Relationship between the white striping and woody breast myopathies in broiler breast fillets

Authors: Bowker, Brian; Zhuang, Hong; Yoon, Seung-Chul

Submitted to: International Congress of Meat Science and Technology Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/22/2018
Publication Date: 8/12/2018
Citation: Bowker, B.C., Zhuang, H., Yoon, S.C. 2018. Relationship between the white striping and woody breast myopathies in broiler breast fillets. International Congress of Meat Science and Technology Proceedings. http://icomst-proceedings.helsinki.fi/papers/2018_10_19.pdf.

Interpretive Summary: This study demonstrated that the occurrence and severity of the woody breast (WB) and white striping (WS) myopathies are closely related in broiler breast meat, but that the relationship is influenced by breast fillet weight. Data also suggest that visual traits such as WS, fillet shape, and hemorrhaging on the muscle surface may not be accurate indicators of WB.

Technical Abstract: The objective of this study was to evaluate the relationship between WB and WS occurrence and degree of severity in broiler breast fillets. More than 2600 boneless skinless breast fillets (Pectoralis major) were collected at 3 h postmortem from the deboning line of a commercial processing plant that slaughters large broilers (3.6-4.1 kg live weight). Breast fillets were weighed and assessed independent WB and WS scores from 1.0 to 3.0 in 0.5 score increments (normal = 1; moderate = 2; severe = 3). Fillets were also scored for individual WB-related attributes (hardness, muscle rigidity, prominence of caudal bulginess) and petechial hemorrhaging. Data were analyzed using chi-square, frequency, and correlation analyses. Chi-square analysis indicated that there was a significant relationship between WB and WS scores (P<0.0001). Approximately 94% of all WB fillets (WB score = 1.5) also exhibited WS. Of the fillets that did not exhibit WB, 54% exhibited WS. Of the fillets that exhibited severe WB, 28% had severe WS, 51% had moderate WS, and 21% had mild or no WS. Approximately 83% of all WS fillets (WS score = 1.5) exhibited WB. Of the fillets that did not exhibit WS, 26% exhibited WB. Of the fillets that exhibited severe WS, 41% had severe WB, 46% had moderate WB, and 13% had mild or no WB. Overall, there was a significant correlation between WS and WB scores (r = 0.55, P<0.0001), but the incidence of the myopathies varied by fillet weight. Fillet weights were moderately correlated to WB (r = 0.44, P<0.0001) and WS (r = 0.32, P<0.0001) scores. For fillets <407 g, 28% of samples had moderate or severe WS and 22% had moderate or severe WB. However, for fillets > 528 g, 70% of samples had moderate or severe WS and 77% had moderate or severe WB. The strength of the correlation between WS and WB scores decreased with fillet weight. Scores for WB-related attributes of hardness, rigidity, and bulginess were more strongly related to WB (r = 0.88-0.96, P<0.0001) than WS scores (r = 0.44-0.48, P<0.0001). Tactile attributes were strongly related to one another (r = 0.83-0.91, P<0.0001). Although the incidence of severe hemorrhaging was more frequent in fillets with severe WS or WB, the overall relationship between petechial hemorrhaging and myopathy scores was low (r = 0.26-0.38). Although the occurrence and severity of the WS and WB myopathies in breast fillets are closely related, breast fillets exhibiting WS without WB are more likely to be observed than WB fillets without WS. The strength of the relationship between the WB and WS myopathies in breast meat from large broilers is also influenced by fillet weight.