Effect of select nitrocompounds on ruminal fermentation; an initial look at their potential to reduce economic and environmental costs associated with ruminal methanogenesis

Anderson, Robin C.; Callaway, Todd R.; Kessel, Jo Ann S. Van; Jung, Yi‐Sook; Edrington, Thomas S.; Nisbet, David J.

doi:10.1016/s0960-8524(03)00086-5

Cited by 63 publications

(64 citation statements)

References 32 publications

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“…It should be noted that the effect of antimethanogenic compounds on total and individual VFAs may be affected by other factors, such as the rumen fluid used and substrates added. For example, nitrocompounds were shown not to significantly reduce VFA concentrations in ruminal in vitro cultures when the medium consisted entirely of rumen fluid and contained formate or hydrogen only as added substrates (1,3). In the latter studies, there might be little fermentation or VFA production due to the lack of fermentable sugars, and the VFAs detected might be those present in the original rumen fluid.…”

Section: Discussionmentioning

confidence: 98%

Effects of Methanogenic Inhibitors on Methane Production and Abundances of Methanogens and Cellulolytic Bacteria in In Vitro Ruminal Cultures

Zhou

Meng

2011

Appl Environ Microbiol

126

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The objective of this study was to systematically evaluate and compare the effects of select antimethanogen compounds on methane production, feed digestion and fermentation, and populations of ruminal bacteria and methanogens using in vitro cultures. Seven compounds, including 2-bromoethanesulphonate (BES), propynoic acid (PA), nitroethane (NE), ethyl trans-2-butenoate (ETB), 2-nitroethanol (2NEOH), sodium nitrate (SN), and ethyl-2-butynote (EB), were tested at a final concentration of 12 mM. Ground alfalfa hay was included as the only substrate to simulate daily forage intake. Compared to no-inhibitor controls, PA, 2NEOH, and SN greatly reduced the production of methane (70 to 99%), volatile fatty acids (VFAs; 46 to 66%), acetate (30 to 60%), and propionate (79 to 82%), with 2NEOH reducing the most. EB reduced methane production by 23% without a significant effect on total VFAs, acetate, or propionate. BES significantly reduced the propionate concentration but not the production of methane, total VFAs, or acetate. ETB or NE had no significant effect on any of the above-mentioned measurements. Specific quantitative-PCR (qPCR) assays showed that none of the inhibitors significantly affected total bacterial populations but that they did reduce the Fibrobacter succinogenes population. SN reduced the Ruminococcus albus population, while PA and 2NEOH increased the populations of both R. albus and Ruminococcus flavefaciens. Archaeon-specific PCR-denaturing gradient gel electrophoresis (DGGE) showed that all the inhibitors affected the methanogen population structure, while archaeon-specific qPCR revealed a significant decrease in methanogen population in all treatments. These results showed that EB, ETB, NE, and BES can effectively reduce the total population of methanogens but that they reduce methane production to a lesser extent. The results may guide future in vivo studies to develop effective mitigation of methane emission from ruminants.Methane (CH 4 ) emissions from ruminants can result in a significant loss of feed efficiency: up to a 12% loss of gross energy intake for forage-fed cattle and 4% for concentrate-fed cattle (14). Because methane is 25 times more potent than carbon dioxide as a greenhouse gas (11), methane emitted from ruminants amounted to 141 teragrams of CO 2 equivalents (Tg CO 2 eq), accounting for 25% of total methane emissions from anthropogenic activities in the United States in 2008 (26). To mitigate the negative impact on climate change and to improve feed efficiency, numerous strategies for reducing methane emission from ruminant livestock have been tested. Plant extracts (7, 9), vaccines (28), ionophores (27), and dietary strategies (21) have been evaluated for their efficacy in reducing ruminal methane emission. However, only monensin has been used in animal-feeding operations, and it typically achieves only transient reductions in methane production (12). More importantly, the monensin-driven reduction in methane reduction is largely attributable to decreased feed digestibility (4,19...

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Section: Discussionmentioning

confidence: 98%

Effects of Methanogenic Inhibitors on Methane Production and Abundances of Methanogens and Cellulolytic Bacteria in In Vitro Ruminal Cultures

Zhou

Meng

2011

Appl Environ Microbiol

126

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“…This prompted the hypothesis that headspace gas composition, CO 2 in particular, which is in exchange with H 2 CO 3 /HCO 3 − in the medium, depending on concentration, acid-base balance and gas pressure, may affect fermentation characteristics and gas production in ruminal in vitro cultures. A range of initial headspace composition of in vitro cultures has been reported, including 100% CO 2 (Anderson et al, 2003;Weimer et al, 2005), 100% N 2 (Hoover et al, 1976) and a mixture of gases typical of an anaerobic chamber (85% N 2 , 10% H 2 , and 5% CO 2 ; Zhou et al, 2011;Patra et al, 2012). Patra and Yu (2013) investigated the effects of three different headspace gases (N 2 + CO 2 + H 2 in the ratio of 90:5:5, 100% CO 2 , and 100% N 2 ) and the interaction with type of substrate (alfalfa hay or alfalfa hay and concentrate) and media bicarbonate concentration on gas and CH 4 production.…”

Section: Headspace Gas Compositionmentioning

confidence: 99%

Design, implementation and interpretation of in vitro batch culture experiments to assess enteric methane mitigation in ruminants—a review

Yáñez-Ruíz

Bannink

Dijkstra

et al. 2016

Animal Feed Science and Technology

131

120

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a b s t r a c tIn vitro fermentation techniques (IVFT) have been widely used to evaluate the nutritive value of feeds for ruminants and in the last decade to assess the effect of different nutritional strategies on methane (CH4) production. However, many technical factors may influence the results obtained. The present review has been prepared by the 'Global Network' FACCE-JPI international research consortium to provide a critical evaluation of the main factors that need to be considered when designing, conducting and interpreting IVFT experiments that investigate nutritional strategies to mitigate CH 4 emission from ruminants. Given the increasing and wide-scale use of IVFT, there is a need to critically review reports in the literature and establish what criteria are essential to the establishment and implementation of in vitro techniques. Key aspects considered include: i) donor animal species and number of animal used, ii) diet fed to donor animals, iii) collection and processing of rumen fluid as inoculum, iv) choice of substrate and incubation buffer, v) incubation procedures and CH 4 measurements, vi) headspace gas composition and vii) comparability of in vitro and in vivo measurements. Based on an evaluation of experimental evidence, a set of technical recommendations are presented to harmonize IVFT for feed evaluation, assessment of rumen function and CH 4 production.

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“…Inhibition of methanogenesis is accompanied by increased formate production when BCM (a coenzyme M inhibitor) and other CH 4 analogues are incubated with methanogens or complex consortia of methanogens Bleicher and Winter 1994). In contrast to the majority of inhibitors, these nitro-compounds do not bring about marked changes in the molar proportions of VFA produced by the mixed microbial population (Bleicher and Winter 1994;Anderson et al 2003;Brown et al 2011). Any H 2 released by reversal of cofactor reduction does not yet have an identified sink other than that attributable to reduction of the nitrocompound itself, and on the basis of stoichiometry, this could account for only a small fraction of the H 2 removed (Božic et al 2009).…”

Section: Inhibition Of Methanogenesis With Short-chain Nitrocompoundsmentioning

confidence: 99%

“…Nitro-compounds such as nitroethane inhibit ruminal methanogenesis by as much as 90% in vitro (Anderson et al 2003) and by more than 43% in vivo (Anderson et al 2006), via inhibition of formate and H 2 oxidation (Anderson et al 2008). If rumen protozoa depend on associated methanogens to enable reduced cofactors to be re-oxidised, then protozoal populations should be reduced in the presence of short chain nitrocompounds.…”

Section: Inhibition Of Methanogenesis With Short-chain Nitrocompoundsmentioning

confidence: 99%

Interactions between microbial consortia in biofilms: a paradigm shift in rumen microbial ecology and enteric methane mitigation

Leng¹

2014

Anim. Prod. Sci.

133

105

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Abstract. Minimising enteric CH 4 emissions from ruminants is a current research priority because CH 4 contributes to global warming. The most effective mitigation strategy is to adjust the animal's diet to complement locally available feed resources so that optimal production is gained from a minimum of animals. This essay concentrates on a second strategy -the use of feed additives that are toxic to methanogens or that redirect H 2 (and electrons) to inhibit enteric CH 4 emissions from individual animals. Much of the published research in this area is contradictory and may be explained when the microbial ecology of the rumen is considered.Rumen microbes mostly exist in organised consortia within biofilms composed of self-secreted extracellular polymeric substances attached to or within feed particles. In these biofilms, individual colonies are positioned to optimise their use of preferred intermediates from an overall process of organic matter fermentation that generates end-products the animal can utilise. Synthesis of CH 4 within biofilms prevents a rise in the partial pressure of H 2 (pH 2 ) to levels that inhibit bacterial dehydrogenases, and so reduce fermentation rate, feed intake and digestibility. In this context, hypotheses are advanced to explain changes in hydrogen disposal from the biofilms in the rumen resulting from use of anti-methanogenic feed additives as follows.Nitrate acts as an alternative electron sink when it is reduced via NO 2 -to NH 3 and CH 4 synthesis is reduced. However, efficiency of CH 4 mitigation is always lower than that predicted and decreases as NO 3 -ingestion increases. Suggested reasons include (1) variable levels of absorption of NO 3 -or NO 2 -from the rumen and (2) increases in H 2 production. One suggestion is that NO 3 -reduction may lower pH 2 at the surface of biofilms, thereby creating an ecological niche for growth of syntrophic bacteria that oxidise propionate and/or butyrate to acetate with release of H 2 .Chlorinated hydrocarbons also inhibit CH 4 synthesis and increase H 2 and formate production by some rumen methanogens. Formate diffuses from the biofilm and is converted to HCO 3 -and H 2 in rumen fluid and is then excreted via the breath. Short-chain nitro-compounds inhibit both CH 4 and formate synthesis when added to ruminal fluid but have little or no effect in redirecting H 2 to other sinks, so the pH 2 within biofilms may increase to levels that support reductive acetogenesis. Biochar or activated charcoal may also alter biofilm activity and reduce net CH 4 synthesis; direct electron transfer between microbes within biofilms may also be involved. A final suggestion is that, during their sessile life stage, protozoa interact with biofilm communities and help maintain pH 2 in the biofilm, supporting methanogenesis.

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Effect of select nitrocompounds on ruminal fermentation; an initial look at their potential to reduce economic and environmental costs associated with ruminal methanogenesis

Cited by 63 publications

References 32 publications

Effects of Methanogenic Inhibitors on Methane Production and Abundances of Methanogens and Cellulolytic Bacteria in In Vitro Ruminal Cultures

Effects of Methanogenic Inhibitors on Methane Production and Abundances of Methanogens and Cellulolytic Bacteria in In Vitro Ruminal Cultures

Design, implementation and interpretation of in vitro batch culture experiments to assess enteric methane mitigation in ruminants—a review

Interactions between microbial consortia in biofilms: a paradigm shift in rumen microbial ecology and enteric methane mitigation

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