The nutritive value of sun-dried and ensiled cassava leaves for growing pigs

摘要

AsurveyintheEasternregionofsouthVietnamshowedthatcassavagrowinghasincreasedinrecentyearsduetotheopportunitiesforsaleoftherootstofactoriesproducingstarch,sodiumglutamateandcassavarootmeal.Thevarietiesmostpopularwithfarmerswere:Gon,quot;Japanquot;,quot;Indiaquot;,KM60,KM94andKM95.Thecrudeproteinintheleavesrangedfrom23.9to34.7%andthefibrefrom9to14%(bothas%ofDM).TwodigestibilityandNbalancetrials,ofdoubleLatinsquaredesign,weredonewithgrowingpigstoevaluatelevelsofsubstitutionofsoyabeanmealbycassavaleaves(0,15,30and45%ofthedietprotein)indietsbasedoncassavarootmeal.Thetrialsweredoneinsuccessiveperiodsfirstwithensiledleaves(Meanpigliveweight40-50kg)andthenwithsun-driedleaves(50-70kgliveweight).Thereweresignificantdecreasesinapparentdietdigestibilityofallnutrients(from94.3to85.1fordrymatterandfrom88.2to65.7%forprotein)whencassavaleafproteinreplaced45%ofthatfromsoyabean.Thedeclineappearedtobelessmarkedfortheensiledcomparedwiththesun-driedleaves.Thelinearregressionbetweendrymatterdigestibilityandpercentcassavaleafproteinpredictedadigestibilityoftheleafdrymatterof76.5%forensilingand72.8forsun-drying.NitrogenretentionaspercentofNintakeandNdigestedshowedonlyaslightreductionuptothe30%levelofsoyaproteinsubstitutionbytheleaves,butdecreasedmarkedlyatthe45%level.Itwasalsoobservedthatthepigswerereluctanttoconsumethedietswithhighlevelofleaf.Therewerenoindicationsofcyanidetoxicityonanyofthediets.