摘要Background Chronic heat stress(CHS)is a detrimental environmental stressor with a negative impact on the meat quality of broilers.However,the underlying mechanisms are not fully understood.This study investigates the effects of CHS on long non-coding RNA(lncRNA)expression and muscle injury in broilers,with a focus on its implications for meat quality.Results The results showed that CHS diminished breast muscle yield,elevated abdominal fat deposition,induced cellular apoptosis(P＜0.05),and caused myofibrosis.Transcriptomic analysis revealed 151 differentially expressed(DE)lncRNAs when comparing the normal control(NC)and HS groups,214 DE lncRNAs when comparing the HS and PF groups,and 79 DE lncRNAs when comparing the NC and pair-fed(PF)groups.After eliminating the confounding effect of feed intake,68 lncRNAs were identified,primarily associated with cellular growth and death,signal transduc-tion,and metabolic regulation.Notably,the apoptosis-related pathway P53,lysosomes,and the fibrosis-related gene TGF-β2 were significantly upregulated by lncRNAs.Conclusions These findings indicate that chronic heat stress induces cellular apoptosis and muscle injury through lncRNA,leading to connective tissue accumulation,which likely contributes to reduced breast muscle yield and meat quality in broilers.