| Variable | Young hens | Aged hens | SEM | P-value | ||||
|---|---|---|---|---|---|---|---|---|
| −2 | + | − | + | Age (A) | Enzyme (E) | A × E | ||
| TTTR of DM3 (%) | 73.7 | 77.0 | 79.7 | 79.5 | 3.19 | 0.20 | 0.64 | 0.58 |
| TTTR of energy (%) | 83.2 | 84.9 | 88.8 | 88.4 | 1.29 | <0.01 | 0.60 | 0.41 |
| TTTR of N4 (%) | 53.4 | 54.6 | 44.5 | 50.9 | 3.43 | 0.08 | 0.28 | 0.46 |
| TTTR of crude fat (%) | 80.5 | 86.5 | 97.6 | 101.9 | 3.50 | <0.01 | 0.16 | 0.81 |