A study on the possibility of cystine synthesis in the rumen of sheep together with the effect of cystine supplementation on the nitrogen utilization of lucerne in young stock

Abstract

By means of metabolism experiments on rats it was shown that the biological value of the rumen ingesta is better than that of lucerne. When rumen ingesta are supplemented by cystine their biological value is significantly enhanced. In sheep experiments it was shown that the inclusion of cystine in a lucerne ration for mature sheep did not influence the biological value of the latter. For growing sheep the supplementation of lucerne by cystine increased its biological value by 10 per cent. It is concluded that the action of the micro-organisms is purely a question of interception, that is, utilizing exogenous protein for its own use and supplying it back to the animal in the bacterial and infusorial form.