Mechanism of Silybin in Alleviating Liver Damage Induced by Heat Stress of Peking Ducks

This study aimed to explore the protective mechanism of silybin against heat stress-induced liver injury in Peking ducks as a result of oxidative stress, inflammation, and lipid metabolism. One hundred and ninety-five 1-day-old healthy male Peking ducks with similar body weights were randomly divided into a control group, a heat-stress group, and three intervention groups treated with 400, 800, and 1600 mg/kg silybin under heat-stress from 21 d to 35 d for two weeks. The function indices, oxidative stress, inflammatory factor levels, histopathological changes and non-targeted lipidomic profiling in liver as well as growth performance were evaluated. Results showed that silybin supplementation partially alleviated the heat-stress-induced decreases in average daily feed intake and body weight gain (p > 0.05). Silybin supplementation at 400 and 800 mg/kg significantly reduced the heat-stress-induced increases in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and γ-glutamyl transpeptidase (γ-GGT) (p < 0.05), whereas the effect of 1600 mg/kg silybin was not significant. Albumin (ALB) and globulin (GLB) levels were mainly improved in the 800 mg/kg group, and GLB was also increased in the 400 mg/kg group (p < 0.05). Silybin supplementation significantly improved hepatic antioxidant capacity, especially in the 400 and 800 mg/kg groups, as indicated by increased superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC), and decreased malondialdehyde (MDA) and reactive oxygen species (ROS) levels (p < 0.05). In addition, the 400 and 800 mg/kg groups showed more significant reductions in the pro-inflammatory factors IL-6 and TNF-α, while IL-10 was increased in silybin-supplemented groups (p < 0.05). Lipid metabolism disorders were improved through regulation of the sphingolipid and glycerophospholipid metabolism pathways, while it alleviated heat stress damage by reducing the expression of heat shock proteins. In conclusion, silybin holds promise as an effective feed additive to alleviate heat stress in poultry. This study provides a theoretical basis and practical approach for improving the health and productive performance of Peking ducks under heat-stress conditions.