White Striping Myopathy in Broilers: A Review of Genetic Factors and Non-Genetic Modulators

White Striping (WS) is a macroscopic defect of the pectoralis major muscle, characterized by distinct white striations that impair meat acceptability and commercial value. It is a phenotype with polygenic inheritance, controlled by several QTLs and genes associated with muscle repair and metabolism. Beyond genetic factors, phenotypic manifestation is strongly modulated by the environment. This review integrates research on genetic predispositions and modulating factors to provide a holistic overview of WS in broilers. The defect predominantly affects heavier birds with high breast yield and elevated ultimate breast pH. LRSAM1 gene, on chromosome GGA17, is identified as a putative candidate gene as its expression co-localizes with the phenotypic QTL. Chromosome GGA5 has recently been identified as the primary genomic region of interest hosting a cluster of specific markers. Research on dietary strategies has extensively explored the manipulation of feed formulations, especially of amino acids. While results for some nutrients like methionine remain conflicting, restricting lysine during the growth phase could be an effective dietary intervention for reducing WS severity. Management offers the most practical short-term solutions, whereas selective breeding enables meaningful and permanent progress across generations, given the moderate heritability of many quality-related traits. Effective mitigation requires an integrated approach combining welfare, environmental control, and precision feeding throughout the production cycle, while acknowledging trade-offs with productivity. To meet evolving consumer expectations, the industry must embrace practices that are simultaneously scientifically rigorous, ethically responsible, and environmentally sustainable.