Design of non-destructive methodologies to assess skeletal integrity in laying hens

Abstract

Conventional methods of assessing bone integrity of layers have involved destructive testing on dissected samples. Bone ash, calcium and phosphorus levels give an indication of mineral content while breaking strength is at best a relative measure subject to numerous potential errors in methodology. More recently non-destructive methodologies have been accepted in human medicine, the most promising being quantitative ultrasonography (QUS) and axial x-ray micro-computed tomography (Micro CT). QUS relies on capturing sound waves that have travelled through the bone, where density will influence time between emitting and capture of the signal. In our preliminary studies, the humerus is the most appropriate bone for such studies since there is a minimum of overlying tissue. Micro CT relies on 720 images, taken at 0.5° angles around a sample, and then software allows rebuilding of a 3-D image. Micro CT also provides quantitation of density in selected areas on the image. Most Micro CT scanners currently necessitate isolated bone samples, although second generation machines will have the capacity to scan sedated animals such as chickens and small mammals.

Keywords::

• bone
• laying hen
• density
• skeletal integrity