中文摘要：

选取4只1.5～2.0岁龄、体重约40 kg,安装了永久性瘤胃瘘管的健康小尾寒羊公羊,采用4×4拉丁方设计,在精粗比为50∶50的日粮条件下,研究添喂甲硝唑对绵羊瘤胃微生物区系和消化代谢的影响。结果表明,在日粮中添喂0.00,0.05,0.10,0.20 g/kg甲硝唑时,3组试验组的绵羊瘤胃液原虫总数分别比对照组减少了30.3%（P〈0.01）,50.0%（P〈0.01）,59.6%（P〈0.01）;细菌总数分别比对照组增加了45.7%（P〈0.01）,55.4%（P〈0.01）,65.8%（P〈0.01）;瘤胃真菌DNA拷贝数分别比对照组增加了27.6%（P〈0.05）,34.0%（P〈0.05）,36.0%（P〈0.05）;瘤胃液氨态氮浓度分别比对照组降低了6.8%（P〈0.01）,16.5%（P〈0.01）,18.6%（P〈0.01）;总挥发性脂肪酸、乙酸、丙酸和丁酸均有增加趋势。日粮中添加甲硝唑0.05,0.10,0.20 g/kg组干物质采食量与对照组比分别增加了6.6%（P〈0.01）,12.2%（P〈0.01）,7.8%（P〈0.01）;干物质消化量分别增加了7.8%,17.7%,2.7%;有机物消化量分别增加了7.6%（P〈0.05）,17.4%（P〈0.01）,3.5%（P〉0.05）;粗蛋白消化量分别增加了13.4%（P〈0.01）,25.3%（P〈0.01）,11.2%（P〈0.01）;氮保留量比对照分别增加了13.1%（P〈0.05）,21.0%（P〈0.01）,10.9%（P〈0.05）。给绵羊添喂一定剂量的甲硝唑,可增加绵羊的自由采食量,其日粮的消化率呈增加趋势,并可使瘤胃液原虫数量减少,细菌总数和真菌数增加,氨态氮浓度降低,增加绵羊的氮保留。

英文摘要：

This experiment was performed to select four healthy,weighing about 40 kg,1.5~2.0 years old Han sheep installed with a permenent rumen,using 4×4 Latin square to study the effects of metronidazole on ruminal microflora and metabolism of sheep with the diet of ratio of forage to concentrate of 50∶50.The results indicated that when the sheep diet were adding metronidazole with 0.00,0.05,0.10 and 0.20 g/kg,under the condition of the ratio of concentrate to roughage（50∶50） the results showed that the total number of protozoa was reduced by 30.3%（P0.01）,50.0%（P0.01）and 59.6%（P0.01）compared with control group respectively,the total number of bacteria was increased by 45.7%（P0.01）,55.4%（P0.01）and 65.8%（P0.01） respectively,the total number of rumen fungi DNA copies was increased by 27.6%（P0.05）,34.0%（P0.05）and 36.0%（P0.05） respectively,the con-centration of rumen NH3-N was reduced by 6.8%（P0.01）,16.5%（P0.01）and 18.6%（P0.01）respectively compared with control group; the total VFA,the acetic acid,the propionic acid and the butyric acid had the tendency of increase.The intake of DM were increased by 6.6%（P0.01）,12.2%（P0.01）and 7.8%（P0.01）respectively by oral supplement of metronidazole with 0.05,0.10 and 0.20 g/kg diet,compared with control group.The digestibility of dry matter was increased by 7.8%,17.7% and 2.7% respectively,the digestibility of organic matter were increased by 7.6%（P0.05）,17.4%（P0.01） and 3.5%（P0.05） respectively,the digestibility of crude protein increased by 13.4%（P0.01）,25.3%（P0.01）and 11.2%（P0.01） respectively,and the nitrogen retentions were increased by 13.1%（P0.05）,21.0%（P0.01）and 10.9%（P0.05）respectively.It is concluded that the oral supplement of certain dosages of metronidazole could increase the voluntary intake,the digestibility of diet had the tendency of increase,decrease the rumen protozoa,increase the rumen bacteria and fungi,decease the concentration of rumen NH3-N,increase nitrogen ret