Effect of supplementation with a tree legume forage on rumen function

摘要

Multi-purposetrees,ascomponentsofproductionsystemsinthetropics,playanimportantroleinsoilconservationandprovisionofshade,aswellasbeinganimportantalternativeasasourceofprotein-richforagesource.Theyarealsomoredrought-resistantthangrasses.Thepresentexperimentaimedatevaluatingtheeffectonrumenfunctionofsupplementingsheepwiththreelevels(0,100and300g/d)ofdryleavesofatreelegume(Enterolobiumciclocarpum),whichisnaturallyconsumedbyruminantswhenbranchesareaccessibletothem.Themainresultsoftheexperimentwerethefollowing:ItappearsthatdietaryandmaybebacterialaminoacidabsorptionatthesmallintestinewasincreasedbysupplementationwithleavesofE.ciclocarpum,asindicatedbythepositivecorrelationbetweenwoolgrowthrateandintakeofE.ciclocarpum.Supplementationwithlowlevels(100g/d;approximately10%oftotaldrymatterintake)ofE.ciclocarpum,increasedvoluntaryfeedintake,digestiblematterintakeandnitrogenbalancebyincreasingnitrogendigestibility.However,thehighlevelofsupplementation(300g/d;approximately34%DMI)reduceddigestibledrymatterintake,which,couldbeanimportantlimitationtoitsinclusioninthedietathighlevels.ThepopulationofrumenfungiwasincreasedbysupplementationwithlowandhighlevelsofleavesofEnterolobiumciclocarpum.Rumenciliateprotozoawereincreasedbytheinclusionoflowlevelsinthediet(10%ofDMI),butstronglydecreasedinsheepreceivinghighlevelsofsupplementation(34%ofDM).Rumenbacteriashowednoresponsetosupplementation.ThepresenceofsaponinsinleavesofEnterolobiumciclocarpummayhavecontributedtothereductioninprotozoanumbersintherumenfluid,particularlyHolotrichprotozoa.