A question of temperature related differences in plasma oxolinic acid concentrations achieved in rainbow trout ( Oncorhynchus mykiss) under laboratory conditions following multiple oral dosing

• Published in: Aquaculture 2005-03, Vol.245 (1), p.13-17
• Main Authors: Coyne, Rosie, Bergh, Øivind, Smith, Peter, Samuelsen, Ole
• Format: Article
• Language: English
• Subjects: anadromous fish; Animal aquaculture; Animal productions; antimicrobial agents; Aquaculture; Biological and medical sciences; blood plasma; Breakpoint MIC; chemotherapy; disease control; feed intake; Feeds; fish culture; fish diseases; Fundamental and applied biological sciences. Psychology; General aspects; Multiple oral dosing; Oncorhynchus mykiss; oral administration; Oxolinic acid; pharmacokinetics; Plasma Cmax; Temperature; trout; water temperature
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2004.11.039

This work investigated the plasma oxolinic acid (OXA) concentrations achieved by multiple administrations of medicated feed to laboratory held rainbow trout ( Oncorhynchus mykiss) at 6 °C. These data were compared with previously published data obtained with trout held at 12 °C. Both sets of fish were administered oxolinic acid at 50 mg/kg at 1% body weight on six occasions during a 9-day period and sampled 1 day after the last administration of medicated feed. The mean plasma OXA concentrations were 0.14±0.07 and 0.15±0.10 mg/l while the 80th percentiles were 0.09 and 0.08 mg/l, at 12 °C and 6 °C, respectively. The extent of fish to fish variation, measured as the percentage coefficient of variation (CV), were 47% and 66% at the two temperatures. These data indicate that temperature, over the range 6–12 °C is not a significant factor in determining plasma concentrations achieved following multiple oral administrations of medicated feed. It is argued that a single breakpoint MIC value could be applied to any therapeutic treatment performed within this temperature range.