Intramuscular Collagen Synthesis, Muscle Fiber Growth and Histomorphology ofof a Fast-Growing Broiler Strain.

Abstract

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 ofand the affected tissue have reduced protein quality. This study measured thesoluble (S-) and insoluble (I-) collagen fractional synthesis and degradation rates (FSR and FDR) inover typical grow-out cycle of broiler using stable isotope of 1-C proline as metabolic tracer. Collagen content and muscle fiber histomorphology ofwere 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 inin 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 inat 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.