title: Dietary L-homoserine spares threonine in chicks.
abstract: Four chick bioassays were conducted to evaluate the threonine (Thr) replacement value of l-homoserine (HS). Growth rate was increased (P < 0.05) by dietary addition of 800 mg l-HS/kg diet to a purified diet severely deficient in Thr or by the addition of 800 or 1000 mg of l-HS/kg diet to a corn-peanut meal diet distinctly deficient in Thr. The addition of an isomolar level of alpha-ketobutyrate, a catabolic product of both Thr and HS, did not elicit a response. Standard-curve methodology predicted a Thr replacement value of 38 +/- 9% for HS. Interactions (P < 0.01) were observed in assays 2 and 4 between dietary Thr adequacy and 800 or 1000 mg l-HS/kg supplementation. Thus, HS improved growth performance when added to a Thr-deficient diet (0.46 g Thr/100 g diet), but it decreased growth performance when added to the same diet containing surfeit Thr (0.80 g Thr/100 g diet). The results indicate that low levels of HS elicit a growth response in young chicks fed Thr-deficient diets.
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL 61802, USA.
authors.forename: Kasey I
authors.initials: KI
authors.lastname: Bryant
authors.forename: Ryan N
authors.initials: RN
authors.lastname: Dilger
authors.forename: Carl M
authors.initials: CM
authors.lastname: Parsons
authors.forename: David H
authors.initials: DH
authors.lastname: Baker
mesh_terms: D000821:Animal Feed; D000818:Animals; D010367:Arachis; D002645:Chickens / Q000254:growth & development / Q000378:metabolism*; D004032:Diet; D006714:Homoserine / Q000378:metabolism* / Q000494:pharmacology*; D013912:Threonine / Q000172:deficiency* / Q000378:metabolism*; D015430:Weight Gain; D003313:Zea mays
chemical_list: D013912:Threonine; D006714:Homoserine