Submitted to: Conference on Rumen Function
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2000
Publication Date: 11/15/2000
Citation: RYCHLIK, J.L., RUSSELL, J.B. ISOLATION AND IDENTIFICATION OF A BACTERIUM THAT INHIBITS HYPERAMMONIA PRODUCING BACTERIA. CONFERENCE ON RUMEN FUNCTION. 2000.
Technical Abstract: When ruminal fluid from a cow fed hay was serially diluted into broth containing 15 mg/ml of Trypticase and Casaminoacids, little OD (<0.25) or ammonia accumulation was observed at dilutions greater than 107, and hyperammonia producing bacteria (HAB) could not be isolated. These high dilution tubes, however, contained thin rods that caused zones of clearing in C. sticklandii, C. aminophilum and P. anaerobius agar overlays. The thin rods stained Gram-positive and were monensin sensitive. Little growth was observed on Trypticase, but glucose, xylose and variety of other sugars were rapidly fermented. Because butyrate was the predominant end-product of carbohydrate fermentation, the thin rods were presumptively identified as butyrivibrio. The isolate (JL5) most active against C. sticklandii also inhibited a variety of other Gram-positive ruminal bacteria. Cell-free-supernatants from exponentially growing cultures that were autoclaved retained more than 50% activity. The activity was not sensitiv to proteinase K, pronase E or trypsin, but it was reversibly inactivated by oxygen. The "butyrivibriocin" could be precipitated with 60% ammonium sulfate, dialyzed (3500 MW cutoff) and separated on a PAGE gel. Based on these results, it appears that most probable number methods cannot be used to enumerate ruminal HAB. When ruminal fluid was diluted in broth, HAB were inhibited by bacteriocin producing bacteria, and the isolation of HAB was also prevented.