Index >> Population Interactions >> Interaction between Microbes and the Rumen

These bacterial populations produce acetate, the predominant acid within the rumen. The bacteria also produce propionate, the only fermentation acid that can be converted into carbohydrates by the ruminant. Some nitrogen fixation activity also takes place in the rumen.

The next abundant population of microflora is the protozoans. Most are ciliates, but some flagellates such as Diplodinium, Sarcodina, etc. are also present. They digest cellulose and starch, some ferment dissolved carbohydrates. Some are predators on bacterial populations. The proteins of the protozoan are in turn digested by the ruminant's enzymes. The rumen protozoa store large amounts of carbohydrates which the ruminants digests along with the proteins of the protozoan biomass. The protozoans are digested readily than the bacteria because the latter have resistant cell walls and high nucleic acid contents.

The high diversity of microbial population in the rumen depends on the diet of the ruminant. When there is a sudden change in the diet, there is an upset of the rumen fermentation system resulting in excessive production of methane that can distend the rumen, sometimes to the extent that it compresses the lungs thus suffocating the animal. The fungal population is comparatively low and only some genera of yeasts are present. The food consumed by the ruminant goes to the rumen where there is great microbial diversity and this diversity helps in the digestion of the food consumed. The rumen microbes digest the food for the ruminant and in turn the ruminant provides shelter and food to the microbes.