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A study was conducted to investigate water and feed intake patterns, abdominal fat and carcass lipid levels, feed efficiency and growth in high (H) and low (L) body weight lines of Japanese quail divergently selected under complete diet (CD) or split diet (SD) environments. Birds under the SD environment could self-select from high-protein low-energy or low-protein high-energy diets. Progeny from both the selected and control (C) lines were evaluated under the SD environment in Generations 6 and 10, and under the CD environment in Generation 10. Under the SD environment, body weights of the H lines were similar as were body weights of the L lines; however, under the CD environment, there were significant differences between H lines and between L lines. Body weights were higher under the CD than under the SD environment. Differences between H and L lines in body weights and 1-wk relative growth rates within SD and CD environments were attributed to differences in water and feed consumption and feed efficiency. Water consumption was greater in the SD than CD environments. Feed consumption was greater in the SD than CD environment from 0 to 2 wk of age; thereafter, feed consumption was higher in the CD environment. Abdominal fat and carcass lipid levels were greater in H than L lines, with the magnitude of the difference greater in the SD environment, indicating that the SD may be a better environment than the CD environment for the study of abdominal fat and carcass lipids in Japanese quail.

Studies were conducted to investigate the influence of dietary salt on water consumption and subsequent carcass lipids in Japanese quail at various ages. In Experiment 1, randombred nongrowth-selected (C) quail were fed 28% protein diets containing .0, .4, .8, 1.6, and 3.2% added salt. In Experiment 2, growth-selected P- and C-line quail were fed 20%-protein diets containing .4% and 3.2% added salt. The different dietary salt levels did not exert a consistent effect on body weight in Experiment 1. There was no adverse effect of salt level on feed consumption and efficiency and no direct effect on abdominal fat or carcass lipid levels. High salt (1.6 and 3.2%) stimulated water consumption and increased water:feed ratios. Water:feed ratios were higher for quail than for broilers, suggesting a species difference. In Experiment 2, C-line quail demonstrated similar effects to the high-salt (3.2%) diet in Experiment 1. High salt (3.2%) adversely affected body weight, feed consumption, abdominal fat, and carcass lipid in P-line quail. There was no affect on feed efficiency, and a substantial stimulation of water consumption with concomitantly increased water:feed ratios. The relatively low abdominal fat observed at 4 weeks of age indicate that nongrowth-selected quail may not be a good model for the study of abdominal fat in broilers.

Japanese quail were divergently selected for 4-wk body weight under two different nutritional environments. In one environment quail were divergently selected for high and low body weight (H and L) under a split diet (SD) with quail having the opportunity to self-select feed from high protein and high energy diets. In the other environment, quail were similarly selected (H and L) under a normal (28% protein) complete diet (CD). After 11 generations of selection, H-SD and H-CD lines were 48.9 and 49.7% higher in 4-wk body weight than controls. Quail from L-SD and L-CD lines were 46.5 and 45.4% lower in 4-wk body weight than controls. Realized heritabilities for 4-wk body weight were .36 +/- .03, .30 +/- .03, .52 +/- .02, and .47 +/- .03 for H-SD, L-SD, H-CD, and L-CD lines, respectively. Selection differentials were significantly higher in the SD than in the CD environment. Changes in 2-wk, adult body, and egg weight across generations paralleled that of the trait under selection (4-wk body weight). Selection also resulted in decreased hatchability and egg production with increased age to sexual maturity in both environments. The SD environment was determined to be a stress environment because of birds' inferior growth there compared with growth in the CD environment. Rate of growth, however, to reach adult body size was superior for L-SD quail once the stress environment was removed. There was also evidence that eggs were larger for quail in the SD than the CD environment.