Serum antibiotic levels in adult sockeye salmon as a function of route of administration

Abstract

Adult sockeye salmon, Oncorhynchus nerka (Walbaum), in three different stages of sexual maturity were administered the antibiotic, oxytetracycline, by injection (intraperitoneal and intramuscular), water bath exposure and stomach capsule implant. Concentrations of the antibiotic in, and its disappearance from the serum were determined. For all three stages of sexual maturity the most efficacious route of administration based on maximum titre and duration in the serum was provided by intraperitonial injection. Intramuscular application produced a positive effect, albeit at a markedly lower level, in all three groups of fish. Oral implants resulted in only a minor uptake of the antibiotic in the fully ripe fish. Immersion of the fish in water solutions of oxytetracycline was without effect.