Effects of inclusion of purple prairie clover (Dalea purpurea Vent.)with native coolseason grasses on in vitro fermentation and in situ digestibility of mixed forages  

作　　者：Kai Peng Gemma L.Gresham Tim A.McAllister Zhongjun Xu Alan Iwaasa Mike Schellenberg Alex V.Chaves Yuxi Wang 

机构地区：[1]Key Laboratory of Animal Nutrition and Feed Science(South China)of Ministry of Agriculture,Guangdong Key Laboratory of Animal Breeding and Nutrition,Institute of Animal Science,Guangdong Academy of Agricultural Science,Guangzhou 510640,People’s Republic of China [2]Agriculture and Agri-Food Canada,Lethbridge Research and Development Centre,Lethbridge,AB T1J 4B1,Canada [3]School of Life and Environmental Sciences,The University of Sydney,Sydney,NSW 2006,Australia [4]Agriculture and Agri-Food Canada,Swift Current Research and Development Centre,Swift Current,SK S9H 3X2,Canada

出　　处：《Journal of Animal Science and Biotechnology》2020年第2期563-576,共14页畜牧与生物技术杂志（英文版）

基　　金：This study was funded from AAFC/Canadian Beef Cattle Industry Science Cluster;Alberta Livestock and Meat Agency.This is Lethbridge Research and Development Centre contribution number 38717038.

摘　　要：Background:Incorporation of legume species into native North American pastures is considered an effective method to increase native pasture productivity and improve the nutritive value of forage.This study evaluated the effects of inclusion of purple prairie clover(PPC,Dalea purpurea Vent.),a native legume forage,with native coolseason grasses on the in vitro fermentation and in situ digestibility of mixed forages.Methods:Whole plant PPC and mixtures of cool-season grasses were harvested when the PPC reached the vegetative(VEG),full flower(FL)and seedpod(SP)stages,and were combined in ratios(DM basis)of 0:100,25:75,50:50,75:25 and 100:0 at each maturity.In vitro ruminal incubations using these mixtures were conducted for 48 h to determine gas production(GP),in vitro DM disappearance(IVDMD),total volatile fatty acids(VFA)and ammonia-N production.Mixtures of forages harvested when the PPC reached the FL stage and 50:50 mixture of forages harvested at VEG,FL and SP stages were incubated in the rumen of three heifers for 0,2,6,12,24,48,72 and 96 h to determine in situ degradabilities of DM,neutral detergent fibre(aNDF)and crude protein(CP).Results:Contents of aNDF and ADF increased(P<0.01),while CP decreased(P<0.001)as PPC matured.Concentrations of extractable condensed tannins in PPC ranked as FL>VEG>SP(P<0.05).Regardless of PPC proportions in the mixture,GP decreased(P<0.05)with increasing PPC maturity.Increasing PPC proportions linearly increased(P<0.001)GP,IVDMD and total VFA at VEG,but linearly decreased(P<0.001)them at SP.Irrespective of PPC maturity,ammonia-N production linearly increased(P<0.01)with increasing proportions of PPC and the concentration was higher(P<0.05)at VEG than at FL and SP stages.Increasing proportion of PPC at either maturity linearly increased(P<0.001)molar percentage of acetate(A)and branched-chain VFA,but linearly decreased(P<0.001)molar percentage of propionate(P),resulting in a linearly increase(P<0.001)in the A:P ratio.Increasing FL PPC in the mixture linearly and quadratically(P<0.

关 键 词：Condensed tannins Cool-season grass In vitro fermentation In situ digestibility Purple prairie clover 

分 类 号：S816[农业科学—饲料科学]