Dynamics of Bacterial Community and Fermentation Quality in Leymus chinensis Silage Treated With Lactic Acid Bacteria and/or Water

Abstract

This study aimed to reveal the bacterial community and fermentation quality of Leymus chinensis silage during the fermentation process. L. chinensis was harvested at the heading stage, and ensiled with lactic acid bacteria (LAB, L), water (W), or a combination of both (LW) in vacuum-sealed plastic bags. As a control silage, untreated L. chinensis silage was also assessed. The samples were taken at 0, 5, 15, 35, and 60 days after ensiling. The bacterial community structure was assessed by plate cultivation and Illumina sequencing, and the fermentation parameters were also analyzed. Fresh L. chinensis contained low moisture (509 g/kg) and LAB (3.64 log colony-forming units/g fresh weight). Control silage displayed higher pH and lower lactic acid (LA) than other treatments during ensilage (p < 0.05); moreover, LW-treatment had lower pH from 5 to 35 days and greater LA at 5 days than L- and W-treatments (p < 0.05). During the fermentation process, Lactobacillus in L- and LW-treatments was the most dominant bacterial genus (>97%), had higher abundance than that in control silage and W-treatment (p < 0.05), and correlated negatively with other main genera and pH, and positively with LA and acetic acid (p < 0.05). Moreover, Lactobacillus had considerable abundance in W-treatment from 5 to 15 days (81.38–85.86%). Enterobacteriaceae had the most abundance among bacteria in control silage during ensiling (49.31–69.34%), and in W-treatment from 35 to 60 days (47.49–54.15%). The L-, W-, and LW-treatments displayed the aggregated bacterial community at 5 and 15 days, with W-treatment diverging from L- and LW-treatments at 35 and 60 days. Overall, the low moisture and/or insufficient LAB in fresh L. chinensis led to Enterobacteriaceae dominating bacterial community and contributing to the high pH and low LA in control silage during the fermentation process. Applying L, W, or LW contributed to Lactobacillus succession, LA production, and pH reduction during early stage of fermentation; moreover, treating with L and LW displayed more efficiency. Lactobacillus dominated the entire ensilage process in L- and LW-treatments and the early stage of fermentation in W-treatment, and contributed to the satisfactory fermentation quality of L. chinensis silage. The L- and LW-treatments displayed a similar pattern of bacterial succession during ensiling.

Effects of Lactic Acid Bacteria Additives on the Quality, Volatile Chemicals and Microbial Community of Leymus chinensis Silage During Aerobic Exposure

“…Zhang et al (2018) showed that the addition of lactic acid bacteria and water promoted microbial succession during the early stages of fermentation. Xu et al (2021) showed that the addition of sodium benzoate and acetic acid improved quality and aerobic stability. There are few studies on the dynamics of quality, volatile chemicals and microorganisms in L. chinensis silage during aerobic exposure, and the relationship between them is unclear.…”

Effects of different additives on the bacterial community and fermentation mode of whole-plant paper mulberry silage

“…Numerous studies have shown that there is a complex correlation network in the silage fermentation micro-ecosystem ( Bai J. et al, 2021 ; Du et al, 2021 ; Sun et al, 2021 ; Xu H. et al, 2021 ), while silage with high fermentation quality is characterized by a simplified bacterial-associated structure and aggregation of beneficial microorganisms ( Bai C. et al, 2021 ). The LAB inoculation treatment in this study simplifies the microbial correlation structure and promotes fermentation.…”

Fermentation quality, bacterial community, and aerobic stability of ensiling Leymus chinensis with lactic acid bacteria or/and water after long-term storage

“…Its quality, palatability, and productivity were affected by the seasonal changes ( Kang et al, 2007 ), and it is difficult to provide high-quality L. chinensis year-round under grazing and haymaking systems ( Li et al, 2022 ). Ensiling is a satisfactory method for preserving L. chinensis to overcome the above shortcomings ( Pahlow et al, 2003 ; Xu et al, 2021 ). However, the insufficient epiphytic lactic acid bacteria (LAB) and the low moisture content (less than 600 g/kg) in materials negatively affect the fermentation process and the microbial dynamics and induce the Enterobacteriaceae succession in L. chinensis silage ( Xue et al, 2017 ; Xu et al, 2021 ).…”

“…Ensiling is a satisfactory method for preserving L. chinensis to overcome the above shortcomings ( Pahlow et al, 2003 ; Xu et al, 2021 ). However, the insufficient epiphytic lactic acid bacteria (LAB) and the low moisture content (less than 600 g/kg) in materials negatively affect the fermentation process and the microbial dynamics and induce the Enterobacteriaceae succession in L. chinensis silage ( Xue et al, 2017 ; Xu et al, 2021 ). Previous studies reported that inoculating LAB at ensiling can improve the fermentation quality, aerobic stability, and digestibility of L. chinensis silage ( Tian et al, 2014 ; Zhang et al, 2015a ; Zhang and Yu, 2017 ).…”

“…Previous studies reported that inoculating LAB at ensiling can improve the fermentation quality, aerobic stability, and digestibility of L. chinensis silage ( Tian et al, 2014 ; Zhang et al, 2015a ; Zhang and Yu, 2017 ). Moreover, Xu et al (2021) revealed that ensiling L. chinensis with LAB or/and water promotes the fermentation process and LAB succession during fermentation and improves the fermentation quality in the terminal silage, and Enterobacteriaceae dominates the bacterial community during late fermentation phase (from 35 to 60 days) in the silage treated with water.…”