Protease and deaminase activities and the metabolism of peptides were measured in rumen fluid from ciliate-free sheep and from sheep with a limited population of small entodinia. The same measurements were repeated following inoculation of the latter group with a more typical mixed ciliate population. Protease and dialanine uptake activities of mixed rumen micro-organisms were not significantly influenced by protozoa. Trialanine uptake, leucine aminopeptidase (EC 22.214.171.124), deaminase and trypsin-like protease activities were 70, 107, 73 and 91% higher with the limited population, and 72, 58, 64 and 55% higher when mixed protozoa were present, indicating a major role for the protozoa in these activities.
Wallace, R. J., Broderick, G. A., & Brammall, M. L. (1987). Microbial protein and peptide metabolism in rumen fluid from faunated and ciliate-free sheep. British Journal of Nutrition, 58(1), 87-93. https://doi.org/10.1079/BJN19870072