Effect of Some Antibiotics and Sulphonamides on Cellulose Breakdown by Mixed Rumen Microorganisms in Vitro

Abstract

The effect of some antibiotics and sulphonamides on the breakdown of cellulose by mixed rumen microorganisms in vitro was studied. At the low levels tested colistin, kanamycin, neomycin, and streptomycin had no effect, while ten other antibiotics reduced cellulose digestion—ampicillin, erythromycin, methicillin and oleandomycin being completely inhibitory. All the sulphonamides tested at the level of 150 μg./20 ml. partially reduced cellulose digestion, but never completely. Sulfathiazole and sulfamethylthia-diazole were most inhibitory.