紫花苜蓿与披碱草混合青贮对体外瘤胃发酵特征的影响OA北大核心CSTPCD

In order to explore the influence of the mixed silage effect of different proportions of Medi-cago sativa and Elymus dahuricus on artificial in vitro rumen fermentation parameters,the in vitro ru-men fermentation method was used on mix silage of Medicago sativa and Elymus dahuricus in different proportions,with alfalfa silage as the control,to study in vitro gas production(GP),methane production(CH4),ammonia nitrogen(NH3-N),in vitro dry matter degradation rate(IVDMD),pH,volatile fatty acid(TVFA)and other in vitro digestion parameters of silage within 6 h～24 h,then multiple index com-prehensive index(MFAEI)was comprehensively evaluated in each test group.The results showed that the GP,CH4,NH3-N,and IVDMD of each group increased with time.The pH value was between 6.24 and 6.77 and there was no significant difference(P＞0.05).The GP,CH4,IVDMD,AA,TVFA and acetic acid/propionic acid(AA/PA)in mixed silage group showed a trend of A2＞A3＞A4 in each period,which were all significantly higher than group A1(P＜0.05).The concentration of NH3-N showed a trend of A4＞A3＞A2 with fermentation time and was significantly higher than that of A1(P＜0.05).When Medicago sativa was made silage(group A1),AA/PA＜3,which illustrated the fermentation in the rumen was pro-pionic acid fermentation.As the content of Elymus dahuricus in mixed silage increased,the AA/PA value increased significantly in each period(P＜0.05).In group A2,the AA/PA＞3 within 6 h～24 h,showing the type of fermentation in the rumen had evolved from propionic acid fermentation to acetic acid fermenta-tion.According to the indexes of rumen fermentation and the comprehensive index of multiple indexes,group A2 got the highest mark,indicating that the mixed silage of 30％Medicago sativa+70％Elymus dahuricus has the best in vitro digestive effect.