DIETARY SUPPLEMENTATION OF TERRAMYCIN AND ROMET-30 DOES NOT ENHANCE GROWTH OF CHANNEL CATFISH BUT DOES INFLUENCE TISSUE RESIDUES

Two controlled feeding trials were conducted in which Terramycin and/o r Romet-30 were incorporated into either semipurified or practical die ts to provide 25, 50 and 100% of the recommended dosages when fed to j uvenile channel catfish at 3% of body weight per day, Data for 4-wk an d 8-wk weight gain, feed efficiency, and survival of channel catfish f ed the various diets were analyzed to determine if these responses cou ld be enhanced by dietary inclusion of either or both antibiotics. In addition, 3-wk and 8-wk muscle samples from fish of each dietary treat ment were analyzed by high performance liquid chromatography for oxyte tracycline (OTC), ormetoprim (OMP) and sulfadimethoxine (SDM) residues . The performance of juvenile channel catfish was not enhanced by the inclusion of Romet-30 or Terramycin in semipurified or practical diets . Moreover, fish performance tended to decrease relative to that of fi sh fed the control diet when antibiotics were supplemented in the diet . Residues of OTC, OMP and SDM in the fillets of catfish fed medicated diets generally increased in a time-and dose-dependent fashion. Resid ue concentrations above the legal tolerance limit of 0.1 mg/kg were no ted in most samples from fish fed diets medicated at 100% of recommend ed levels and in many of the samples from fish subjected to lesser dos ages, particularly in those that had been fed diets with Romet-30. All owing catfish that were previously fed medicated diets a 3-wk or 4-wk withdrawal period effectively decreased the OTC, OMP and SDM contents of fillets to undetectable levels.