Energy Nutrition of Rumen Micro-Organisms

  • M. Ryle
  • E. R. Ørskov


The rumen has often been compared to a fermentation vat. However, although its temperature and anaerobic state are stable and its pH fluctuations are limited, nothing else is reminiscent of industrial conditions. Both the chemical composition and the physical structure of the ingested substrates can vary widely and rapidly. Instead of one or two types of micro-organism providing the enzymes for fermentation, there may be significant numbers of many species belonging to each of three main groups — bacteria, fungi and protozoa. The relative numbers of the different species vary with the composition and structure of the feed and their mutual interactions are highly complex. Yet although the proportions of the different end-products also vary, they nevertheless normally consist principally of carbon dioxide, methane and the three volatile fatty acids (VFAs) acetic acid, propionic acid and butyric acid, together with ammonia, traces of some other VFAs and sometimes lactic acid.


Volatile Fatty Acid Soluble Carbohydrate Rumen Fluid Cellulolytic Bacterium Ciliate Protozoan 
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Copyright information

© Elsevier Science Publishers Ltd 1990

Authors and Affiliations

  • M. Ryle
    • 1
  • E. R. Ørskov
    • 2
  1. 1.Stocksbridge, SheffieldUK
  2. 2.Applied Research DepartmentThe Rowett Research InstituteUK

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