Modifications of a Device for Maintenance of the Rumen Microbial Population in Continuous Culture.

An improved and simplified apparatus for maintaining the rumen microbial population in continuous culture was constructed. All components were easily obtained from commercial sources or were simple to construct. Mechanical difficulties were minimal, and little attention was needed on the part of the operator. The deoxyribonucleic acid (DNA) content of the cultures (100 to 150 mug/ml) varied little during 7 days of continuous culture, and protozoal concentration decreased from 10(5) per ml to a steady-state level of 2 x 10(3) per ml in 4 days. Volatile fatty acid and methane production followed the normal in vivo pattern for 7 days of continuous culture. DNA, protozoal concentrations, and fermentation patterns did not significantly change between 4 and 21 days of continuous culture.