Computed tomographic analysis of tibiotarsal bone mineral density and content in turkeys as influenced by age and sex

Abstract

Changes in the volumetric bone mineral density (vBMD) and bone mineral content (BMC) of tibiotarsal bones of growing turkeys as affected by birds’ age, sex, and within-the-bone location, respectively, were determined by computed tomography. The research was performed on 165 heavy-type BIG 6 turkeys reared between weeks (wk) 3–16 of age. The computed tomography (pQCT) measurement, conducted at 18 and 50% of the bone length, comprised a bone fragment which was 0.07 mm thick for the compact and the spongious substance collectively. It should be noted that the diaphyses of the tibiotarsal bones in turkeys (580 mg/cm<sup>3</sup>) had greater vBMD than the proximal metaphyses (300 mg/cm<sup>3</sup>), (P ≤ 0.001). BMC was higher in metaphyses for both sexes. Significant differences between the BMC of the metaphyses and the diaphyses were observed in males and females at wk 3 (P ≤ 0.01), 6 (P ≤ 0.05), and 9 (P ≤ 0.001), and at wk 3 (P ≤ 0.05) and 12 (P ≤ 0.01), respectively. vBMD in the diaphyses gradually attenuated with age for both sexes, from 688 mg/cm<sup>3</sup> (wk 3) to 532 mg/cm<sup>3</sup> (wk 16). vBMD of the metaphyses was constant in females, but in males it achieved maximum values of 350 mg/cm<sup>3 </sup>at wk 6 and 12 and minimum of 260 mg/cm<sup>3 </sup>at wk 9 and 16. Correlations between body weight (BW) and vBMD of the diaphyses were observed in males (r = –0.85, P ≤ 0.001) and females (r = –0.52, P ≤ 0.01). It can be concluded that vBMD loss in diaphyses diminished bone-breaking strength leading in investigated turkeys to deformities and bone fractures.