In Vitro Fermentation

A special issue of Fermentation (ISSN 2311-5637). This special issue belongs to the section "Microbial Metabolism, Physiology & Genetics".

Deadline for manuscript submissions: closed (25 June 2022) | Viewed by 35282

Special Issue Editor


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Guest Editor
College of Animal Science and Technology, Yangzhou University, Yangzhou, China
Interests: ruminant; rumen; caecum; microbiology; bacteria; protozoa; fermentation; fermenter; VFA; amino acid
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In vitro fermentation is a critical technology for studying and evaluating feed nutritional value, nutrient metabolism mechanism and fermentation state. In vitro fermentation includes simulated rumen in vitro fermentation, in vitro gas production, in vitro microbial fermentation, in vitro enzyme fermentation, combined two-step fermentation, etc. Over the years, in vitro fermentation has evaluated the feeding value of a large number of feeds to ruminants and monogastric animals such as swine. It not only enriches the feed database, but also makes an important contribution to the development and utilization of microbial resources and the improvement of feed utilization rate.

Substrate, microorganism, enzyme and fermentation state are important elements of in vitro fermentation, and equipment and fermentation regulation of in vitro fermentation are also important guarantees for fermentation. Therefore, the goal of this Special Issue is to publish both recent innovative research results and review papers on in vitro fermentation with nutrients or new feed resources. Review and research papers on the development of novel enzymes, microbial strains, and fermentation equipment are also of interest. If you would like to contribute a review paper, please contact one of the editors to discuss the relevance of the topic before submitting the manuscript.

Dr. Mengzhi Wang
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fermentation is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • microbe
  • microbial ecology
  • nutrients
  • digestibility
  • enzyme
  • metabolite
  • gas
  • rumen
  • fermenter
  • medium

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Published Papers (16 papers)

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Editorial

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3 pages, 161 KiB  
Editorial
In Vitro Fermentation
by Mengzhi Wang
Fermentation 2023, 9(2), 86; https://doi.org/10.3390/fermentation9020086 - 19 Jan 2023
Viewed by 1234
Abstract
The rumen of ruminants, as well as the colon of monogastric animals, are inhabited by over one trillion bacteria, fungi, and protozoa, and these are emerging as critical regulators in dietary micronutrients and animal health [...] Full article
(This article belongs to the Special Issue In Vitro Fermentation)

Research

Jump to: Editorial, Review

16 pages, 591 KiB  
Article
Comparisons of Ramie and Corn Stover Silages: Effects on Chewing Activity, Rumen Fermentation, Microbiota and Methane Emissions in Goats
by Xu Tian, Cheng Gao, Zhengping Hou, Rong Wang, Xiumin Zhang, Qiushuang Li, Zhongshan Wei, Duanqin Wu and Min Wang
Fermentation 2022, 8(9), 432; https://doi.org/10.3390/fermentation8090432 - 01 Sep 2022
Cited by 3 | Viewed by 1598
Abstract
The study aimed to investigate the nutritional value of ramie (Boehmeria nivea) silage, and its consequences for chewing activity, rumen fermentation, and enteric methane (CH4) emissions in goats, by comparing it with corn stover (CS) silage. An in vitro [...] Read more.
The study aimed to investigate the nutritional value of ramie (Boehmeria nivea) silage, and its consequences for chewing activity, rumen fermentation, and enteric methane (CH4) emissions in goats, by comparing it with corn stover (CS) silage. An in vitro ruminal experiment was firstly performed to investigate the substrate degradation and fermentation of CS and ramie silage. The ramie silage diet was formulated by replacing 60% of CS silage with ramie silage (dry matter (DM) basis). Eight female Xiangdong Black goats (a local breed in Southern China, 1 to 1.2 years of age) with BW of 21.0 ± 1.05 kg were used for this experiment and were randomly assigned to either one of the two dietary treatments in a cross-over design. The ramie silage had higher crude protein (CP) and ash content and lower hemicellulose content, together with decreased (p < 0.05) nutrient degradation and methane production and increased (p < 0.05) acetate molar percentage and acetate to propionate ratio through in vitro ruminal fermentation. Feeding the ramie silage diet did not alter feed intake (p > 0.05), decreased (p < 0.05) nutrient digestibility, and increased (p < 0.05) chewing activity and rumination activity, with reductions (p < 0.05) in eating activity and idle activity. Although feeding the ramie silage diet caused a greater (p < 0.05) molar percentage of acetate and lower molar percentage of propionate, it decreased the rumen-dissolved CH4 concentration and enteric CH4 emissions (p < 0.05). Feeding the ramie silage diet did not alter (p > 0.05) the population of bacteria, protozoa, and fungi; it increased the 16S rRNA gene copies of Ruminococcus flavefaciens (p < 0.05). Further 16SrRNA gene amplicon analysis indicated a distinct bacterial composition between the two treatments (p < 0.05). Feeding the ramie silage diet led to a lower abundance of genera Lawsonibacter, Sedimentibacter, Saccharofermentans, Sediminibacterium, and Bifidobacterium (p < 0.05). Ramie can be an alternative forage resource to stimulate chewing activity and reduce CH4 emissions in ruminants. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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15 pages, 3217 KiB  
Article
The Potential Use of Endophyte-Free inebrians as Sheep Feed Evaluated with In Vitro Fermentation
by Yaling Ma, Hucheng Wang, Chunjie Li and Kamran Malik
Fermentation 2022, 8(9), 419; https://doi.org/10.3390/fermentation8090419 - 24 Aug 2022
Cited by 2 | Viewed by 1576
Abstract
Endophytic fungal infection is the major reason for intoxication of animals caused by drunken horse grass. Fortunately, it has been established that seed detoxification techniques and isolation of endophytic fungi infect non-endophytic fungi populations with the same genetic background as endophyte-infected Achnatherum  [...] Read more.
Endophytic fungal infection is the major reason for intoxication of animals caused by drunken horse grass. Fortunately, it has been established that seed detoxification techniques and isolation of endophytic fungi infect non-endophytic fungi populations with the same genetic background as endophyte-infected Achnatherum inebrians. Moreover, sheep can use endophyte-free Achnatherum inebriants (EF) without obvious toxicity symptoms. The present study selected EF as a representative grass, consisting of five different replacement levels, EF0, EF25, EF50, EF75, and EF100, corresponding to 0%, 25%, 50%, 75%, and 100% of the fermentation substrate, respectively. Simultaneously, in vitro fermentation and the 16S rRNA amplicon sequencing method was used to explore the effect of EF on sheep ruminal fermentation and microbial diversity. The results revealed that EF100 had the highest values for pH, acetate: propionate, the Patescibacteria, Kiritimatiellaeota, and Synergistetes phylum levels, Ruminococcaceae, Prevotellaceae, and Saccharofermentans genus levels than the other treatments (p < 0.05). In contrast, EF25 was associated with higher levels of abundance-based coverage estimator (ACE), Chaol index of the phyla Synergistetes and Bacteroidetes, and of the genus Erysipelotrichaceae, Rikenellaceae, and Prevotella as compared with other treatments (p < 0.05). EF50 resulted in the greatest values for the genus Christensenellaceae and Lachnospiraceae as compared with other treatments (p < 0.05). EF75 resulted in the greatest values for the Shannon index as compared with other treatments (p < 0.05). EF0 resulted in the greatest values for gas production (GP), ammonia nitrogen (NH3-N), total volatile fatty acid (TVFA), acetate, propionate, butyrate, valerate, isobutyrate, isovalerate, and the phyla Firmicutes, Proteobacteria, and Spirochaetes, and the genus Succiniclasticum, Ruminobacter, Family_XIII and Treponema as compared with other treatments (p < 0.05). PICRUSt2 analysis indicated that most of the functional prediction pathways were involved in Carbohydrate metabolism and, Amino acid metabolism. Therefore, the recommended ratio of EF in sheep diet should range from 25% to 50%, and the maximum proportion should not exceed 75%. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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16 pages, 621 KiB  
Article
Evaluation of Gas Production, Fermentation Parameters, and Nutrient Degradability in Different Proportions of Sorghum Straw and Ammoniated Wheat Straw
by Jing Wang, Zhendong Zhang, Huihui Liu, Jianfeng Xu, Ting Liu, Cailian Wang and Chen Zheng
Fermentation 2022, 8(8), 415; https://doi.org/10.3390/fermentation8080415 - 22 Aug 2022
Cited by 7 | Viewed by 1945
Abstract
The purpose of this study was to investigate the optimum proportion of sorghum straw and ammoniated wheat straw in vitro and in vivo to apply in ruminant diets. One-factor and two-factor experimental designs were used in the in vitro tests, with different ratios [...] Read more.
The purpose of this study was to investigate the optimum proportion of sorghum straw and ammoniated wheat straw in vitro and in vivo to apply in ruminant diets. One-factor and two-factor experimental designs were used in the in vitro tests, with different ratios of sorghum straw to ammoniated wheat straw (S:AWS) of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, and 8:2 to measure the in vitro total gas production, CH4 production, in vitro dry matter degradability (IVDMD), in vitro organic matter degradability (IVOMD) and in vitro fermentation parameters. Additionally, the nylon bag technique was used to determine the dynamic degradation of these different ratios of mixed feedstuffs for incubating in sheep rumen for 6 h, 12 h, 24 h, and 48 h. The results show that IVDMD, IVOMD, and the molar ratio of propionate were the highest when the ratio of S:AWS was 8:2 (p < 0.05) in vitro; however, this ratio released much more CH4 (p < 0.05). In addition, the degradability of DM, OM, CP, and ash and the effective degradability of DM and CP were the highest when the ratio of S:AWS was 8:2 cultured in sheep rumen for 48 h (p < 0.05). In the in vitro and in situ nylon bag tests, IVDMD, IVOMD, rumen nutrient degradability, and effective degradability of DM and CP increased with the increase in the sorghum straw proportion. In conclusion, the higher the proportion of sorghum straw, the higher the nutrient degradability in vivo and in vitro, but also the higher the emissions of CH4. Therefore, when the ratio of S:AWS is 8:2, ruminants can effectively utilize nutrients in feed. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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10 pages, 7480 KiB  
Communication
Apple Pomace Modulates the Microbiota and Increases the Propionate Ratio in an In Vitro Piglet Gastrointestinal Model
by Sandrine Dufourny, Sarah Lebrun, Caroline Douny, Benjamin Dubois, Marie-Louise Scippo, José Wavreille, Pierre Rondia, Nadia Everaert and Véronique Delcenserie
Fermentation 2022, 8(8), 408; https://doi.org/10.3390/fermentation8080408 - 19 Aug 2022
Cited by 1 | Viewed by 1804
Abstract
Apple pomace (AP) contains biomolecules that induce changes in intestinal fermentation of monogastrics with positive expected health effects. The weaning of piglets can induce economic losses due to intestinal disturbances; new weaning strategies are, thus, welcome. The purpose of this study was to [...] Read more.
Apple pomace (AP) contains biomolecules that induce changes in intestinal fermentation of monogastrics with positive expected health effects. The weaning of piglets can induce economic losses due to intestinal disturbances; new weaning strategies are, thus, welcome. The purpose of this study was to test the effect of AP on fermentation products by using baby-SPIME, an in vitro multi-compartment model dedicated to piglet weaning. A comparison was done on short chain fatty acid (SCFA) ratio and the microbiota induced in bioreactors between a control culture medium vs. an AP culture medium. The results of 2 preliminary runs showed that AP medium increased the molar ratio of propionate (p = 0.021) and decreased the molar ratio of butyrate (p = 0.009). Moreover, this medium increased the cumulative relative abundance of Prevotella sp. and Akkermansia sp. in bioreactors. AP could promote an ecosystem enriched with bacteria known as next-generation probiotics (NGP)—likely influencing the energy metabolism of piglets by their fermentation metabolites. AP could be used as a dietary strategy to influence bacterial changes in the intestine by stimulating the growth of bacteria identified as NGP. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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15 pages, 2453 KiB  
Article
Responses of Fermentation Characteristics and Microbial Communities to Vitamin B12 Supplementation in In Vitro Ruminal Cultures
by Kun Wang, Zihao Liu, Chunmei Du, Benhai Xiong and Liang Yang
Fermentation 2022, 8(8), 406; https://doi.org/10.3390/fermentation8080406 - 19 Aug 2022
Cited by 2 | Viewed by 1854
Abstract
Vitamin B12, an important cofactor involved in propionate formation, is synthesized exclusively by bacteria and archaebacteria. Humans need to intake vitamin B12 through food, and dairy products are generally the best source of vitamin B12. In the present [...] Read more.
Vitamin B12, an important cofactor involved in propionate formation, is synthesized exclusively by bacteria and archaebacteria. Humans need to intake vitamin B12 through food, and dairy products are generally the best source of vitamin B12. In the present study, the effects of vitamin B12 supplementation in diets on in vitro ruminal fermentation characteristics and microbial communities were investigated to provide a reference for increasing the vitamin B12 content in milk by dietary supplementation. A completely randomized design was carried out using the in vitro rumen culture technique, and 5 vitamin B12 dose levels (0, 0.5, 1.0, 2.0, and 4 mg/g of dry matter) were used. The results showed that vitamin B12 supplementation in diets decreased acetate: propionate ratio and butyrate concentration. The change in the acetate: propionate ratio can be attributed to the increased relative abundances of the Proteobacteria phylum and the Negativicutes class, both of which are involved in propionate metabolism. The decrease in butyrate concentration can likely be attributed to a reduction in relative abundance of species belonging to the Clostridia class, which are known as the predominant butyrate producers in the mammalian intestine. In addition, vitamin B12 supplementation in diets reduced the CH4 production by altering the species composition of the archaeal community. In conclusion, dietary supplementation of vitamin B12 resulted in rumen perturbation. In vivo studies should be conducted cautiously when evaluating the effects of vitamin B12 supplementation on the synthesis and absorption of it, as well as its content in milk. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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13 pages, 2416 KiB  
Article
Rumen Metaproteomics Highlight the Unique Contributions of Microbe-Derived Extracellular and Intracellular Proteins for In Vitro Ruminal Fermentation
by Tao Shi, Xi Guo, Yuqin Liu, Tingting Zhang, Xiangnan Wang, Zongjun Li and Yu Jiang
Fermentation 2022, 8(8), 394; https://doi.org/10.3390/fermentation8080394 - 15 Aug 2022
Cited by 1 | Viewed by 1739
Abstract
Rumen microorganisms can be used in in vitro anaerobic fermentation to encourage the sustainable exploitation of agricultural wastes. However, the understanding of active microbiota under in vitro ruminal fermentation conditions is still insufficient. To investigate how rumen microbes actively participate in the fermentation [...] Read more.
Rumen microorganisms can be used in in vitro anaerobic fermentation to encourage the sustainable exploitation of agricultural wastes. However, the understanding of active microbiota under in vitro ruminal fermentation conditions is still insufficient. To investigate how rumen microbes actively participate in the fermentation process in vitro, we resolved the metaproteome generated from ruminal fermentation broth after seven days of in vitro incubation. Herein, the sample-specific database for metaproteomic analysis was constructed according to the metagenomic data of in vitro ruminal fermentation. Based on the sample-specific database, we found in the metaproteome that Bacteroidetes and Firmicutes_A were the most active in protein expression, and over 50% of these proteins were assigned to gene categories involved in energy conversion and basic structures. On the other hand, a variety of bacteria-derived extracellular proteins, which contained carbohydrate-active enzyme domains, were found in the extracellular proteome of fermentation broth. Additionally, the bacterial intracellular/surface moonlighting proteins (ISMPs) and proteins of outer membrane vesicles were detected in the extracellular proteome, and these ISMPs were involved in maintaining microbial population size through potential adherence to substrates. The metaproteomic characterizations of microbial intracellular/extracellular proteins provide new insights into the ability of the rumen microbiome to maintain in vitro ruminal fermentation. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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14 pages, 1173 KiB  
Article
Characterization of Lactic Acid-Producing Bacteria Isolated from Rumen: Growth, Acid and Bile Salt Tolerance, and Antimicrobial Function
by Guanghui Hu, Hui Jiang, Yujie Zong, Osmond Datsomor, Linlin Kou, Yujie An, Jingwen Zhao and Lin Miao
Fermentation 2022, 8(8), 385; https://doi.org/10.3390/fermentation8080385 - 12 Aug 2022
Cited by 3 | Viewed by 2576
Abstract
Lactic acid bacteria are some of the dominant bacteria in the rumen, and they have a high ability for lactic acid production. The present study aimed to screen and evaluate the performance of culturable rumen bacteria from Chinese Holstein dairy cows as a [...] Read more.
Lactic acid bacteria are some of the dominant bacteria in the rumen, and they have a high ability for lactic acid production. The present study aimed to screen and evaluate the performance of culturable rumen bacteria from Chinese Holstein dairy cows as a potential probiotic or inoculant for silage production, in order to isolate ruminal lactic acid bacteria and evaluate their potential as probiotics. Three strains of Enterococcus avium (E. avium, EA1-3); three strains of Streptococcus lutetiensis (S. lutetiensis, SL1-3); and six strains of Streptococcus equinus (S. equinus, SE1-6) were successfully identified from the rumen fluid using modified De Man Rogosa sharp medium supplemented with 0.325% lactic acid. E. avium, S. lutetiensis and S. equinus are clustered in the phylogenetic tree. All the 12 Gram-positive strains reached the plateau growth phase in 6–10 h, with an OD600 at about 1.8. Both gas and acid accumulation reached plateaus at about 10–12 h in all strains, and S. equinus showed the strongest capacity. The highest lactic acid accumulation was detected in S. equinus broth (up to 219.77 μmol/L). The growth of all isolates was inhibited at pH 4.0, and EA2, SL1, SL2, SL3 and SE2 were tolerant to 0.1%, 0.2% and 0.3% bile salt. In addition, the supernatants of the strains had inhibitory effects on Escherichia coli and Staphylococcus aureus. Specifically, the S. equinus strains exhibited the strongest inhibition of the pathogens. In conclusion, these 12 strains had good potential as silage inoculants or probiotics for edible animals, especially S. equinus. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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13 pages, 6693 KiB  
Article
Mixed Fermentation of Lactiplantibacillus plantarum and Bacillus licheniformis Changed the Chemical Composition, Bacterial Community, and Rumen Degradation Rate of Tea Residue
by Xiaoyun Huang, Yinying Xu, Xinyan Wu, Yuhang Ding, Caiyun Fan, Yanfeng Xue, Zhao Zhuo and Jianbo Cheng
Fermentation 2022, 8(8), 380; https://doi.org/10.3390/fermentation8080380 - 09 Aug 2022
Cited by 4 | Viewed by 1874
Abstract
Tea residue, as a byproduct in tea processing, is highly nutritious and can be used as a good raw material for ruminant feed. This study aimed to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) and Bacillus licheniformis (B. licheniformis) mixed fermentation of [...] Read more.
Tea residue, as a byproduct in tea processing, is highly nutritious and can be used as a good raw material for ruminant feed. This study aimed to investigate the effects of Lactiplantibacillus plantarum (L. plantarum) and Bacillus licheniformis (B. licheniformis) mixed fermentation of tea residue mixture (tea residue:wheat bran, 7:3) on chemical composition, bacterial community, and rumen degradation rate. Changes in chemical composition and bacterial community were evaluated after 0 (F0), 1 (F1), 3 (F3), and 5 (F5) days of fermentation. The rumen degradation rate was studied by the in situ nylon bag method. Compared with group F0, acid soluble protein in other groups increased while pH and neutral detergent fiber decreased (p < 0.05). The group F5 was the best. The diversity of bacterial communities in group F0 was significantly lower than those in the other groups (p < 0.05). The relative abundance of phylum Firmicutes and the genus Lactobacillus increased with increasing fermentation time. The rumen degradation rates of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber were increased after fermentation. In conclusion, mixed fermentation of tea residue by L. plantarum and B. licheniformis can ameliorate chemical composition, reduce bacterial community diversity, and improve the rumen degradation rate. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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12 pages, 1093 KiB  
Article
Inhibitory Effect Mediated by Deoxynivalenol on Rumen Fermentation under High-Forage Substrate
by Fan Zhang, Qichao Wu, Weikang Wang, Shanshan Guo, Wenjuan Li, Liangkang Lv, Hewei Chen, Fengliang Xiong, Yingyi Liu, Ying Chen, Shengli Li and Hongjian Yang
Fermentation 2022, 8(8), 369; https://doi.org/10.3390/fermentation8080369 - 31 Jul 2022
Cited by 5 | Viewed by 1614
Abstract
Deoxynivalenol (DON) is a type B trichothecene mycotoxin produced by Fusarium fungi. To investigate its ruminal degradability and its effect on rumen fermentation, a 2 × 5 factorial experiment was conducted in vitro with two feed substrates with different forage levels (high forage [...] Read more.
Deoxynivalenol (DON) is a type B trichothecene mycotoxin produced by Fusarium fungi. To investigate its ruminal degradability and its effect on rumen fermentation, a 2 × 5 factorial experiment was conducted in vitro with two feed substrates with different forage levels (high forage (HF), forage-to-concentrate = 4:1; low forage (LF), forage-to-concentrate = 1:4) and five DON additions per substrate (0, 5, 10, 15, and 20 mg/kg of dry matter). After 48 h incubation, the DON degradability in the HF group was higher than in the LF group (p < 0.01), and it decreased along with the increase in DON concentrations (p < 0.01), which varied from 57.18% to 29.01% at 48 h. In addition, the gas production rate, total VFA production and microbial crude protein decreased linearly against the increase in DON additions (p < 0.05). Meanwhile, the proportion of CH4 in the fermentation gas end-products increased linearly, especially in the HF group (p < 0.01). In brief, rumen microorganisms presented 29–57% of the DON degradation ability and were particularly significant under a high-forage substrate. Along with the increasing DON addition, the toxin degradability decreased, showing a dose-dependent response. However, DON inhibited rumen fermentation and increased methane production when it exceeded 5 mg/kg of dry matter. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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15 pages, 1320 KiB  
Article
Rumen Bacteria Abundance and Fermentation Profile during Subacute Ruminal Acidosis and Its Modulation by Aspergillus oryzae Culture in RUSITEC System
by Tongqing Guo, Tao Guo, Long Guo, Fei Li, Fadi Li and Zhiyuan Ma
Fermentation 2022, 8(7), 329; https://doi.org/10.3390/fermentation8070329 - 14 Jul 2022
Cited by 5 | Viewed by 1614
Abstract
This study aimed at characterizing changes in rumen bacteria abundance and fermentation profiles by artificial saliva (AS) pH, and at evaluating the potential modulatory role of Aspergillus oryzae culture (AOC) in a rumen simulation technique (RUSITEC) system. The treatment included high AS pH [...] Read more.
This study aimed at characterizing changes in rumen bacteria abundance and fermentation profiles by artificial saliva (AS) pH, and at evaluating the potential modulatory role of Aspergillus oryzae culture (AOC) in a rumen simulation technique (RUSITEC) system. The treatment included high AS pH (pH 6.8) or low AS pH (pH 5.5) according to the McDougall’s method, and low AS pH was sustained by changing the composition of the AS (NaHCO3 from 9.8 to 1.96 g/L, Na2HPO4 from 9.3 to 1.86 g/L). In low AS pH condition, the diets contained either 0% AOC, 1.25% AOC, or 2.5% AOC. Therefore, there are four treatments: (1) high AS pH, 0% AOC (HASP); (2) low AS pH, 0% AOC (AOC0); (3) low AS pH, 1.25% AOC (AOC1); (4) low AS pH, 2.5% AOC (AOC2), respectively. The experimental diets were supplemented with 16 g basic diets with the forage to concentrate ratio of 40:60. The experiments were conducted two independent 13 days, with 9 days adaption periods and 4 days sample collection. The results showed that low AS pH decreased the degradabilites of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) (p < 0.05), which occurred due to a decreased abundance of fibrolytic Ruminococcus albus (p < 0.001). The total concentration of volatile fatty acid (VFA) and proportion of propionate were decreased in the low AS pH (p = 0.026) and tended to increase the molar proportion of butyrate (p = 0.086) and the ratio of acetate to propionate (p = 0.088). The abundances of phylum Firmicutes (p = 0.065) and Proteobacteria (p = 0.063) tended to be greater in low AS pH group than high AS pH group. Low AS pH increased the abundance of phylum Actinobacteria (p = 0.002) compared to the high AS pH and decreased the abundances of phylum Spirochaetes (p = 0.032). Compared with the high AS pH, low AS pH increased the abundances of Prevotella (p = 0.003), Pseudoscardovia (p = 0.001), Mitsuokella (p = 0.005), and Dialister (p = 0.047), and decreased the abundances of Olivibacter (p = 0.026), Ruminobacter (p = 0.025), Treponema (p = 0.037), and Sphaerochaeta (p = 0.027) at genus level. Under a severe SARA in RUSITEC, supplementation of 2.5% AOC increased OM degradability, the copy numbers of Selenomonas ruminantium and Fibrobacter succinogenes. These findings indicate that the reduction AS pH at 5.5 caused a strong shift in bacterial composition in rumen. In addition, the addition of AOC in diets increased the growth rate of certain rumen bacteria that digest fiber or utilize lactate under SARA condition in RUSITEC system. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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13 pages, 928 KiB  
Article
Starch Properties, Nutrients Profiles, In Vitro Ruminal Fermentation and Molecular Structure of Corn Processed in Different Ways
by Chengxing Han, Yanli Guo, Xiaofang Cai and Ruixing Yang
Fermentation 2022, 8(7), 315; https://doi.org/10.3390/fermentation8070315 - 03 Jul 2022
Cited by 8 | Viewed by 2615
Abstract
Processing will improve the digestion of corn by ruminant animals. The objectives of this study were to investigate the effects of processing methods (grinding, G; steam flaking, SF; extrusion, E) on the starch properties, nutrient profiles, in vitro ruminal fermentation and molecular structure [...] Read more.
Processing will improve the digestion of corn by ruminant animals. The objectives of this study were to investigate the effects of processing methods (grinding, G; steam flaking, SF; extrusion, E) on the starch properties, nutrient profiles, in vitro ruminal fermentation and molecular structure of corn. Compared with G, SF and E increased (p < 0.05) the starch content, starch gelatinization, ruminal gas production (GP, 0.5–32 h), propionic acid, starch degradability (SD), the area and height of carbohydrate peaks, and decreased (p < 0.05) starch crystallinity, content of crude protein, neutral detergent fiber and acid detergent fiber, ruminal NH3-N, the area and height of amide I and II, α-helix, and β-sheet. The total VFA (24 h, 48 h) tended to be increased by SF and E (p < 0.10). The carbohydrate peak area and height were positively (p < 0.05) correlated with GP (1–24 h) and SD. The protein molecular absorption intensity was negatively correlated with SD (p < 0.05). The change in starch properties, GP (1–24 h) and molecular structure caused by E was greater than SF (p < 0.05). These results indicated that the higher starch gelatinization and lower starch crystallinity of E corn, induced by the high temperature and pressure, enabled more fermentation and digestion in the artificial rumen. The carbohydrate and protein molecular structures were correlated with the nutritional characteristics of corn. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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20 pages, 1847 KiB  
Article
The Effect of Different Lactic Acid Bacteria Inoculants on Silage Quality, Phenolic Acid Profiles, Bacterial Community and In Vitro Rumen Fermentation Characteristic of Whole Corn Silage
by Yan-Lu Wang, Wei-Kang Wang, Qi-Chao Wu, Fan Zhang, Wen-Juan Li, Zhuo-Meng Yang, Yu-Kun Bo and Hong-Jian Yang
Fermentation 2022, 8(6), 285; https://doi.org/10.3390/fermentation8060285 - 17 Jun 2022
Cited by 13 | Viewed by 2916
Abstract
Corn silage is an important source of forage, but whether or not bacterial inoculants should be applied is somewhat controversial in ruminant feeding practice. In the present study, chopped whole corn plants treated with a single inoculant of Lactobacillus buchneri (LB), Lactobacillus plantarum [...] Read more.
Corn silage is an important source of forage, but whether or not bacterial inoculants should be applied is somewhat controversial in ruminant feeding practice. In the present study, chopped whole corn plants treated with a single inoculant of Lactobacillus buchneri (LB), Lactobacillus plantarum (LP), Pediococcus pentosaceus (PP) served as either homofermentation (e.g., lactate only) or heterofermentation (e.g., lactate and acetate) controls and compared with those treated with either a mixture of the lactic acid bacteria (QA: 60% LP, 10%PP, 30% LB) or a mixture of the lactic acid bacteria (QB: 60% LP, 15% PP, 25% LB), to investigate their effects on the fermentation quality, ester-linked phenolic acids, and in vitro digestibility. After 60 day ensiling, the addition of QA exhibited the lowest pH (3.51) with greater lactic acid (LA) production. The ester-linked ferulic acid (FAest) and p-coumaric acid (pCAest) concentrations were significantly decreased during 60 days ensiling. And among all these groups, the LB and QA treated group showed a lower concentration of FAest and pCAest than other groups. After 60 days ensiling, Lactobacillus was the dominant genus in all LAB treated groups. Meanwhile, negative correlations of Bacillus, Bacteroides, Bifidobacterium, Blautia, Prevotella, Ruminococcus, and Roseburia with FAest content after 60 days ensiling occurred in the present study. Komagataeibacter was mainly found in LB and PP addition silages, and presented a significant negative effect with the level of acid detergent fiber (ADF). To explore whether the addition of LABs can improve digestibility of whole corn silage, an in vitro rumen fermentation was conducted using the 60 day ensiled whole corn silages as substrates. The QA addition group exhibited a greater 48 h and 96 h in vitro dry matter and ADF disappearance, greater 48 h gas production and less methane emissions. Even though there were the same neutral NDF levels in corn silages treated with LB and QA after 60 days ensiling, the QA treated silages with lower FAest and pCAest presented higher IVDMD after 96 h and 48 h in vitro fermentation. In brief, the addition of mixed inoculants of 60% LB,10% PP, 30% LB compared with the addition of whichever single HoLAB or HeLAB inoculants, facilitated the release of ester-linked phenolic acids (e.g., ferulic and p-coumaric acids) and remarkably, improved silage quality in terms of sharp pH decline and greater lactate production. Taken together with the improvement in rumen microbial fermentation, the results obtained in the present study provided concrete evidence for the role of mixed LAB application in corn silage preparation for ruminant feeding practices. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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15 pages, 1019 KiB  
Article
Dynamic Variations in Rumen Fermentation Characteristics and Bacterial Community Composition during In Vitro Fermentation
by Xiao Wei, Kehui Ouyang, Tanghui Long, Zuogui Liu, Yanjiao Li and Qinghua Qiu
Fermentation 2022, 8(6), 276; https://doi.org/10.3390/fermentation8060276 - 14 Jun 2022
Cited by 12 | Viewed by 3019
Abstract
This study aimed to explore the dynamic variations of rumen fermentation characteristics and bacterial community composition during a 24 h in vitro fermentation. A total of twenty-three samples were collected from original rumen fluid (ORF, n = 3), fermentation at 12 h (R12, [...] Read more.
This study aimed to explore the dynamic variations of rumen fermentation characteristics and bacterial community composition during a 24 h in vitro fermentation. A total of twenty-three samples were collected from original rumen fluid (ORF, n = 3), fermentation at 12 h (R12, n = 10), and fermentation at 24 h (R24, n = 10). Results showed that gas production, concentrations of microbial crude protein, ammonia nitrogen, and individual volatile fatty acids (VFA), as well as total VFA and branched-chain VFA concentrations, were higher in R24 when compared with R12 (p < 0.05). However, no significant differences were observed in acetate to propionate ratio and fermentation efficiency between R12 and R24 (p > 0.05). Bacterial diversity analysis found that Shannon index and Simpson index were higher in R24 (p < 0.05), and obvious clusters were observed in rumen bacterial community between R12 and R24. Taxonomic analysis at the phylum level showed that the abundances of Proteobacteria and Fibrobacteres were higher in R12 than that in R24, and inverse results were observed in Bacteroidetes, Firmicutes, Cyanobacteria, Verrucomicrobia, Lentisphaerae, and Synergistetes abundances. Taxonomic analysis at the genus level revealed that the abundances of Rikenellaceae RC9 gut group, Succiniclasticum, Prevotellaceae UCG-003, Christensenellaceae R-7 group, Ruminococcaceae UCG-002, Veillonellaceae UCG-001, and Ruminococcaceae NK4A214 group were higher in R24, whereas higher abundances of Succinivibrionaceae UCG-002, Ruminobacter, and Fibrobacter, were found in R12. Correlation analysis revealed the negative associations between gas production and abundances of Proteobacteria, Succinivibrionaceae UCG-002, and Ruminobacter. Moreover, the abundances of Firmicutes, Rikenellaceae RC9 gut group, Christensenellaceae R-7 group, and Ruminococcaceae UCG-002 positively correlated with VFA production. These results indicate that both rumen fermentation characteristics and bacterial community composition were dynamic during in vitro fermentation, whereas the fermentation pattern, efficiency, and bacterial richness remained similar. This study provide insight into the dynamics of rumen fermentation characteristics and bacterial composition during in vitro fermentation. This study may also provide a reference for decision-making for the sampling time point when conducting an in vitro fermentation for bacterial community investigation. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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21 pages, 2673 KiB  
Article
Assessment of Feed Value of Chicory and Lucerne for Poultry, Determination of Bioaccessibility of Their Polyphenols and Their Effects on Caecal Microbiota
by Yasir Iqbal, Eric N. Ponnampalam, Hieu Huu Le, Olivia Artaiz, Stephanie K. Muir, Joe L. Jacobs, Jeremy J. Cottrell and Frank R. Dunshea
Fermentation 2022, 8(5), 237; https://doi.org/10.3390/fermentation8050237 - 20 May 2022
Cited by 2 | Viewed by 2335
Abstract
Chicory and lucerne possess high feed value for poultry being good sources of protein and fiber. In addition, they are rich in polyphenols that help the body build an integrated antioxidant system to prevent damage from free radicals and positively modulate microbial populations [...] Read more.
Chicory and lucerne possess high feed value for poultry being good sources of protein and fiber. In addition, they are rich in polyphenols that help the body build an integrated antioxidant system to prevent damage from free radicals and positively modulate microbial populations in the gastrointestinal tract. These health-promoting effects of polyphenols depend on their bioaccessibility and absorption in the animal body. The present paper aimed to study the bioaccessibility of polyphenols from chicory and lucerne after subjecting the samples to gastric and intestinal phases of digestion in an in vitro model of chicken gut and assessment of their feed value by measuring the presence of fermentable substrates (in terms of gas production), SCFAs produced and their effects on gut microbiota population during in vitro cecal fermentation. Results revealed that the bioaccessibility of polyphenols varied with different polyphenol compounds. The highest bioaccessibility was recorded for p-hydroxybenzoic acid (90.8%) from chicory following the intestinal phase of digestion. The lowest bioaccessibility was observed for quercetin-3-rhamnoside (12.6%) from chicory after the gastric phase of digestion. From lucerne, the highest bioaccessibility was recorded for kaempferol-3-glucoside (77.5%) after the intestinal phase of digestion. Total gas production was higher for lucerne (39.9 mL/g) than chicory (28.1 mL/g). Similarly, total SCFAs production was higher after 24 h of cecal fermentation with lucerne (42.2 mmol L−1) as compared to chicory (38.1 mmol L−1). Results also revealed that the relative abundance of Clostridium was reduced with chicory (0.225%) and lucerne (0.176%) as compared to the control (0.550%) after 24 h of cecal fermentation. The relative abundance of Streptococcus was reduced by lucerne (4.845%) but was increased with chicory (17.267%) as compared to the control (5.204%) after 24 h of fermentation. These findings indicated that chicory and lucerne differentially affected the microbial populations during in vitro cecal fermentation. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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Review

Jump to: Editorial, Research

11 pages, 288 KiB  
Review
Advances of Rumen Functional Bacteria and the Application of Micro-Encapsulation Fermentation Technology in Ruminants: A Review
by Wenjun Wei, Yongkang Zhen, Yusu Wang, Khuram Shahzad and Mengzhi Wang
Fermentation 2022, 8(10), 564; https://doi.org/10.3390/fermentation8100564 - 20 Oct 2022
Cited by 3 | Viewed by 2508
Abstract
Rumen functional bacteria are crucial for the homeostasis of rumen fermentation and micro-ecology. Cellulolytic bacteria, amylolytic bacteria, protein- and fat-degrading bacteria, lactic acid-producing bacteria, lactic acid-consuming bacteria, methanogens, and others can all be found in the rumen flora and help the host and [...] Read more.
Rumen functional bacteria are crucial for the homeostasis of rumen fermentation and micro-ecology. Cellulolytic bacteria, amylolytic bacteria, protein- and fat-degrading bacteria, lactic acid-producing bacteria, lactic acid-consuming bacteria, methanogens, and others can all be found in the rumen flora and help the host and other microorganisms convert feed into energy. For instance, Ruminococcus flavefaciens, Ruminococcus albus, and Fibrobacter succinogenes are the three most prevalent fiber-degrading bacteria. The digestion and metabolism of various nutrients and the absorption in rumen epithelium can greatly enhance host defense mechanisms and health production in ruminants. However, directly feeding live bacteria is prone to negative environmental effects. Therefore, the micro-encapsulation of film-forming and acid-resistant wall materials can become a great means of encapsulating naked bacteria into tiny particles. It can maintain the activity of functional flora, boost the function of the intestinal barrier, and improve its capacity for colonization on the surface of the rumen and colon mucosa. Therefore, the present review evaluates the latent progress of main functional bacteria and the applied techniques of micro-encapsulation in the rumen, in order to provide more references for the development and application of rumen-functional bacteria. Full article
(This article belongs to the Special Issue In Vitro Fermentation)
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