Oxytetracycline Residues in Four Species of Fish after 10‐Day Oral Dosing in Feed

• Published in: Journal of aquatic animal health 2004-12, Vol.16 (4), p.208-219
• Main Authors: Chen, C. Y., Getchell, R. G., Wooster, G. A., Craigmill, A. L., Bowser, P. R.
• Format: Article
• Language: English
• Subjects: Ictalurus punctatus; Morone chrysops; Morone saxatilis; Oncorhynchus; Oreochromis niloticus; Paralichthys dentatus; Salmo; Sander vitreus
• ISSN: 0899-7659; 1548-8667
• DOI: 10.1577/H04-071.1

Residues of oxytetracycline (OTC) in serum, liver, and muscle–skin were measured in sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis), Nile tilapia Oreochromis niloticus, summer flounder Paralichthys dentatus, and walleyes Sander vitreus (formerly Stizostedion vitreum). These studies were conducted to compare the time for OTC concentrations to fall below 2.0 μg/g (the current tolerance set by the U.S. Food and Drug Administration (USFDA)) among fish species representing various culture conditions of freshwater and salt water as well as different temperature niches. The sum of mean tissue OTC concentration plus two standard deviations in the edible portion (muscle plus skin) of all fish was below 2.0 μg/g at 11 d postdosing. When possible, depletion data were fitted to a one‐compartment pharmacokinetic model. Although temperature niche did not appear to consistently affect residue depletion within species, the warmwater species (sunshine bass and Nile tilapia) often had lower residue concentrations at each time point than did the coolwater species (summer flounder and walleye). For all test species, the period of OTC residue depletion below the USFDA tolerance level was less than the currently established 21‐d withdrawal period for OTC in trout Salmo spp., salmon Oncorhynchus spp., and channel catfish Ictalurus punctatus.