SUMMARY:Effects on body nitrogen gains of supplying nonessential nitrogen as glutamic or aspartic acids, as glutamine or asparagine or as wheat were investigated. It was found that nitrogen gains of rats fed diets containing only purified amino acids as the nitrogen source and relatively high levels of amide nitrogen were significantly lower than those of rats fed the same amounts of total nitrogen, all as α‐amino nitrogen. However, they were significanty higher than those of rats fed the same amounts of α‐amino nitrogen, but no additional amide nitrogen, indicating some effect of amide nitrogen in body nitrogen storage. Rats fed ad libitum consumed more of the glutamine‐containing diet than of one containing isonitrogenous amounts of glutamic acid; analysis of covariante indicated that ad libitum‐fed rats also utilized the nitrogen of glutamic acid more efficiently than that of glutamine. Addition of enough sodium bicarbonate to neutralize the hydrochlorides of dietary amino acids had no effect on utilization of amide nitrogen. No differences in nitrogen utilization were found between two groups of rats fed different levels of amide nitrogen
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