Tissue levels of thiasin in rainbow trout

The tissue concentrations of thiasin (3, 4-dimethyl-5-sulfanilamido-isoxazole) given to rainbow trout at the rate of 100, 150 and 200 miligrams per one kilogram of fish per day were examined. The rainbow trouts, weighing on the average 15 grams per fish were kept in troughs and fed with the drug-containing food once a day at the rate of about 2.5% of fish weight per day. The water had the temperature of 12.7-14.0°C during the experiments. The determinations were made by extracting the ground tissue in alcohol, treating the extract with Tsuda's reagent (β-diethyl aminoethyl-α-naphthyl amine oxalate) and proceeding with a photo electric colorimeter. The results are presented in the Table 1 and Fig. 1.