Production performance of laying hens fed L-tryptophan

• Published in: Poultry science Vol. 68; no. 2; pp. 323 - 326
• Main Authors: Ohtani, H, Saitoh, S, Ohkawara, H, Akiba, Y, Takahashi, K, Horiguchi, M, Goto, K
• Format: Journal Article
• Language: English
• Published: England 01.02.1989
• Subjects: Animal Feed; Animals; Chickens - physiology; Diet; Egg Shell - ultrastructure; Eggs; Female; Fertility; Food, Fortified; Random Allocation; Tryptophan - administration & dosage
• ISSN: 0032-5791
• DOI: 10.3382/ps.0680323

The purpose of this study was to determine whether supplementing L-tryptophan to a nutritionally complete diet would influence egg production rate and egg shell quality in laying hens. One hundred and twenty layers (Rhode Island Red x White Leghorn) were randomly allocated into three groups. Birds were fed a basal diet or diets supplemented with L-tryptophan at 250 or 500 mg/kg for 405 days from 25 wk of age. Hen day egg production and daily egg output were proportionately higher with higher levels of supplemental dietary L-tryptophan; the differences were significant (P less than .05) for layers fed the 500 mg tryptophan/kg diet. The improvement in egg production by dietary L-tryptophan was greatest during the latter part of the laying period. These findings suggest that supplemental L-tryptophan improves the egg production rate in laying hens.