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Safety of aquaflor (florfenicol, 50% type a medicated article), administered in feed to channel catfish, Ictalurus punctatus

Gaikowski, M. P., Wolf, J. C., Endris, R. G., and Gingerich, W. H., 2003, Safety of aquaflor (florfenicol, 50% type a medicated article), administered in feed to channel catfish, Ictalurus punctatus: Toxicologic Pathology, v. 31, no. 6, p. 689-697.

Abstract

Aquaflor, a feed premix containing the broad spectrum antibacterial agent florfenicol (50% w/w), is being developed for use to control enteric septicemia (ESC) in channel catfish Ictalurus punctatus caused by the gram-negative enterobacterium Edwardsiella ictaluri. The recommended dose of Aquaflor to control ESC is 10 mg/kg body weight (BW)/day for 10 days. The study objective was to determine the safety of Aquaflor administered in feed to channel catfish at doses of 0 (control), 10, 30, and 50 mg/kg BW/day for 20 consecutive days. Parameters evaluated included daily mortality, behavioral (appetite, distribution, flight/fright response), and water chemistry observations, initial and terminal weight measurements, and gross and microscopic pathology. Medicated feed consumption was 67-86% of target with group mean doses of 8.5 mg/kg BW/day, 24.6 mg/kg BW/day, and 34.9 mg/kg BW/day. There were no mortalities or clinically observable changes noted at any of the dose levels tested. Aquaflor-related changes were limited to the food consumption and histopathology data. Although Aquaflor-related decreased feed consumption was noted in the 30 and 50 mg/kg BW/day groups, there were no differences in fish growth among the treatment groups. Aquaflor-related histopathology findings were limited to a histomorphologically evident dose-dependent decrease in hematopoietic/lymphopoietic tissue in the anterior kidneys, posterior kidneys, and spleens of channel catfish.

Keywords: Aquaflor, florfenicol, channel catfish, enteric septicemia, medicated feed, Cyprinus-carpio L, trout Oncorhynchus-mykiss, experimental-animals, Atlantic salmon, immune-system, in-vitro, chloramphenicol, oxytetracycline, fish, thiamphenicol