[Protein quality of dietary yeast ribonucleic acid in experiments using growing rats. 1. Effect of ribonucleic acid on the body composition].

In a feeding trial with growing rats the influence of dietary ribonucleic acid on the composition of body gain was investigated. To a control ration with casein + 50% DL-methionine as the sole protein source (1,64 N% in DM) ribonucleic acid (RNA) from yeast was supplemented at four levels ranging from 7,8% to 31,2% of diets nitrogen. The portion of daily feed and nitrogen intake derived from the basal diet was designed to be equal for all the animals. RNA was ingested in addition. Gain of body fresh and dry matter slightly increased with the dietary RNA-level, due to an increased deposition of body fat. Protein efficiency ratio as well as productive protein value decreased linearly with increasing N-intake. It may be concluded that RNA-N has slightly contributed to body mass gain but was not utilised for protein deposition.