Immunotoxicity and effects of gut microbiota in chicks exposed to low doses of deoxynivalenol and 15-acetyl-deoxynivalenol

Deoxynivalenol (DON) contamination in animal feed threatens livestock health due to chronic low-dose exposure and masked forms. 15-acetyl-deoxynivalenol (15ADON), a major masked form, exhibits stronger toxicity than DON in cell models, yet in vivo data, particularly in poultry, remain scarce. To address this gap, 1-day-old chickens were fed diets containing 3 mg/kg DON, 3 mg/kg 15ADON, or a combination of 1.5 mg/kg each. Immunotoxicity and cecal microbiota were evaluated through immune parameters and 16S rRNA sequencing. To examine cumulative effects, chickens were also exposed to low-dose DON at different developmental stages. Both DON and 15ADON induced evident immunotoxicity, including immune organ damage. Compared with controls, 15ADON reduced antibody titers against infectious bronchitis and Marek's disease viruses by 30 % and IgM levels by 50 % during early immune development. Co-exposure produced no synergistic effects, whereas prolonged low-dose DON exposure initially enhanced antibody production but later caused a 20–50 % decline relative to controls. Microbiota analysis revealed an increased abundance of Lactobacillus in DON and 15ADON treated groups, while overall microbial richness and diversity remained unchanged. These findings demonstrate that 15ADON exerts comparable immunotoxicity to DON, highlight the importance of exposure timing and duration, and reveal masked mycotoxins as underappreciated risks in poultry production. Our results provide valuable in vivo evidence to support the reassessment of regulatory limits and further investigation into masked mycotoxin toxicity.