The use of quantitative computed tomography for bone ash quantification may avoid euthanasia of young broiler chickens

The objective of the current study was to compare bone ash and digital bone mineral content (BMC) calculated from clinical quantitative computed tomography (QCT) in young broiler chickens. A total of 576 male broiler chickens (initial BW = 190 ± 17 g) on d 8 post hatching were allotted to the 6 experimental diets in a randomized complete block design. The 6 diets included a phosphorus (P)-deficient basal diet based on corn and soybean meal, basal diet plus 0.9 or 1.8 g/kg of inorganic P from monosodium phosphate (MSP), and basal diet plus 500, 1,000, or 2,000 FYT/kg of exogenous phytase. On d 11 post hatching, 7 birds from each cage were euthanized and the 5 remaining birds were euthanized on d 18. The entire left leg was collected from the bird with median weight from each cage on d 11 and 18. Digital BMC of femur and tibia in the collected whole left legs was estimated using clinical QCT scan. Subsequently, the tissues attached to the left legs were manually removed using a scalpel, and bone ash of femur and tibia was analyzed. An interaction between bone trait (bone ash or digital BMC) and MSP or phytase was not observed. There was no statistical difference in femur and tibia on d 11 and 18 between digital BMC and bone ash. In conclusion, clinical QCT may replace sacrificing birds for bone ash estimation in young broiler chickens irrespective of their bone mineralization status.