Feed intake and tissue distribution of florfenicol in cod (Gadus morhua) administered feed with different fat contents

P>This study was performed to examine the appetite and the corresponding plasma and tissue distribution of florfenicol when administered to healthy groups of cod using medicated and non-medicated salmonid and marine feeds. Marine feed contains approximately 18% fat whereas salmonid feed contains approx. 30% fat. Two groups of fish were medicated with florfenicol at a dosage of 10 mg kg-1 day-1 for 10 consecutive days when the drug was administered either via marine or salmonid pellets. Two groups of fish also received either non-medicated marine or salmonid pellets. Twenty-four hours after giving the medicated marine feed, 14 out of 20 fish contained detectable concentrations of florfenicol with mean values (n = 14) of 4.67 +/- 4.02 mu g ml-1 in plasma, 2.29 +/- 2.11 mu g g-1 in muscle and 0.79 +/- 0.69 mu g g-1 in the liver. In the fish given medicated salmonid feed, 18 of 20 fish contained detectable concentrations of florfenicol with mean values (n = 18) of 1.77 +/- 1.84 mu g ml-1 in plasma, 0.75 +/- 0.66 mu g g-1 in muscle and 0.30 +/- 0.25 mu g g-1 in the liver. Decreased feed intake of the salmonid feed, both medicated and non-medicated, was noted when compared to medicated and non-medicated marine feed. No difference in feed consumption was registered between medicated and non-medicated marine feed, however a difference was noted between the medicated and non-medicated salmonid feed.