title: Inheritance of plasma insulin-like growth factor-I and growth rate, food intake, food efficiency and abdominal fatness in chickens.
abstract: 1. The inheritance of, and genetic and phenotypic correlations between, plasma insulin-like growth factor-I (IGF-I) and 28-(28dW) and 56-d (56dW) body weight, 28- to 56-d body weight gain (BWG), food intake (FI), food conversion ratio (FCR) and abdominal fatness (AF) at 56 d were determined by sib analyses in a population of 327 pedigreed progeny produced by matings between 18 cockerels and 72 pullets from a broiler strain of chickens bred at random for 8 generations. 2. Plasma IGF-I was measured in fed (IGF-If) and fasted (IGF-I) birds at 42 d. 3. Heritability estimates (sire + dam) were: 28dW 0.35 +/- 0.11, 56dW 0.49 +/- 0.13, BWG 0.51 +/- 0.13, FI 0.55 +/- 0.13, FCR 0.73 +/- 0.14, AF 0.49 +/- 0.13, IGF-If 0.10 +/- 0.08, IGF-Is 0.08 +/- 0.08. 4. The low heritability estimates with their high standard errors for the IGF-I measures precluded the calculation of meaningful genetic correlations between these and the performance traits. There were moderate to strong positive genetic correlations between 28dW, 56dW, FI and AF.
authors.affiliation: Department of Farm Animal Medicine and Production, University of Queensland, St Lucia, Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: Pym
authors.forename: R J
authors.initials: RJ
authors.lastname: Johnson
authors.forename: D B
authors.initials: DB
authors.lastname: Etse
authors.forename: P
authors.initials: P
authors.lastname: Eason
mesh_terms: D000005:Abdomen; D000273:Adipose Tissue / Q000254:growth & development*; D000818:Animals; D001947:Breeding; D002645:Chickens / Q000097:blood / Q000235:genetics* / Q000254:growth & development; D004435:Eating / Q000235:genetics*; D005260:Female; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male
chemical_list: D007334:Insulin-Like Growth Factor I