An Accurate in vivo Technique for Measuring Bone Mineral Mass in Chickens

Abstract

The purpose of this study was to adapt the Cameron-Sorenson technique for measuring bone-mineral content, in vivo, in humans to chickens. Bone-mineral content is determined by measuring the transmission of a monoenergetic photon beam through the right tibia (3 cm proximal from the tibia-metatarsal joint) with a scintillation detector. The radioactive source is 125I, and the mineral content is expressed as bone mass units. The correlation between bone mass units and ash weight per centimeter bone is 0.955 for a live chicken with no flesh equivalent present, and 0.934 when a flesh equivalent material is present. The bone mass determined on a thin cross section of the bone is representative of the total mineral content of the bone. The bone mass as determined by this system is reproducible within 3.2%. Repositioning and varying the chart speed did not have an effect on bone mass, and changing the time constant from 0.5 to 1.0 second produced no significant effect on bone mass. Bone weight and size are poorly correlated with bone mass units. There is a poor correlation between percent bone ash and bone mass units since bone moisture, protein, and fat content affect bone ash percentage but do not change bone mass units.