silage. The microbial community shifted from primarily <italic>Klebsiella</italic> species initially to <italic>Lactobacillus</italic> and <italic>Acetobacter</italic> species post-ensiling. During the aerobic exposure phase, <italic>A. pasteurianus</italic> and <italic>A. fabarum</italic> became the dominant species. Response Surface Methodology (RSM) analysis identified optimal conditions for the proliferation of <italic>A. pasteurianus</italic> during the aerobic phase, which occurred at 28°C, 25% DM, and 52% initial concentration at 3 ml/kg.</p></sec><sec id="sec83"><title>Discussion</title><p>These findings confirm that <italic>A. pasteurianus</italic> plays a critical role in reducing the aerobic stability of whole-plant corn silage. Additionally, the study identifies the optimal conditions that favor the proliferation of <italic>A. pasteurianus</italic>, offering valuable insights for the development of strategies to prevent and control this bacterium, thereby improving the aerobic stability of silage in hot and humid regions.</p></sec>