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Khairunisa BH, Heryakusuma C, Ike K, Mukhopadhyay B, Susanti D. Evolving understanding of rumen methanogen ecophysiology. Front Microbiol 2023; 14:1296008. [PMID: 38029083 PMCID: PMC10658910 DOI: 10.3389/fmicb.2023.1296008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 10/12/2023] [Indexed: 12/01/2023] Open
Abstract
Production of methane by methanogenic archaea, or methanogens, in the rumen of ruminants is a thermodynamic necessity for microbial conversion of feed to volatile fatty acids, which are essential nutrients for the animals. On the other hand, methane is a greenhouse gas and its production causes energy loss for the animal. Accordingly, there are ongoing efforts toward developing effective strategies for mitigating methane emissions from ruminant livestock that require a detailed understanding of the diversity and ecophysiology of rumen methanogens. Rumen methanogens evolved from free-living autotrophic ancestors through genome streamlining involving gene loss and acquisition. The process yielded an oligotrophic lifestyle, and metabolically efficient and ecologically adapted descendants. This specialization poses serious challenges to the efforts of obtaining axenic cultures of rumen methanogens, and consequently, the information on their physiological properties remains in most part inferred from those of their non-rumen representatives. This review presents the current knowledge of rumen methanogens and their metabolic contributions to enteric methane production. It also identifies the respective critical gaps that need to be filled for aiding the efforts to mitigate methane emission from livestock operations and at the same time increasing the productivity in this critical agriculture sector.
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Affiliation(s)
| | - Christian Heryakusuma
- Genetics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, VA, United States
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, United States
| | - Kelechi Ike
- Department of Biology, North Carolina Agricultural and Technical State University, Greensboro, NC, United States
| | - Biswarup Mukhopadhyay
- Genetics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, VA, United States
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, United States
- Virginia Tech Carilion School of Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Dwi Susanti
- Microbial Discovery Research, BiomEdit, Greenfield, IN, United States
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Zhao Y, Zhao G. Decreasing ruminal methane production through enhancing the sulfate reduction pathway. ANIMAL NUTRITION 2022; 9:320-326. [PMID: 35600554 PMCID: PMC9097629 DOI: 10.1016/j.aninu.2022.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/28/2021] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Methane (CH4) production from ruminants accounts for 16% of the global greenhouse gas emissions and represents 2% to 12% of feed energy. Mitigating CH4 production from ruminants is of great importance for sustainable development of the ruminant industry. H2 is the primary substrate for CH4 production in the processes of ruminal methanogenesis. Sulfate reducing bacteria are able to compete with methanogens for H2 in the rumen, and consequently inhibit the methanogenesis. Enhancing the ruminal sulfate reducing pathway is an important approach to mitigate CH4 emissions in ruminants. The review summarized the effects of sulfate and elemental S on ruminal methanogenesis, and clarified the related mechanisms through the impacts of sulfate and elemental S on major ruminal sulfate reducing bacteria. Enhancing the activities of the major ruminal sulfate reducing bacteria including Desulfovibrio, Desulfohalobium and Sulfolobus through dietary sulfate addition, elemental S and dried distillers grains with solubles can effectively decrease the ruminal CH4 emissions. Suitable levels of dietary addition with different S sources for reducing the ruminal CH4 production, as well as maintaining the performance and health of ruminants, need to be investigated in the future.
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Kawasaki K, Wada K, Sato A, Zhao J, Takao N, Sato M, Ban T, Yano K. Effects of dietary bamboo (
Phyllostachys pubescens
Mazel) culm powder on blood properties and intestinal environment of rabbits. Anim Sci J 2022; 93:e13774. [PMID: 36274650 DOI: 10.1111/asj.13774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 11/28/2022]
Abstract
This study investigated the effects of bamboo powder as an alternative feed for rabbits. The normal hay diet of rabbits was replaced with bamboo culm powder (10% and 20%) and fed to the rabbits until they were 90 days old. The blood samples were collected when the rabbits were 46, 66, and 90 days old to assess the effects of bamboo powder on blood parameters. The organs and intestinal contents were harvested at the age of 90 days, and the functions and morphologies of different organs were evaluated. The concentration of short-chain fatty acids (SCFAs) and the composition of microbiota in the cecum were measured. Substituting bamboo powder did not affect the growth, hematology profile, intestinal morphologies, and cecum SCFA concentration in rabbits. In contrast, it significantly altered the cecum microbiota composition, particularly the abundance of Ruminococcus and Bacteroides related to fiber degradation and Tyzzerella spp., associated with large intestine inflammation. These findings suggest that the substitution of hay with bamboo powder in rabbit diets does not negatively affect the overall health of rabbits and could be considered an alternative feed for rabbits; nevertheless, the protein and lipid deficiency in the bamboo powder should be taken into account.
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Affiliation(s)
- Kiyonori Kawasaki
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Kazuki Wada
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Asagi Sato
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Junliang Zhao
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Natsu Takao
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Masaki Sato
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Takuma Ban
- Department of Applied Biological Science, Faculty of Agriculture Kagawa University Kita‐gun Kagawa Japan
| | - Kiminobu Yano
- University Farm Kagawa University Sanuki Kagawa Japan
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The Relationship Between Mucosal Microbiota, Colitis, and Systemic Inflammation in Chronic Granulomatous Disorder. J Clin Immunol 2021; 42:312-324. [PMID: 34731398 DOI: 10.1007/s10875-021-01165-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/22/2021] [Indexed: 12/31/2022]
Abstract
PURPOSE Chronic granulomatous disorder (CGD) is a primary immunodeficiency which is frequently complicated by inflammatory colitis and is associated with systemic inflammation. Herein, we aimed to investigate the role of the microbiome in the pathogenesis of colitis and systemic inflammation. METHODS We performed 16S rDNA sequencing on mucosal biopsy samples from each segment of 10 CGD patients' colons and conducted compositional and functional pathway prediction analyses. RESULTS The microbiota in samples from colitis patients demonstrated reduced taxonomic alpha-diversity compared to unaffected patients, even in apparently normal bowel segments. Functional pathway richness was similar between the colitic and non-colitic mucosa, although metabolic pathways involved in butyrate biosynthesis or utilization were enriched in patients with colitis and correlated positively with fecal calprotectin levels. One patient with very severe colitis was dominated by Enterococcus spp., while among other patients Bacteroides spp. abundance correlated with colitis severity measured by fecal calprotectin and an endoscopic severity score. In contrast, Blautia abundance is associated with low severity scores and mucosal health. Several taxa and functional pathways correlated with concentrations of inflammatory cytokines in blood but not with colitis severity. Notably, dividing patients into "high" and "low" systemic inflammation groups demonstrated clearer separation than on the basis of colitis status in beta-diversity analyses. CONCLUSION The microbiome is abnormal in CGD-associated colitis and altered functional characteristics probably contribute to pathogenesis. Furthermore, the relationship between the mucosal microbiome and systemic inflammation, independent of colitis status, implies that the microbiome in CGD can influence the inflammatory phenotype of the condition.
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Mizrahi I, Wallace RJ, Moraïs S. The rumen microbiome: balancing food security and environmental impacts. Nat Rev Microbiol 2021; 19:553-566. [PMID: 33981031 DOI: 10.1038/s41579-021-00543-6] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2021] [Indexed: 02/03/2023]
Abstract
Ruminants produce edible products and contribute to food security. They house a complex rumen microbial community that enables the host to digest their plant feed through microbial-mediated fermentation. However, the rumen microbiome is also responsible for the production of one of the most potent greenhouse gases, methane, and contributes about 18% of its total anthropogenic emissions. Conventional methods to lower methane production by ruminants have proved successful, but to a limited and often temporary extent. An increased understanding of the host-microbiome interactions has led to the development of new mitigation strategies. In this Review we describe the composition, ecology and metabolism of the rumen microbiome, and the impact on host physiology and the environment. We also discuss the most pertinent methane mitigation strategies that emerged to balance food security and environmental impacts.
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Affiliation(s)
- Itzhak Mizrahi
- Department of Life Sciences, Ben-Gurion University of the Negev and the National Institute for Biotechnology in the Negev, Marcus Family Campus, Be'er-Sheva, Israel.
| | - R John Wallace
- The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Sarah Moraïs
- Department of Life Sciences, Ben-Gurion University of the Negev and the National Institute for Biotechnology in the Negev, Marcus Family Campus, Be'er-Sheva, Israel
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Liu F, Wang Z, Wu B, Bjerg JT, Hu W, Guo X, Guo J, Nielsen LP, Qiu R, Xu M. Cable bacteria extend the impacts of elevated dissolved oxygen into anoxic sediments. THE ISME JOURNAL 2021; 15:1551-1563. [PMID: 33479492 PMCID: PMC8114917 DOI: 10.1038/s41396-020-00869-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 11/26/2020] [Accepted: 12/07/2020] [Indexed: 01/30/2023]
Abstract
Profound biogeochemical responses of anoxic sediments to the fluctuation of dissolved oxygen (DO) concentration in overlaying water are often observed, despite oxygen having a limited permeability in sediments. This contradiction is indicative of previously unrecognized mechanism that bridges the oxic and anoxic sediment layers. Using sediments from an urban river suffering from long-term polycyclic aromatic hydrocarbons (PAHs) contamination, we analyzed the physicochemical and microbial responses to artificially elevated DO (eDO) in the overlying water over 9 weeks of incubation. Significant changes in key environmental parameters and microbial diversity were detected over the 0-6 cm sediment depth, along with accelerated degradation of PAHs, despite that eDO only increased the porewater DO in the millimeter subfacial layer. The dynamics of physicochemical and microbial properties coincided well with significantly increased presence of centimeter-long sulfide-oxidizing cable bacteria filaments under eDO, and were predominantly driven by cable bacteria metabolic activities. Phylogenetic ecological network analyses further revealed that eDO reinforced cable bacteria associated interspecific interactions with functional microorganisms such as sulfate reducers, PAHs degraders, and electroactive microbes, suggesting enhanced microbial syntrophy taking advantage of cable bacteria metabolism for the regeneration of SO42- and long-distance electron transfer. Together, our results suggest cable bacteria may mediate the impacts of eDO in anaerobic sediments by altering sediment physiochemical properties and by reinforcing community interactions. Our findings highlight the ecological importance of cable bacteria in sediments.
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Affiliation(s)
- Feifei Liu
- grid.464309.c0000 0004 6431 5677Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070 China
| | - Zhenyu Wang
- grid.464309.c0000 0004 6431 5677Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070 China ,grid.12981.330000 0001 2360 039XSchool of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006 China
| | - Bo Wu
- grid.12981.330000 0001 2360 039XSchool of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006 China
| | - Jesper T. Bjerg
- grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Department of Biology, Aarhus University, DK-8000 Aarhus, Denmark
| | - Wenzhe Hu
- grid.464309.c0000 0004 6431 5677Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070 China
| | - Xue Guo
- grid.216417.70000 0001 0379 7164Key Laboratory of Biometallurgy of Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083 China ,grid.12527.330000 0001 0662 3178State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084 China
| | - Jun Guo
- grid.464309.c0000 0004 6431 5677Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070 China
| | - Lars Peter Nielsen
- grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Department of Biology, Aarhus University, DK-8000 Aarhus, Denmark
| | - Rongliang Qiu
- grid.12981.330000 0001 2360 039XSchool of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006 China ,grid.12981.330000 0001 2360 039XGuangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou, 510006 China
| | - Meiying Xu
- grid.464309.c0000 0004 6431 5677Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070 China
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Schmitz-Esser S. The Rumen Epithelial Microbiota: Possible Gatekeepers of the Rumen Epithelium and Its Potential Contributions to Epithelial Barrier Function and Animal Health and Performance. MEAT AND MUSCLE BIOLOGY 2021. [DOI: 10.22175/mmb.11672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Ruminants are characterized by their unique mode of digesting cellulose-rich plant material in their forestomach, the rumen, which is densely populated by diverse microorganisms that are crucial for the breakdown of plant material. Among ruminal microbial communities, the microorganisms in the rumen fluid or attached to feed particles have attracted considerable research interest. However, comparatively less is known about the microorganisms attached to the rumen epithelium. Generally, the tissue lining the gastrointestinal tract serves the dual role of absorbing nutrients while preventing the infiltration of unwanted compounds and molecules as well as microorganisms. The rumen epithelium fulfills critical physiological functions for the ruminant host in energy absorption, metabolism, and nutrient transport. Essential host metabolites, such as short-chain fatty acids, ammonia, urea, and minerals, are exchanged across the rumen wall, thereby exposing the rumen epithelial microbiota to these nutrients. The integrity of the gastrointestinal barrier is central to animal health and productivity. The integrity of the rumen epithelium can be compromised by high ruminal microbial fermentation activity resulting in decreased rumen pH or by stress conditions such as heat stress or feed restriction. It is important to keep in mind that feeding strategies in cattle have changed over the last decades in favor of energy- and nutrient-rich concentrates instead of fiber-rich forages. These dietary shifts support high milk yields and growth rates but raised concerns regarding a possibly compromised rumen function. This paper will provide an overview of the composition of rumen epithelial microbial communities under physiological and disease conditions and will provide insights into the knowledge about the function and in situ activity of rumen epithelial microorganisms and their relevance for animal health and production. Given that an impaired intestinal barrier will negatively affect economically significant phenotypes, a better understanding of rumen wall microbiota is urgently needed.
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Diversity, Abundance, and Some Characteristics of Bacteria Isolated from Earth Material Consumed by Wild Animals at Kudurs in the Sikhote-Alin Mountains, Russia. Int J Microbiol 2020; 2020:8811047. [PMID: 33488723 PMCID: PMC7803285 DOI: 10.1155/2020/8811047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/20/2020] [Accepted: 11/25/2020] [Indexed: 11/29/2022] Open
Abstract
In this work, geochemical and microbiological studies were performed at kudurs in the southeastern part of the Sikhote-Alin mountain range and in the Sikhote-Alin Nature Reserve located in Primorsky Krai, Russia. It was found that the earth material eaten by wild animals in both sites is represented by clay-zeolite tuffs of dacite-rhyolite composition. In the earth material, Na is predominant in bioavailable macronutrients and Zn, light lanthanides, and Y in trace elements. Microbiological studies of geophagic earths revealed a wide range of heterotrophic and autotrophic aerobes and anaerobes involved in the conversion of carbon, nitrogen, and sulfur. Iron- and manganese-oxidizing bacteria and silicate bacteria were identified as well. The isolated pure cultures of heterotrophic bacteria were represented mainly by Gram-positive spore-forming large rods of Bacillus sp. and Gram-negative heterotrophic aerobic and facultative anaerobic microorganisms Burkholderia sp. and Microvirgula aerodenitrificans, which oxidize iron and reduce sulfate. The ability of the bacteria M. aerodenitrificans to reduce sulfates is shown for the first time. According to the literature, the isolated microorganisms are able to actively extract rare earth elements from earth materials, transforming them from the bioinert state to a state accessible to herbivorous mammals.
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Kushkevych I, Abdulina D, Kováč J, Dordević D, Vítězová M, Iutynska G, Rittmann SKMR. Adenosine-5'-Phosphosulfate- and Sulfite Reductases Activities of Sulfate-Reducing Bacteria from Various Environments. Biomolecules 2020; 10:E921. [PMID: 32560561 PMCID: PMC7357011 DOI: 10.3390/biom10060921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 12/13/2022] Open
Abstract
A comparative study of the kinetic characteristics (specific activity, initial and maximum rate, and affinity for substrates) of key enzymes of assimilatory sulfate reduction (APS reductase and dissimilatory sulfite reductase) in cell-free extracts of sulphate-reducing bacteria (SRB) from various biotopes was performed. The material for the study represented different strains of SRB from various ecotopes. Microbiological (isolation and cultivation), biochemical (free cell extract preparation) and chemical (enzyme activity determination) methods served in defining kinetic characteristics of SRB enzymes. The determined affinity data for substrates (i.e., sulfite) were 10 times higher for SRB strains isolated from environmental (soil) ecotopes than for strains from the human intestine. The maximum rate of APS reductase reached 0.282-0.862 µmol/min×mg-1 of protein that is only 10 to 28% higher than similar initial values. The maximum rate of sulfite reductase for corrosive relevant collection strains and SRB strains isolated from heating systems were increased by 3 to 10 times. A completely different picture was found for the intestinal SRB Vmax in the strains Desulfovibrio piger Vib-7 (0.67 µmol/min × mg-1 protein) and Desulfomicrobium orale Rod-9 (0.45 µmol/min × mg-1 protein). The determinant in the cluster distribution of SRB strains is the activity of the terminal enzyme of dissimilatory sulfate reduction-sulfite reductase, but not APS reductase. The data obtained from the activity of sulfate reduction enzymes indicated the adaptive plasticity of SRB strains that is manifested in the change in enzymatic activity.
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Affiliation(s)
- Ivan Kushkevych
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic; (J.K.); (M.V.)
- Department of Molecular Biology and Pharmaceutical Biotechnology, University of Veterinary and Pharmaceutical Sciences Brno, 61242 Brno, Czech Republic
| | - Daryna Abdulina
- Department of General and Soil Microbiology, D.K. Zabolotny Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine, Acad. Zabolotnogo str. 154, 03143 Kyiv, Ukraine; (D.A.); (G.I.)
| | - Jozef Kováč
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic; (J.K.); (M.V.)
| | - Dani Dordević
- Department of Plant Origin Foodstuffs Hygiene and Technology, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences, 61242 Brno, Czech Republic;
| | - Monika Vítězová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic; (J.K.); (M.V.)
| | - Galyna Iutynska
- Department of General and Soil Microbiology, D.K. Zabolotny Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine, Acad. Zabolotnogo str. 154, 03143 Kyiv, Ukraine; (D.A.); (G.I.)
| | - Simon K.-M. R. Rittmann
- Archaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, Universität Wien, Althanstraße 14, 1090 Vienna, Austria
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Greening C, Geier R, Wang C, Woods LC, Morales SE, McDonald MJ, Rushton-Green R, Morgan XC, Koike S, Leahy SC, Kelly WJ, Cann I, Attwood GT, Cook GM, Mackie RI. Diverse hydrogen production and consumption pathways influence methane production in ruminants. ISME JOURNAL 2019; 13:2617-2632. [PMID: 31243332 PMCID: PMC6776011 DOI: 10.1038/s41396-019-0464-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 06/03/2019] [Accepted: 06/07/2019] [Indexed: 01/17/2023]
Abstract
Farmed ruminants are the largest source of anthropogenic methane emissions globally. The methanogenic archaea responsible for these emissions use molecular hydrogen (H2), produced during bacterial and eukaryotic carbohydrate fermentation, as their primary energy source. In this work, we used comparative genomic, metatranscriptomic and co-culture-based approaches to gain a system-wide understanding of the organisms and pathways responsible for ruminal H2 metabolism. Two-thirds of sequenced rumen bacterial and archaeal genomes encode enzymes that catalyse H2 production or consumption, including 26 distinct hydrogenase subgroups. Metatranscriptomic analysis confirmed that these hydrogenases are differentially expressed in sheep rumen. Electron-bifurcating [FeFe]-hydrogenases from carbohydrate-fermenting Clostridia (e.g., Ruminococcus) accounted for half of all hydrogenase transcripts. Various H2 uptake pathways were also expressed, including methanogenesis (Methanobrevibacter), fumarate and nitrite reduction (Selenomonas), and acetogenesis (Blautia). Whereas methanogenesis-related transcripts predominated in high methane yield sheep, alternative uptake pathways were significantly upregulated in low methane yield sheep. Complementing these findings, we observed significant differential expression and activity of the hydrogenases of the hydrogenogenic cellulose fermenter Ruminococcus albus and the hydrogenotrophic fumarate reducer Wolinella succinogenes in co-culture compared with pure culture. We conclude that H2 metabolism is a more complex and widespread trait among rumen microorganisms than previously recognised. There is evidence that alternative hydrogenotrophs, including acetogenic and respiratory bacteria, can prosper in the rumen and effectively compete with methanogens for H2. These findings may help to inform ongoing strategies to mitigate methane emissions by increasing flux through alternative H2 uptake pathways, including through animal selection, dietary supplementation and methanogenesis inhibitors.
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Affiliation(s)
- Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia.
| | - Renae Geier
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Cecilia Wang
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Laura C Woods
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Sergio E Morales
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Michael J McDonald
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Rowena Rushton-Green
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Xochitl C Morgan
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Satoshi Koike
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Sinead C Leahy
- Grasslands Research Centre, AgResearch Ltd., Palmerston North, 4410, New Zealand
| | | | - Isaac Cann
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Graeme T Attwood
- Grasslands Research Centre, AgResearch Ltd., Palmerston North, 4410, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Roderick I Mackie
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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11
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Islam M, Lee SS. Advanced estimation and mitigation strategies: a cumulative approach to enteric methane abatement from ruminants. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2019; 61:122-137. [PMID: 31333869 PMCID: PMC6582924 DOI: 10.5187/jast.2019.61.3.122] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/09/2019] [Accepted: 05/13/2019] [Indexed: 11/20/2022]
Abstract
Methane, one of the important greenhouse gas, has a higher global warming
potential than that of carbon dioxide. Agriculture, especially livestock, is
considered as the biggest sector in producing anthropogenic methane. Among
livestock, ruminants are the highest emitters of enteric methane.
Methanogenesis, a continuous process in the rumen, carried out by archaea either
with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to
methane or with methylotrophic pathway, which the substrate for methanogenesis
is methyl groups. For accurate estimation of methane from ruminants, three
methods have been successfully used in various experiments under different
environmental conditions such as respiration chamber, sulfur hexafluoride tracer
technique, and the automated head-chamber or GreenFeed system. Methane
production and emission from ruminants are increasing day by day with an
increase of ruminants which help to meet up the nutrient demands of the
increasing human population throughout the world. Several mitigation strategies
have been taken separately for methane abatement from ruminant productions such
as animal intervention, diet selection, dietary feed additives, probiotics,
defaunation, supplementation of fats, oils, organic acids, plant secondary
metabolites, etc. However, sustainable mitigation strategies are not established
yet. A cumulative approach of accurate enteric methane measurement and existing
mitigation strategies with more focusing on the biological reduction of methane
emission by direct-fed microbials could be the sustainable methane mitigation
approaches.
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Affiliation(s)
- Mahfuzul Islam
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, Sunchon National University, Suncheon 57922, Korea
| | - Sang-Suk Lee
- Ruminant Nutrition and Anaerobe Laboratory, Department of Animal Science and Technology, Sunchon National University, Suncheon 57922, Korea
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Wu H, Meng Q, Zhou Z, Yu Z. Ferric citrate, nitrate, saponin and their combinations affect in vitro ruminal fermentation, production of sulphide and methane and abundance of select microbial populations. J Appl Microbiol 2019; 127:150-158. [PMID: 31004543 DOI: 10.1111/jam.14286] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/10/2019] [Accepted: 04/14/2019] [Indexed: 01/22/2023]
Abstract
AIMS This study investigated the effects of ferric citrate, nitrate and saponin, both individually and in combination, on sulphidogenesis, methanogenesis, rumen fermentation and abundances of select microbial populations using in vitro rumen cultures. METHODS AND RESULTS Ferric citrate (50 mg l-1 ), Quillaja saponin (0·6 g l-1 ) and sodium nitrate (5 mmol l-1 ) were used in in vitro ruminal fermentation. Ferric citrate alone, its combination with saponin and/or nitrate lowered the aqueous sulphide concentration and total sulphide production. Methane production was suppressed by nitrate alone (by up to 32·92%), its combination with saponin (25·04%) and with both saponins with nitrate (25·92%). None of the treatments adversely affected feed digestion or rumen fermentation. The population of sulphate-reducing bacteria was increased by nitrate and saponin individually, while that of total Archaea was decreased by nitrate alone and the combination of the three inhibitors. CONCLUSIONS Nitrate and its combination with saponin or both ferric citrate and saponin substantially decreased methane production. Most importantly, the decreased methane production was not at the expense of feed digestion or fermentation. Sulphidogenesis from the sulphate present in the high-sulphur diets can be suppressed competitively by ferric citrate, although it was elevated by saponin and nitrate. SIGNIFICANCE AND IMPACT OF THE STUDY The results of this study demonstrated that combinations of certain methane inhibitors, which have different mechanisms of antimethanogenic actions or inhibit different guilds of microbes involved in methane production and sulphate reduction, can be more effective and practical than individual inhibitors, not only in mitigating enteric methane emission but also in lowering the risk of sulphur-associated polioencephalomalacia in feedlot cattle fed high sulphur diets.
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Affiliation(s)
- H Wu
- College of Animal Science and Technology and State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China.,Department of Animal Sciences, The Ohio State University, Columbus, OH, USA
| | - Q Meng
- College of Animal Science and Technology and State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Z Zhou
- College of Animal Science and Technology and State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Z Yu
- Department of Animal Sciences, The Ohio State University, Columbus, OH, USA
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Lan W, Yang C. Ruminal methane production: Associated microorganisms and the potential of applying hydrogen-utilizing bacteria for mitigation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 654:1270-1283. [PMID: 30841400 DOI: 10.1016/j.scitotenv.2018.11.180] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 05/16/2023]
Abstract
Methane emission from ruminants not only causes serious environmental problems, but also represents a significant source of energy loss to animals. The increasing demand for sustainable animal production is driving researchers to explore proper strategies to mitigate ruminal methanogenesis. Since hydrogen is the primary substrate of ruminal methanogenesis, hydrogen metabolism and its associated microbiome in the rumen may closely relate to low- and high-methane phenotypes. Using candidate microbes that can compete with methanogens and redirect hydrogen away from methanogenesis as ruminal methane mitigants are promising avenues for methane mitigation, which can both prevent the adverse effects deriving from chemical additives such as toxicity and resistance, and increase the retention of feed energy. This review describes the ruminal microbial ecosystem and its association with methane production, as well as the effects of interspecies hydrogen transfer on methanogenesis. It provides a scientific perspective on using bacteria that are involved in hydrogen utilization as ruminal modifiers to decrease methanogenesis. This information will be helpful in better understanding the key role of ruminal microbiomes and their relationship with methane production and, therefore, will form the basis of valuable and eco-friendly methane mitigation methods while improving animal productivity.
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Affiliation(s)
- Wei Lan
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China; MoE Key Laboratory of Molecular Animal Nutrition, China
| | - Chunlei Yang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China; MoE Key Laboratory of Molecular Animal Nutrition, China.
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Kohl KD, Brun A, Magallanes M, Brinkerhoff J, Laspiur A, Acosta JC, Bordenstein SR, Caviedes-Vidal E. Physiological and microbial adjustments to diet quality permit facultative herbivory in an omnivorous lizard. ACTA ACUST UNITED AC 2017; 219:1903-12. [PMID: 27307545 DOI: 10.1242/jeb.138370] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/31/2016] [Indexed: 11/20/2022]
Abstract
While herbivory is a common feeding strategy in a number of vertebrate classes, less than 4% of squamate reptiles feed primarily on plant material. It has been hypothesized that physiological or microbial limitations may constrain the evolution of herbivory in lizards. Herbivorous lizards exhibit adaptations in digestive morphology and function that allow them to better assimilate plant material. However, it is unknown whether these traits are fixed or perhaps phenotypically flexible as a result of diet. Here, we maintained a naturally omnivorous lizard, Liolaemus ruibali, on a mixed diet of 50% insects and 50% plant material, or a plant-rich diet of 90% plant material. We compared parameters of digestive performance, gut morphology and function, and gut microbial community structure between the two groups. We found that lizards fed the plant-rich diet maintained nitrogen balance and exhibited low minimum nitrogen requirements. Additionally, lizards fed the plant-rich diet exhibited significantly longer small intestines and larger hindguts, demonstrating that gut morphology is phenotypically flexible. Lizards fed the plant-rich diet harbored small intestinal communities that were more diverse and enriched in Melainabacteria and Oscillospira compared with mixed diet-fed lizards. Additionally, the relative abundance of sulfate-reducing bacteria in the small intestine significantly correlated with whole-animal fiber digestibility. Thus, we suggest that physiological and microbial limitations do not sensu stricto constrain the evolution of herbivory in lizards. Rather, ecological context and fitness consequences may be more important in driving the evolution of this feeding strategy.
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Affiliation(s)
- Kevin D Kohl
- Department of Biological Sciences, Vanderbilt University, 465 21st Ave South, Nashville, TN 37235, USA Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, Consejo Nacional de Investigaciones Científicas y Técnicas, San Luis 5700, Argentina Departamento de Bioquímica y Ciencias Biológicas, Universidad Nacional de San Luis, Chacabuco 917, San Luis 5700, Argentina
| | - Antonio Brun
- Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, Consejo Nacional de Investigaciones Científicas y Técnicas, San Luis 5700, Argentina Departamento de Bioquímica y Ciencias Biológicas, Universidad Nacional de San Luis, Chacabuco 917, San Luis 5700, Argentina
| | - Melisa Magallanes
- Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, Consejo Nacional de Investigaciones Científicas y Técnicas, San Luis 5700, Argentina Departamento de Bioquímica y Ciencias Biológicas, Universidad Nacional de San Luis, Chacabuco 917, San Luis 5700, Argentina
| | - Joshua Brinkerhoff
- Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, Consejo Nacional de Investigaciones Científicas y Técnicas, San Luis 5700, Argentina Departamento de Bioquímica y Ciencias Biológicas, Universidad Nacional de San Luis, Chacabuco 917, San Luis 5700, Argentina
| | - Alejandro Laspiur
- Departamento de Biología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, Av. José I. de la Roza 590 Oeste, J5402DCS, San Juan 5400, Argentina
| | - Juan Carlos Acosta
- Departamento de Biología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, Av. José I. de la Roza 590 Oeste, J5402DCS, San Juan 5400, Argentina
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University, 465 21st Ave South, Nashville, TN 37235, USA Department of Pathology, Microbiology, and Immunology, Vanderbilt University, 465 21st Ave South, Nashville, TN 37235, USA
| | - Enrique Caviedes-Vidal
- Laboratorio de Biología Integrativa, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis, Consejo Nacional de Investigaciones Científicas y Técnicas, San Luis 5700, Argentina Departamento de Bioquímica y Ciencias Biológicas, Universidad Nacional de San Luis, Chacabuco 917, San Luis 5700, Argentina
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15
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Wu H, Meng Q, Yu Z. Evaluation of ferric oxide and ferric citrate for their effects on fermentation, production of sulfide and methane, and abundance of select microbial populations using in vitro rumen cultures. BIORESOURCE TECHNOLOGY 2016; 211:603-609. [PMID: 27043055 DOI: 10.1016/j.biortech.2016.03.126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 06/05/2023]
Abstract
This study systematically evaluated the effect of ferric iron on sulfate reduction to sulfide, feed digestion and fermentation, methane production, and populations of select ruminal microbes using in vitro rumen cultures. Ferric oxide (Fe2O3) and ferric citrate (C6H5FeO7) at six concentrations (0, 25, 50, 100, 150, and 200mg/L as Fe(3+)) were tested. Ferric iron decreased production of both H2S gas in culture headspace (up to 71.9%) and aqueous sulfide (up to 80.8%), without adversely affecting other fermentation parameters, with ferric citrate being more effective than ferric oxide. Total archaeal population was increased by ferric citrate, but methane production was not affected significantly. The population of sulfate reducing bacteria was affected differently by ferric oxide than by ferric citrate. The results of this study could guide future in vivo studies to develop effective solutions to abate sulfur-associated polioencephalomalacia in cattle fed high-sulfur diet such as dried distiller's grains with solubles.
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Affiliation(s)
- Hao Wu
- College of Animal Science and Technology and State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China; Department of Animal Science, The Ohio State University, Columbus, OH 43210-1094, USA
| | - Qingxiang Meng
- College of Animal Science and Technology and State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100193, China
| | - Zhongtang Yu
- Department of Animal Science, The Ohio State University, Columbus, OH 43210-1094, USA.
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16
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Wallace RJ, Rooke JA, McKain N, Duthie CA, Hyslop JJ, Ross DW, Waterhouse A, Watson M, Roehe R. The rumen microbial metagenome associated with high methane production in cattle. BMC Genomics 2015; 16:839. [PMID: 26494241 PMCID: PMC4619255 DOI: 10.1186/s12864-015-2032-0] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 10/08/2015] [Indexed: 02/01/2023] Open
Abstract
Background Methane represents 16 % of total anthropogenic greenhouse gas emissions. It has been estimated that ruminant livestock produce ca. 29 % of this methane. As individual animals produce consistently different quantities of methane, understanding the basis for these differences may lead to new opportunities for mitigating ruminal methane emissions. Metagenomics is a powerful new tool for understanding the composition and function of complex microbial communities. Here we have applied metagenomics to the rumen microbial community to identify differences in the microbiota and metagenome that lead to high- and low-methane-emitting cattle phenotypes. Methods Four pairs of beef cattle were selected for extreme high and low methane emissions from 72 animals, matched for breed (Aberdeen-Angus or Limousin cross) and diet (high or medium concentrate). Community analysis was carried out by qPCR of 16S and 18S rRNA genes and by alignment of Illumina HiSeq reads to the GREENGENES database. Total genomic reads were aligned to the KEGG genes databasefor functional analysis. Results Deep sequencing produced on average 11.3 Gb per sample. 16S rRNA gene abundances indicated that archaea, predominantly Methanobrevibacter, were 2.5× more numerous (P = 0.026) in high emitters, whereas among bacteria Proteobacteria, predominantly Succinivibrionaceae, were 4-fold less abundant (2.7 vs. 11.2 %; P = 0.002). KEGG analysis revealed that archaeal genes leading directly or indirectly to methane production were 2.7-fold more abundant in high emitters. Genes less abundant in high emitters included acetate kinase, electron transport complex proteins RnfC and RnfD and glucose-6-phosphate isomerase. Sequence data were assembled de novo and over 1.5 million proteins were annotated on the subsequent metagenome scaffolds. Less than half of the predicted genes matched matched a domain within Pfam. Amongst 2774 identified proteins of the 20 KEGG orthologues that correlated with methane emissions, only 16 showed 100 % identity with a publicly available protein sequence. Conclusions The abundance of archaeal genes in ruminal digesta correlated strongly with differing methane emissions from individual animals, a finding useful for genetic screening purposes. Lower emissions were accompanied by higher Succinovibrionaceae abundance and changes in acetate and hydrogen production leading to less methanogenesis, as similarly postulated for Australian macropods. Large numbers of predicted protein sequences differed between high- and low-methane-emitting cattle. Ninety-nine percent were unknown, indicating a fertile area for future exploitation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2032-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- R John Wallace
- Rowett Institute of Nutrition and Health, University of Aberdeen, Bucksburn, Aberdeen, AB21 9SB, UK.
| | | | - Nest McKain
- Rowett Institute of Nutrition and Health, University of Aberdeen, Bucksburn, Aberdeen, AB21 9SB, UK.
| | | | | | | | | | - Mick Watson
- Edinburgh Genomics, The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Edinburgh, EH25 9RG, UK.
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17
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The use of direct-fed microbials for mitigation of ruminant methane emissions: a review. Animal 2014; 8:250-61. [DOI: 10.1017/s1751731113002085] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Abstract
Two rumen nitrate-reducing isolates of Desulfovibrio desulfuricans were found to hydrolyze cysteine with the production of sulfide and pyruvate. When cultured on agar medium containing yeast extract with nitrate as the primary electron acceptor and ferrous chloride as the indicator, blackening of colonies occurred. The blackening of colonies appeared sooner and was more intense when either cysteine or sulfate was added to the culture medium with nitrate present.
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Affiliation(s)
- C W Forsberg
- Department of Microbiology, College of Biological Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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19
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Smith RL, Klug MJ. Electron donors utilized by sulfate-reducing bacteria in eutrophic lake sediments. Appl Environ Microbiol 2010; 42:116-21. [PMID: 16345804 PMCID: PMC243972 DOI: 10.1128/aem.42.1.116-121.1981] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mineralization rates of C-labeled substrates were determined in the presence and absence of Na(2)MoO(4), an inhibitor of sulfate reduction, in the profundal sediments of a shallow eutrophic lake. Sulfate reduction was inhibited by Na(2)MoO(4) at all concentrations tested (0.2 to 200 mM), whereas methane production was inhibited at Na(2)MoO(4) concentrations greater than 20 mM. Initial mineralization rates of glucose were unaffected by Na(2)MoO(4); however, Na(2)MoO(4) decreased the mineralization rates of lactate (58%), propionate (52%), an amino acid mixture (85%), and acetate (14%). These decreases in the rates of mineralization were attributed to inhibition of sulfate reduction. Hydrogen stimulated the reduction of SO(4) 2.5- to 2.8-fold, demonstrating potential hydrogen oxidation by sulfate-reducing bacteria. These results indicate that sulfate reducers utilize an array of substrates as electron donors and are of potential significance to the in situ mineralization of lactate, propionate, and free amino acids in these sediments.
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Affiliation(s)
- R L Smith
- W. K. Kellogg Biological Station, Michigan State University, Hickory Corners, Michigan 49060
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Abstract
Microbes, through their specialized metabolic processes and ecologies, play a fundamental part in man’s economy, and their economic roles are widely recognized as important. The sulphur bacteria have had in past geological eras, and are having today, numerous and diverse effects, often deleterious, scattered throughout the economy. Many of their economic roles are not widely known. Their economic and environmental effects arise, according to the type or combination of species involved, principally from (1) the production of acid, (2) the formation or removal of hydrogen sulphide, and (3) the removal of oxygen. In this paper their various effects on industry and the environment are surveyed.
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21
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Affiliation(s)
- M C Pitcher
- MRC Dunn Clinical Nutrition Centre, Cambridge
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22
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Butine TJ, Leedle JA. Enumeration of selected anaerobic bacterial groups in cecal and colonic contents of growing-finishing pigs. Appl Environ Microbiol 1989; 55:1112-6. [PMID: 2757376 PMCID: PMC184262 DOI: 10.1128/aem.55.5.1112-1116.1989] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Selected anaerobic bacterial groups in cecal and colonic contents of clinically healthy pigs fed a corn-soybean meal production diet were determined at sacrifice after 4, 8, and 11 weeks on feed, corresponding to intervals within the growing-finishing growth period. By using ruminal fluid-based media, the densities of the culturable anaerobic population; the cellulolytic, pectin-fermenting, pectin-hydrolyzing, xylan-fermenting; and the xylan-hydrolyzing, sulfate-reducing, and methanogenic bacterial populations were estimated. An analysis of variance was performed on these bacterial group variables to examine the effects of phase (weeks on feed), site (cecum or colon), or the interaction of phase with site. The population of total anaerobic bacteria was twice as dense in the colon as it was in the cecum (2 x 10(10) versus 1 x 10(10)/g [wet weight]; P = 0.001). The proportion of cellulolytic bacteria was lower at 4 weeks on feed than at 8 or 11 weeks (23 versus 32%; P = 0.026), while the proportion of pectin-fermenting bacteria depended on the interaction of phase with site (P = 0.021). The numbers of sulfate-reducing bacteria were significantly higher in the colon than in the cecum (6 x 10(7) versus 3 x 10(7); P = 0.014), as were methanogenic bacteria (19 x 10(7) versus 0.6 x 10(7); P = 0.0002). The remaining bacterial groups were stable with respect to phase and site. The results suggest that except for density differences, the microbial communities of the pig cecum and colon are similar in composition throughout the growing-finishing phase.
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Affiliation(s)
- T J Butine
- Microbiology and Nutrition Research, Upjohn Co., Kalamazoo, Michigan 49001
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Abstract
A sulfate-reducing bacterium has been isolated in pure culture from sheep rumen contents. Its properties agree in all respects tested with those ascribed to Desulfovibrio desulfuricans. The populations observed (about 10(8)/ml) are sufficient to account for published rates of ruminal sulfide production.
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