| Young hens | Aged hens | SEM | P-value | |||||
|---|---|---|---|---|---|---|---|---|
| −2 | + | − | + | Age (A) | Enzyme (E) | A × E | ||
| TTTR of DM3, % | 74.7 | 75.7 | 85.8 | 97.4 | 2.52 | <0.01 | 0.02 | <0.05 |
| TTTR of energy, % | 79.8 | 78.1 | 87.4 | 91.4 | 2.01 | <0.01 | 0.59 | 0.17 |
| TTTR of N4, % | −11.2 | 41.3 | 97.6 | 185.3 | 40.66 | <0.01 | 0.10 | 0.67 |
| TTTR of crude fat, % | 108.5 | 114.5 | 91.3 | 110.7 | 7.15 | 0.16 | 0.09 | 0.36 |