Spaghetti meat and gaping in broilers: emerging myopathies challenging poultry meat quality and processing

The global poultry industry has experienced rapid growth, driven by consumer demand for affordable, high-quality protein. However, this progress has been accompanied by the emergence of growth-related myopathies, notably Spaghetti Meat (SM) and the more recently described Gaping, which compromise meat quality, yield, and marketability. SM, first reported in 2015, is characterized by the detachment and weakening of Pectoralis major fibers, resulting in a stringy, mushy texture of the meat. Gaping, affecting the Pectoralis minor, presents as separations between fiber bundles and tendon tears. Incidence rates of SM vary widely, from 10% to over 36%, while gaping prevalence remains inconsistently reported. Detection traditionally relies on visual scoring, but novel approaches, such as bioelectrical impedance, automated imaging, and spectroscopy, are under investigation to enable early identification. Histological analyses reveal shared features of muscle degeneration, fibrosis, lipid infiltration, and altered collagen structure, with oxidative stress and impaired regeneration implicated in both myopathies. Multiple factors contribute, including genetics, muscle hypertrophy, nutrition, environment, and processing conditions. Notably, delayed chilling, aggressive defeathering, immersion water chilling, and mechanical breast filleting increase SM severity, while dietary antioxidants and trace minerals can sometimes mitigate occurrence. SM and gaping affect technological quality by reducing textural integrity, protein solubility, and water-holding capacity, although their impacts are less severe than wooden breast or white striping. Current mitigation strategies focus on selective breeding, optimized nutrition, and modified processing parameters, but the complexity of these myopathies underscores the need for integrated approaches. Future research should prioritize in short term, the non-genetic strategies, including improvements in processing, nutrition, and management, while in the long term, the genetic basis of this myopathy, particularly the coexistence of affected and unaffected birds within the same population, to support balanced breeding strategies that preserve meat quality and consumer acceptance.