Dietary Supplementation of Novel Aflatoxin Oxidase CotA Alleviates Aflatoxin B1-Induced Oxidative Stress, Lipid Metabolism Disorder, and Apoptosis in the Liver of Japanese Quails

This research explored the role of aflatoxin oxidase CotA in mitigating aflatoxin B₁ (AFB₁)-induced hepatotoxicity in Japanese quails. A total of 225 female Japanese quails, aged two weeks, were randomly assigned to three dietary groups: a control diet, an AFB₁-contaminated diet, and an AFB₁-contaminated diet supplemented with aflatoxin oxidase CotA for three weeks. The results indicate that quails receiving the AFB₁-contaminated diet exhibited reduced body weight gain, pronounced vacuolar degeneration within hepatocytes, and inflammatory cell infiltration. Additionally, the AFB₁ group demonstrated an increased liver index and elevated serum liver enzyme activities (ALT, AST, and ALP). Supplementation with CotA improved body weight gain and conferred protection against AFB₁-induced liver injury. Furthermore, the addition of CotA significantly enhanced liver antioxidant enzyme activities (T-AOC, GST, GSH-Px, POD, and CAT), reduced hepatic H₂O₂ and MDA levels, and upregulated the mRNA expression levels of genes in the Nrf2 pathway in quails exposed to AFB₁. AFB₁ exposure led to lipid droplet accumulation in liver tissues and elevated serum TG and LDL-C levels. However, the introduction of CotA mitigated AFB₁-induced alterations in lipid metabolism. Furthermore, dietary supplementation with CotA inhibited AFB₁-induced hepatocyte apoptosis and decreased the mRNA expression of apoptosis-related genes, including Bax, caspase-9, and caspase-3. Notably, the AFB₁+CotA group exhibited a significant reduction in AFB₁ residues and AFB₁-DNA adducts in quail liver tissues compared to the AFB₁ group. These findings indicate that aflatoxin oxidase CotA holds promise as a feed additive to alleviate AFB₁-induced hepatotoxicity.