体外法评价玉米秸秆、谷草和玉米秸秆青贮饲料组合效应研究

本试验旨在利用体外产气法研究玉米秸秆(CS)、谷草(MS)与玉米秸秆青贮饲料(CSS)间的组合效应,筛选出不同饲料间的适宜组合比例。试验采用单因素试验设计,首先将玉米秸秆与谷草进行体外发酵试验,筛选出的最优组合,再与玉米秸秆青贮饲料组合进行试验,以上组合均以100∶0,80∶20,60∶40,50∶50,40∶60,20∶80,0∶100的比例进行,每个组合设3个重复,测定和分析不同粗饲料组合对体外产气量、干物质消失率、pH、微生物蛋白、氨态氮、挥发性脂肪酸的影响,计算出各组合的单项组合效应值和综合组合效应值。试验结果表明,不同饲料组合对产气量和干物质消失率影响显著或极显著(P<0.05或P<0.01);不同饲料组合间pH差异不显著(P>0.05);各饲料组合间微生物蛋白产量差异显著或极显著(P<0.05或P<0.01),玉米秸秆与谷草组合的微生物蛋白产量随玉米秸秆比例的减少而减少,再与玉米秸秆青贮饲料组合随玉米秸秆青贮饲料比例的增加而增加;不同饲料组合的氨态氮浓度差异显著或极显著(P<0.05或P<0.01),含量为17.35~24.63 mg/dL;各饲料组合间的挥发性脂肪酸产量差异显著或极显著(P<0.05或P<0.01)。以多项组合效应指数评定的最优组合为:玉米秸秆和谷草的搭配比例为60∶40,玉米秸秆、谷草、玉米秸秆青贮饲料的搭配比例为12∶8∶80。

Associative effects of cornstalk,millet straw,and corn stalk onsilage digestibility in vitro

We investigated the associative effects of cornstalk (CS),millet straw (MS),and corn stalk silage (CSS)on silage digestibility using aninvitrorumen fermentation system.A single factor experiment was de-signed with CS and MS to identify the best CS-MS combination,then CSS was added in combination with CS-MS.First,CS and MS were tested at ratios of 100:0,80:20,60:40,50:50,40:60,20:80 and 0:100, with three replicates.Gas production (GP),rate of dry matter loss (DML),pH,microbial crude protein (MCP),ammonia nitrogen (NH3-N),and volatile fatty acids (VFA)were measured for all the CS-MS combi-nations,and the single factor associative effects index and multiple factors associative effects index of different combinations were calculated.The results showed that GP and DML differed among the various combinations significantly (P<0.05)or extremely significantly (P<0.01).However,pH did not differ among the various combinations (P>0.05 ).The MCP yield differed significantly (P<0.05 )or extremely significantly (P<0.01)among the different CS-MS combinations.The MCP yields of CS-MS combinations decreased with de-creasing proportions of CS,while the MCP yields of the CS-MS-CSS (CS:MS= 60:40 )combinations in-creased with increasing proportions of CSS.There were significant (P<0.05)or extremely significant (P<0.01)differences in NH3-N concentrations among the various combinations,ranging from 17.35 mg/dL to 24.63 mg/dL.There were significant (P<0.05)or extremely significant differences (P<0.01)of VFA yield among the various combinations.In conclusion,the CS-MS ratio of 60:40 and the CS-MS-CSS combination at the ratio of 12:8:80 produced the largest associative effects in this study.