FACTORS AFFECTING RESISTANCE OF MONENSIN-RESISTANT AND SENSITIVE STRAINS OF Bacteroides ruminicola

Abstract

Monensin-resistant strains of the rumen bacterium, Bacteroides ruminicola, were selected by stepwise adaptation to media containing 10 μg of monensin/mL. The minimum inhibitory concentrations of monensin and lasalocid were from 16 to 64 times greater in resistant strains and were greatly influenced by potassium concentrations in the medium. Key words: Monensin, lasalocid, rumen bacteria, potassium