不同有机物进食量和外流速度对瘤胃发酵及微生物蛋白合成效率的影响

Effects of different organic matter intake levels and dilution rates on microbial protein production and its efficiency in rumen fermentation

采用 2× 2随机因子试验设计研究持续动态瘤胃模拟装置 (RSI -Ⅱ )不同有机物进食量(OMI) (2 7 6 7g、36 74g、4 6 0 0g)和瘤胃外流速度 (0 0 2 /h、0 0 35/h、0 0 5/h)对稻草 -玉米 -豆粕型日粮瘤胃发酵及微生物蛋白合成效率的影响。结果表明 ,RSI内pH值不受有机物进食量和外流速度的影响 ;在低外流速度下各OMI组瘤胃内 0～ 72h干物质、有机物、粗蛋白、NDF、ADF降解率均高于高外流速度 (P <0 0 5)。随着OMI的增加 ,同一外流速度下日粮可发酵有机物产生VFA量(TVFA/FOM ,mmol/g)逐渐下降 (P <0 0 5) ;相同OMI组饲料降解氮转化为微生物氮的效率在外流速度为 0 0 2 /h时显著高于高外流速度 (P <0 0 5)。

A 2×2 factorial design was arranged in the Rumen Simulation Instrument(RSI)to study effects of three levels of organic matter intakes(OMI)(27 67 g,36 74 g 46 00 g)and three Dilution rates(D)(0 02/h,0 035/h,0 05/h)on microbial protein production(MCP)and Its efficiency of Rice straw-Corn-Soybean meal Rumen Fermentation.Results indicate that digestibilities of DM,OM,CP,NDF,and ADF are significantly decreased as D and OMI increase( P <0 05);The production of VfA and MCP increase with increase of OMI at same D,but VFA production,expressed as TVFA/FOM(mmol/g)tend to decrease( P <0 05);MCP efficiency expressed as MN/FOM,MN/RDN also tend to decrease with increase of OMI at same D,which illustrate that microbial growth efficiency in rumen bepend on both FOM and RDN,and are affected by OMI levels and Dilution rate.