| Group | Control | pSPI (1) | pSPI (2) | pSPI (3) | nSPI |
| D0 (length) | 13.9 ± 0.6 | 14.3 ± 0.7 | 14.3 ± 0.7 | 14.1 ± 0.6 | 14.3 ± 0.7 |
| D7 (length) | 16.0 ± 0.4 | 16.6 ± 0.8 | 16.7 ± 0.7 | 16.6 ± 0.5 | 16.4 ± 0.8 |
| D14 (length) | 18.4 ± 0.5 | 18.6 ± 0.6 | 18.7 ± 0.6 | 18.8 ± 0.5 | 18.8 ± 0.6 |
| D21 (length) | 20.3 ± 0.3 | 20.5 ± 0.5 | 20.7 ± 0.8 | 20.8 ± 0.6 | 20.8 ± 0.7 |
| D28 (length) | 21.5 ± 0.3 | 21.8 ± 0.7 | 22.0 ± 0.7 | 22.1 ± 0.6 | 22.0 ± 0.5 |
| D35 (length) | 22.8 ± 0.3 | 23.0 ± 0.4 | 23.2 ± 0.6 | 23.3 ± 0.5 | 23.3 ± 0.6 |
| D42 (length) | 23.7 ± 0.4 | 24.0 ± 0.5 | 24.1 ± 0.5 | 24.2 ± 0.5 | 24.1 ± 0.7 |
| D49 (length) | 24.3 ± 0.4 | 24.7 ± 0.5 | 24.8 ± 0.6* | 24.8 ± 05* | 24.8 ± 0.5* |
| D56 (length) | 24.8 ± 0.5 | 25.2 ± 0.5 | 25.3 ± 0.5* | 25.3 ± 0.4* | 25.3 ± 0.5* |
| D63 (length) | 25.1 ± 0.4 | 25.4 ± 0.4 | 25.5 ± 0.3* | 25.6 ± 0.4* | 25.5 ± 0.4* |