Kang C W, Sunde M L, Swick R W
Poult Sci. 1985 Feb;64(2):380-7. doi: 10.3382/ps.0640380.
Protein turnover and DNA and RNA levels were measured in the breast (pectoralis thoracica) and leg (gastrocnemius-peroneus) muscles of large white (Nicholas strain) turkey poults from 1 to 8 weeks of age to investigate their cellular growth and to evaluate the influence of protein turnover on muscle growth. Fractional rates of protein deposition (kg) were determined from regression equations of muscle size and protein content on body weights. Protein synthesis rates (ks) were measured by an isotope emulsion technique. Protein degradation rates (kd) were estimated by the difference between ks and kg. Muscle growth involved increases in total deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), an increase in the DNA-unit size, and decreases in concentrations of the nucleic acids without changes in the RNA:DNA ratio or RNA and DNA activity. The muscles showed developmental changes in ks from 56 to 10%/day and from 38 to 13%/day in breast and leg, respectively, over the 7-week period. The fractional degradation rate also fell from 22 to 7%/day in the breast muscle and from 21 to 10%/day in the leg muscle. The disproportionate decline of ks and kd resulted in an age-associated fall in kg from 34 to 4%/day and from 18 to 3%/day in the breast and the leg muscles, respectively. The efficiency of protein deposition decreased from 61 to 35% in breast muscle and 46 to 20% in leg muscle. The results were qualitatively similar to those obtained in a study with broiler chicks.
为了研究大白（尼古拉斯品系）火鸡雏鸡从1至8周龄时胸肌（胸大肌）和腿肌（腓肠肌 - 腓骨肌）的细胞生长情况，并评估蛋白质周转对肌肉生长的影响，对其蛋白质周转以及DNA和RNA水平进行了测定。蛋白质沉积分数率（kg）由肌肉大小和蛋白质含量关于体重的回归方程确定。蛋白质合成率（ks）通过同位素乳剂技术测量。蛋白质降解率（kd）通过ks与kg的差值估算。肌肉生长涉及总脱氧核糖核酸（DNA）和核糖核酸（RNA）增加、DNA单位大小增加，以及核酸浓度降低，而RNA:DNA比值或RNA和DNA活性无变化。在7周的时间里，胸肌和腿肌的ks分别从56%/天降至10%/天以及从38%/天降至13%/天，呈现出发育变化。胸肌的分数降解率也从22%/天降至7%/天，腿肌从21%/天降至10%/天。ks和kd的不成比例下降导致胸肌和腿肌中与年龄相关的kg分别从34%/天降至4%/天以及从18%/天降至3%/天。胸肌中蛋白质沉积效率从61%降至35%，腿肌从46%降至20%。这些结果在性质上与在一项针对肉鸡雏鸡的研究中获得的结果相似。
