Kang C W, Sunde M L, Swick R W
Poult Sci. 1985 Feb;64(2):370-9. doi: 10.3382/ps.0640370.
Growth and protein turnover were examined in the breast (pectoralis thoracica) and the leg (gastrocnemius-peroneus) muscles of broiler chicks at 1, 2, 4, and 6 weeks posthatching. The fractional rate of protein synthesis (ks) was measured by an isotope emulsion method. The fractional degradation rate (kd) was calculated from the difference in ks and fractional deposition rate (kg), which was estimated from regression equations of muscle size and protein content on body weights. The growth rate (%/day) of skeletal muscle exceeded that of the whole body. Muscle growth involved an increase in the total deoxyribonucleic acid (DNA) and the DNA-unit size and a subsequent decrease in the concentrations of nucleic acids without alteration in the ribonucleic acid (RNA):DNA ratio and RNA and DNA activity. The ks in breast muscle protein fell markedly from 48 to 16%/day between 1 and 6 weeks posthatching, whereas in leg muscle, ks underwent a more gradual decrease; from 36 to 17%/day during the same period. These changes resulted mainly from the reduction of DNA and RNA concentrations with age. The kd decreased only slightly between 1 and 2 weeks in the both muscle groups. The kg also showed a developmental fall from 33 to 4%/day and from 21 to 4%/day in the breast and leg muscles, respectively, during the 5-week period.(ABSTRACT TRUNCATED AT 250 WORDS)
在孵化后1周、2周、4周和6周时，对肉仔鸡的胸部（胸肌）和腿部（腓肠肌-腓骨肌）肌肉的生长和蛋白质周转情况进行了研究。蛋白质合成的分数率（ks）通过同位素乳剂法进行测定。蛋白质降解分数率（kd）由ks与蛋白质沉积分数率（kg）的差值计算得出，kg根据肌肉大小和蛋白质含量与体重的回归方程估算。骨骼肌的生长速率（%/天）超过了全身的生长速率。肌肉生长涉及总脱氧核糖核酸（DNA）和DNA单位大小的增加，以及随后核酸浓度的降低，而核糖核酸（RNA）:DNA比率以及RNA和DNA活性没有改变。胸肌蛋白质的ks在孵化后1周和6周之间从48%/天显著降至16%/天，而腿部肌肉的ks下降较为缓慢，同期从36%/天降至17%/天。这些变化主要是由于随着年龄增长DNA和RNA浓度降低所致。两个肌肉组在1周和2周之间kd仅略有下降。在5周期间，胸肌和腿部肌肉的kg也分别从33%/天和21%/天呈发育性下降至4%/天。（摘要截短至250字）
