AUTHOR=Bai Chunsheng , Wang Chao , Sun Lin , Xu Haiwen , Jiang Yun , Na Na , Yin Guomei , Liu Sibo , Xue Yanlin 

TITLE=Dynamics of Bacterial and Fungal Communities and Metabolites During Aerobic Exposure in Whole-Plant Corn Silages With Two Different Moisture Levels

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.663895

DOI=10.3389/fmicb.2021.663895

ISSN=1664-302X

ABSTRACT=<p>The study was aimed to investigate the effect of moisture content on microbial communities, metabolites, fermentation quality, and aerobic stability during aerobic exposure in whole-plant corn silages preserved long time to improve the quality and aerobic stability of the silage during feed-out. Corn plants with two different moisture levels (high-moisture content, 680 g/kg; low-moisture content, 620 g/kg) were harvested at one-third and two-thirds milk-line stages, respectively, ensiled in laboratory-scale silos, and then sampled at 350 day after ensiling and at 2 and 5 day after opening to investigate bacterial and fungal communities, metabolites, and aerobic stability. High-moisture content increased aerobic stability and pH and decreased lactic acid and microbial counts in silages (<italic>P</italic> &lt; 0.05). During aerobic exposure, the low-moisture silages had higher pH and lactic acid bacterial count and lower lactic acid than the high-moisture silages (<italic>P</italic> &lt; 0.05); <italic>Acinetobacter</italic> sp. was the most main bacterial species in the silages; <italic>Candida glabrata</italic> and unclassified <italic>Candida</italic> had an increasing abundance and negatively correlation with aerobic stability of high-moisture silages (<italic>P</italic> &lt; 0.05), while <italic>C. glabrata</italic>, <italic>Candida xylopsoci</italic>, unclassified <italic>Saccharomycetaceae</italic>, and unclassified <italic>Saccharomycetales</italic> negative correlated with aerobic stability of low-moisture silages (<italic>P</italic> &lt; 0.05) with a rising <italic>Saccharomycetaceae</italic>; the silages had a reducing concentration of total metabolites (<italic>P</italic> &lt; 0.05). Moreover, the high-moisture silages contained greater total metabolites, saturated fatty acids (palmitic and stearic acid), essential fatty acids (linoleic acid), essential amino acids (phenylalanine), and non-essential amino acids (alanine, beta-alanine, and asparagine) than the low-moisture silages at 5 day of opening (<italic>P</italic> &lt; 0.05). Thus, the high-moisture content improved the aerobic stability. <italic>Acinetobacter</italic> sp. and <italic>Candida</italic> sp. dominated the bacterial and fungal communities, respectively; <italic>Candida</italic> sp. resulted in the aerobic deterioration in high-moisture silages, while the combined activities of <italic>Candida</italic> sp. and <italic>Saccharomycetaceae</italic> sp. caused the aerobic deterioration in low-moisture silages. The greater aerobic stability contributed to preserve the palmitic acid, stearic acid, linoleic acid, phenylalanine, alanine, beta-alanine, and asparagine during aerobic exposure.</p>