AUTHOR=Zhao Muqier , Bao Jian , Wang Zhijun , Sun Pengbo , Liu Jingyi , Yan Yuting , Ge Gentu 

TITLE=Utilisation of Lactiplantibacillus plantarum and propionic acid to improve silage quality of amaranth before and after wilting: fermentation quality, microbial communities, and their metabolic pathway

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1415290

DOI=10.3389/fmicb.2024.1415290

ISSN=1664-302X

ABSTRACT=<sec id="sec400"><title>Objective</title><p>The aim of this study was to investigate the effects of <italic>Lactiplantibacillus plantarum</italic> (<italic>L. plantarum</italic>) and propionic acid (PA) on fermentation characteristics and microbial community of amaranth (<italic>Amaranthus hypochondriaus</italic>) silage with different moisture contents.</p></sec><sec id="sec401"><title>Methods</title><p>Amaranth was harvested at maturity stage and prepared for ensiling. There were two moisture content gradients (80%: AhG, 70%: AhS; fresh material: FM) and three treatments (control: CK, <italic>L. plantarum</italic>: LP, propionic acid: PA) set up, and silages were opened after 60 d of ensiling.</p></sec><sec id="sec402"><title>Results</title><p>The results showed that the addition of <italic>L. plantarum</italic> and PA increased lactic acid (LA) content and decreased pH of amaranth after fermentation. In particular, the addition of PA significantly increased crude protein content (<italic>p</italic> &lt; 0.05). LA content was higher in wilted silage than in high-moisture silage, and it was higher with the addition of <italic>L. plantarum</italic> and PA (<italic>p</italic> &lt; 0.05). The dominant species of AhGLP, AhSCK, AhSLP and AhSPA were mainly <italic>L. plantarum</italic>, <italic>Lentilactobacillus buchneri</italic> and <italic>Levilactobacillus brevis</italic>. The dominant species in AhGCK include <italic>Enterobacter cloacae</italic>, and <italic>Xanthomonas oryzae</italic> was dominated in AhGPA, which affected fermentation quality. <italic>L. plantarum</italic> and PA acted synergistically after ensiling to accelerate the succession of dominant species from gram-negative to gram-positive bacteria, forming a symbiotic microbial network centred on lactic acid bacteria. Both wilting and additive silage preparation methods increased the degree of dominance of global and overview maps and carbohydrate metabolism, and decreased the degree of dominance of amino acid metabolism categories.</p></sec><sec id="sec403"><title>Conclusion</title><p>In conclusion, the addition of <italic>L. plantarum</italic> to silage can effectively improve the fermentation characteristics of amaranth, increase the diversity of bacterial communities, and regulate the microbial community and its functional metabolic pathways to achieve the desired fermentation effect.</p></sec>