Talaty P N, Katanbaf M N, Hester P Y
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
Poult Sci. 2009 May;88(5):1070-7. doi: 10.3382/ps.2008-00418.
Life cycle changes in bone mineralization and bone size traits of the tibia and humerus were evaluated in commercial male and female broilers using dual-energy x-ray absorptiometry (DEXA). Experiment 1 evaluated weekly changes in bone traits from 2 to 7 wk of age, whereas experiment 2 compared the bone traits of 4 strains of commercial meat-type chickens from 4 to 8 wk of age. Birds were restrained without anesthesia, and the humerus and tibia were scanned in vivo. After each scan, individual BW was determined. From the DEXA scans, bone mineral density (BMD), bone mineral content (BMC), as well as bone length, width, and area were determined. Bone mineralization and size traits were analyzed as an analysis of covariance with BW as the covariate. If BW was NS as a covariate, then an ANOVA was used. The BMD reached its peak at 4 wk of age. The BMC of the humerus changed little from 2 to 8 wk of age, whereas tibial BMC increased as the birds aged, especially in males (P < 0.0001). In experiment 1, bone length, width, and area also increased with age (P < 0.0001), with the tibia growing in length at a faster rate than the humerus. In experiment 2, the BMD did not differ among the 4 strains of commercial broilers. Interactions with strain of chicken were also NS, indicating that all strains of chickens responded similarly with respect to age (4, 6, and 8 wk of age), sex, and type of bone (humerus vs. tibia). Coefficients of variation for BMD ranged from 15 to 16%, indicating a potential use of DEXA for selection to improve skeletal integrity. In conclusion, the tibia continued to grow, especially after the initiation of the growth spurt at 3 to 4 wk of age, as indicated by bone length, width, and BMC, but it did not become denser in mineral after 4 wk of age as its surface area increased.
采用双能X线吸收法（DEXA）对商品肉鸡公母的胫骨和肱骨的骨矿化及骨大小性状的生命周期变化进行了评估。实验1评估了2至7周龄时骨骼性状的每周变化，而实验2比较了4种商品肉用型鸡在4至8周龄时的骨骼性状。鸡在未麻醉的情况下被固定，对肱骨和胫骨进行活体扫描。每次扫描后，测定个体体重。通过DEXA扫描，确定骨矿物质密度（BMD）、骨矿物质含量（BMC）以及骨长度、宽度和面积。骨矿化和大小性状作为协方差分析，以体重作为协变量。如果体重作为协变量不显著，则使用方差分析。BMD在4周龄时达到峰值。肱骨的BMC在2至8周龄时变化不大，而胫骨的BMC随着鸡龄增加而增加，尤其是雄性（P < 0.0001）。在实验1中，骨长度、宽度和面积也随着年龄增长而增加（P < 0.0001），胫骨长度的生长速度比肱骨快。在实验2中，4种商品肉鸡品系之间的BMD没有差异。与鸡品系的交互作用也不显著，表明所有鸡品系在年龄（4、6和8周龄）、性别和骨骼类型（肱骨与胫骨）方面的反应相似。BMD的变异系数在15%至16%之间，表明DEXA可用于选择以改善骨骼完整性。总之，胫骨持续生长，尤其是在3至4周龄生长突增开始后，这由骨长度、宽度和BMC表明，但在4周龄后随着表面积增加其矿物质密度并未增加。
