Submitted to: American Society for Bone and Mineral Research
Publication Type: Abstract Only
Publication Acceptance Date: October 3, 1999
Publication Date: N/A
Technical Abstract: Because meat-type poultry exhibit a high incidence of leg bone problems during their growth period we investigated the changes in allometric, physical, biomechanical, and the compositional parameters of tibial bones of 5 to 55 week-old male broiler chickens to understand bone quality. The length, weight, and diaphyseal diameter of tibia reached a plateau by 25 weeks whereas bone density and ash percentage reached their maximum levels at 35 weeks of age. The bone density changed by 20 % whereas the ash content changed by ~6% from lowest to highest values. The breaking strength of bones reached their maximum levels at 25 weeks. However, the Young's modulus which indicates stiffness of bones was highest in 5 week old bones. The stiffness of bones decreased at 15 and 25 weeks and increased thereafter. The toughness of bones evident from their plastic deformation, also increased to reach a plateau by 35 weeks. There were no changes in the collagen content of bones but the relative content of pyridinoline and deoxypyridinoline changed significantly to reach a maximum by 25 weeks. These findings indicate that bone density and toughness may be partly related to collagen crosslinks. Although a significant correlation existed between bone strength and its physical parameters such as diameter and density, it is nevertheless clear that bones from younger birds with lower concentrations of collagen crosslinks are relatively more fragile. On a relative weight basis, the bones from young birds are exposed to a similar amount of body weight as birds from other ages which could enhance risk for a higher incidence of bone deformity and breakage.