Abstract
Rising temperatures and intensified agricultural practices have heightened heat stress (HS)-related challenges in poultry farming, notably heat-induced sudden death in chickens. Wenchang chickens, recognized for their heat resistance, have emerged as the potential candidates for improving the economic efficiency of poultry farming. The adrenal gland plays a crucial role in preventing HS-induced heart failure sudden death by secreting hormones. However, little is known about the damage to and resilience of Wenchang chicken adrenal glands during HS. In this study, 34 healthy Wenchang chickens with similar weights were selected for formal experimentation, with 10 as the control group (Con). Following a single exposure to acute HS of 42 ± 1°C and 65% relative humidity for 5 h, 15 deceased individuals formed the HS death (HSD) group, and 9 survived comprised the HS survival (HSS) group. ELISA revealed significant higher (P < 0.05) levels of COR and NE in the HSS and the lowest levels of CORT and EPI in the HSD. Histopathological analysis indicated major degeneration in HSS cortical and chromaffin cells and extensive cell necrosis (nuclear pyknosis) in HSD. Proteomic analysis identified 572 DEPs in HSD vs. Con and 191 DEPs in HSS vs. Con. Bioinformatics highlighted ER protein processing, especially ERAD as a key pathway for heat stress resistance (HSR) in the adrenal gland, with HSPH1, DNAJA1, HSP90AA1, HSPA8 and HERPUD1 identified as regulating key molecules. Western blotting validated significantly higher (P < 0.01) protein levels in both HSS and HSD compared to the Con. Immunohistochemical staining showed increased cytoplasmic HSPH1-positive signal intensity under HS and enhanced HSP90AA1 nuclear signals, strongest in HSS. In summary, HS induces pathological damage in Wenchang chicken adrenal glands, affecting hormone secretion, and various heat shock proteins play crucial roles in cellular resistance. These results elucidate the biological basis of HSR in Wenchang chickens from the perspective of the adrenal gland and provide necessary research foundations for enhancing economic performance of various broilers in high-heat environments and screening drugs for HS treatment.