Metabolism of Glutamic and Aspartic Acids in Whole Rumen Contents

Abstract

AMINO-ACIDS occur at low concentrations in the liquid phase of rumen contents^1,2 as intermediates in the breakdown of dietary proteins and in the production of microbial protein. The metabolism of these amino-acids has been investigated, mainly in washed suspensions of mixed rumen micro-organisms and pure cultures. There is abundant evidence of interaction in the metabolism of the amino-acids by the rumen microflora^3,4. To obtain meaningful rates of utilization, physiological concentrations of all the amino-acids must be used. We report experiments in which glutamic and aspartic acids uniformly labelled with carbon-14 were added to whole rumen contents in true tracer amounts under conditions closely approaching those in the living animal.