title: Production performance of laying hens fed L-tryptophan.
abstract: 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.
authors.affiliation: Fukushima Prefectural Poultry Experimental Station, Koriyama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohtani
authors.forename: S
authors.initials: S
authors.lastname: Saitoh
authors.forename: H
authors.initials: H
authors.lastname: Ohkawara
authors.forename: Y
authors.initials: Y
authors.lastname: Akiba
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Horiguchi
authors.forename: K
authors.initials: K
authors.lastname: Goto
mesh_terms: D000821:Animal Feed; D000818:Animals; D002645:Chickens / Q000502:physiology*; D004032:Diet; D004528:Egg Shell / Q000648:ultrastructure; D004531:Eggs; D005260:Female; D005298:Fertility; D005527:Food, Fortified; D011897:Random Allocation; D014364:Tryptophan / Q000008:administration & dosage*
chemical_list: D014364:Tryptophan