Experience

• Over hundred fish were fed with the novel medicated feed within the framework of a larger study on the total residue depletion and metabolic profile of selected drugs in salmonids.  The study, including the preparation of the drug delivery system and the administration to fish was carried out according to GLP guidelines and was audited by an independent quality assurance officer.  Fish were housed individually in 75 L glass aquaria.  The ingestion of the medicated feed was monitored.  Fish ingested the medicated feed readily, usually within a couple of minutes. 
• Medicated fish feed was stored at 4°C for 7 months without substantial loss of drug activity.  The loss was 6.5% in case of methyltestosterone-containing feed.  
• Bioavailability of methyltestosterone in rainbow trout was 73.1% when administered as the novel medicated fish pellet.
• Leaching was measured in 15°C water.  In experiments with methyltestosterone-containing feed only 1.71% of the drug was found in the water after one hour contact time.
• Fish feed was medicated with 17-alpha-methyltestosterone.
• Fish feed was medicated with flumequine, a drug very similar to oxolinic acid. 
• Preliminary experiments were performed to medicate floating and sinking fish feed pellets with oxytetracyline hydrochloride.