Table 2.
The effect of thermal manipulation at 12 to 18 d of incubation on embryonic development.
| Treatments | G1 | G2 | P value |
|---|---|---|---|
| (Control) | (T.M.) | ||
| Traits at the 12th day of incubation | |||
| Egg weight (g) | 46.35 ± 0.80 | 46.38 ± 0.77 | 0.994 |
| Embryonic weight (g) | 6.27 ± 0.15 | 6.30 ± 0.18 | 0.780 |
| Yolk sac (%) | 80.43 ± 0.46 | 79.71 ± 0.53 | 0.133 |
| Shell weight (%) | 11.07 ± 0.30 | 10.64 ± 0.32 | 0.397 |
| Shell thickness (mm) | 0.33 ± 0.01 | 0.31 ± 0.03 | 0.082 |
| At the 18th day of incubation | |||
| Egg weight (g) | 41.46 ± 0.44 | 41.33 ± 0.73 | 0.942 |
| Embryonic weight (g) | 22.88b ± 0.44 | 24.05a ± 0.65 | 0.009 |
| Yolk sac (%) | 23.92a ± 1.45 | 20.25b ± 1.15 | 0.037 |
| Shell weight (%) | 9.83 ± 0.52 | 9.67 ± 0.36 | 0.871 |
| Shell thickness (mm) | 0.30 ± 0.01 | 0.28 ± 0.01 | 0.145 |
| Tibia length (cm) | 1.09b ± 0.03 | 1.61a ± 0.04 | 0.003 |
| Tibia weight (g) | 0.19b ± 0.01 | 0.21a ± 0.01 | 0.055 |
| Heart weight (g) | 0.14a ± 0.00 | 0.12b ± 0.01 | 0.005 |
a,b
Means having different letters in the same row are significantly different (P ≤ 0.05).
T.M. = temperature manipulation. % = as a percentage of egg weight.