Abstract
The present study was designed to investigate the pharmaco-dynamic properties of trimethoprim (TMP) in ayu, Plecoglossus altivelis, after oral administration of TMP-sulfadoxine (SDX) mixture for the control of vibriosis. The results obtained are summarized as follows:
1. Following a single administration of 30 mg of TMP-SDX (1:5) mixture per kg body weight, the highest tissue levels of TMP were obtained 2 hours after medication in the liver at the level of 10.8 mcg/g, 6 hours in the kidney at the level of 4.4 mcg/g, 2-3 hours in the muscle at the level of 1.8 mcg/g, and 1 hour in the blood at the level of 0.4 mcg/ml.
2. Following daily administration of 30 mg of TMP-SDX (1:5) mixture per kg body weight per day for 10 days, TMP level became undetectably low 24 hours after the last medication in the liver, 48 hours in the kidney and the muscle, and 6 hours in the spleen and the blood.
3. It is concluded that TMP is once retained in the tissue for some hours, and is excreted almost completely from the fish body within a day. Therefore, it is necessary to administer TMP-SDX mixture to ayu more than once a day to maintain constant tissue levels of TMP in ayu.
