In vitro and in sacco ruminal protein degradability of common Indian feed ingredients

摘要

ProteindegradabilitybyinsaccomethodandproteinfractionationbylaboratoryanalysisusingCNCP(CornellNetCarbohydrateandProtein)systemwasdeterminedtodevelopapredictionequationforpredictingdegradabilityfromdifferentproteinfractions.nbsp;Sixteendifferenttypesoffeedsnamely,maizegrain(MZ),maizeglutenmeal(MGM),maizefibre(MF),maizeoilcake(MOC),wheat(WT),wheatbran(WB),barley(BRL),soybeanmeal(SBM),sunflowermeal(SFM),deoiledcoconutcake(DCC),cottonseedcake(CSC),groundnutcake(GNC),mustardcake(MC),fishmeal(FM),guarchuni(GC)andsubabulleaves(LLM)wereanalysedfor(A+B1),B2,B3andC.Theabovefeedswerealsoincubatedintherumenofthreefistulated,adultcrossbredcattletoestimatetheeffectiveproteindegradability(EPD)ofindividualfeeds.AlinearregressionequationwasdrawnforEPDfromdifferentproteinfractions.nbsp;HigherA+B1fractionwasobservedinMC,GNCandBRL,whereaslowervalueswerenotedinMGM,MFandMZ.B2fractionwashighestinMFfollowedbyMZandLLMandlowervalueswerefoundinGNC,MCandSBM.B3fractionwasgreaterinMGM,FMandCSC,whereasthelowervalueswerenotedinMC,LLMandMF.LigninboundnitrogenorCfractionwasgreaterinMGM,GCandLLMandwithlowervaluesinBRL,WT,WB,MFandMZ.HigherEPDwasfoundinMC,GNCfollowedbyBRL,MOCandWB,whereaslowervalueswereobtainedinMGM,MF,LLMandCSC.nbsp;ECPDatdifferentoutflowrateswerehighlyandpositivelycorrelated(r=0.84to0.88)with(A+B1)fraction,whereaswithB2,B3andCitwasnegativelyassociated(r=0.55to0.62,0.29to0.32and0.50to0.52forB2,B3andC,respectively).nbsp;Significantpredictedvariablesinstepwiseregressionincluded(A+B1),(A+B1)2andB32atfractionaloutflowrateof0.02h-1withR2valueof0.90.However,thepredictedequationsatfractionaloutflowrateof0.04and0.06h-1contained(A+B1),(A+B1)2,B3,B32andC2predictivevariableswithhighdegreeofprediction(R2=0.93).B3alonewasweakpredictorforUDPcontentoffeeds.nbsp;Therefore,toavoidthemaintenanceoffistulatedanimalsandtosavetimeforinsaccoexperiment,laboratoryanalysisofproteinfractionsandfittingthemintheregressionequationmaypredicttheEPDvalueseffectively.nbsp;nbsp;