Résumé
Mycotoxins contamination of agricultural commodities poses a serious risk to animal health, including aquaculture species. While chronic effects of mycotoxins, including immunosupression, are much more important than acute toxicities, they are much less evident. Ochratoxin A [OA] is the most immunotoxic ochratoxin, yet little is known about its effect on immune function in fish. Antimicrobial polypeptides [AMPPs] are one of the most potent, innate, host defense factors, yet very little is known about what types of chronic stressors affect their expression. Among the most prevalent and potent AMPPs in fish are histone-like proteins [HLP]. In this study, fish were fed 2, 4, or 8 ppm OA. Skin antibacterial activity was measured on Days 0, 28 and 56. Feeding 2, 4 or 8 ppm OA resulted in no changes in AMPP expression in any treatment group. Our data suggests that the immunosuppression of OA is probably due to impaired cell-mediated immune mechanisms other than a direct effect on antimicrobial polypeptide expression