THE IMPORTANCE OF METHANOGENS ASSOCIATED WITH CILIATE PROTOZOA IN RUMINAL METHANE PRODUCTION IN-VITRO

The importance of methanogenic bacteria associated with ciliate protoz oa was estimated either by removing protozoa from whole rumen fluid (u sing defaunated rumen fluid to correct for the effects of centrifugati on on bacteria) or by isolating the protozoa. Rumen fluid was withdraw n from sheep inoculated with either Polyplastron multivesiculatum, a c o-culture of Isotricha prostoma plus Entodinium spp. or a mixed type B fauna of Entodinium, Eudiplodinium and Epidinium spp. Methanogenesis was highest in rumen fluid containing a mixed protozoal population of the following genera: Entodinium, Eudiplodinium and Epidinium, was low er in defaunated rumen fluid and lowest in rumen fluid containing eith er I, prostoma plus Entodinium or P. multivesiculatum. Methanogenic ba cteria associated with rumen ciliates were apparently responsible for between 9 and 25% of methanogenesis in rumen fluid.