AUTHOR=Zhao Muqier , Wang Zhijun , Du Shuai , Sun Lin , Bao Jian , Hao Junfeng , Ge Gentu 

TITLE=Lactobacillus plantarum and propionic acid improve the fermentation quality of high-moisture amaranth silage by altering the microbial community composition

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1066641

DOI=10.3389/fmicb.2022.1066641

ISSN=1664-302X

ABSTRACT=<sec><title>Objective</title><p>The objective of this study was to determine the effect of <italic>Lactobacillus plantarum</italic> (<italic>L. plantarum</italic>) and propionic acid (PA) on the microbial community and fermentation performance of high-moisture amaranth silage.</p></sec><sec><title>Methods</title><p>Amaranth silages were rown without addition (AhGCK) as a control and with <italic>L. plantarum</italic> JYLP-002 (AhGLP) or propionic acid (AhGPA) and then were opened after 60 days of ensiling to determine the microbial community and fermentation quality.</p></sec><sec><title>Results</title><p>Crude protein (CP) content, lactic acid (LA) content, and lactic acid bacteria (LAB) counts were significantly higher in AhGLP and AhGPA compared with those in AhGCK (<italic>p</italic> &lt; 0.05). In contrast, pH, acetic acid (AA) content, and yeast and aerobic bacteria counts were significantly lower in AhGLP and AhGPA compared with those in AhGCK (<italic>p</italic> &lt; 0.05). In addition, propionic acid (PA) levels were markedly higher in AhGPA (<italic>p</italic> &lt; 0.05). In terms of microbial communities, the silage in the additive groups showed an increased relative abundance of <italic>Lactiplantibacillus plantarum</italic> and <italic>Lentilactobacillus buchneri</italic> and a reduced relative abundance of <italic>Enterobacter cloacae</italic> and <italic>Clostridium tyrobutyricum</italic>. The abundance of <italic>Xanthomonas oryzae</italic> was significantly increased in AhGPA, but completely inhibited in the silage supplemented with <italic>L. plantarum</italic>. Spearman’s correlation analysis revealed that <italic>Lentilactobacillus buchneri</italic> and <italic>Levilactobacillus brevis</italic> were positively associated with LA and negatively associated with pH. Conversely, <italic>Clostridium tyrobutyricum</italic> and <italic>Enterobacter cloacae</italic> were negatively associated with LA, but positively associated with pH and AA content. AA content was inversely correlated with <italic>Lentilactobacillus buchneri</italic>. Functional prediction analysis showed that LAB dominated the three groups of silage and the silages containing additives had improved carbohydrate and amino acid metabolism compared with the control silage; in particular, the AhGLP group had more heterotypic fermentation processes and a richer metabolic pathway. Furthermore, the epiphytic <italic>Lactiplantibacillus plantarum</italic> and <italic>Lentilactobacillus buchneri</italic> could inhibit the reproductive activity of undesirable microorganisms to a certain extent, thus slowing the spoilage process of the silage.</p></sec><sec><title>Conclusion</title><p>In conclusion, <italic>L. plantarum</italic> can improve fermentation characteristics by modulating the microbial community attached to high-moisture amaranth silage and will prove useful for preserving high-moisture silage.</p></sec>