LAUSR

BACKGROUND This study aimed to investigate the molecular mechanisms involved in the onset of the White Striping (WS) myopathy with particular attention to the role of oxidative stress and protein oxidation in the loss of meat quality. RESULTS WS-M (moderate degree; white stripes <1 mm thickness) and WS-S (severe degree; white stripes >1 mm thickness) breasts presented higher pH, hardness, redness, lipid, and collagen content, and lower lightness compared to the Normal breast. Compared to the latter, WS-S had a more severe loss of protein thiols (70.7% less thiols than in N), reduced activity of antioxidant enzymes such as catalase (23 vs 40 U/g), glutathione peroxidase (0.21 vs 0.54 U/g) and superoxide dismutase (56 vs 73 U/g), and consequently, had greater accretion of thiobarbituric acidreactive substances (0.64 vs 0.22 mg MDA/kg muscle), allysine (3.1 vs 1.9 nmol/mg protein) and Schiff base structures (645 vs 258 fluorescent units). The analysis of sarcoplasmic proteins revealed that muscles severely affected by the myopathy suffered a chronic impairment of physiological (upregulation of sarcoplasmic reticulum Ca2+ ATPase, sarcalumenin and calsequestrin-2) and metabolic processes (downregulation of pyruvate kinase, creatine kinase and L-lactate dehydrogenase). CONCLUSION The overexpression of ribonuclease/angiogenin inhibitor 1 and Kelch-like proteins in WS chicken breasts indicates altered protein turnover plausibly mediated by oxidative stress and accumulation of oxidized proteins. This article is protected by copyright. All rights reserved.