scholarly journals Pectin Degradation is an Important Determinant for Alfalfa Silage Fermentation through the Rescheduling of the Bacterial Community

2020 ◽  
Vol 8 (4) ◽  
pp. 488 ◽  
Author(s):  
Bing Wang ◽  
Zhiqiang Sun ◽  
Zhu Yu

This study aimed to evaluate the effects of the four kinds of additives on the silage quality and the relevant bacterial community diversity by Illumina HiSeq 16S rRNA sequencing. The four kinds of additives were Lactobacillus plantarum (LP), organic acids including gallic acid (GA) and phenyllactic acid (PA), pectin (PEC), and enzymes including pectinase (PEE) and cellulase (CE). After 30 d of fermentation, the pH value was shown to have the lowest value in the PEE and PEC groups, followed by the PA group, and then in CE and GA groups; the highest value of pH was found in both LP and control groups. The ammonia nitrogen concentration was lower in the PEE group compared to the other groups except for the PA group. In the comparisons among the seven groups, Lactobacillus was higher in the LP group, Paracoccus was higher in the GA group, Weissella was higher in the PA group, Leuconostoc was higher in the PEC group, Bacillus, Aeromonas, and Curvibacter were higher in the PEE group, and Coriobacteriaceae_UCG_002 was higher in the CE group compared to the other groups. This study proposed that the addition of PEC and PEE improved the fermentation quality of alfalfa silage compared to other additives by improving the bacterial community of Leuconostoc, and Bacillus and Aeromonas, respectively. Moreover, the enhanced fermentation quality of alfalfa silage by the supplementation of PEC and PEE might be attributed to other unclassified genera. This study provides an implication that pectin degradation is an important determinant for alfalfa silage fermentation through the rescheduling of bacterial community diversity.

2021 ◽  
Vol 12 ◽  
Author(s):  
Qiang Lu ◽  
Zhen Wang ◽  
Duowen Sa ◽  
Meiling Hou ◽  
Gentu Ge ◽  
...  

This study investigated the fermentation quality of alfalfa grown in different salt stress regions in China. Following the production of silage from the natural fermentation of alfalfa, the interplay between the chemical composition, fermentation characteristics, and microbiome was examined to understand the influence of these factors on the fermentation quality of silage. The alfalfa was cultivated under salt stress with the following: (a) soil content of <1%0 (CK); (b) 1–2%0 (LS); (c) 2–3%0 (MS); (d) 3–4%0 (HS). The pH of the silage was high (4.9–5.3), and lactic acid content was high (26.3–51.0 g/kg DM). As the salt stress increases, the NA+ of the silages was higher (2.2–5.4 g/kg DM). The bacterial alpha diversities of the alfalfa silages were distinct. There was a predominance of desirable genera including Lactococcus and Lactobacillus in silage produced from alfalfa under salt stress, and this led to better fermentation quality. The chemical composition and fermentation characteristics of the silage were closely correlated with the composition of the bacterial community. Furthermore, NA+ was found to significantly influence the microbiome of the silage. The results confirmed that salt stress has a great impact on the quality and bacterial community of fresh alfalfa and silage. The salt stress and plant ions were thus most responsible for their different fermentation modes in alfalfa silage. The results of the study indicate that exogenous epiphytic microbiota of alfalfa under salt stress could be used as a potential bioresource to improve the fermentation quality.


2020 ◽  
Author(s):  
Fengyuan Yang ◽  
Yanping Wang ◽  
Shanshan Zhao ◽  
Yuan Wang

Abstract Background The objective of this study was to investigate the mechanism of Lactobacillus plantarum (L. plantarum) involved in improving fermentation quality of naturally ensiled alfalfa under poor conditions. Results High-moisture wilted alfalfa was ensiled without inoculants (CK) or with inoculation of two L. plantarum additives (LPI and LPII). The pH and fermentation products of silage were investigated, and the bacterial community compositions were analyzed. The L. plantarum inoculants significantly enhanced the lactic acid fermentation in terms of promotions in pH decline, lactic acid accumulation, and Lactobacillus abundance for both periods. At 90 d, silage in CK exhibited a high pH, a loss in dry matter, and a high concentration of ammoniacal nitrogen. The inoculations of L. plantarum significantly inhibited the growth of Clostridia, and reduced ammoniacal nitrogen concentration in silage (P < 0.05). Conclusions Inoculation with L. plantarum improved the fermentation quality of alfalfa silage and inhibited the growth of spoilage microorganisms, and further delayed decomposition of alfalfa silage under adverse ensiling conditions.


LWT ◽  
2021 ◽  
pp. 111308
Author(s):  
Fumin Chi ◽  
Zhankun Tan ◽  
Xuedong Gu ◽  
Lin Yang ◽  
Zhang Luo

2021 ◽  
Author(s):  
Emily K. Bechtold ◽  
Stephanie Ryan ◽  
Sarah E. Moughan ◽  
Ravi Ranjan ◽  
Klaus Nüsslein

Grasslands represent a critical ecosystem important for global food production, soil carbon storage, and water regulation. Current intensification and expansion practices add to the degradation of grasslands and dramatically increase greenhouse gas emissions and pollution. Thus, new ways to sustain and improve their productivity are needed. Research efforts focus on the plant-leaf microbiome, or phyllosphere, because its microbial members impact ecosystem function by influencing pathogen resistance, plant hormone production, and nutrient availability through processes including nitrogen fixation. However, little is known about grassland phyllospheres and their response to environmental stress. In this study, globally dominant temperate and tropical forage grass species were grown in a greenhouse under current climate conditions and drought conditions that mimic future climate predictions to understand if (i) plant host taxa influence microbial community assembly, (ii) microbial communities respond to drought stress, and (iii) phyllosphere community changes correlate to changes in plant host traits and stress-response strategies. Community analysis using high resolution sequencing revealed Gammaproteobacteria as the dominant bacterial class, which increased under severe drought stress on both temperate and tropical grasses while overall bacterial community diversity declined. Bacterial community diversity, structure, and response to drought were significantly different between grass species. This community dependence on plant host species correlated with differences in grass species traits, which became more defined under drought stress conditions, suggesting symbiotic evolutionary relationships between plant hosts and their associated microbial community. Further understanding these strategies and the functions microbes provide to plants will help us utilize microbes to promote agricultural and ecosystem productivity in the future.


2021 ◽  
Vol 9 (2) ◽  
pp. 225-234
Author(s):  
Liuxing Xu ◽  
Zhaohong Xu ◽  
Mingxia Chen ◽  
Jianguo Zhang

Whole-crop wheat (WCW) is rich in nutrients and is widely used as a forage crop. This study consisted of 2 experiments: Experiment 1 studied the yield, nutritive value and silage quality of WCW at 3 seeding rates (320 kg/ha, S320; 385 kg/ha, S385; and 450 kg/ha, S450) and different fertilizing times, i.e. 60% at seedling stage and the remaining 40% at the jointing stage vs. heading stage; and Experiment 2 examined the yield, nutritive value and silage quality of WCW receiving different fertilizer types, i.e. urea, compound fertilizer (N:P:K) and urea + compound fertilizer (all iso-nitrogenous). With the increased seeding rate, dry matter (DM) and crude protein (CP) yields tended to increase, but relative feed value tended to decrease. Experiment 1: there was no significant interaction between time of applying the second fertilizer dose and seeding rate in terms of concentrations of CP, crude fiber, ether extract, crude ash, nitrogen-free extract, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in wheat (P>0.05). However, a significant interaction between fertilizing time and seeding rate was observed in terms of silage fermentation quality (pH, lactic acid, butyric acid and NH3-N concentrations) (P<0.05). Experiment 2: DM yield, CP yield and concentrations of CP, ADF and water-soluble carbohydrate were not affected by fertilizer type (P>0.05). Fertilizer type had significant effects on pH of silage and concentrations of organic acids (except propionic acid) and NH3-N in WCW silage (P<0.05). Under the present study conditions, considering DM yield, nutrient composition and silage fermentation quality, an optimal seeding rate of wheat for forage appears to be about 385 kg/ha. N fertilizer should be applied at the seedling stage and jointing stage. Although applying a mixture of urea and compound fertilizer had no significant effects on yield and nutritive value of WCW relative to applying urea alone, it did improve silage fermentation quality. Results may differ on different soils.


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