OXYTETRACYCLINE WITHDRAWAL TIME AND RESIDUE IN TILAPIA (Oreochromis niloticus) AFTER ORAL ADMINISTRATION in FEED

Ratna Amalia Kurniasih*, Rd. Kusyadi
 
*Center of Fish Diseases and Environmental Investigation
Ministry of Marine Affairs and Fisheries Republic of Indonesia
Jl. Raya Carita Ds. Umbul Tanjung Kec. Cinangka
PO BOX 123 Anyer Lor Serang 42167
lppil_serang@yahoo.co.id  

Oxytetracycline is one of common antibiotic that has a wide use in aquaculture. This antibiotic becomes one of best choice because its effect in many diseases. However the antibiotic usage does not followed by public education to use antibiotic safely. The determination of withdrawal time in fish aquaculture takes an important role in food safety and quality assurance. The aim of this study is to understand residue and determine withdrawal time of oxytetracycline 10 days post treatment. Many residue studies still ongoing and this study may support to monitor and control the concentration of oxytetracycline.

Two groups of tilapia were prepared to this study, control and treated. Each group was divided in three fiber tanks and each tank contain of 70 fish. All of the fish was kept in fiber tanks with appropriate water quality aeration and were fed either medicated or non-medicated commercial feed at the rate of 3% of fish body weight per day. Oxytetracycline was applied in treated group with the dose 1gr/4kg fish body weight. The antibiotic was mixed with the feed and given 3 times per day for 10 days. Water quality (temperature, pH, dissolved oxygen, ammonia, and nitrite) was examined during the study. Water temperature during this study was between 24.3-32.3oC (approximately 27,6oC).

The fish was sampled for each tank (5 fish per tank) during treatment period (day 0, 1, 3, 5, 7, and 9) and post treatment (day 0, 1, 2, 4, and 5). Liver and edible tissue (muscle-skin) of fish was collected and tested for OTC by ELISA. The result of this study shows that the highest oxytetracycline residue in muscle-skin and liver is 204.89 ± 77.65µg/kg and 541.27µg/kg, respectively. This result explains that in Tilapia oxytetracycline is easier to be residue in liver than in muscle. Withdrawal time in this study was analyzed by statistic correlation and regression. Withdrawal time calculation based on the time post treatment at which the tissue OTC concentration in the muscle depleted below the MRL (Maximum Residue Limit). Graphic 1 shows the statistical analysis withdrawal time of oxytetracyline in tilapia by oral administration. Table 1 describes withdrawal time calculation. From the table we conclude that for this study, withdrawal time of oxytetracycline is 3 days post treatment.  This result indicates that the concentration of oxytetracycline is under residue limit and the product is safe to consume.