Table 6.
The influence of AKG supplementation during the experimental period (31–60 weeks of age) on general, geometric and mechanical (structural and material) properties of tibia in laying hens at the age of 60 weeks.
| Parameter | CONT | AKG | p-Value |
|---|---|---|---|
| Bone weight, g | 11.87 ± 0.11 | 11.68 ± 0.25 | 0.525 |
| Tibia bone weight of BW, % | 0.610 ± 0.010 | 0.576 ± 0.016 | 0.091 |
| Bone length, mm | 121 ± 1 | 122 ± 1 | 0.547 |
| Seedor index, mg/mm | 98.1 ± 1.3 | 95.7 ± 1.7 | 0.341 |
| MRWT | 0.350 ± 0.026 | 0.363 ± 0.031 | 0.738 |
| Cortical index, % | 25.5 ± 1.4 | 26.0 ± 1.6 | 0.805 |
| CSA, mm2 | 18.2 ± 0.8 | 19.0 ± 1.2 | 0.586 |
| CSMI, mm4 | 78.8 ± 4.1 | 85.4 ± 6.6 | 0.707 |
| Yield load, N | 94 ± 4 | 98 ± 6 | 0.552 |
| Elastic work, mJ | 18.6 ± 1.5 | 19.5 ± 1.6 | 0.700 |
| Fracture load, N | 171 ± 6 | 176 ± 7 | 0.794 |
| Work to fracture, mJ | 121 ± 6 | 124 ± 7 | 0.696 |
| Stiffness, N/mm | 259 ± 9 | 270 ± 13 | 0.495 |
| Young’s modulus, GPa | 7.94 ± 0.38 | 7.54 ± 0.48 | 0.523 |
| Yield strain, % | 0.615 ± 0.021 | 0.650 ± 0.028 | 0.322 |
| Yield stress, MPa | 49.0 ± 3.4 | 48.8 ± 3.6 | 0.665 |
| Fracture strain, % | 1.92 ± 0.05 | 1.97 ± 0.07 | 0.610 |
| Fracture stress, MPa | 94.0 ± 6.3 | 87.7 ± 5.5 | 0.840 |
| BMD, g/cm2 | 0.245 ± 0.021 | 0.227 ± 0.026 | 0.611 |
Data are expressed as mean ± standard error. MRWT—bone diaphysis mean relative wall thickness; CSA—bone diaphysis cross-sectional area; CSMI—bone diaphysis cross-sectional moment of inertia; BMD—bone mineral density. The CONT group included laying hens not supplemented with AKG; the AKG group included laying hens supplemented with AKG at a dose of 1.0% (10 g/kg feed).