Background The enteric methane inhibitor 3-nitrooxypropanol(3-NOP)inhibits the key enzyme in ruminal methanogenesis,but whether short-term(ST)and long-term(LT)dietary supplementation has similar effects on rumen micro...Background The enteric methane inhibitor 3-nitrooxypropanol(3-NOP)inhibits the key enzyme in ruminal methanogenesis,but whether short-term(ST)and long-term(LT)dietary supplementation has similar effects on rumen microbiota in beef cattle and how microbes change after 3-NOP withdrawal have not been studied.This study investigated changes in rumen bacteria,archaea,and protozoa after ST and LT dietary supplementation and removal of 3-NOP using metataxonomic analysis.Results A total of 143 rumen samples were collected from two beef cattle studies with 3-NOP supplementation.The ST study(95 samples)used eight ruminally cannulated beef cattle in a 4×4 Latin square design with four 28-d of 3-NOP treatments[mg/kg of dry matter(DM)]:control:0,low:53,med:161,and high:345.The LT study(48 samples)was a completely randomized design with two 3-NOP treatments[control:0,and high:280 mg/kg of DM)fed for 112-d followed by a 16-d withdrawal(without 3-NOP).Bacterial and archaeal communities were significantly affected by 3-NOP supplementation but limited effects on protozoal communities were observed.Under ST supplementation,the relative abundances of Prevotella,Methanobrevibacter(Mbb.)ruminantium,Methanosphaera sp.ISO3-F5,and Entodinium were increased(Q<0.05),whereas those of Mbb.gottschalkii and Epidinium were decreased(Q<0.05)with 3-NOP supplementation.In LT study,relative abundances of Mbb.ruminantium,and Methanosphaera sp.Group5 were increased(Q<0.05),while those of Saccharofermentans and Mbb.gottschalkii were decreased(Q<0.05)with 3-NOP supplementation.Comparison between 3-NOP supplementation and the withdrawal revealed increased relative abundances of Clostridia UCG-014 and Oscillospiraceae NK4A214 group and decreased those of Eubacterium nodatum group and Methanosphaera sp.Group5(P<0.05)after 3-NOP withdrawal.Further comparison of rumen microbiota between control and 3-NOP withdrawal showed significantly higher(P=0.029)relative abundances of Eggerthellaceae DNF00809,p-1088-a5 gut group,and Family XII UCG-001 in control group while no significant differences were detected for archaea and protozoa.Microbial network analysis revealed that microbial interactions differed by both 3-NOP dose and durations.Conclusions Both ST and LT supplementation affected overall rumen microbial profile,with individual microbial groups responded to 3-NOP supplementation differently.After 3-NOP withdrawal,not all microbes showed recovery,indicating that the 3-NOP driven shifts were only partially reversible.These findings provide an understanding of the effects of 3-NOP on rumen microbial communities and their adaptability to methane mitigation strategies.展开更多
Background Methane(CH_(4))emissions from ruminants significantly contribute to greenhouse gas effects and energy loss in livestock production.Methyl-coenzyme M reductase(MCR)is the key enzyme in methanogenesis,making ...Background Methane(CH_(4))emissions from ruminants significantly contribute to greenhouse gas effects and energy loss in livestock production.Methyl-coenzyme M reductase(MCR)is the key enzyme in methanogenesis,making it a promising target for CH_(4) mitigation.This study aimed to identify and validate plant-derived inhibitors by using molecular docking to screen compounds with strong binding affinity to the F430 active site of MCR and assessing their efficacy in reducing CH_(4) emissions.Results Molecular docking analysis identified salvianolic acid C(SAC)as a potent inhibitor of MCR,showing a strong binding affinity to the F430 active site(binding energy:-8.2 kcal/mol).Enzymatic inhibition assays confirmed its inhibitory effect,with a half-maximal inhibitory concentration(IC50)of 692.3μmol/L.In vitro rumen fermentation experiments demonstrated that SAC supplementation(1.5 mg/g DM)significantly reduced CH_(4)production(P<0.01)without negatively affecting major fermentation parameters.Microbial community analysis using 16S rRNA sequencing and metagenomics revealed that SAC selectively altered the rumen microbiota,increasing the relative abundance of Bacteroidota while significantly reducing Methanobrevibacter(P=0.04).Moreover,metagenomic analysis showed the downregulation of key methanogenesis-related genes(mcrA and rnfC),suggesting a dual mechanism involving direct enzymatic inhibition and microbial community modulation.Conclusions These findings indicate that SAC effectively reduces CH_(4)production by inhibiting MCR activity and reshaping the rumen microbial community.As a plant-derived compound with strong inhibitory effects on methanogenesis,SAC presents a promising and sustainable alternative to synthetic CH_(4) inhibitors,offering potential applications for mitigating CH_(4)emissions in livestock production.展开更多
In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting...In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting protein degradation to avoid excess release of ammonia, and activation of fiber digestion. The main approach has been the use of dietary supplements. Since growth-promoting antibiotics were banned in European countries in2006, safer alternatives including plant-derived materials have been explored. Plant oils, their component fatty acids,plant secondary metabolites and other compounds have been studied, and many originate or are abundantly available in Asia as agricultural byproducts. In this review, the potency of selected byproducts in inhibition of methane production and protein degradation, and in stimulation of fiber degradation was described in relation to their modes of action. In particular, cashew and ginkgo byproducts containing alkylphenols to mitigate methane emission and bean husks as a source of functional fiber to boost the number of fiber-degrading bacteria were highlighted. Other byproducts influencing rumen microbiota and fermentation profile were also described. Future application of these feed and additive candidates is very dependent on a sufficient, cost-effective supply and optimal usage in feeding practice.展开更多
Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degrada...Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degradation process of CHBr3 from A taxiformis in the rumen and whether this process is diet-dependent.An in vitro batch culture system was used according to a 2×2 factorial design,assessing two A taxiformis inclusion rates[0(CTL)and 2%DM diet(AT)]and two diets[high-concentrate(HC)and high-forage diet(HF)].Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0,0.5,1,3,6,8,12,16,24,48 and 72 h to assess the pattern of degradation of CHBr_(3) into dibromomethane(CH_(2)Br_(2))and fermentation parameters.Additionally,an in vitro experiment with pure cultures of seven methanogens strains(Methanobrevibacter smithii,Methanobrevibacter ruminantium,Methanosphaera stadtmanae,Methanosarcina barkeri,Methanobrevibacter millerae,Methanorhermobacter wolfei and Methanobacterium mobile)was conducted to test the effects of increasing concentrations of CHBr3(0.4,2,10and 50μmol/L).Results The addition of AT significantly decreased CH_(4) production(P=0.002)and the acetate:propionate ratio(P=0.003)during a 72-h incubation.The concentrations of CHBr_(3) showed a rapid decrease with nearly 90%degraded within the first 3 h of incubation.On the contrary,CH_(2)Br_(2) concentration quickly increased during the first 6 h and then gradually decreased towards the end of the incubation.Neither CHBr_(3) degradation nor CH_(2)Br_(2) synthesis were affected by the type of diet used as substrate,suggesting that the fermentation rate is not a driving factor involved in CHBr_(3)degradation.The in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of M.smithii,M.ruminantium,M.stadtmanae,M.barkeri,M.millerae,M.wolfei,and M.mobile.Conclusions The present work demonstrated that CHBr_(3) from A.taxiformis is quickly degraded to CH_(2)Br_(2)in the rumen and that the fermentation rate promoted by different diets is not a driving factor involved in CHBr_(3)degradation.展开更多
Enteric methane emissions account for approximately 17%of global anthropogenic greenhouse gas emissions and represent 2%to 12%of energy losses from energy intake in ruminants.To reduce these emissions and accelerate t...Enteric methane emissions account for approximately 17%of global anthropogenic greenhouse gas emissions and represent 2%to 12%of energy losses from energy intake in ruminants.To reduce these emissions and accelerate the achievement of carbon neutrality,it is critical to understand the factors driving methanogenesis in the rumen and develop effective methane mitigation strategies.Methanogenesis inhibitors,when used in conjunction with nutritional and breeding management strategies,are widely regarded as effective additives for optimizing rumen function,enhancing nutrient utilization and reducing enteric methane emissions.The field of inhibitor development is evolving rapidly under increasing mitigation pressure,necessitating continual review to guide the understanding of their mechanisms of action,effectiveness,risk and potential for widespread use in ruminant production systems.This review compiles data from 78 peer-reviewed in vivo studies conducted over the past 5 years,focusing on 10 inhibitors,which demonstrates 5%to 75%in daily methane emission reduction,2%to 70%in methane yield reduction,and 11%to 74%in methane intensity reduction.Among the inhibitors,macroalgae are the most effective,achieving 22%to 75%of methane reductions,followed by small targeted molecule inhibitors 3-nitrooxypropanol(3-NOP)with 13%to 62%of methane reductions.Additionally,this review discusses the mechanisms underlying these mitigation strategies,their impact on animal productivity performance,the barriers to their widespread adoption,and directions for future research.Special attention is given to the effects of these inhibitors on rumen hydrogen partial pressure and other metabolic pathways,as improper use may adversely affect nutrient utilization,overall metabolism and animal performance.Future mitigation efforts should focus on the developing nextgeneration inhibitors that precisely target methanogenic archaea and the methanogenesis pathway.These novel inhibitors must meet on a principle of safety for the host animals,human health and environment,and be economically viable and technically supported with efficiency in achieving longterm mitigation with minimal lifecycle carbon footprints.展开更多
Biochar has been reported to mitigate short-term methane(CH4)emissions from paddy soil.Currently,CH4 mitigation by biochar has primarily focused on the abundance and variations of methanogens and methanotrophs,and cha...Biochar has been reported to mitigate short-term methane(CH4)emissions from paddy soil.Currently,CH4 mitigation by biochar has primarily focused on the abundance and variations of methanogens and methanotrophs,and changes in their activities during methane production and consumption.However,long-term effects of biochar on methane mitigation from paddy soil remain controversial.This review overviewed the existing mechanisms for CH4 mitigation as a result of biochar application.In addition,the two existing opinions on the long-term CH4 mitigation effect upon biochar application were highlighted.Combining the already explored mechanisms of fresh biochar on CH4 mitigation from paddy soil and a novel discovery,the potential mechanisms of biochar on long-term methane emission response were proposed.This review also revealed the uncertain responses of biochar on long-term CH4 mitigation.Therefore,to achieve carbon neutral goal,it is important to further explore the mechanisms of long-term CH4 mitigation under biochar application.展开更多
基金funded by the Beef Cattle Research Council Cluster(FDE.18.21C)Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery,NSERC Canadian Research Chair(Tier 1)program+2 种基金NSERC Alliance program(ALLRP 588541‐23)Foundation for Food&Agriculture Research Greener Cattle Initiative(Award ID 22‐000373)DSM Nutritional Products,Kaiseraugst,Switzerland。
文摘Background The enteric methane inhibitor 3-nitrooxypropanol(3-NOP)inhibits the key enzyme in ruminal methanogenesis,but whether short-term(ST)and long-term(LT)dietary supplementation has similar effects on rumen microbiota in beef cattle and how microbes change after 3-NOP withdrawal have not been studied.This study investigated changes in rumen bacteria,archaea,and protozoa after ST and LT dietary supplementation and removal of 3-NOP using metataxonomic analysis.Results A total of 143 rumen samples were collected from two beef cattle studies with 3-NOP supplementation.The ST study(95 samples)used eight ruminally cannulated beef cattle in a 4×4 Latin square design with four 28-d of 3-NOP treatments[mg/kg of dry matter(DM)]:control:0,low:53,med:161,and high:345.The LT study(48 samples)was a completely randomized design with two 3-NOP treatments[control:0,and high:280 mg/kg of DM)fed for 112-d followed by a 16-d withdrawal(without 3-NOP).Bacterial and archaeal communities were significantly affected by 3-NOP supplementation but limited effects on protozoal communities were observed.Under ST supplementation,the relative abundances of Prevotella,Methanobrevibacter(Mbb.)ruminantium,Methanosphaera sp.ISO3-F5,and Entodinium were increased(Q<0.05),whereas those of Mbb.gottschalkii and Epidinium were decreased(Q<0.05)with 3-NOP supplementation.In LT study,relative abundances of Mbb.ruminantium,and Methanosphaera sp.Group5 were increased(Q<0.05),while those of Saccharofermentans and Mbb.gottschalkii were decreased(Q<0.05)with 3-NOP supplementation.Comparison between 3-NOP supplementation and the withdrawal revealed increased relative abundances of Clostridia UCG-014 and Oscillospiraceae NK4A214 group and decreased those of Eubacterium nodatum group and Methanosphaera sp.Group5(P<0.05)after 3-NOP withdrawal.Further comparison of rumen microbiota between control and 3-NOP withdrawal showed significantly higher(P=0.029)relative abundances of Eggerthellaceae DNF00809,p-1088-a5 gut group,and Family XII UCG-001 in control group while no significant differences were detected for archaea and protozoa.Microbial network analysis revealed that microbial interactions differed by both 3-NOP dose and durations.Conclusions Both ST and LT supplementation affected overall rumen microbial profile,with individual microbial groups responded to 3-NOP supplementation differently.After 3-NOP withdrawal,not all microbes showed recovery,indicating that the 3-NOP driven shifts were only partially reversible.These findings provide an understanding of the effects of 3-NOP on rumen microbial communities and their adaptability to methane mitigation strategies.
基金funded by the Integrated Demonstration of Scalable and Efficient Healthy Breeding for Cattle and Sheep(Grant No.2022YFD1301100)Instant Intelligent Diagnosis and Risk Warning Methods for Nutritional and Metabolic-Type Periparturient Cow Paralysis(Grant No.2024-YWF-ZYSQ-10)。
文摘Background Methane(CH_(4))emissions from ruminants significantly contribute to greenhouse gas effects and energy loss in livestock production.Methyl-coenzyme M reductase(MCR)is the key enzyme in methanogenesis,making it a promising target for CH_(4) mitigation.This study aimed to identify and validate plant-derived inhibitors by using molecular docking to screen compounds with strong binding affinity to the F430 active site of MCR and assessing their efficacy in reducing CH_(4) emissions.Results Molecular docking analysis identified salvianolic acid C(SAC)as a potent inhibitor of MCR,showing a strong binding affinity to the F430 active site(binding energy:-8.2 kcal/mol).Enzymatic inhibition assays confirmed its inhibitory effect,with a half-maximal inhibitory concentration(IC50)of 692.3μmol/L.In vitro rumen fermentation experiments demonstrated that SAC supplementation(1.5 mg/g DM)significantly reduced CH_(4)production(P<0.01)without negatively affecting major fermentation parameters.Microbial community analysis using 16S rRNA sequencing and metagenomics revealed that SAC selectively altered the rumen microbiota,increasing the relative abundance of Bacteroidota while significantly reducing Methanobrevibacter(P=0.04).Moreover,metagenomic analysis showed the downregulation of key methanogenesis-related genes(mcrA and rnfC),suggesting a dual mechanism involving direct enzymatic inhibition and microbial community modulation.Conclusions These findings indicate that SAC effectively reduces CH_(4)production by inhibiting MCR activity and reshaping the rumen microbial community.As a plant-derived compound with strong inhibitory effects on methanogenesis,SAC presents a promising and sustainable alternative to synthetic CH_(4) inhibitors,offering potential applications for mitigating CH_(4)emissions in livestock production.
基金supported by JSPS KAKENHI Grant Numbers JP20380146,JP23380156,JP23658213,JP26660207
文摘In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting protein degradation to avoid excess release of ammonia, and activation of fiber digestion. The main approach has been the use of dietary supplements. Since growth-promoting antibiotics were banned in European countries in2006, safer alternatives including plant-derived materials have been explored. Plant oils, their component fatty acids,plant secondary metabolites and other compounds have been studied, and many originate or are abundantly available in Asia as agricultural byproducts. In this review, the potency of selected byproducts in inhibition of methane production and protein degradation, and in stimulation of fiber degradation was described in relation to their modes of action. In particular, cashew and ginkgo byproducts containing alkylphenols to mitigate methane emission and bean husks as a source of functional fiber to boost the number of fiber-degrading bacteria were highlighted. Other byproducts influencing rumen microbiota and fermentation profile were also described. Future application of these feed and additive candidates is very dependent on a sufficient, cost-effective supply and optimal usage in feeding practice.
基金funded by Blue Ocean Barns.AB has a Ramón y Cajal research contract(RYC2019-027764-I)funded by the Spanish State Research Agency(AEI)。
文摘Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degradation process of CHBr3 from A taxiformis in the rumen and whether this process is diet-dependent.An in vitro batch culture system was used according to a 2×2 factorial design,assessing two A taxiformis inclusion rates[0(CTL)and 2%DM diet(AT)]and two diets[high-concentrate(HC)and high-forage diet(HF)].Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0,0.5,1,3,6,8,12,16,24,48 and 72 h to assess the pattern of degradation of CHBr_(3) into dibromomethane(CH_(2)Br_(2))and fermentation parameters.Additionally,an in vitro experiment with pure cultures of seven methanogens strains(Methanobrevibacter smithii,Methanobrevibacter ruminantium,Methanosphaera stadtmanae,Methanosarcina barkeri,Methanobrevibacter millerae,Methanorhermobacter wolfei and Methanobacterium mobile)was conducted to test the effects of increasing concentrations of CHBr3(0.4,2,10and 50μmol/L).Results The addition of AT significantly decreased CH_(4) production(P=0.002)and the acetate:propionate ratio(P=0.003)during a 72-h incubation.The concentrations of CHBr_(3) showed a rapid decrease with nearly 90%degraded within the first 3 h of incubation.On the contrary,CH_(2)Br_(2) concentration quickly increased during the first 6 h and then gradually decreased towards the end of the incubation.Neither CHBr_(3) degradation nor CH_(2)Br_(2) synthesis were affected by the type of diet used as substrate,suggesting that the fermentation rate is not a driving factor involved in CHBr_(3)degradation.The in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of M.smithii,M.ruminantium,M.stadtmanae,M.barkeri,M.millerae,M.wolfei,and M.mobile.Conclusions The present work demonstrated that CHBr_(3) from A.taxiformis is quickly degraded to CH_(2)Br_(2)in the rumen and that the fermentation rate promoted by different diets is not a driving factor involved in CHBr_(3)degradation.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFD1300902,2022YFD1300602)Guangxi Science and Technology Major Project(Guike AA22068099-5)Hunan Province Science and Technology Plan(2022RC3058).
文摘Enteric methane emissions account for approximately 17%of global anthropogenic greenhouse gas emissions and represent 2%to 12%of energy losses from energy intake in ruminants.To reduce these emissions and accelerate the achievement of carbon neutrality,it is critical to understand the factors driving methanogenesis in the rumen and develop effective methane mitigation strategies.Methanogenesis inhibitors,when used in conjunction with nutritional and breeding management strategies,are widely regarded as effective additives for optimizing rumen function,enhancing nutrient utilization and reducing enteric methane emissions.The field of inhibitor development is evolving rapidly under increasing mitigation pressure,necessitating continual review to guide the understanding of their mechanisms of action,effectiveness,risk and potential for widespread use in ruminant production systems.This review compiles data from 78 peer-reviewed in vivo studies conducted over the past 5 years,focusing on 10 inhibitors,which demonstrates 5%to 75%in daily methane emission reduction,2%to 70%in methane yield reduction,and 11%to 74%in methane intensity reduction.Among the inhibitors,macroalgae are the most effective,achieving 22%to 75%of methane reductions,followed by small targeted molecule inhibitors 3-nitrooxypropanol(3-NOP)with 13%to 62%of methane reductions.Additionally,this review discusses the mechanisms underlying these mitigation strategies,their impact on animal productivity performance,the barriers to their widespread adoption,and directions for future research.Special attention is given to the effects of these inhibitors on rumen hydrogen partial pressure and other metabolic pathways,as improper use may adversely affect nutrient utilization,overall metabolism and animal performance.Future mitigation efforts should focus on the developing nextgeneration inhibitors that precisely target methanogenic archaea and the methanogenesis pathway.These novel inhibitors must meet on a principle of safety for the host animals,human health and environment,and be economically viable and technically supported with efficiency in achieving longterm mitigation with minimal lifecycle carbon footprints.
基金supported by National Natural Science Foundation of China[Grant numbers 42077032 and 41571241]the National Key Technology Research and Development Program of the Ministry of Science and Technology of China[Grant number 2015BAC02B01]We thank the editors and reviewers for their constructive comments.
文摘Biochar has been reported to mitigate short-term methane(CH4)emissions from paddy soil.Currently,CH4 mitigation by biochar has primarily focused on the abundance and variations of methanogens and methanotrophs,and changes in their activities during methane production and consumption.However,long-term effects of biochar on methane mitigation from paddy soil remain controversial.This review overviewed the existing mechanisms for CH4 mitigation as a result of biochar application.In addition,the two existing opinions on the long-term CH4 mitigation effect upon biochar application were highlighted.Combining the already explored mechanisms of fresh biochar on CH4 mitigation from paddy soil and a novel discovery,the potential mechanisms of biochar on long-term methane emission response were proposed.This review also revealed the uncertain responses of biochar on long-term CH4 mitigation.Therefore,to achieve carbon neutral goal,it is important to further explore the mechanisms of long-term CH4 mitigation under biochar application.
