Some factors influencing the chemical composition of mixed rumen bacteria
Some factors influencing the chemical composition of mixed rumen bacteria
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影响混合瘤胃细菌化学成分的一些因素
DOI：
10.1079/bjn19740005
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发表时间：
1974
影响因子：
3.6
通讯作者：
A. Mcallan
中科院分区：
文献类型：
--
作者：
R. H. Smith;A. Mcallan
1. 装有瘤胃插管的绵羊、奶牛和小牛的日粮主要含 10-16 克氮/千克干物质，并由粗饲料和谷物组成。从瘤胃内容物样品中分离出混合细菌。 2. 与成年羊接触饲养的小牛（环境 C）但以相同方式处理的类似细菌相比，在不与成年动物接触的实验牛舍（环境 A）中饲养的小牛饲料后 4-6 小时采集的细菌含有更多 α-葡聚糖、更少的总氮和更高的核酸：总氮比。 3. 喂食后 4-6 小时从绵羊和牛身上采集的混合细菌在含氮成分方面与来自“环境 C”小牛的细菌相似。当饮食中含有不同比例的粗饲料时，这种成分没有显着变化。 4.“环境A”的小牛没有纤毛虫原生动物。当它们与成年牛（环境 B）的瘤胃内容物接触并接种时，它们迅速形成正常的原虫种群，并且它们的瘤胃细菌的化学成分变得与来自“环境 C”小牛的细菌相似。 5. 与饲喂后 4-6 小时采集的细菌相比，在饲喂前采集的混合细菌（无论是奶牛还是“环境 A”小牛）的 RNA-N：总 N 比率显着较低，而 DNA-N：总 N 比率略高（但通常不显着）。喂食后细菌的总氮含量随时间变化并不一致。 6. 讨论了这些差异对于宿主动物营养的可能意义。
1. Sheep, cows and calves fitted with rumen cannulas were given diets mostly containing 10–16 g nitrogen/kg dry matter and consisting of roughage and cereals. Mixed bacteria were separated from samples of their rumen contents. 2. Bacteria taken 4–6 h after a feed from calves which were kept in an experimental calf-house with no contact with adult animals (environment A) contained more α-dextran, less total N and higher nucleic acid:total N ratios than similar bacteria from calves reared in contact with adult sheep (environment C) but otherwise treated in an identical way. 3. Mixed bacteria taken 4–6 h after a feed from sheep and cows were similar in composition, with respect to nitrogenous components, to those from the ‘environment C’ calves. This composition did not vary significantly when diets containing differing proportions of roughage were given. 4. The ‘environment A’ calves were free of ciliate protozoa. When they were placed in contact with, and were inoculated with rumen contents from, adult cattle (environment B), they rapidly developed a normal protozoal population and the chemical composition of their rumen bacteria became like that of the bacteria from the ‘environment C’ calves. 5. Mixed bacteria taken just before a feed, from either cows or ‘environment A’ calves, showed significantly lower RNA-N:total N ratios and slightly (but not usually significantly) higher DNA-N:total N ratios than bacteria taken 4–6 h after feeding. Total N contents of the bacteria did not change consistently with time after feeding. 6. The possible significance of these differences in relation to the nutrition of the host animal is discussed.