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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