Assessment of Biosafety and Fillet-Residues After Florfenicol Exposures in Trachinotus Blochii to Ensure Safe-Applications in Disease Incidences

Abstract

Trachinotus blochii is a promising mariculture fish species. Scientific data on biosafety and fillet residues of florfenicol exposure, one recommended amphenicol antimicrobial for aquaculture use, remains unknown in T. blochii, despite its criticality for prudent application. Accordingly, the paper evaluated the safety (regarding mortality, symptoms, weight gain, and histopathology) of dietary florfenicol after therapeutic (10 mg Kg-1 for ten days) and excessive (three, five, and ten times the therapeutic dose for 10, 20, and 30 days) exposures. There was no mortality in any group. The clinical abnormalities were noted only in 10X group from the 25th exposure day, which disappeared on the fourth day after withdrawal. Reduced growth was recorded at 5X and 10X groups from 20 and 30 exposure days, respectively. Histological lesion`s severity was in the liver > kidney > gill > spleen > muscle > intestine. The lesion severity relied on the quantity and duration of exposures, with maximum severity in 5X and 10X groups on the 30th day. After recommended therapeutic exposure, fillet residues were below the maximum residual limit accepted by the European Union (1000 μg Kg-1) from day three of the withdrawal, showing a minimum three-day is necessary to reach a safe, acceptable level.