The distribution of carboxymethylcellulase between fractions taken from the rumens of sheep containing no protozoa or one of five different protozoal populations

SUMMARYThe distribution of carboxymethylcellulase (CMCase) between various rumen fractions has been determined at three times after feeding in sheep containing no ciliate protozoa or five different protozoal populations. The total rumen CMCase was lowest in defaunated animals and tended to be higher in animals containing the amylolyticEntodinium caudatumor a natural mixed protozoal population and highest in sheep containing single cellulolytic species. In animals containing the cellulolytic species,Epidinium ecaudatum caudatumorEudiplodinium maggii, 70% of the CMCase was associated with the protozoal fraction whereas less than 15% was present in a fraction prepared in the same way from sheep containing no protozoa or onlyEntodinium caudatum. The activity associated with the free bacteria was higher in sheep containing onlyEntodinium caudatumthan in defaunated animals or those containing the cellulolytic species. Similar results were obtained 1·5, 6·5 or 24 h after feeding. Almost no activity was present in the cell-free rumen liquor under any condition. A variable amount of CMCase (up to 25% of the total) was associated with the plant debris in the rumen and the specific activity of the enzyme released by sonication was often higherthan that released from the free bacteria under the same conditions.