Whole genome scan in chickens for quantitative trait loci affecting growthand feed efficiency

A feed efficiency experiment was conducted in a population consisting of pr ogeny from 10 full sib families of a cross between two broiler lines. Micro satellite genotypes were determined on Generation (G) 1 and 2. In G(3), BW at 23 and 48 d and feed intake were measured and were used to calculate gro wth between 23 and 48 d, feed intake adjusted for BW, and feed efficiency. Average adjusted progeny trait values were calculated for G(2) animals afte r adjusting phenotypic observations on offspring for fixed effects, covaria bles, maternal genetic effects, the additive genetic contribution of the ma te, and heterogeneity between sexes and were used as dependent variable in the quantitative trait loci (QTL) analysis. A full sib interval mapping approach was applied using genotypes from 420 m arkers on 27 autosomal linkage groups. Four QTL exceeded significance thres holds. The most significant QTL was located on Chromosome 1 at 235 cM and h ad a 4% genomewise significance for feed intake between 23 and 48 d. Furthe rmore, this QTL exceeded suggestive Linkage for growth between 23 and 48 d and BW at 48 d. A second QTL was located on linkage group WAU26 at 16 cM an d showed suggestive linkage for feed intake between 23 and 48 d. On Chromos ome 4, at 147 cM a third QTL, which had an effect on both feed intake trait s, was found. Finally, a fourth QTL, which affected feed intake adjusted fo r BW, was located on Chromosome 2 at 41 cM.