Divergent Selection for Growth in Japanese Quail Under Split and Complete Nutritional Environments.: 6. Differential Body Weights in Reciprocal Crosses

Abstract

Growth patterns were investigated in reciprocal crosses of quail lines divergently selected for 4-wk BW. In Experiment 1, quail from two sets of high lines (H), and two sets of low lines (L), and their reciprocal crosses (HL and LH) from Generation 23 breeders were reared intermingled and fed a 28% CP diet. Individual BW data were collected weekly through 9 wk. Experiment 2 involved only reciprocal cross progeny (HL, LH) from Generation 26 breeders with quail placed in divided decks of battery brooders to allow collection of feed intake and feed efficiency (FE) data. Feed intake data were collected from 0 to 38 days and BW data from 0 to 69 days. Quail from the LH cross were significant1ly (P < .05) larger than quail from the HL cross from 0 to 14 days and 0 to 69 days in Experiments 1 and 2, respectively. Initial BW differences were expected because of the large egg size difference between H and L line dams; however, persistent BW differences were not anticipated. Initial feed intake was greater (25%) for LH than HL quail; however, when adjusted for BW, HL quail consistently consumed more feed per gram of BW than LH quail. Feed efficiencies were not significantly different for the two genotypes; however, smaller HL quail tended to have superior FE after 2 wk of age. Initial relative growth rates were 17 to 38% higher in HL quail; however, after Week 2 absolute gain was essentially identical for the reciprocal crosses.