Absorption of Selected Antimicrobic Drugs from Water by Channel Catfish, Ictalurus punctatus

Abstract

Although anitmicrobial drugs are frequently added to water to treat bacterial diseases of fish, their absorption is largely unquantified. Channel catfish weighing 3–5 g each were exposed to varying concentrations (4 mg/L to 32 mg/L) of chloramphenicol, erythromycin, furpyrinol, and oxytetracycline, respectively. Antibiotic levels measured after 5 h utilizing Bacillus subtilus spore germination inhibition showed that furpyrinol and oxytetracycline were absorbed by the fish in proportion to the antimicrobial concentration in the water. Minimum inhibitory concentrations can be attained in the fish with practical concentrations of these drugs in the water. Erythromycin (carrier-free) was poorly absorbed and chloramphenicol was not absorbed. Significant antibiotic degradation in water occurred in all drugs except furpyrinol.Key words: fish, antimicrobic, chloramphenicol, erythromycin, furance, oxytetracycline