Thermal stress responses and heat stress resilience genes in chickens are revealed through genomic and transcriptomic insights.

Climate change creates major challenges in livestock industry, making chickens vulnerable to heat stress because they can tolerate a narrow range of temperatures. Heat stress disrupts metabolic and physiological homeostasis, leading to reduced growth, productivity, reproduction, and immune function, thereby threatening the economic viability of poultry farming. This review explores the multifaceted impacts of heat stress on poultry, including physiological responses, production performance, and immune function. Recent advances in transcriptomic and genomic research have shed light on the molecular mechanisms underlying heat stress resilience in poultry. Key genes such as HSP70, HSP90, HSP27, and HSP47 are significantly upregulated under heat stress, playing vital roles in protein folding, preventing aggregation, and protecting cellular integrity. Additionally, genes like SOD and CAT enhance antioxidant defenses, mitigating oxidative damage. Genes such as RB1CC1, BAG3, and TRMT1L regulate apoptosis and oxidative stress, promoting cell survival. In the liver, CCK, DIO3, and ANGPTL4 improve energy homeostasis and reduce metabolism-related heat production, while BMP10 and MYH7 in the heart contribute to cardiac adaptation during thermal stress. Genetic adaptations such as the Naked neck, Frizzle, and Dwarf gene provide intrinsic thermotolerance by reducing feather mass, altering feather structure, and minimizing body size, thereby improving heat dissipation. These genetic traits, combined with transcriptomic insights into heat resilience genes, offer opportunities for developing heat-tolerant chicken breeds. By integrating molecular genetics, transcriptomics, and management strategies, this review highlights the importance of selective breeding programs to enhance poultry thermotolerance. Future research should focus on leveraging indigenous breeds, advanced molecular tools, and nutritional interventions to mitigate the effects of rising global temperatures. Enhancing heat stress resilience in poultry is imperative to ensure sustainable production and global food security in this climate change.