This study was conducted to investigate the effects of forage sources in diet on the diversity of bacte-rial communities in rumen fluid of dairy cows. Eight Holstein dairy cows [ ( 632 ± 12 ) kg of body weight;(135±16) days in milk] were used in a replicated 4×4 Latin square design, and each group contained two cows. Oat hay, Leymus chinensis, rice straw and alfalfa were used as forage sources to form four isonitroge-nous and isocaloric diets, which were based on corn silage and had equivalent neutral detergernt fiber ( NDF) and non-fiber carbohydrates ( NFC) contents; each test period lasted for 21 days with the first 14 days for a-daption. The results showed as follows: 1 ) Bacteroidertes, Firmicutes, Spirochaetes and Fibrobacteres were the most abundant in rumen under phyla level; Prevotella, Butyrivibrio, Fibrobacter and Treponema were the most abundant under genus level. 2) Similarity of the bacterial community feeding the same diet was high un-der genus level, and the genetic distance was near in rumen fluid of cows fed oat hay, rice straw and alfalfa. 3) The four groups comprised of 9 329 operational taxonomic units ( OTUs) at the 97% similarity level and 4 120 OTUs were shared, which accounted for 44.16% of the total OTUs. The results indicate that cows fed di-ets with different forage sources with equivalent NDF and NFC contents have similar diversity of bacterial com-munities.%本试验旨在研究不同牧草来源饲粮对奶牛瘤胃细菌群落结构多样性的影响. 选用8头荷斯坦奶牛[体重(632±12) kg;泌乳天数(135±16) d],采用4×4拉丁方设计,每组2头. 分别以燕麦草、羊草、稻草和苜蓿为牧草来源,给奶牛饲喂以玉米青贮为基础、等能等氮且中性洗涤纤维( NDF)和非纤维型碳水化物( NFC)含量相同的4种饲粮;每期试验21 d,前14 d为预试期. 结果表明:1)瘤胃中拟杆菌门、硬壁菌门、螺旋体门和纤维杆菌门为优势菌门;普雷沃氏菌属、丁酸弧菌属、纤维杆菌属和密螺旋体属为优势菌属. 2)在属水平上,相同牧草饲喂的奶牛瘤胃液中细菌相似性更高,燕麦草组、稻草组和苜蓿组细菌的遗传距离更接近. 3)在97%相似性水平下,4组共产生9 329 个操作分类单元( OTU) ,它们共享4 120 个 OTU,占瘤胃液细菌总OTU数目的44.16%. 综合得出,当饲粮等能等氮且NDF和NFC含量相同时,不同牧草饲喂的奶牛瘤胃液中的细菌群落结构多样性存在一定的相似性.
展开▼
