Condensed tannins in temperate forage species: effects on the productivity of ruminants infected with internal parasites (a review)

摘要

Condensedtannins(CT)arecomplexsubstances(plantpolyphenols)whichcombinewithproteinsandotherpolymerstoformstablecomplexesaccordingtoconcentration,structureandmolecularweight.CTsaresecondarycompoundsthatoccurintemperateforageplants.ConcentrationsofCTrangefrom0,01to10%ofdrymatter(DM).Dietswithtanninconcentrationsof2to4%ofDMenhancenutritivevalue,productiveandsanitaryperformanceofgrazinganimals,forexamplecultivarsofLotuspedunculatusandLotuscorniculatusgaveimproveddailyliveweightgainandsanitaryaspects,itispossiblethatCTconcentrationsimprovedtheefficiencyofnitrogendigestion.Cold-solubleQuebrachoextracthasbeenusedasthesourceofcondensedtanninstoreducethelevelofparasitismandimprovetheperformanceofanimalsinfectedwithinternalparasites.Thepossibilityexiststhatinspecieslikesulla(Hedysariumcoronarium)therearedirecteffectsofTC.Itwillbenecessarytoinvestigatetheanthelminticpropertiesofforagespecieswithadequatetanninlevelsforreducingbothparasitismlossesaswellastheuseofchemicalanthelmintics.