INDUCTION OF NITRATE AND NITRITE METABOLISM IN BOVINE RUMEN FLUID AND THE TRANSFER OF THIS CAPACITY TO UNTREATED ANIMALS

Nitrate, given intraruminally (0.1 g NO3- per kg of body weight) to cattle, stimulated the capacity of the rumen microflora to degrade nitrite (NO2-) and nitrate in vitro. Threefold to fourfold increases in rates of NO2- and NO3- reduction were observed during NO3- treatment. The treatment also appeared to stimulate nitropropanol degradation but this effect was less pronounced. The enhanced capacity of rumen microbes to degrade NO2- and NO3- was transferred to noninduced (untreated) animals housed in adjacent pens. The transfer of induced metabolism was not observed when induced animals were widely separated from the noninduced ones. This apparent transfer of microbial activities between adjacent animals may complicate studies in which treated and control animals are not separately housed.