title: Circulating IGF-I in plasma of growing male and female turkeys of medium and heavy weight lines.
abstract: Plasma concentrations of insulin-like growth factor-I (IGF-I) were determined in male and female turkeys from a medium weight (RBC2) and a related heavy weight line (F) from 1 to 28 wks of age. At hatch, the concentrations of IGF-I were relatively low and not different between lines or sexes. During the neonatal period (1 to 7 wks), the concentrations of IGF-I increased and were higher in the faster growing F line and in males. During the juvenile period (8 to 15 wks) the concentrations of IGF-I were higher in males but not different between lines. During the preadolescent period (16 to 21 wks), the concentrations of IGF-I were higher in males but was not different between lines in males while the females of the RBC2 line had higher concentrations than females of the F line. During the adolescent period (22 to 28 wks) the concentrations of IGF-I were higher in males but was not different between lines in males while the females of the RBC2 line had higher concentrations than females of the F line. A phenotypic correlation (+.25) between plasma IGF-I and growth rate was present after statistical absorption of model effects during the neonatal period but not at the later ages. We conclude that IGF-I concentration was positively correlated with growth rate during the neonatal period, but that this relationship changed during the preadolescent and adolescent periods so that IGF-I concentrations were not related to growth rate in males but were negatively related to growth rate in females.
authors.affiliation: Department of Poultry Science, Ohio State University, Wooster 44691.
authors.forename: W L
authors.initials: WL
authors.lastname: Bacon
authors.forename: K E
authors.initials: KE
authors.lastname: Nestor
authors.forename: D A
authors.initials: DA
authors.lastname: Emmerson
authors.forename: R
authors.initials: R
authors.lastname: Vasilatos-Younken
authors.forename: D W
authors.initials: DW
authors.lastname: Long
mesh_terms: D000375:Aging / Q000097:blood / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000235:genetics; D005260:Female; D006128:Growth / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis* / Q000378:metabolism; D008297:Male; D011863:Radioimmunoassay; D011994:Recombinant Proteins / Q000378:metabolism; D012727:Sex Characteristics; D014422:Turkeys / Q000097:blood / Q000235:genetics / Q000254:growth & development*; D015430:Weight Gain
chemical_list: D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I