不同精粗比日糧泌乳奶牛氮素代謝及限制性氨基酸的研究.pdf

1、中國農(nóng)業(yè)科學(xué)院博士學(xué)位論文不同精粗比日糧泌乳奶牛氮素代謝及限制性氨基酸的研究姓名：李樹聰申請學(xué)位級別：博士專業(yè)：動物營養(yǎng)與飼料科學(xué)指導(dǎo)教師：王加啟20050601AbstractFourCOWSfittedwithpermanentixlmencannulasandsimpleTtypeduodenalcannulaswerefirstusedtocomparetheeffectsofexternaldigestamarkers(CoE

2、DTA，YbCl3andCrmordantedstraw)andrecombinedmarkersystems0ntheflowofdigestaenteringtheduodenalcanaloflactatingdairyCOWSSamplesofdigestagotfromtheduodenalcanalwerepooledandseparatedusingfiltrationandhigh—speedcentrifugation

3、intotwoorthreefractionsdefinedastheliquidphaseandsolidphase(smallparticulateandlargeparticulate)Cowasprimarilyassociatedwiththeliquidphase；Ybwasconcentratedinsmallparticulatematter，whilstCrwasassociatedwithlargepaniclesT

4、heresultsshowedthatthesamplescollectedatduodenumWelenotrepresentativeof‘‘true“’digestaUseofsinglemarkersresultedinlargevarianceindrymatterflowestimationcomparedwiththecombinationoftwoorthreemaskersTheresultsshowedthatthe

5、combinationoftwoorthinemarkerscouldincreasetheaCcuracyofestimationoftheAIA(AcidInsolubleAsh)flowatduodenumThesecondpartwasmainlyconductedtostudytheeffectsoffourtypicaldietsonrunlennitrogenmetabolism，proteindigestionandab

6、sorptioni11thesmallintestine，anddairycow’smilkperformanceFourFumenduodenumandIleumearmulatedcowswereusedina4X4Latinsquareexperimentdesignwithdifferentforagetoconcentrateratios，Thegrowthofrtunenbacteriawasinhibitedduetoth

7、eshortageofthenitrogensupplyinthehighforagediet(70％Chinesewildryeand30％concentrate)TherewerenosignificantdifferencesoftheconversionofdietaryRDOM(RumenDigestibleOrganicMatzointomicrobialnitrogenamongthedietsTheefficiencyo

8、fmicrobialnitrogensynthesiswas29089&gRDOM111enonammonianitrogenflowatduodenumwasincreasedduetotheincrementofmicrobialnitrogennmratiosofmicrobialnitrogentothetotalnitrogenflowattheduodemtmrangedfrom528％to629％amongthefourd

9、ietsTherewasnosignificantdifferenceinthedigestibilityofthenonammonianitrogen(average6770191％)enteringintothesmallintestineTheconversionratesofdietarynitrogenintomill【nitrogenanddepositionnitrogeninthetissuewereincreasedw

10、ithhigherconcentrateAmongthetotalnitrogenintakeabout2561％and4856％nitrogenwereexcludedthrovIgllfecesandurinerespectivelyMilkproductionandproteincontentwereinerea∞dbyincmasnigthequalityoftheforageandtheleveloftheconcentrat

11、einthedietTherewasapositivecorrelationbetweenmilkproteincontentandthenonammoniaflowinthesmallintestineThe也irdpartwasconducetdtocomparetheeffectsoffourtypicaldietsonthesupplyoftheaminoacidsinsmallintestineandutilizationof

12、themForagetoconcentamteratiosdidnotaffecttheaminoacidprofilesofIumenbacteriaandmilkproteinThefollrdietsdidnotaffecttheaminoacidsdigestibility(rangedfrom4647％to8298％1insmallintestineexceptforArginineBasedonessentialaminoa

13、eidprofileofthemilkprotein，thesmallintestinalidealaminoacidmodelwasevaluatedinfonrdietsandtheresultsshowedthattheLysineandMethionineWerethemain1imitedaminoacidsBCAA(BranchChainAminoAcids】werenexttothemInthefoOFthpartfooF