A Simple and Safe Procedure for the Removal of Holotrich Ciliates from the Rumen of an Adult Fistulated Sheep

Abstract

DURING recent years, increasing attention has been paid to the role of the rumen ciliate protozoa in ruminant nutrition, particularly with regard to the fermentative activity of the holotrich protozoa which contribute to the production of lactic and volatile fatty acids^1,2. It has, however, become evident that further progress in this direction cannot be made until the contribution of each component species of the rumen microfauna can be studied separately both in vitro and in vivo. Attempts to cultivate the rumen ciliates in vitro have hitherto not met with outstanding success. Gutierrez³ managed to separate the two holotrich genera in vitro but only to give a limited yield. The differences in fermentation reactions in vitro found by Gutierrez between Isotricha Stein and Dasytricha Schuberg (cf. Oxford²) seem to justify attempts to establish single species of holotrichs in vivo unmixed with other species. A method is required which would be as effective as, but less drastic than, the use of prolonged starvation and copper sulphate administration⁴. This objective has so far been reached by us in the one sheep used, to the extent that all three species of holotrichs and the large oligotrichs originally present were removed, leaving only the smaller oligotrich Diplodinium dentatum Stein and a few Entodinia spp. Following this, Dasytricha ruminantium has successfully been reestablished in the rumen so that fairly large ‘pure’ samples of this organism in the living state can now be obtained for in vitro studies, by the normal separation process of Heald, Oxford and Sugden⁵.