title: Oxytetracycline residues in channel catfish: a feeding trail.
abstract: Channel catfish were fed a sinking diet containing 3% oxytetracycline (OTC) once-a-day (SID) or twice-a-day (BIO) for 2 and 3 weeks and liver and muscle residues were determined. HPLC analysis for muscle indicated mean OTC levels of 0.052 ppm (0-0.15) for control, 0.242 ppm (0-2.95) for SID, and 0.979 ppm (0-11.0) for BID-dosed fish. Liver was 0.003 ppm (0-0.08) for control, 0.188 ppm (0-0.52) for SID, and 1.022 ppm (0-9.3) for BID-dosed fish. The Charm 11 assay detected OTC (control point set at 100 ppb) in 6.9% of muscle and 10.0% of liver in controls, 47.4% of muscle and 56.0% of liver in the SID group, and 78.0% of muscle and 80.0% of liver in the BID group. An interfering peak on HPLC was detected in 24.0% of the muscle samples of controls, but not livers, which affects this assessment. Liver false negative rate was 29.0% and false positive rate was 13.0%, and setting the optimal control point changed the false positive rate to 12.9%. A positive correlation (0.946) for muscle and liver OTC levels was calculated, indicating liver may be a suitable alternative to muscle for screening OTC in channel catfish. The CITE PROBE Tetracycline test kit failed to reliably detect OTC in catfish muscle homogenates.
authors.affiliation: College of Veterinary Medicine, Mississippi State University, MS 39762, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: O'Hara
authors.forename: A
authors.initials: A
authors.lastname: Azadpour
authors.forename: J
authors.initials: J
authors.lastname: Scheemaker
authors.forename: P D
authors.initials: PD
authors.lastname: Gerard
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D017756:Aquaculture; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004334:Drug Administration Schedule; D004350:Drug Residues / Q000032:analysis / Q000493:pharmacokinetics*; D007059:Ictaluridae / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D010118:Oxytetracycline / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D011897:Random Allocation; D012015:Reference Standards; D015203:Reproducibility of Results; D012984:Software
chemical_list: D000900:Anti-Bacterial Agents; D010118:Oxytetracycline