Search

1. In two experiments, the dietary lysine concentration which supported maximal gain through 14 days of age in a subline of Japanese quail selected for 4-week body weight (HW) was higher than that needed by the random-bred population (R1) from which it was initially developed. 2. The lysine concentrations needed to minimize feather depigmentation and maximize breast and leg muscle development were higher in HW quail than in R1 quail.

1. Divergent selection for body weight resulted in significant increases and decreases in body weight and the relative weight of the pectoralis major breast muscle in heavy (HW) and light weight (LW) strains of Japanese quail compared with a randombred control strain (R1). 2. The relative weights of the abdominal fat pad and total carcass lipid were increased in the HW strain, particularly in the females. 3. Sexual maturity was similar in HW and R1 hens but was delayed in the LW hens. HW hens laid significantly more double-yolked eggs.

1. Selection for body weight in Japanese quail has altered the protein requirements for growth and reproductive development in the selected line and randombred control population from which it was developed. 2. In both the selected and randombred lines, the protein requirement for growth is different from that for maximal reproductive development.