Part played by Ciliate Protozoa in Rumen Function

Abstract

IN general, the population of ciliate protozoa in the rumen is large with more than 10⁶ organisms/g of rumen contents and a mass approximately equal to that of the rumen bacteria¹. These protozoa are known to possess active systems for hydrolysing carbohydrates, proteins and lipids, but their effects on the efficiency of utilization of nutrients are not clear. In some experiments, removal of the fauna of the rumen has not influenced performance^2–4 while in others the patterns of rumen fermentation, growth rate and efficiency of food utilization were altered^5–7. Protozoa have been implicated as causal agents in bloat, and Clarke⁸ has shown that the introduction of an anti-protozoal agent to the rumen of cattle reduces the rate of rumen fermentation and the susceptibility to bloat.