Abstract
The purpose of the experiment in this paper was to study the effect of diets containing excessive L-lysine on the nutritional efficiency for young rats.
(1) When fed on the L-lysine replaced diets, rats showed very slight growth depression. The test diets were prepared by replacing the casein in basal diet with excess of L-lysine and they had1.5%, 1.0%dietary nitrogen level and had various lysine/tryptophan ratios (LIT), ranging between 8 to 40.
(2) When fed on the diets of excessive L-lysine over 1.5%, 1.0% of dietary nitrogen level, rats showed very slight growth depression. However, when fed on the L-lysine excess diets having 0.6% dietary nitrogen level, they showed depression in the growth and nitrogen efficiency.
(3) In general, the effect of L-lysine excess diets on rat growth was not appeared in the diet of L/T about20and it appeared in the diet of L/T over 30.
(4) The excretion of L-lysine in rat urine fed on lysine excess diets, was very slight and was not over 1% to ingested lysine.
(5) Urinary ammonia-nitrogen content of rat, fed on lysine excess diet, amounted to about 30% of total nitrogen in urine.
