Piscine cytochromes P450 (CYP) and their response to antimicrobial drugs

Most research on the P450 (CYP) system in teleosts has been done on environmental factors that influence their induction. Less is known about CYP metabolism of aquaculture antibiotics. This article outlines the impact of aquaculture antimicrobials on the piscine CYP system, with particular regard to interactions with tetracyclines, fluoroquinolones, sulphonamides, berberine and chloramphenicol, as paradigms for current, potential and discontinued piscine antimicrobial drugs. It gives an overview of literature reports and advances in the field of biological significance of the CYP in fish. Emphasis has been placed on highlighting the most significant isoforms for biotransformation of drugs, and their drug response mechanisms. The challenge is to elucidate the differences in responses of CYP enzymes in different species to antimicrobial treatment as they may have relevance for the use of antimicrobials in aquaculture, especially as drug interactions with the fish CYP may alter their distribution, metabolism and elimination. They can impact the metabolism of other drugs metabolized by the same system with an effect on the physiology of fish administered these antimicrobials. Also, they can affect the persistence of residues and the length of the withdrawal period. For food animals such as farmed fish, this knowledge is a fundamental biomedical goal.