The bacterial community and metabolome dynamics and their interactions modulate fermentation process of whole crop corn silage prepared with or without inoculants

Abstract

Summary Multi‐omics approach was adopted to investigate the modulation of bacterial microbiota and metabolome as well as their interactions in whole crop corn ensiling systems by inoculating homofermentative Lactobacillus plantarum or heterofermentative Lactobacillus buchneri. Inoculations of the two different inoculants resulted in substantial differences in microbial community and metabolic composition as well as their dynamics in ensiled corn. Inoculants also altered the correlations of microbiota in different manners, and various keystone species were identified in corn silages with different treatments. Many metabolites with biofunctional activities like bacteriostatic, antioxidant, central nervous system inhibitory and anti‐inflammatory were found in the present silage. A constitutive difference in microbiota dynamics was found for several pathways, which were upregulated by specific taxa in middle stage of fermentation, and widespread associations between metabolites with biofunctions and the species of lactic acid bacteria dominated in silage were observed. Multiple microbial and metabolic structures and dynamics were correlated and affected the fermentation process of the corn ensiling systems. Results of the current study improve our understanding of the complicated biological process underlying silage fermentation and provide a framework to re‐evaluate silages with biofunctions, which may contribute to target‐based regulation methods to produce functional silage for animal production.

Different lactic acid bacteria and their combinations regulated the fermentation process of ensiled alfalfa: ensiling characteristics, dynamics of bacterial community and their functional shifts

“…These routes lead to lactic acid accumulation during fermentation. Here, the relative abundance of energy metabolism was higher in the control and lower in Pp-and Ef-inoculated silages during the entire ensiling period, which was inconsistent with the report of Xu et al (2020) which energy metabolism was predicted to be upregulated in the inoculated silages in the middle stage of fermentation. The abundance of nucleotide metabolism was higher in the Pp-inoculated silages The relative abundance (%)…”

“…2). Our previous study showed that inoculation changed the correlation of bacterial communities, and the identified keystone taxa were completely different among the control, L. plantarum, and L. buchneri-inoculated silages (Xu et al, 2020). Similarly, the present results also indicated that different inoculants and their combinations obviously altered the correlations within microbiota and the keystone species for modulating the fermentation process.…”

“…Based on the network analysis, unclassified Enterobacterales, and Klebsiella in the control silage, E. cloacae and L. plantarum in the Lp-inoculated silage, L. pentosus and unclassified Proteobacteria in the Pp-inoculated silage, unclassified Yersiniaceae and Proteobacteria in the Efinoculated silage, L. plantarum and Pantoea agglomerans in the LpPp-inoculated silage, unclassified Proteobacteria and Pantoea in the LpEf-inoculated silage, and L. pentosus and unclassified Proteobacteria in the LpPpEf-inoculated silage were identified as the keystone taxa. The keystone taxa have considerable influence on the microbial community and function, but their abundances were not directly proportional to their effects (Banerjee et al, 2018;Xu et al, 2020). Confusingly, undesirable bacteria were identified as the keystone taxa in the control, Ef-and LpEf-inoculated silages.…”

Succession of Bacterial Community During the Initial Aerobic, Intense Fermentation, and Stable Phases of Whole-Plant Corn Silages Treated With Lactic Acid Bacteria Suspensions Prepared From Other Silages

“…In the past decade, the microbial communities during ensiling have become a research focus of silages with the development of next-generation sequencing technologies (Romero et al, 2018). Gharechahi et al (2017), Keshri et al (2018), and Xu et al (2020) reported the dynamics of microbial community during the ensiling of whole-plant corn silages treated with LAB or collected from different locations. Guan et al (2018) determined the bacterial community in corn silages prepared with farm bunker-silo in Southwest China.…”

“…The LAB was usually used as silage additives to promote the ensiling process and improve the fermentation quality of end-silages (Weinberg and Muck, 1996). Some recent studies indicated that adding inoculants (containing selected LAB strains) changed the microbial community by making LAB dominated microorganism as soon as possible (Keshri et al, 2018;Guan et al, 2020;Xu et al, 2020). Several authors have reported that LAB prepared from alfalfa is more effective in improving the fermentation quality of alfalfa silage than that from other forage sources (Ohshima et al, 1997;Wang et al, 2009;Denek et al, 2011).…”