Table 3. Effects of stocking density (SD) and dietary supplementation of vitamin C (Vit C) on stress indicators of broiler chickens.
| Treatment | Stress indicators | ||
|---|---|---|---|
| SD (birds/m2) | Vit C (mg/kg) | Blood H:L | Feather CORT concentrations (pg/mm) |
| 9 | 0 | 0.40 | 9.2 |
| 200 | 0.40 | 10.3 | |
| 18 | 0 | 0.83 | 18.5 |
| 200 | 0.75 | 17.6 | |
| SEM (n = 6) | 0.038 | 0.96 | |
| Main effect | |||
| SD (birds/m2) | |||
| 9 | 0.40 | 9.8 | |
| 18 | 0.79 | 18.0 | |
| SEM (n = 12) | 0.027 | 0.68 | |
| Vit C (mg/kg) | |||
| 0 | 0.61 | 13.8 | |
| 200 | 0.57 | 14.0 | |
| SEM (n = 12) | 0.027 | 0.68 | |
| Effect (p-value) | df | ||
| SD | 1 | < 0.01 | < 0.01 |
| Vit C | 1 | 0.30 | 0.91 |
| SD × Vit C | 1 | 0.29 | 0.31 |
CORT, corticosterone; H:L, heterophil:lymphocyte.