Comparative Effects of Dietary Sucrose and Cornstarch on Tryptophan Requirement of the Rat. ∗

Summary

Immature female rats were fed tryptophan-free rations supplemented with graded levels of dl-tryptophan and containing either sucrose or cornstarch as the source of dietary carbohydrate. Rats fed dl-tryptophan at a level of 600 mg/kg of diet grew poorly when sucrose was the dietary carbohydrate but showed a significant increment in body weight over that observed on the sucrose-containing diet when cornstarch replaced sucrose as the source of dietary carbohydrate. At higher levels of tryptophan supplementation (1.8 g or 5.4 g dl-tryptophan/kg of diet) no significant difference in weight increment occurred between rats fed cornstarch or sucrose-containing rations.