Erythromycin in aquaculture: studies for drug incorporation in feed and for residual depletion in fish

Abstract

Aquaculture is an intensive system dedicated to production of aquatic animals such as fish and crustaceans, this practice generates more homogenous and traceable products, but represents an environment favorable to spread diseases. In Brazil, aquaculture is growing rapidly. Although there is a growing market for animal health products and veterinary drugs, there are few options for regulated medicines for use in aquaculture in Brazil, which may lead to inappropriate use of products and substances. In this view, there is a scenario of great demand for new therapeutic alternatives that are effective against the major diseases that affect aquaculture species of commercial interest for Brazil and that may be regulated for veterinary use in this sector. Erythromycin is a macrolide antimicrobial, widely known and used in human and veterinary medicine, which acts by interfering with bacterial protein synthesis. This drug has a wide activity against gram-positive bacteria, such as streptococci, staphylococci and gram-positive diplococci, with at least three Streptococcus species causing outbreaks with great losses and economic impact in Brazil. Although erythromycin is a high potency antibiotic, its use in fish farming is not regulated in Brazil yet, although it is already approved for use in other countries. In this project, it is proposed to carry out a residual depletion study of erythromycin in pacu after oral administration aiming at estimating a minimum withdrawal time to be recommended, considering food safety issues. To do so, a study of drug incorporation in the feed will also be carried out aiming at obtaining a homogenous process and capable of avoiding or mitigating the risk of leaching of the drug from the feed to the aquatic environment. Furthermore, an analytical method will be developed employing the promising dispersive liquid-liquid microextraction technique in the sample preparation stage and the high efficiency liquid chromatography coupled to mass spectrometry. (AU)