The dual action of astaxanthin: activating the Nrf2 pathway and suppressing NF-κB to combat AFB1-induced liver injury in broilers.

Aflatoxin B1 (AFB1), a mycotoxin that primarily targets the liver, poses a serious threat to the poultry industry. Astaxanthin (AST), a potent natural antioxidant, has been shown in our previous research to alleviate the toxic effects of AFB1 on chick embryo liver cells (CELs). This study advances our prior observation by providing the first in vivo evidence to investigate tissue damage caused by AFB1 in broilers and the protective effect and mechanism of AST, and compared its efficacy with that of biphenyl dimethyl dicarboxylate (DDB), a clinical hepatoprotective drug. The broilers were divided into control, AFB1 model, positive control DDB (25 mg/kg), and low-, medium-, and high-dose AST intervention groups (20, 40, 80 mg/kg). After the experimental period, blood and liver samples were collected for analysis. The findings showed that AFB1 increased the serum enzyme activities of GOT(105%± 5.9), GPT(56%±3.2), and ALP (46%±2.6), as well as the levels of TBIL (200%±8.3) and MDA (250%±10.4), while decreasing the activities of CAT (27.5%±1.8) and SOD (68.75%±4.4) and the level of GSH (33.33%±6.7). It also promoted the expression of inflammatory factors TNF-α (81.8%±5.3), IL-6 (75%±8.2), and IL-1β (56.25%±1.7), resulting in significant liver injury. AST (80 mg/kg) treatment significantly reversed these AFB1-induced alterations (P < 0.01), and alleviated liver damage. Western blot analysis demonstrated that AST activated the AFB1-suppressed Nrf2 signaling pathway, as evidenced by the upregulated expression of its downstream targets HO-1, NQO1, GCLC, and GCLM. Furthermore, AST inhibited the AFB1-induced phosphorylation of P65 and IκBα proteins in the NF-κB signaling pathway. In summary, AST mitigated AFB1-induced hepatotoxicity in AA broilers by activating the Nrf2 antioxidant pathway and suppressing the NF-κB inflammatory pathway. These findings support the direct incorporation of astaxanthin into broiler diets as a practical, nutraceutical strategy to mitigate AFB1-related losses in poultry production.