【doc】添加不同比例的亚油酸和亚麻酸对体外瘤胃发酵和甲烷生成的影响

【doc】添加不同比例的亚油酸和亚麻酸对体外瘤胃发酵和甲烷生成的影响 添加不同比例的亚油酸和亚麻酸对体外瘤 胃发酵和甲烷生成的影响 动物营养2008,20(2):223—227 ChineseJournalofAnimalNutrition EffectsofAddingMixturesofLinoleicAcidandLinolenicAcidwithDifferent ProportionsonRumenFermentationandMethan0genesisinvitro ZHANGChun.meiYIXian.wuYUANZhi-pengLIUJian-xinZHUWei-yun. (1.CollegeofAnimalScience,MOEKeyLaboratoryofMolecularAnimalNutrition,ZhejiangUniversity,Hangzhou310029,China; 2.NanjingAgriculturalUniversity,Nanying210095,China) Abstract:Thisstudywascarriedouttoinvestigatetheeffectsofmixturesoflinoleicacidandlinolenicacidwithdifferentpro- portionsonrumenfermentationandmethanogenesisbyusinggasproductionfunctionofartificialrumen.Linoleicacidand linolenicacidweremixedattheproportionof0:0,10:0,8:2,6:4,5:5,4:6,2:8and0:10,andthemixtures wereaddedintotubesatalevelof5%DMofsubstrates.Anon-supplementedsubstratetubewasemployedasthecontro1. The24hgasproductionandmethanogenesisweresignificantlyreducedwiththeadditionofanymixture(P<0.05).The morethelinolenicacidadded.themorethedecreasewas.ThepHofthefermentationfluidweresignificantlyincreased(P< 0.05),whentheproportionofLinolenicacidwasmorethan40%.AlltreatmentshadnosignificanteffectonNH3-Npro- ductionandmicrobialmass.Thetotalvolatilefattyacidsincreasedwiththeincreasingratiooflinolenicacid,beingsignifi- cantlyhigherwiththeadditionoflinolenicacidalonethanlinoleicacidalone(P<0.05).The fermentationpatternwasalso changed,beingreflectedbylowerproportionofacetateandhigherproportionofpropionatew iththeincreasingratiooflin- olenicacid(P<0.05).Itisinferredthatreductionofmethanogenesisisassociatedwiththede greeofunsaturationofC18 fattyacids. Keywords:Methane;Gasproductioninvitro;Linoleicacid;Linolenicacid Methaneisproducedasanunavoidableby- productoforganicmatterfermentationintheru- menandtakesup2%to12%lossofgrossenergy intakeE.Theconcentrationofmethaneintheat. mospherehasincreasedatarateof10nL/Lper yearsincethepreindustrialrevolutionE引.Domes. ticatedruminantswereestimatedtoproduceabout 80Tgofmethaneannually(1Tg=1millionmet- rictons),accountingforabout22%ofmethane emissionsfromhuman.relatedactivitiesE.There. fore,reducingmethaneemissionhasimplications notonlyforglobalenvironmentalprotectionbut alsoforefficientanimalproduction.Longchain unsaturatedfattyacidsareknowntohaveahigh potentialinsuppressingruminalmethanogene. sis[引. Inthepreviousstudy,weinvestigatedthe effectsofoctadeca.carbonfattyacidsonrumen fermentationandmethaneemissionfnvitro,and foundthatlinolenicacidhadthemostefficient methane-suppressingeffect,followedbylinoleic acidE.However,whetherreductioninmethane emissionisassociatedwiththedegreeofunsatura. tionhasbeeninsufficientlyreported.Therefore, theobjectiveofthisstudywastoinvestigatethe effectsofmixturesof1inoleicandlinolenicacids onrumenfermentationandmethanOgenesisfn vitrousingpressuretransducertechnique. 1MATERIALSANDMETHoDS 1.1Materials Thelinoleicacid(L1376990g/kg)andlino. 1enicacid(L2376990g/kg)werepurchasedfrom Datereceived:2007-09—21 Financialsupport:theNationalNaturalSciencefoundationofChina(NSFC)(No. 30530560)andJointFAO/IAEADivision,IAEA(No 12665/R0) Authorinformation:ZHANGChun-mei(1976一),female,Yucheng,Henan,doctor,researchonrumlnalmicrobiology.Ernail:zcm304@1 63.com *Correspondingauthor:LIUJian—xin,professor,E—mail:liujx@zju.edu.cn 224动物营养20卷 SIGMA.AmixtureofChinesewildryemealand cornmeal(DM,1:1,w/w)wasusedasthesub. strateintheinvitroexperiment.Bothmaterials weremilledthrougha1mmscreen. 1.2Experimentaldesign Theinvitrogasproduction(GP)wasdeter. minedintriplicatewiththesemi.automatedRead. ingPressureTechnical[引.Mixturesoffattyacids wereaddedtobasalsubstrateatalevelof5Og/kg DM,providedinlinoleictolinolenicacidratios of0:0,10:0,8:2,6:4,5:5,4:6,2:8 and0:10.At4,8,12and24hincubation.gas pressurewasrecorded,andthenthegaswere drawnoutbyaneedlethroughthestopperto measuremethaneconcentrationbygaschroma— tography. 1.3Equipmentandtechnique Incubationswereconductedin180mL flasks.About750mgsubstrateswereaccurately weighedintotheflasks,andthen90mLartificial salivaL.]wasaddedtoeachflaskwhichwerethen sealedwithabutylrubberstopperandstoredo? vernightat4?.Therumenfluidinoculumwas collectedfromthreedonorsheepfedtwicedaily onamixeddietoflucernehayandmixedconcen— trates(3:2,w/w)beforemorningfeeding.The rumenfluidwasstrainedthroughfourlayersof cheeseclothandheldunderCO2inawater.bathat 39?untilused.Eachflask(pre.warmedto39?) wastheninjectedwith10mLpreparedinoculum throughthestopperusingasyringe.Thedis? placedgaswasallowedtoescapebeforethenee? dlewasremoved.Theflaskswerethenswirledto mixthecontentsandplacedinanincubatorat 39?.Onthepointoftimeformeasuringthegas production,apressuretransducer,interfaced withacomputerallowedtheaccumulatedhead—— spacegaspressurevaluestobedirectlyenteredin? tothecomputer.Thesepressuremeasurements werethenusedtoestimatethecumulativegasvo1. umeswiththecorrectionofcontrolgroup.The followingformulaisusedtotranslatepressurein? tovo1umes. GP=(P一P0)×(V0—100) 101.3×w GPt:thegasproductionattpointoftime( Pt:gaspressureattpointoftime(kPa);P0 pressureofcontrolgroupattpointoftime; thevolumeofflask(mL);W:drymatterw ofsample(g). 1.4Samplingandmeasurement Afterterminationofincubationat24h,the fluidwassampledtodeterminepH,ammonia.N, volatilefattyacids(VFA)andmicrobialcrude protein(MCP)usingthemethodsdescribedbyHu etaZ.L73. 1.5Statisticalanalysis Thedatawereanalysedbythegenerallinear modelprocedureofSAS(1999).Allmultiple comparisonsamongmeanswereperformedusing Duncan'snewmultiplerangetest. 2RESULTS 2.1EffectsonGPandmethaneemission Gasproductionandmethaneemissionde. creasedsignificantly(P<O.05)byanymixtureof fattyacids(Table1).Theeffectwaspronounced withtheincreasingratiooflinolenicacid.There. gressionequationbetweenmethaneemissionand thecontentoflinolenicacid(g)wereformulated asfollow:v=0.0003x.一0.019x+0.8925(R. :0.9034,P<O.001).Gasproductionandmeth. anereleasewereallreducedbytheincreasingra. tiooflinolenicacid,buttheextentwasnotthe same.AdditionoflinolenicaciddecreasedGPby 26.7%.whilemethaneemissionwasdepressedbv 53.8%(Table1). 2.2Effectsonfermentationcharacteristics AsshowninTable2,themixturesinwhich linolenicacidtookup4O%atleastsignificantly increasedPHoffermentationfluid(P<O.O5). Ammonianitrogenandmicrobialcrudeprotein concentrationswerelittleaffectedbyadditionof linoleicandlinolenicacidsmixtures(P>O.O5). Totalvolatilefattyacidsincreasedwiththein. creasingratiooflinolenicacid,andsignificant 2期zHANGchun.meief? 1.:EffectsofAddingMixturesofLinoleicAcidandLinolenicAcidwith…225 differencesweredetectedbetweencontrol,lino— leicacidaloneand80%linolenicacid,linolenic acidalonetreatments(P<O.05).Molarpropor— tionofacetateandbutyratewasreduced(P< 0.05),butpropionateproportionwasenhanced significantly(P<0.05)withincreasingratioof linolenicacid.Thus,theacetatetopropionatera— tiowasdecreased(P<0.05)bytheadditionof mixturesoffattyacids. Table1Influenceofmixturesoflinoleicandlinolenicacidsadditiononcumulativegasproduc tionand methaneemissionsoffnvitroincubation Inthesamerow.valueswithdifferentsmalllettersuperscriptsmeansignificantdifference(P <0.05).Thesameasbelow. Table2Effectofmixtureoflinoleicandlinolenicacidsadditionongasproduction,methanee mission andfermentationparametersof24hinvitroincubation 3DISCUSSION Thereductioninmethaneemissionarising fromthedietaryinclusionofunsaturatedfatty acidscanbeattributedtothefollowinginterrelat— edfactors.Totalruminalhydrogensupplywould bereducedbyashiftintheratiooftheendprod. uctsoffermentationfromacetatetowardspropio. nate[8_.Ruminalhydrogensupplyavailablefor thereductionofCO2tomethanewouldbefurther reducedbytheunsaturatedfattyacidsservingas analternativehydrogensinkthroughbio?-hydro?- 226动物营养20卷 genation,althoughthetotalamountofmetabolic hydrogenusedinthebio-hydrogenationofunsatu. ratedfattyacidsissmallcomparedtothatused forthereductionofCO2tomethane[.Inaddi. tion,byreducingtheruminalciliatepopula- tion[',interspecieshydrogentransferwillbe reducedandoverallmethaneproductionlow. ered[12-13].Rumenmethanogenicbacterianumbers canalsobesignificantlyreducedwhenexposedto dietaryunsaturatedfattyacids.Inapureculture study,thegrowthofMethanobacteriumrumi. nantiumandMethanobacteriumM.o.H.strains wasinhibitedbyadditionoflinoleicandlinolenic acidc.Inamixedculturestudy,thetotalmeth. anogenpopulationwasdepressedsignificantlyby additionofunsaturatedC18fattyacidsL.Atthe presentstudy,allmixturesoflinoleicandlinole. nicacidsreducedmethaneemission,theeffect beingpronouncedwithincreasingratiooflinole- nicacid.Itisinferredthatreductioninmethane emissionisassociatedwiththedegreeofunsatura. tionofC18fattyacids. Therumenfermentationpatternwasinflu- encedbyallmixturesoflinoleicandlinolenic acids.Asexpected,reducedmethaneproduction wasaccompaniedbyincreasedpropionateandre- ducedacetateproduction,theformerproviding themainalternativesinkformetabolichydrogen duringrumenfermentation.Asimilarshiftinru. menvolatilefattyacidsconcentrationhasbeenre. portedc._引.Effectofunsaturatedfattyasidson ammonia.Nconcentrationwasinconsistent.Jalc Paf.[引foundthatammonia.Nconcentration wasincreasedsignificantlybyadditionof10% linolenicoil,butlittleaffectedbysunflowerand rapeseedoil.However,stearicacid,linoleicacid or9%linolenic,sunflowerandrapeseedhadno effectonammonia.Nconcentration[引.Thiswas inlinewiththepresentstudy. 4CONCLUSIoN Additionofmixturesoflinoleicandlinolenic acidsdecreasedmethanerelease,andtheeffect wasenhancedwithincreasingratiooflinolenic acid.Methanesuppressionwasaccompaniedbya shiftofthefermentationpatterntowardsen. hancedpropionateproduction.Itisinferredthat reductioninmethaneemissionisassociatedwith thedegreeofunsaturationofC18fattyacids. 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DohmeF,MachmullerA,WasserfallenlA,Kreuzer M.Ruminalmethanogenesisasinfluencedbyindivid— ualfattyacidssupplementedtOcompleteruminantdi— ets.LettersinAppliedMicrobiology,2001,32:47— 51. 添加不同比例的亚油酸和亚麻酸对体外瘤 胃发酵和甲烷生成的影响 张春梅易贤武苑志朋刘建新h朱伟云 (1.浙江大学动物科学学院动物分子营养学教育部重点实验室,杭州310029; 2.南京农业大学动物科技学院,南京210095) 摘要:利用人工瘤胃体外产气法研究添加亚油酸与亚麻酸不同比例混合物对瘤胃发酵和甲烷生成的影响.试验 共设8个处理,亚油酸与亚麻酸的比例为0:0,10:0,8:2,6:4,5:5,4:6,2:8和0:10,每个处理设3个重 复.亚油酸与亚麻酸混合物的添加水平为发酵底物干物质的5%,未添加脂肪酸组为对照.结果明,所有组合均 显着降低产气量和甲烷生成量(P<O.05),且随着亚麻酸比例的升高效果增强.亚麻酸比例超过40%时显着升高 发酵液的pH(P<O.05),所有处理对氨态氮和微生物蛋白均未产生影响;总挥发性脂肪酸随着亚麻酸比例的提高 而升高,亚麻酸单独添加显着高于亚油酸单独添加(P<O.05).随着亚麻酸比例的升高,丙酸比例显着提高.由 本研究结果可知,不饱和脂肪酸降低甲烷的生成与不饱和度密切相关.[动物营养,2008,20(2):223-227][中 文全文见《动物营养》网站(WWW.ChinaJAN.COI1])中文版2008年20卷02期] 关键词:甲烷;体外产气法;亚油酸;亚麻酸 *通讯作者;教授,E?mail:liujx@zju.edu.cn(编辑纪鹏)