Rumen bacteria

The rumen is the most extensively studied gut community and is characterized by its high population density, wide diversity and complexity of interactions. This complex, mixed microbial culture is comprised of prokaryote organisms including methaneproducing archaebacteria, eukaryote organisms, such as ciliate and flagellate protozoa, anaerobic phycomycete fungi and bacteriophage. Bacteria are predominant (up to 10¹¹ viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (10⁴-10⁶/g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 10 ²-10⁴/g distributed over 5 genera). The occurrence of bacteriophage is well documented (10⁷-10⁹ particles/g). This section focuses primarily on the widely used methods for the cultivation and the enumeration of rumen microbes, especially bacteria, which grow under anaerobic conditions. Methods that can be used to measure hydrolytic enzymes (cellulases, xylanases, amylases and proteinases) are also described, along with cell harvesting and fractionation procedures. Brief reference is also made to fungi and protozoa, but detailed explanations for culturing and enumerating these microbes is presented in Chapters 2.4 and 2.5.