Abstract
A long term (24 weeks) feeding experiment was conducted using 8.5-month-old White Leghorn pullets receiving a large dose of tryptophan. Each group consisted of 12 birds, and initial body weight was 1.66 and 1.73kg, and average egg production rate before experi-ment was 92.6% and 93.5% in experimental and control groups, respectively. A commer-cial laying ration was used as a controt diet, which contained 15.5% of crude protein and adequate amounts of amino acids (tryptophan 0.16%) for layers. An experimental diet was formulated by supplementing the control diet with 0.5% of L-tryptophan, and the total try-ptophan content of this diet was 0.66%. Several parameters, such as body weight change, feed intake, egg production rate, egg weight, albumen weight, protein/albumen ratio, try-ptophan content of albumen, were measured to compare the normal and excess dosages of tryptophan. The result indicates that a large dose of tryptophan to the laying hens did not show any ill-effect even in a long period of feeding.The authors are grateful to the Ajinomoto Co. Ltd, for the support of this work.
