AUTHOR=Hou Meiling , Wang Zhijun , Sun Lin , Jia Yushan , Wang Shicong , Cai Yimin 

TITLE=Characteristics of lactic acid bacteria, microbial community and fermentation dynamics of native grass silage prepared in Inner Mongolian Plateau

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1072140

DOI=10.3389/fmicb.2022.1072140

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>To prepare high-quality silage, we studied the chemical composition, silage fermentation, characterization, and identification of lactic acid bacteria (LAB) associated with the silage fermentation of native grass on the Inner Mongolian Plateau.</p></sec><sec><title>Methods</title><p>LAB were isolated from fresh native grass and their silage, and silages were prepared using a small-scale fermentation system with 2–3 cm length in plastic bags.</p></sec><sec><title>Results</title><p>The dominant species of native grasses used were <italic>Stipa baicalensis</italic>, <italic>Leymus chinensis</italic>, <italic>Cleistogenes squarrosa</italic>, <italic>Melissilus ruthenicus</italic> and <italic>Pulsatilla turczaninovii</italic>, which contained 47.83–59.43 % moisture, 55.12–67.74 % neutral detergent fiber (NDF), and 8.72–14.55 crude protein (CP), and these nutrients did not change greatly during ensiling. Good preservation with a relatively low pH (below 4.44) and high (<italic>p</italic> &lt; 0.05) lactic acid content (&gt;0.58) was obtained after ensiling. Based on the morphological and biochemical characteristics, these isolates were divided into 12 groups (A-L). All isolate strains were gram-positive and catalase-negative bacteria that produce lactic acid from glucose. Group A-K were cocci, while group L was rod-shaped. Group A-E formed D-lactic acid, but group H-K formed L-lactic acid, and other groups formed DL-lactic acid. Group A-E were heterofermentative, and Group F-L were homofermentative types of LAB. According to the 16S rRNA gene sequences analysis, strains were identified as genus <italic>Leuconostoc</italic> (A, B, and C), <italic>Weissellla</italic> (D, E), <italic>Pediococcus</italic> (F, G), <italic>Enterococcus</italic> (H, I, J and K), and <italic>Lactiplantibacillus</italic> (L). <italic>Enterococcus</italic> (E.) <italic>faecium</italic> (29.17%, percentage of total isolates) and <italic>Pediococcus (P.) acidilactici</italic> (18.75%) were the most frequently occurring dominant species.</p></sec><sec><title>Discussion</title><p>This study suggests that the native grasses contained abundant LAB species, and they can be used as good-quality silages in animal husbandry. In addition, the strains <italic>P. acidilactici</italic> and <italic>E. faecium</italic> were the most frequently isolated from native grass silages as dominant species which can be a potentially excellent inoculant for native grass silage.</p></sec>