Topic Editors

Institute of Ensiling and Processing of Grass, College of Agro-Grassland Science, Nanjing Agricultural University, Nanjing, China
Dr. Qing Zhang
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
Inner Mongolia Engineering Research Center of Development and Utilization of Microbial Resources in Silage, Inner Mongolia Academy of Agriculture and Animal Husbandry Science, Hohhot 010031, China
Henan Provincial Key Laboratory of Ion Beam Bio-Engineering, Zhengzhou University, Zhengzhou 450051, China
College of Animal Science and Technology, Hainan University, Haikou, China

Fungi and Their Metabolites Affecting Quality, Safety and Functionality of Silage

Abstract submission deadline
closed (1 June 2023)
Manuscript submission deadline
1 August 2023
Viewed by
3437

Topic Information

Dear Colleagues,

Ensiling is an effective and widespread technique for long-term feed preservation with the characteristics of low cost and easy operation. At the early stage of ensiling, water-soluble carbohydrates (WSC) are broken down into water, carbon dioxide, and energy under the respiration of aerobic bacteria. When oxygen is depleted, lactic acid bacteria (LAB) attached to forage multiply and convert WSC into organic acids, thereby creating an acidic and anaerobic environment, inhibiting the activities of undesirable microbes, such as molds and yeasts, and reducing the risk of forage spoilage. Generally, molds and yeasts are usually considered undesirable and pathogenic eukaryotes during ensiling. With the lactic acid production and the decrease in pH level during fermentation, growth of spoilage microorganisms containing aerobic bacteria, yeasts, and filamentous fungi can be limited. However, even if anaerobic and acidic conditions are ensured, a low fungal population can survive in silage and may activate their metabolism if necessary. Various yeasts, such as Candida, Hansenula, Saccharomyces, and Torulopsis spp., can produce lactic acid, acetic acid, and ethanol under anaerobic conditions, although their presence in silage is considered undesirable. To the best of our knowledge, the fungal microbiota and their metabolites and functionality involved in ensilage, and whether bacterial and fungal microbiota interact during ensiling, has not been well investigated. To date, an increasing number of studies have reported how silage microbiota, determined by high-throughput amplicon sequencing, could differ between crops and by the use of additives, but many studies have focused solely on bacterial microbiota. Few studies have examined the fungal microbiota involved in ensiling. Information on the correlation between fungal populations and fermentation characteristics of silage is currently not enough. Therefore, it is critical to perform a qualitative and quantitative assessment of the fungi communities during ensiling and to evaluate some methods to improve the quality, hygiene and safety of silage.

We are pleased to invite you to submit papers that showcase and discuss fungi community and their metabolites in silages. The submitted papers should use Next Generation Sequencing, Metagenomics, and Metabolomics methods to characterize fungi community compositions, diversity, interaction, and their functionality and metabolites during ensiling or aerobic exposure. This Topic aims to provide a fruitful collection of papers (both research articles and review articles) based on different silage managements including chemical additives and inoculants, harvest pretreatments, and other techniques, to ensure the silage quality, safety and hygiene.

We look forward to receiving your contributions.

Dr. Siran Wang
Dr. Qing Zhang
Dr. Lin Sun
Dr. Huili Pang
Dr. Musen Wang
Topic Editors

Keywords

  • fungi
  • ensiling
  • metabolism
  • function
  • silage
  • yeast
  • aerobic stability

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Agriculture
agriculture
3.408 3.1 2011 18.6 Days 2000 CHF Submit
Animals
animals
3.231 2.7 2011 17 Days 1800 CHF Submit
Fermentation
fermentation
5.123 5.3 2015 13.4 Days 2000 CHF Submit
Microorganisms
microorganisms
4.926 4.1 2013 14.1 Days 2200 CHF Submit
Toxins
toxins
5.075 6.6 2009 14.6 Days 2400 CHF Submit

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Published Papers (3 papers)

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Article
Effects of Alfalfa Hay to Oat Hay Ratios on Chemical Composition, Fermentation Characteristics, and Fungal Communities during Aerobic Exposure of Fermented Total Mixed Ration
Fermentation 2023, 9(5), 480; https://doi.org/10.3390/fermentation9050480 - 16 May 2023
Viewed by 518
Abstract
The application of fermented total mixed ration (FTMR) is an effective method to prolong the use time of feed, but the understanding of the interaction mechanism between fungal microorganisms and silage quality and aerobic stability in FTMR is still limited. This study aimed [...] Read more.
The application of fermented total mixed ration (FTMR) is an effective method to prolong the use time of feed, but the understanding of the interaction mechanism between fungal microorganisms and silage quality and aerobic stability in FTMR is still limited. This study aimed to evaluate the effects of alfalfa (Medicago sativa L.) hay to oat (Avena sativa L.) hay ratios on chemical composition, fermentation characteristics, and fungal communities during aerobic exposure of fermented total mixed ration (FTMR). The supplement levels of oat were as follows: 200 g/kg oat hay (LO), 300 g/kg oat hay (MO), and 400 g/kg oat hay (HO). The water content of the three treatments was adjusted to 50% using a sprayer. After 60 days of ensiling, the bags were opened, and the chemical composition, fermentation characteristics, and fungal communities were measured after 3, 6, 9, and 12 days of aerobic exposure. The results suggested that the LO treatment significantly (p < 0.05) increased the aerobic stability than that in other treatments. The crude protein and lactic acid content in the three treatments were significantly decreased with the extension of the aerobic exposure period. Additionally, there was a remarkable (p < 0.05) higher lactic acid content observed in the LO treatment than that in the HO treatment during the aerobic stage. The PCoA showed that the compositions of the fungal community in the HO treatment were distinctly separated from the other two treatments. Compared with HO and LO treatments, the MO treatment observed relatively higher OTU, Shannon, and Chao1 indexes. Compared with LO and MO treatments, the abundances of the genes Saccharomyces and Wallemia were greater increased and decreased in the HO treatment, respectively. Integrated correlation analysis also underscores a possible link between the fermentation characteristics, aerobic stability, and significantly altered fungal community. This study suggested that the use of FTMR in production might prolong aerobic storage time when alfalfa was fermented in a mixture with ≤30% oat. Full article
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Article
Fermentation Characteristics, Microbial Compositions, and Predicted Functional Profiles of Forage Oat Ensiled with Lactiplantibacillus plantarum or Lentilactobacillus buchneri
Fermentation 2022, 8(12), 707; https://doi.org/10.3390/fermentation8120707 - 04 Dec 2022
Viewed by 695
Abstract
This study aimed to investigate the effects of lactic acid bacteria (LAB) inoculants on the fermentation quality, microbial compositions, and predicted functional profiles of forage oat. The forage oat was inoculated with distilled water, Lentilactobacillus buchneri (LB), and Lactiplantibacillus plantarum (LP) as the [...] Read more.
This study aimed to investigate the effects of lactic acid bacteria (LAB) inoculants on the fermentation quality, microbial compositions, and predicted functional profiles of forage oat. The forage oat was inoculated with distilled water, Lentilactobacillus buchneri (LB), and Lactiplantibacillus plantarum (LP) as the control (CON), LB and LP treatments, respectively, and the addition of Lentilactobacillus buchneri (LB) or Lactiplantibacillus plantarum (LP) resulted in 1 × 106 colony-forming units/g of fresh weight. After 30 days of fermentation, the lowest pH (4.23) and the lowest content of ammoniacal nitrogen (NH3-N) in dry matter (DM, 4.39%) were observed in the LP treatment. Interestingly, there was a significant (p < 0.05) difference in lactic acid (LA) concentration among the three treatments. The LP treatment had the highest lactate concentration (7.49% DM). At the same time, a markedly (p < 0.05) elevated acetic acid (AA) concentration (2.48% DM) was detected in the LB treatment. The Shannon and Chao1 indexes of bacterial and fungal communities in all the silage samples decreased compared to those in the fresh materials (FM). Proteobacteria was the dominant phylum in the FM group and shifted from Proteobacteria to Firmicutes after ensiling. Lactobacillus (64.87%) and Weissella (18.93%) were the predominant genera in the CON, whereas Lactobacillus dominated the fermentation process in the LB (94.65%) and LP (99.60%) treatments. For the fungal community structure, the major genus was Apiotrichum (21.65% and 60.66%) in the FM and CON groups after 30 days of fermentation. Apiotrichum was the most predominant in the LB and LP treatments, accounting for 52.54% and 34.47%, respectively. The genera Lactococcus, Pediococcus, and Weissella were negatively associated with the LA content. The genus Ustilago and Bulleromyces were positively associated with the LA content. These results suggest that the addition of LAB regulated the microbial community in oat silage, which influenced the ensiling products, and LP was more beneficial for decreasing the pH and NH3-N and increasing the LA concentration than LB in forage oat silage. Full article
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Article
Effect of Homo-Fermentative Lactic Acid Bacteria Inoculants on Fermentation Characteristics and Bacterial and Fungal Communities in Alfalfa Silage
Fermentation 2022, 8(11), 621; https://doi.org/10.3390/fermentation8110621 - 10 Nov 2022
Cited by 2 | Viewed by 1037
Abstract
We evaluated the effects of a homo-fermentative lactic acid bacteria (homo-LAB) inoculant on the fermentation and microbial communities of alfalfa ensiled at two dry matter (DM) contents of 38 and 46% DM. At both DMs, alfalfa was treated or not with an inoculant [...] Read more.
We evaluated the effects of a homo-fermentative lactic acid bacteria (homo-LAB) inoculant on the fermentation and microbial communities of alfalfa ensiled at two dry matter (DM) contents of 38 and 46% DM. At both DMs, alfalfa was treated or not with an inoculant containing Pediococcus acidilactici, Enterococcus faecium and Lactobacillus plantarum at a targeted application rate of 165,000 cfu/g of fresh weight and stored for 3, 30 and 60 days. Treatment with the inoculant resulted in a lower drop in pH and, in general, higher lactic acid and lower acetic acid when applied to medium DM silage. For the four most abundant microbial genera, increased abundances of Bacteroides and Lactobacillus (p < 0.05), as well as decreased abundances of Muribaculaceae were observed in high DM and inoculated silages. The abundance of Prevotellaceae-UCG-001 was lower in medium DM control silages than in high DM control silages. Inoculation and DM affected abundances of Vishniacozyma (p < 0.05). Increased abundances of Vishniacozyma, as well as decreased abundances of Leucosporidium were observed in medium DM-inoculated silages. Changes in the relative abundance (RA) of the main populations of bacteria and yeasts did explain the fermentation and nutrition differences among treatments. Full article
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