scholarly journals Succession of Microbial Communities of Corn Silage Inoculated with Heterofermentative Lactic Acid Bacteria from Ensiling to Aerobic Exposure

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 258
Author(s):  
Hao Guan ◽  
Qifan Ran ◽  
Haiping Li ◽  
Xinquan Zhang

To further explore the effects of heterofermentative lactic acid bacteria (LAB) on silage fermentation and aerobic stability, whole-plant corn at around the 1/2 milk-line stage was freshly chopped and ensiled in laboratory silos with deionized water (control), Lactobacillus buchneri (LB), or L. rhamnosus (LR). Each treatment was prepared in triplicate for 3, 14, and 60 d of fermentation, followed by 3 and 7 days of aerobic exposure. The dynamic changes in microbial community were studied by single molecule real-time (SMRT) sequencing. The results showed that the two LAB inoculants altered the microbial communities in different ways. Succession from L. plantarum to L. buchneri and L. rhamnosus was observed in LB- and LR-treated silage, respectively. Both silages improved aerobic stability (82 and 78 h vs. 44 h) by occupying the microbial niche to produce higher levels of acetic acid at terminal fermentation. Because Acetobacter fabarum dominated in the silages after aerobic exposure, beta diversity dramatically decreased. In this study, a. fabarum was reported for the first time in silage and was related to aerobic spoilage. The two heterofermentative LAB produced acetic acid and improved the aerobic stability of the corn silage by occupying the microbial niche at terminal fermentation. Inoculated L. rhamnosus had a greater pH for a longer period of time after opening and less DM loss at day 7.

2020 ◽  
Vol 11 ◽  
Author(s):  
Fu-gui Jiang ◽  
Hai-jian Cheng ◽  
Dong Liu ◽  
Chen Wei ◽  
Wen-juan An ◽  
...  

We investigated the variation in microbial community and fermentation characteristics of whole-plant corn silage after treatment with lactic acid bacteria (LAB) and organic acids. The fresh corn forages were treated with a combination of L. acidophilus and L. plantarum (106 CFU/g fresh material) or a 7:1:2 ratio of formic acid, acetic acid, and propionic acid (6 mL/g fresh material) followed by 45 or 90 days of ensiling. Silages treated with LAB showed increased lactic acid content and decreased pH after 45 days. Although treatment with LAB or organic acids decreased the common and unique operational taxonomic units, indicating a reduction in microbial diversity, the relative abundance of Lactobacillus was elevated after 45 and 90 days compared with control, which was more distinct in the organic acid groups. Moreover, we found higher levels of acetic acid and increased abundance of Acetobacter in silages treated with organic acids whereas undesirable microorganisms such as Klebsiella, Paenibacillus, and Enterobacter were reduced. In summary, the quality of corn silages was improved by LAB or organic acid treatment in which LAB more effectively enhanced lactic acid content and reduced pH while organic acid inhibited the growth of undesirable microorganisms.


2021 ◽  
pp. 395-410
Author(s):  
Tânia Mara Becher Ribas ◽  
◽  
Mikael Neumann ◽  
Egon Henrique Horst ◽  
Fernando Braga Cristo ◽  
...  

The objective was to evaluate the efficiency of two bacterial inoculants, 11CFT and 11C33, with different genera of lactic acid bacteria on the chemical and fermentation composition of the silage, and the temperature and pH behavior of the silage during the feed out period. The experimental design used was randomized blocks, with three treatments: corn silage without inoculant (control); corn silage with 11CFT inoculant (consisting of strains of Lactobacillus buchneri and L. casei); and corn silage with 11C33 inoculant (consisting of strains of L. buchneri, L. plantarum and Enterococcus faecium). The use of both inoculants increased the concentration of lactic acid in the silage (22.42 g kg-1 for control against 36.00 and 33.33 g kg-1 for 11CFT and 11C33, respectively) and reduced aerobic dry matter losses. The silage treated with 11C33 obtained a higher concentration of acetic acid (17.44 g kg-1) and propionic acid (2.08 g kg-1). The 11CFT inoculant provided a lower concentration of ethanol, however, without differing from the silage with 11C33 (0.70 and 1.61 g kg-1, respectively). Even without variations in temperature and pH at silage unloading, the use of the 11C33 inoculant generated a higher concentration of acetic and propionic acid, providing better aerobic stability days after unloading. Both inoculants also improved the in situ ruminal digestibility of corn silage compared to control silage. They provide an increase in the content of lactic and propionic acids, which assist to reduce dry matter losses and ethanol production. There were no variations in temperature and pH at the silo unloading, however, the use of the 11C33 inoculant generated a higher concentration of acetic and propionic acids providing better aerobic stability after exposure to air.


Author(s):  
Chunjian Lin ◽  
K. K. Bolsen ◽  
B. E. Brent ◽  
D.Y.C. Fung ◽  
W. R. Aimutis

Epiphytic LAB, e.g., lactobacilli, lactococci, enterococci, pediococci, streptococci, and leuconostocs, play a major role in silage fermentation. Their numbers and populations have become a concern in predicting the adequacy of silage fermentation and in determining whether or not to apply a bacterial inoculant (Bolsen et al, 1989). Epiphytic LAB counts are usually low and variable on silage crops (Lin et al, 1991), and increases in the LAB counts usually occur coincident to the chopping process. Only limited information is available concerning the succession of epiphytic LAB species during the ensiling period of alfalfa (Medicago sativaL.) and maize (Zea mays L.), the two major silage crops in North America. The present studies investigated the epiphytic LAB succession during the pre-ensiling and ensiling periods for two cuttings of alfalfa, each harvested at three stages of maturity, and three whole-plant maize hybrids.A second-year stand of alfalfa was harvested at the 2nd and 4th cuttings and at the late-bud, 10% bloom, and 50% bloom stages of maturity within each cutting in 1989. Following mowing, the alfalfa was wilted in the windrow for 5 to 6 hours prior to precision chopping.


2020 ◽  
Vol 98 (8) ◽  
Author(s):  
Érica B da Silva ◽  
Rebecca M Savage ◽  
Amy S Biddle ◽  
Stephanie A Polukis ◽  
Megan L Smith ◽  
...  

Abstract We evaluated the effects of a chemical additive on the microbial communities, fermentation profile, and aerobic stability of whole-plant corn silage with or without air stress during storage. Whole-plant corn was either untreated or treated with a chemical additive containing sodium benzoate, potassium sorbate, and sodium nitrite at 2 or 3 liters/t of fresh forage weight. Ten individually treated and replicated silos (7.5 liters) were made for each treatment. Half of the silos remained sealed throughout a 63-d storage period, and the other half was subjected to air stress for 2 h/wk. The composition of the bacterial and fungal communities of fresh forage and silages untreated or treated with 2 liters/t of fresh forage weight was analyzed by Illumina Miseq sequencing. Treated silage had greater (P < 0.05) aerobic stability than untreated, even when subjected to air stress during storage, but the numbers of yeasts culturable on selective agar were not affected. However, the additive reduced the relative abundance (RA) of the lactating-assimilating yeast Candida tropicalis (P < 0.01). In air-stressed silages, untreated silage had a greater (P < 0.05) RA of Pichia kudriavzevii (also a lactate assimilator) than treated silage, whereas treated silage was dominated by Candida humilis, which is usually unable to assimilate lactate or assimilates it slowly. The additive improved the aerobic stability by specifically preventing the dominance of yeast species that can consume lactate and initiate aerobic spoilage. To the best of our knowledge, this is the first work that identifies the specific action of this additive on shifting the microbial communities in corn silage.


2019 ◽  
Vol 7 (1-2) ◽  
pp. 127-132
Author(s):  
Judit Peter Szucs ◽  
Agnes Suli ◽  
Timea Suli Zakar ◽  
Elizabet Berecz ◽  
Mate Pek

The object of the trial was to study the effect of some lactic acid bacteria strains on the fermentation and aerobic stability of whole plant maize silages.The whole plant maize raw material was 32% DM, in soft cheddar stage of grain ripeness. It was ensiled in 4.2 litre capacity glass micro-size silos in 5 replicates /each treatment and stored on constant air conditioned room temperature (22 oC) during 95 days. The average packing density of raw material was 211 kg DM/m3.The applied treatments: 1. Untreated control maize, 2. Enterococcus faecium 100,000 CFU/g fresh maize (FM), 3. Lactobacillus plantarum 50,000 CFU/g FM + Enterococcus faecium 50,000 CFU/g FM, 4. Lactococcus lactis 100,000 CFU/g FM, 5. Lactobacillus plantarum 50,000 CFU/g FM + Lactococcus lactis 50,000 CFU/g FM, 6. Lactobacillus plantarum 100,000 CFU/g FM.Aerobic stability study:  Applied Honig (1990 system).The main experiences are the following: Applied lactic acid bacteria strains improved the quality of fermentation of maize in general compare to untreated control one.Lactic acid bacteria strains significantly stimulated lactic acid production and decreased propionic and butyric acid production. The origin of ammonia decreased also under influence of lactic acid bacteria strains in unaerobic conditions.Enterococcus faecium and.Lactococcus lactis are not able to protect the maize silages against the aerobic deterioration with the applied dosage.  Lactobacillus plantarum itself produced the most favourable fermentation characteristics and protected the aerobic stability of silage the most effectively (during 4 day) compare to all other treated maize silages.


2020 ◽  
Vol 8 (5) ◽  
pp. 719 ◽  
Author(s):  
Hao Guan ◽  
Yang Shuai ◽  
Yanhong Yan ◽  
Qifan Ran ◽  
Xia Wang ◽  
...  

To develop a silage fermentation technique to adapt to global climate changes, the microbiome and fermentation dynamics of corn silage inoculated with heat-resistant lactic acid bacteria (LAB) under high-temperature conditions were studied. Corn was ensiled in laboratory silo, with and without two selected strains, Lactobacillus salivarius LS358 and L. rhamnosus LR753, two type strains L. salivarius ATCC 11741T and L. rhamnosus ATCC 7469T. The ensiling temperatures were designed at 30 °C and 45 °C, and the sampling took place after 0, 3, 7, 14, and 60 days of fermentation. The higher pH and dry matter losses were observed in the silages stored at 45 °C compared to those stored at 30 °C. Silages inoculated with strains LS358 and LR753 at 30 °C had a lower ratio of lactic acid/acetic acid. The dominant bacterial genera gradually changed from Pediococcus and Lactobacillus to Lactobacillus in silages during ensiling at 30 °C, while the bacterial community became more complex and fragmented after 7 d of ensiling at 45 °C. The high temperatures significantly led to a transformation of the LAB population from homo-fermentation to hetero-fermentation. This study is the first to describe microbial population dynamics response to high temperature during corn ensiling, and the results indicate that L. rhamnosus 753 shows potential ability to improve silage fermentation in tropics and subtropics.


Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 335
Author(s):  
Ana Paula Maia dos Santos ◽  
Edson Mauro Santos ◽  
Gherman Garcia Leal de Araújo ◽  
Juliana Silva de Oliveira ◽  
Anderson de Moura Zanine ◽  
...  

The current study aimed to evaluate the application effects of the preactivated Lactobacillus buchneri and urea on the fermentative characteristics, chemical composition and aerobic stability in corn silages. The design was completely randomized, in a 6 × 5 factorial arrangement, with six types of additive and five opening times. The treatments consisted of corn silage; corn silage with freeze-dried inoculant; corn silage with freeze-dried inoculant +1.0% urea; corn silage with activated inoculant; corn silage with activated inoculant +1.0% urea, and corn silage with 1.0% urea. Populations of lactic acid bacteria stabilized at the 70th day, with average values of 8.91 and 9.15 log cfu/g for corn silage with freeze-dried inoculant +1.0% urea and corn silage with freeze-dried inoculant, respectively. In contrast, the silages without additives showed significantly lower values of 7.52 log cfu/g forage at the 70th day. The silages with urea (isolated or associated with the inoculant) increased the total nitrogen content. The maximum temperature values were highest in the corn silages without additives, indicating that these silages were more prone to deterioration. The use of Lactobacillus buchneri activated proved to be more efficient in improving the fermentative profile of corn silages than the freeze-dried inoculant. The use of urea as an additive reduced the losses and improved the nutritional value and aerobic stability of corn silages. Additionally, the combination of Lactobacillus buchneri activated and urea may be used as a technique to improve the fermentative profile, chemical composition and aerobic stability of corn silages.


2014 ◽  
Vol 54 (2) ◽  
pp. 165
Author(s):  
H. Mohammadzadeh ◽  
M. Khorvash ◽  
G. R. Ghorbani

A multi-species lactic acid bacterial inoculant (Lactisil maize, LM) was applied to whole-crop corn at different maturities in laboratory silos, to evaluate its effects on biochemical characteristics and aerobic stability. The corn crop was harvested at hard dough (HD, 253.1 g/DM kg), one-third milkline (ML, 293.7 g/DM kg) and one-third milkline with a killing frost (MLF, 297.6 g/DM kg). Crops were chopped to a 2.5-cm theoretical cut length, subsampled and treated with two levels of inoculant (LB1 = 1.5 × 105 cfu/g forage, LB2 = 3 × 105 cfu/g forage) or untreated (WO). The chemical composition of MLF crops was very similar to that of ML crops. However, lower (P < 0.01) numbers of lactic acid bacteria and higher numbers of yeast were enumerated in MLF than in ML crops. Higher percentages of DM and neutral detergent fibre and higher pH, but lower (P < 0.01) concentrations of water soluble carbohydrate and crude protein were measured in ML and MLF crops than in HD crops. Application of the inoculant increased (P < 0.01) concentrations of volatile fatty acids, neutral detergent fibre and acid detergent fibre in silages. Lactic acid concentration increased (P < 0.01) in HD treatments with an increasing level of inoculant. In contrast, the highest (P < 0.01) lactic acid concentration was measured in LB1 treatment compared with WO and LB2 in ML and MLF silages. Silages prepared from ML and MLF crops had higher (P < 0.01) lactic and acetic acid concentrations but lower (P < 0.01) butyric acid concentrations than did those prepared from HD. The pH in LB1 and LB2 silages was higher (P < 0.01) than that measured in WO silages. Aerobic stability was not influenced by inoculant treatment but low-DM silages were more (P < 0.01) resistant to spoilage. Frost-killed corn crops had a good potential to produce well fermented silage. Using LM resulted in silages with slightly higher fermentation products but it failed to improve aerobic stability of silage after 120 days of ensiling. These results indicated that inoculation of corn crops with LM for a short-duration ensilage period cannot enhance aerobic stability of silages due to insufficient acetic acid production from lactic acid conversion.


2021 ◽  
Vol 9 (1) ◽  
pp. 52-59
Author(s):  
Xuxiong Tao ◽  
Chongwen Ji ◽  
Sifan Chen ◽  
Jie Zhao ◽  
Siran Wang ◽  
...  

This study was conducted to investigate the effects of adding citric acid residue (CAR) with or without lactic acid bacteria (LAB) to Napier grass (Cenchrus purpureus; syn. Pennisetum purpureum) cv. Sumu No. 2 at ensiling on the fermentation quality and aerobic stability of the resulting silage. Treatments included: Control (Napier grass forage without additives); and Napier grass inoculated with lactic acid bacteria (Lactobacillus plantarum and L. buchneri) at 1 × 106 cfu/gfresh weight (FW) forage (LAB) or 36 g citric acid residue/kg FW forage (CAR) or a mixture of CAR and LAB (CL). Forty-five days after ensiling the silages were tested for chemical and microbial composition and an aerobic stability test was conducted. The addition of CAR with or without LAB increased the DM and lactic acid concentrations in silage and decreased pH plus acetic acid, ammonia nitrogen (NH3-N), neutral detergent fiber and cellulose concentrations relative to Control. The pH in LAB silage was lower than in Control, while lactic acid concentration was higher. During the first 2 days of aerobic exposure, all additives increased the water-soluble carbohydrate (WSC) and lactic acid concentrations and decreased pH plus NH3-N and acetic acid concentrations. Moreover, CL silages had the highest WSC and the lowest NH3-N and acetic acid concentrations during aerobic exposure. However, all additives failed to improve the aerobic stability of the silage. While CAR with or without LAB inoculant improved the fermentation quality of silage made from Napier grass, more studies are warranted to identify additives which can improve aerobic stability of the silage after opening.


2019 ◽  
Vol 59 (8) ◽  
pp. 1584
Author(s):  
Huazhe Si ◽  
Hanlu Liu ◽  
Zhipeng Li ◽  
Weixiao Nan ◽  
Chunai Jin ◽  
...  

Changes in the microbial community are closely related to the fermentation of silage. However, how host genetic variation shapes the community structure of the silage microbiota and its metabolic phenotype is poorly understood. The objective of present study was to evaluate the effects of the application of the homo-fermentative Lactobacillus plantarum and hetero-fermentative Lactobacillus buchneri strains to lucerne silage on the fermentation characteristics, aerobic stability, and microbial community and their correlations. The three silages treated with L. plantarum or L. buchneri were well preserved and had significantly lower pH values, butyric acid, propionic acid, and ammonia-N concentrations, and significantly higher residual water-soluble carbohydrate, dry matter and lactic acid contents than the controls. The treated groups had more lactic acid bacteria and lower quantities of other bacteria in their microbial communities. Inoculation of lactic acid bacteria influenced the abundances of other bacteria and controlled the silage fermentation characteristics. L. buchneri inhibited the abundance of Enterobacter_ludwigii to increase the crude protein content, L. plantarum improve the neutral detergent fibre content by affecting the abundance of Arthrobacter_sp._Ens13. In conclusion, the application of L. plantarum and L. buchneri improved the quality of lucerne silage fermentation, and L. buchneri resulted in greater improvements after aerobic exposure.


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