Effects of nitrogen supplementation of acorns (Quercus coccifera) on in vitro fermentation, intake and digestion by lambs

摘要

TheeffectsofNitrogen(N)supplementationofkermesoakacornsoninvitrogasproduction(experiment1)andonintakeanddigestibilitybylambs(experiment2)whereinvestigated.Inexperiment1,sevensimulateddietscomposedofamixtureof200mgofoat-vetchhayand100mgofacornsasbasaldiet(controldiet:HA)wereevaluated.Dietsincludedthebasaldietaboveplusseverallevelsofurea(1%,2%and3%ofbasaldietOM,respectivelyHAU1,HAU2andHAU3)andamountsofgroundsoybeanmealtogiveequivalentamountsofNasthe3ureadiets(HASb1,HASb2andHASb3).Thekineticofinvitrogasproductionfromincubateddietswasdeterminedusingthecalibratedglasssyringetechnique.Inexperiment2,fourBarbarinelambs(agedabout6month,initialaverageBW26kg)wereusedin4x4LatinsquaresdesigntostudytheeffectofthetypeofNsupplementationonintakeanddigestionofdietscontainingacorns.Experimentaldietsprovidedoat-vetchhayadlibitumpluseitherprocessedbarley(HB)orshady-driedprocessedacorns(HA).TheHAdietwassupplementedwitheither10gofurea(HAU)orwithaniso-nitrogenousamountofsoybeanmeal(HASb).Everyexperimentalperiodcomprised21daysforadaptationand7daysformeasurements.Feedandwaterintakes,apparentdigestibilityofOM,CPandCFandNbalanceweredetermined.Thelevel3%ofurea(HAU3)resultedinhigher(P0.05)totalgasproductionthan1%urea(respectively65.7and63ml),butnodifferenceswereobservedamongsoybeandiets.Levelsofureadidnotaffectinvitrofermentation,butaddedsoybeanmealincreased(P0.01)gasproductionofacornsdietcomparativelytocontrolandureadiets.ProteinsourcesdidnotaffecttotaldietandhayDMintakeorOMandCFdigestibility.Theacornsdiet(HA)exhibitedalower(P0.01)Ndigestibility(32%)thanthethreeotherdiets,whichweresimilar(meanvalue54.7%).RetainedNwasnegativeinHA.ThehighestNretentionvalues(P0.01)werenotedwithHBandHASb,whichweresimilar(meanvalue1.7gday-1).