Maharjan Pramir, Owens Casey M, Coon Craig
Department of Poultry Science, Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, United States.
Front Vet Sci. 2020 Jan 10;6:470. doi: 10.3389/fvets.2019.00470. eCollection 2019.
Collagen protein has been considered as major culprit to myopathy condition affecting , called woody breast (WB) in (broiler). The WB myopathy is characterized by macroscopic stiffness of and the affected tissue have reduced protein quality. This study measured the soluble (S-) and insoluble (I-) collagen fractional synthesis and degradation rates (FSR and FDR) in over typical grow-out cycle of broiler using stable isotope of 1-C proline as metabolic tracer. Collagen content and muscle fiber histomorphology of were also assessed simultaneously. The FSR and FDR for S- and I-collagen decreased over age, however FSR remained higher than FDR suggesting collagen was accreting during the grow-out period. This was reflected by increment in total collagen content in in maturing broiler. Histomicrographs showed myodegeneration occurring as early as 21 days followed by greater accumulation of collagenous tissue in perimysial and endomysial connective tissue spaces of muscle fibers as bird aged. The findings suggest that reduced turnover of collagen in at the later age of bird could have evolved due to adaptive physiological feedback mechanism against further synthesis and deposition of collagen in the extracellular matrix.
胶原蛋白被认为是影响肉鸡所谓“木质胸肌”（WB）病症的主要元凶。WB肌病的特征是胸肌宏观僵硬，且受影响组织的蛋白质质量下降。本研究使用1-C脯氨酸稳定同位素作为代谢示踪剂，在肉鸡典型的生长周期内测量了胸肌中可溶性（S-）和不可溶性（I-）胶原蛋白的分数合成和降解率（FSR和FDR）。同时还评估了胸肌的胶原蛋白含量和肌纤维组织形态学。S-和I-胶原蛋白的FSR和FDR随年龄增长而降低，但FSR仍高于FDR，表明在生长期间胶原蛋白在积累。这反映在成熟肉鸡胸肌中总胶原蛋白含量的增加上。组织显微镜照片显示，早在21日龄时就出现了肌纤维变性，随着鸡龄增长，肌纤维的肌束膜和肌内膜结缔组织间隙中胶原组织的积累更多。研究结果表明，鸡龄较大时胸肌中胶原蛋白更新率降低可能是由于针对细胞外基质中胶原蛋白进一步合成和沉积的适应性生理反馈机制所致。
