An investigation of the altered textural property in woody breast myopathy using an integrative omics approach

Authors: WELTER, AMELIA - Kansas State University; WU, WAN JUN - Kansas State University; MAURER, RYAN - Kansas State University; O'QUINN, TRAVIS - Kansas State University; CHAO, MICHAEL - Kansas State University; BOYLE, DANIEL - Kansas State University; GEISBRECHT, ERIKA - Kansas State University; HARTSON, STEVE - Oklahoma State University; Bowker, Brian; Zhuang, Hong

Submitted to: Frontiers in Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2022
Publication Date: 3/17/2022
Citation: Welter, A.A., Wu, W., Maurer, R., O'Quinn, T.G., Chao, M.D., Boyle, D.L., Geisbrecht, E.R., Hartson, S.D., Bowker, B.C., Zhuang, H. 2022. An investigation of the altered textural property in woody breast myopathy using an integrative omics approach. Frontiers in Physiology. https://doi.org/10.3389/fphys.2022.860868.
DOI: https://doi.org/10.3389/fphys.2022.860868

Interpretive Summary: The poultry industry has seen many improvements in the growth efficiency of broilers, such as a reduction to the time of slaughter, and increases in overall body weight, muscle yield and feed conversion efficiency in the past couple decades. However, the improvement in production efficiency have also led to the increased incidence of a number of meat quality issues, most notably, the Woody Breast (WB) syndrome. Meat suffering from WB is characterized by hardened areas and ridge-like bulges at both the caudal and cranial regions of raw broiler breast fillets. As of 2015 in the United States, the incident rates of WB ranged from 30 to 50% and costed the industry over $200 million per year in economic losses. The apparent tough and rubbery texture abnormalities in WB are well defined, but the exact cause of WB in broilers remains unknown. Therefore, the objective of this study was to investigate biochemical factors contributing to the abnormal texture observed in WB and enzymatic activities that may influence WB texture during postmortem aging. Our data showed that the WB fillets were heavier (522.9 vs. 446.9g) and had a higher pH (6.17 vs. 5.83). There was no difference in objective tenderness measurements of cooked meat (34.09 vs. 37.69 N), but raw WB tended to have shorter sarcomeres (1.70 vs. 2.02 µm) and less intact muscle protein troponin-T. The WB had more activated calpain (71.05 vs. 59.12% calpain autolyzed) and collagenase (13.24 vs. 7.84%). Purge from WB had higher levels of free calcium (6.2 vs. 4.2 nmol calcium/mg protein). There was increased collagen in WB (3.89 vs. 2.08 mg collagen/g muscle tissue), as well as more mature crosslinks in WB (0.23 vs. 0.14 mol PYD/mol collagen; 0.07 vs. 0.04 mol DPD/mol collagen). Finally, WB had a higher peak transitional temperature (65.47 vs. 63.72°C). The results indicated that the cause of texture abnormality of WB may be the combined effects of more calcium being released from the sarcoplasmic reticulum early postmortem resulting in shorter sarcomere length and more collagen being deposited in the chicken breast meat.

Technical Abstract: Woody breast (WB) is a myopathy observed in chicken Pectoralis major characterized by its tough and rubbery texture. Unfortunately, the exact causation of WB texture remains unknown. The objective of this study was to investigate factors and enzymatic activities that may contribute to the abnormal texture observed in WB. Fourteen Ross line broiler breast fillets (7 severe WB and 7 normal) were collected at 3 h postmortem from a commercial processing plant. Each sample was trimmed, weighed, vacuum packaged and frozen at -20°C at approximately 8 h postmortem. One 1.9 cm strip across the cranial end of each fillet was fabricated and pulverized in liquid nitrogen to measure pH, objective tenderness, sarcomere length, proteolysis, calpain activity, collagenase activity, collagen content, collagen crosslinks and peak transitional temperature measurements. Purge was collected from each sample to evaluate free calcium concentration. The WB fillets were heavier (522.9 vs. 446.9g; P<0.05) and had a higher pH (6.17 vs. 5.83; P<0.05). Objective tenderness was not significantly different (34.09 vs. 37.69 N; P>0.10), but WB tended to have shorter sarcomeres (1.70 vs. 2.02 µm; P=0.0543) and less intact troponin-T (relative intact troponin-T band density: 49.98 vs. 56.97%; P=0.0515). The WB had more autolyzed µ/m calpain (71.05 vs. 59.12% calpain autolyzed; P<0.01) and more activated collagenase (13.24 vs. 7.84% activated MMP2; P<0.05). Purge from WB had higher levels of free calcium (6.2 vs. 4.2 nmol calcium/mg protein; P<0.05). There was increased collagen in WB (3.89 vs. 2.08 mg collagen/g muscle tissue; P<0.05), as well as more mature crosslinks in WB (0.23 vs. 0.14 mol PYD/mol collagen; P < 0.05; 0.07 vs. 0.04 mol DPD/mol collagen; P < 0.01). Finally, WB had a higher peak transitional temperature (65.47 vs. 63.72°C; P<0.05). The results indicated that the cause of texture abnormality of WB may be the combined effects of more calcium being released from the sarcoplasmic reticulum early postmortem resulting in shorter sarcomere length and more collagen being deposited in the chicken breast meat.