Mitchell A D, Conway J M, Scholz A M
Growth Biology Laboratory, USDA, Beltsville 20705, USA.
Growth Dev Aging. 1996 Summer;60(2):95-105.
The pig was used as a model for the application of dual-energy x-ray absorptiometry (DXA) for measuring changes in total and regional body composition that accompany body growth. Ten pigs were scanned at the beginning of the study (26.3 +/- 8.2 kg) and at 14 day intervals until reaching a final weight of 88.6 +/- 2.3 kg. Final body composition was validated by chemical analysis of the carcass. DXA fat and lean tissue measurements were corrected by using values based on previous calibration studies. From individual growth curves, rates of fat (295 +/- 50 g/d), lean (531 +/- 50 g/d) and bone mineral (16.7 +/- 1.4 g/d) deposition rates were estimated. Furthermore, using regional analysis these tissue deposition rates partitioned into front legs, back legs and body trunk. The final DXA measurements of 87.5 kg for total tissue mass, 27.9% for percent body fat and 24.4 kg for total fat mass were not significantly different (P > .05) from direct or chemical measurements. The DXA measurement of bone mineral content 1912 g (2.18%) was similar to the estimate based on total body ash, 1980 g (2.23%). Also, from the final DXA values for lean tissue mass, it was predicted that the body contained 13.5 kg or 15.4% protein and 45.74 kg or 52.3% water. These results indicate that DXA could be an appropriate method for studies involving sequential measurements of body composition during growth.
猪被用作双能X线吸收法（DXA）应用的模型，以测量伴随身体生长的全身和局部身体成分变化。在研究开始时（26.3±8.2千克）对10头猪进行扫描，并每隔14天扫描一次，直至达到最终体重88.6±2.3千克。通过对胴体的化学分析验证最终身体成分。DXA脂肪和瘦肉组织测量值通过使用基于先前校准研究的值进行校正。根据个体生长曲线，估计脂肪（295±50克/天）、瘦肉（531±50克/天）和骨矿物质（16.7±1.4克/天）的沉积率。此外，通过区域分析，将这些组织沉积率划分为前腿、后腿和躯干。总组织质量87.5千克、体脂百分比27.9%和总脂肪质量24.4千克的最终DXA测量值与直接测量或化学测量值无显著差异（P>.05）。骨矿物质含量的DXA测量值1912克（2.18%）与基于全身灰分的估计值1980克（2.23%）相似。同样，根据瘦肉组织质量的最终DXA值预测，身体含有13.5千克或15.4%的蛋白质以及45.74千克或52.3%的水。这些结果表明，DXA可能是一种适用于涉及生长过程中身体成分连续测量研究的方法。
