Characteristics of the gastrointestinal microbial communities, with special reference to the chicken
Characteristics of the gastrointestinal microbial communities, with special reference to the chicken
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DOI：
10.1079/wps20040017
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发表时间：
2004-06-01
影响因子：
2.7
通讯作者：
Graham, H
中科院分区：
文献类型：
--
作者：
Apajalahti, J;Kettunen, A;Graham, H
自然界中的细菌表现为不同的群落，可能由数百个不同的物种组成。细菌群落在任何可以想象到的条件下的共同适应能力是非凡的。许多细菌有尚未发现的生长要求，这是通过它们的自然栖息地来满足的。事实上，细菌群落有专门从事不同功能的成员，并为生活在同一群落中的其他细菌提供至关重要的元素。因此，大多数细菌不能很容易地通过目前大多数实验室使用的常规培养方法从它们的栖息地分离出来。为了克服培养单个微生物的困难，现代方法通过确定从群落样本中提取的微生物DNA的特征来分析细菌群落的结构。使用这种技术，我们发现90%(如果鸡胃肠道中的细菌代表以前未知的物种)。此外，在发现的640个不同物种中，超过一半代表了以前未知的细菌属。胃肠道中的细菌的大部分碳和能量来自饮食化合物，这些化合物要么能抵抗消化液的攻击，要么被宿主吸收得如此缓慢，以至于细菌可以成功地竞争它们。使用促生长饲料抗生素的性能改善是由于减少了对小肠营养的竞争，由于控制了病原体而减少了局部炎症，以及缩小了肠道大小。由于细菌物种对底物的偏好和生长要求不同，消化液的化学成分和结构在很大程度上决定了胃肠道细菌群落的物种分布。因此，通过改变饮食，将微生物群落从有害细菌转变为无害细菌应该是可能的。
Bacteria in nature appear as diverse communities, which may comprise of hundreds of different species. The shared capacity of the bacterial communities to adapt in any imaginable set of conditions is remarkable. Many bacteria have growth requirements, as yet undiscovered, which are fulfilled by their natural habitats. Indeed, bacterial communities have members specialized on different functions and providing vital elements to other bacteria living in the same community. Therefore, most bacteria cannot easily be isolated from their habitats by the routine culturing methods used in most laboratories today. To overcome the difficulties in culturing of individual microbes, modern approaches analyse the structure of bacterial communities by determining the characteristic features of the microbial DNA extracted from the community samples. Using such techniques we have found that 90% (if the bacteria in the chicken gastrointestinal tract represent previously unknown species. Furthermore, more than half of the 640 different species found represent previously unknown bacterial genera. Bacteria in the gastrointestinal tract derive most of their carbon and energy from dietary compounds which are either resistant to attack by digestive fluids or absorbed so slowly by the host that bacteria can successfully compete for them. The performance improvements on use of a growth promoting feed antibiotic is due to factors such as reduced competition for nutrients in the small intestine, reduced local inflammation due to control of pathogens, and reduced size of intestine. Since bacterial species differ in their substrate preferences and growth requirements, the chemical composition and structure of the digesta largely determines the species distribution of the bacterial community in the gastrointestinal tract. Consequently, it should be possible to shift the microbial community from harmful to non-harmful bacteria by changing the diet.