Clausena lansium (Lour.) Skeels Leaf Volatile Oil Emulsion Alleviates Heat Stress-Induced Liver Injury in Broilers Accompanied by Modulation of Autophagy- and Ferroptosis-Related Pathways

Heat stress (HS) severely compromises broilers’ health and production performance. This study aimed to evaluate the protective effects of Clausena lansium (Lour.) Skeels (wampee) leaves volatile oil emulsion (WVOE) against HS-induced liver injury in broilers and to investigate its underlying mechanisms. A total of 120 broilers were randomly allocated into five groups (3 replicate cages per group, 8 broilers per cage): Control (22 ± 2 °C), HS (Heat stress, 35 ± 2 °C and 80 ± 10% relative humidity for 8 h/day for 7 consecutive days), VitC (HS + Vitamin C, 60 mg/kg), WVOE-H (HS + WVOE, 3 mg/kg), and WVOE-L (HS + WVOE, 0.75 mg/kg). VitC and WVOE were administered intragastrically 1 h after daily HS exposure. HS impaired growth performance, as evidenced by decreased final body weight and average daily gain (ADG) and an increased feed conversion ratio (FCR). WVOE-L administration reduced FCR compared with the HS group. HS also impaired liver function and induced oxidative injury, as reflected by increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity, decreased total protein (TP) and albumin (ALB) levels, elevated hepatic malondialdehyde (MDA) content, reduced superoxide dismutase (SOD) activity and glutathione (GSH) levels. WVOE and VitC ameliorated these alterations, thereby alleviating liver injury and oxidative stress. Both WVOE and VitC treatment partially ameliorated these alterations and were associated with milder histopathological changes, suggesting alleviation of HS-induced liver injury and oxidative stress. Under HS conditions, WVOE decreased HSP70 and IL-6 protein expression and was accompanied by changes in autophagy-related signaling, including increased LC3-II/LC3-I ratio, protein expressions of Beclin-1, ULK1, ATG4B, ATG5, and ATG7, and reduced p62 accumulation. WVOE increased gene and protein expression of GPX4 and SLC7A11 and decreased ACSL4 expression. In conclusion, WVOE alleviated several indices of HS-induced liver injury in broilers, accompanied by changes in autophagy-related signaling and ferroptosis-related molecular responses.