Culture of the rumen holotrich ciliate Dasytricha ruminantium schuberg.

The successful cultivation of the anaerobic ciliate Dasytricha ruminantium is described. The cultures were established in a salts medium containing 30% clarified rumen fluid. Sucrose and extract of rumen holotrich protozoa were fed once daily for 2 to 4 hr, and Dasytricha was then transferred to medium free from these nutrients. Rumen fluid was essential. Omission of protozoal extract resulted in gradual death of the ciliates. Bovine serum satisfactorily substituted for the protozoal extract, but various rumen bacteria, extract of rumen bacteria, and extracts of plant materials could not. There was a positive correlation between formation of methane in the cultures and growth of the ciliates. It is possible that methane bacteria were ingested, but it is not excluded that survival of both dasytrichs and the methanogenic bacteria depended on a low redox potential of the medium.