Postmortem muscle proteomics reveals breed specific responses to environmental enrichment and broiler meat quality.

The meat industry faces growing pressure to adopt sustainable and welfare-friendly practices. This study used mass spectrometry-based proteomics to examine the effects of genetics and on-farm environmental enrichment on broiler performance and meat quality. Slower-growing (SG; Hubbard S757N) and faster-growing (FG; Hubbard JA787) broilers were raised in enriched and non-enriched environments within higher-welfare systems. The SG broilers showed higher expression of detoxification and cytoskeletal proteins, supporting robust muscle architecture, higher protein content and reduced moisture retention. Enriched environments further enhanced immune function, metabolic resilience and physical health in SG broilers. Conversely, FG broilers prioritised anabolic pathways, driving rapid muscle growth and intramuscular fat accumulation. Growing in enriched conditions led to reduced breast yield in FG broilers, likely due to higher proteasome activity. These findings highlight the importance of breed-specific strategies to support sustainable farming, as only SG broilers benefited from environmental enrichment, potentially improving meat quality while supporting welfare outcomes.