Table 4.
Effect of a higher eggshell temperature (EST) of 38.9°C during week 2 of incubation (Higher) and/or a lower EST of 36.7°C during week 3 of incubation (Lower) compared to a control EST of 37.8°C (Control) and sex on natural antibodies (NAb) titer against keyhole limpet hemocyanin of broilers at hatch, day 14, 22, and slaughter age (day 41 or 42).
| NAb titer | ||||
|---|---|---|---|---|
| Treatment | Hatch1 | Day 142 | Day 222 | Slaughter2 |
| EST week 2 | ||||
| Control | 9.2 | 3.5 | 2.3 | 2.4 |
| Higher | 9.6 | 3.6 | 2.2 | 2.5 |
| SEM | 0.5 | 0.2 | 0.2 | 0.2 |
| EST week 3 | ||||
| Lower | 9.0 | 3.4 | 2.2 | 2.4 |
| Control | 9.8 | 3.7 | 2.4 | 2.4 |
| SEM | 0.5 | 0.2 | 0.2 | 0.2 |
| EST week 2 × week 3 | ||||
| Control × Lower | 8.7 | 3.4 | 2.3 | 2.4 |
| Control × Control | 9.7 | 3.6 | 2.4 | 2.3 |
| Higher × Lower | 9.3 | 3.5 | 2.2 | 2.5 |
| Higher × Control | 10.0 | 3.7 | 2.3 | 2.5 |
| SEM | 0.7 | 0.2 | 0.2 | 0.2 |
| P-value | ||||
| Week 2 | 0.54 | 0.74 | ||
| Week 3 | 0.24 | 0.38 | ||
| Week 2 × week 3 | 0.87 | 0.93 | ||
| Sex | 0.70 | 0.76 | ||
| Week 2 × day | n.a. | 0.80 | ||
| week 3 × day | n.a. | 0.74 | ||
| Week 2 × week 3 × day | n.a. | 0.97 | ||
| Day | n.a. | <0.001 | ||
| Sex × day | n.a. | 0.08 | ||
1
n = 13, 12, 12, 12 chicks for treatments Control x Lower, Control × Control, Higher × Lower, Higher × Control, respectively.
2
n = 16 pens/treatment.