Ruminal microbes of adult steers extensively degrade L-glutamine but not L-glutamate or L-citrulline

An abstract of a study by Gilbreath et al investigating ruminal microbes of adult steers that extensively degrade l-glutamine but not l-glutamate or l-citrulline is presented. The microbial population within the rumen has long been considered to have the capability of extensively degrading all dietary AA. Results from our feeding trial showed that this view might not be accurate. In vivo and in vitro studies were conducted to test the hypothesis that certain AA undergo little degradation by ruminal microbes. They suggest that l-citrulline without any encapsulation or protection from rumen microbes can be effectively supplemented to the diets of ruminants to increase its concentrations and of l-arginine in plasma for utilization and metabolism by various organs and tissues.