Degradation of quillaja saponins by mixed culture of rumen microbes

Quillaja saponin (QS) was incubated at 39 degrees C in an in vitro medium containing rumen liquor from a cow fed a roughage diet. No degradation of QS was observed up to 6 h of fermentation. Incubation for 9, 12 and 24 h decreased the content of QS by 16%, 15% and 100%. The content of QS did not decrease when incubated for 24 h in the medium containing autoclaved rumen liquor, suggesting that rumen microbes have enzyme(s) capable of degrading QS. The fate of QS will help gain a better understanding of mechanisms of action of QS on rumen fermentation, and its beneficial effects mediated by binding to ammonia.