2. Body weight gain, age at 50% egg production, mortality, hen‐day egg production and food conversion values showed significant improvement with proportionate increase in cage space per layer.

3. Egg weight gradually increased with age but shell thickness was influenced neither by age of the hen nor by stocking density.

4. Yolk index and colour were superior in the lowest stocking density (more cage space) group; other egg quality traits and egg weight were not influenced by stocking density.

5. The albumen index, internal quality unit, yolk index and yolk colour values increased with age.  相似文献   

2. Average daily food intake, daily weight gain and food conversion were similar among treatments.

3. There were linear increases in plasma and liver Cu concentrations (P< 0.01) as dietary Cu increased.

4. Bioavailability of Cu as carbonate was 0.66 that of Cu in the acetate based on the multiple regression slope ratio of liver Cu concentration on added dietary Cu. Although responses for the two Cu sources did not differ significantly, the relative bioavailability of the Cu carbonate was similar (0.66 vs 0.68) to that obtained in an earlier study (Ledoux et al., 1991) with greater dietary Cu contents (150, 300 and 450 mg/kg) in which the slopes of the equations representing the two sources differed (P<0.05).  相似文献