Hristov A N, Ivan M, Rode L M, McAllister T A
Department of Animal and Veterinary Science, University of Idaho, Moscow 83844-2330, USA.
J Anim Sci. 2001 Feb;79(2):515-24. doi: 10.2527/2001.792515x.
Fermentation characteristics were measured and numbers and distribution by genera of ciliate protozoa were determined in ruminal fluid samples collected from 10 ruminally cannulated steers during the first 30 d of their being fed barley-based diets containing 62% (Medium Barley) or 95% (High Barley) barley grain (DM basis). Ruminal samples were collected at 5-d intervals over the 30-d periods beginning after adaptation (i.e., at the first full feeding of each diet). Ruminal pH and ammonia concentrations were lower (P < 0.001) with the High Barley than with the Medium Barley diet. Concentrations of total VFA and propionate and amylase activity of ruminal fluid were higher (P < 0.001) on High Barley than on Medium Barley. Total protozoal numbers in ruminal fluid were 42% lower (P < 0.05) on High Barley (470 x 10(3)/mL) than on Medium Barley (804 x 10(3)/mL). On Medium and High Barley diets, respectively, Entodinium spp. made up 89 and 91% of the ciliate protozoal populations. With the Medium Barley diet, relative proportions of Dasytricha, Ophryoscolex, Ostracodinium, Diplodinium, and Metadinium spp. in the total ciliate population were 4.5, 0.4, 0.5, 0.7, and 0.3%, respectively. When the High Barley diet was fed, these genera were not detected. In a subsequent survey, ruminal samples were collected from 200 finishing cattle at slaughter. Average protozoal population was 328 x 10(3)/mL, and Entodinium spp. constituted 97% of the total. These data demonstrate that a large population of Entodinium spp. can persist in the rumen of cattle fed high barley grain-based finishing diets.
在最初30天内，从10头安装了瘤胃瘘管的肉牛采集瘤胃液样本，测定其发酵特性，并确定纤毛虫原生动物的属别数量及分布情况。这些肉牛被饲喂以大麦为基础的日粮，其中大麦谷物含量分别为62%（中等大麦组）或95%（高等大麦组）（以干物质计）。在适应期（即每种日粮首次全量饲喂）后的30天内，每隔5天采集一次瘤胃样本。与中等大麦日粮相比，高等大麦日粮的瘤胃pH值和氨浓度更低（P < 0.001）。高等大麦日粮组的瘤胃液总挥发性脂肪酸（VFA）、丙酸浓度及淀粉酶活性均高于中等大麦日粮组（P < 0.001）。高等大麦日粮组瘤胃液中的原生动物总数（470×10³/mL）比中等大麦日粮组（804×10³/mL）低42%（P < 0.05）。在中等大麦和高等大麦日粮组中，内毛虫属分别占纤毛虫原生动物种群的89%和91%。对于中等大麦日粮，多泡虫属、蛇形毛滴虫属、有壳双毛虫属、双腰滴虫属和后双腰滴虫属在纤毛虫总种群中的相对比例分别为4.5%、0.4%、0.5%、0.7%和0.3%。饲喂高等大麦日粮时，未检测到这些属。在随后的一项调查中，从200头育肥牛屠宰时采集瘤胃样本。原生动物平均种群数量为328×10³/mL，内毛虫属占总数的97%。这些数据表明，大量的内毛虫属可在饲喂高大麦谷物育肥日粮的肉牛瘤胃中持续存在。
