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Title: ENDOCRINE FACTORS IN A UNIQUE INBRED X OUTBRED F2 CHICKEN POPULATION

Author
item Ashwell, Christopher
item McMurtry, John
item DEEB, NADER - IOWA STATE UNIVERSITY
item LAMONT, SUSAN - IOWA STATE UNIVERSITY

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2002
Publication Date: 7/1/2002
Citation: Proc. 7th World Congr. Genet. Appl. Livestock Prod. 30:329-332, 2002.

Interpretive Summary: A unique population was established by crossing modern broiler chickens with two unrelated highly inbred chicken lines (Leghorn and Fayoumi)then intercrossed to produce two distinct F2 populations. Plasma hormone and metabolite levels were measured for the F2 populations and contemporary founder lines. Significant differences were observed among the 814 birds. Based on a comparison of the F2 populations and their parental lines, the effective number of genes affecting each plasma hormone or metabolite (trait) and was estimated. The results suggest that a low number of genes with major effects are involved in determining the phenotype for these traits. The hormones and metabolites measured have been previously shown to be associated with performance in chickens specifically in determining metabolic rate and energy balance. The estimated number of genes and the phenotypic distributions of the different traits suggest that a QTL (Quantitative Trait Loci) search for energy balance and metabolic rate may be effectively applied for these traits.

Technical Abstract: A resource population was established by crossing one modern broiler sire, from a commercial broiler breeder male line, with dams from two unrelated highly inbred lines (Leghorn and Fayoumi); F1 birds were intercrossed to produce two distinct F2 populations. Plasma hormone and metabolite levels were measured for the F2 populations and contemporary founder lines including insulin, glucagon, triiodothyronine (T3), thyroxine (T4), glucose, and lactate. Significant differences were observed among the 814 birds with respect to line and line x sex. Based on means and phenotypic distributions of the F2 populations compared to their parental lines, the effective number of genes affecting each plasma hormone or metabolite (trait) and heterosis was estimated. The results suggest that a low number of genes with major effects are involved in determining the phenotype for these traits. These hormones and metabolites have been previously shown to be associated with performance in chickens specifically in determining metabolic rate and energy balance. The estimated number of genes and the phenotypic distributions of the different traits suggest that a QTL (Quantitative Trait Loci) search for energy balance and metabolic rate may be effectively applied for these traits due to their apparent low number of involved genes and a high phenotypic distribution among the F2 populations.