Determination of illegal antimicrobials in aquaculture feed and fish: An ELISA study.

Antimicrobials are added to the feed or drinking water of food-producing animals to reduce suscepti-bility to infection, accelerate weight gain, or reduce the amount of food required to gain weight. Somecompounds have been banned for food safety reasons, for other agents the U.S. Food and DrugAdministration (FDA) is implementing a plan with industry to phase out a number of antibiotics.The concentrations of crystal violet (CRY), chloramphenicol (CAP), gentamicin (GEN),fluoroquinolone-enrofloxacin (FQ), malachite green (MG), and the metabolites of furaltadone (FU) and furazolidone (FZ)antibiotics (respectively AMOZ and AOZ) were determined in 30 samples both feed andfish from anaquaculture farm in eastern Sicily (Italy) using commercial ELISA Kits. Levels exceeding the method'sdetection capability were found in all feed and tissue samples. Feed contained all the analytes tested;GEN, CRY and CAP showed the highest mean concentrations, respectively 31.8, 4.05 and 3.67mgkg1. Themean concentrations of CAP, CRY, FQ, MG, AMOZ and AOZ in muscle were 0.57, 2.05, 0.14, 0.48, 0.29 and0.09mgkg1, respectively (the assay was not certified to determine GEN in muscle). The higher levelsdetected in feed are explained by the fact that 50% of farmedfish is used to makefish meal, thuscompounding bio-accumulation. Our data show that aquaculture feed andfish contain banned antimi-crobials. Consumption of farmedfish may therefore involve a risk for consumers, besides contributing tothe growth of antibacterial resistance. Surveys of larger feed andfish samples are needed to achieve amore reliable assessment of consumer risk.