Effect of freeze drying on in vitro ruminal fermentation dynamics of three tropical shrub legumes with and without condensed tannins

摘要

Extensivecomparisonsoftheeffectsoftropicalshrublegumesrichincondensedtannins(CT)requirewell-conservedmaterial.Itis,however,uncleariftheapplicationofevengentlemethodslikefreezedrying(lyophilization)affectstheresultsincomparisontofreshmaterial.Therefore,anexperimentwiththegas-pressuretransducertechnique,simulatingruminalfermentationdynamicsinvitro,wasconductedtoinvestigatetheeffectoffreezedryingontheruminalnutrientdegradabilityofthreetropicalmultipurposeshrublegumes.LeavesoftheCTshrubsCalliandracalothyrsusandFlemingiamacrophyllaandoftheCT-freeshrubCratyliaargenteaweretestedeitherinfreshformorlyophilized.Inordertosimulatepracticalfeedingconditions,thelegumeleaveswereincubatedtogetherwithBrachiariahumidicola(1:2)for144nbsp;h.Additionally,incubationswerecarriedouteitherwithorwithoutpolyethyleneglycol(PEG)tobeabletoseparateeffectseitherdependentorindependentoftheCT.nbsp;Onlyfewdifferenceswerefoundbetweenfreshandlyophilizedleaves.TheseincludedthattheproportionofapparentlyundegradednitrogenouscompoundswashigherinfreshthaninlyophilizedleavesofFlemingiamacrophylla,andfreezedryinghadalimitedinfluenceonvolatilefattyacidproductioninCalliandracalothyrsus.Thevariablesrelatedtodegradationdynamics(i.e.,totalgasproduction,thetimeuntilthepointofinflection,apparentdrymatterdegradability),however,werenotinfluenced.TherewasalsonodifferencebetweenCTandnon-CTplantsinthatrespect,asisalsoobviousfromthelackofinteractionsofstateoftheplantmaterialandPEGaddition.nbsp;Thisindicatesthateffectsoffreezedryingofshrubleavesonoverallruminalnutrientdegradationinmixedgrass-legumedietswereminor.