Exploring the effect of wilting on fermentation profiles and microbial community structure during ensiling and air exposure of king grass silage

Abstract

In order to better understand the effect of wilting treatment on silage, we study analyzed the fermentation quality of unwilted (CK) and wilted (WT) king grass silage, and the dynamic changes of microorganisms in silage and aerobic exposure. After 30 days of silage, WT silage significantly reduced the pH of the silage (p < 0.05) and increased the contents of lactic acid and acetic acid (p < 0.05), but did not reduce the content of Ammonia-N (p > 0.05). Wilting treatment increased bacterial and fungal diversity during silage but decreased fungal diversity during aerobic exposure. The relative abundance of Lactococcus and Enterococcus in wilting silage increased. In the aerobic exposure stage, the relative abundance of Klebsiella decreased, but the relative abundance of Enterobacter increased in wilting treatment silage. In addition, the relative abundance of Acinetobacter and Ignatzschineria increased after 5 days of aerobic exposure. In contrast with unwilted silage, wilting treatment silage after aerobic exposure had no Candida, but the relative abundance of Wickerhamomyces increased. The results showed that wilting treatment could raise the silage quality of king grass. However, WT silage did not inhibit the reproduction of harmful microorganisms during aerobic exposure and did not significantly improve the aerobic stability of silage.

Effects of Alfalfa Hay to Oat Hay Ratios on Chemical Composition, Fermentation Characteristics, and Fungal Communities during Aerobic Exposure of Fermented Total Mixed Ration

“…The Saccharomyces belonging to lactate-assimilating yeasts have been proven to be associated with aerobic spoilage during aerobic exposure [61], which could utilize lactic acid, resulting in an increase in silage temperature and pH [55]. In the present trial, Saccharomyces was the most differentially abundant fungal in the HO treatment during the entire aerobic exposure period, suggesting that the yeast was the most important group of microorganisms causing silage deterioration upon aerobic exposure, which in agreement with the study published by Chen et al [15], who reported that the presence of yeast could induce the increase in pH value, thereby promoting the proliferation of the spoilage microorganisms. This finding may be attributed to the oat could be easily colonized by mycotoxigenic fungi [50].…”

“…In general, there are many factors affecting aerobic stability, such as undissociated acetic acid in plants and the development of yeasts and molds. However, recent research has demonstrated that the improvement of aerobic stability in silage is closely related to dynamic changes in microorganisms during the aerobic exposure stage [15]. The composition and distribution of fugal are the key players in aerobic stability.…”

Investigating the efficacy of an exopolysaccharide (EPS)‐producing strain Lactiplantibacillus plantarum L75 on oat silage fermentation at different temperatures

“…At present, there have many reports on the bacterial community changes during the ensilage process (Bai et al., 2022 ; Muraro et al., 2021 ; Ogunade et al., 2018 ), however, fungal community also had great impact on silage fermentation quality. Generally, Penicillium and Aspergillus are considered toxin producers, which affect the feeding safety of silages (Chen et al., 2022 ). Similar to the bacterial community, fungal community were also affected by the inoculation mentioned in this study.…”

Effects of Cellulase and Xylanase on Fermentation Characteristics, Chemical Composition and Bacterial Community of the Mixed Silage of King Grass and Rice Straw

“…In this study, considering the presence of Acinetobacter in the mixed silage and the increase in acetic acid levels with the prolongation of ensiling time, it is speculated that some Acinetobacter utilize acetic acid to survive in the anaerobic stage of silage. Chen et al also detected Acinetobacter in the king grass silage [ 45 ]. Klebsiella , a facultative anaerobic bacterium, has been found in many silages [ 46 , 47 , 48 ].…”