Concentration of Enrofloxacin Residue from Tilapia （Oreochromis niloticus） Muscular That Infected by Aeromonas salmonicida

Aim of this research was to find out the concentration of enrofloxacin residue in tilapia meat for several weeks after antibiotic treatment. Twenty seven tilapia fishes were divided into three groups. The first group was not infected and treated, the second group was infected with A. salmonicida subsp, smithia and the third group was infected with A. salmonicida subsp. achromogenes intramuscularly. Six days after infection, treatment was carried out using Baytril administered orally for the second group and intramuscularly for the third group during five days. At the 1 st, 4th and 8th week after the treatment, Three fish were taken from each group to be analyzed for its concentration of enrofloxacin residue by diffusion on Mueller Hinton Agar （MHA） method and quantitatively using high performance liquid chromatography （HPLC） method. The MHA test showed the formation of inhibition zone, at the 1 st week and 4th week after the treatment, while at 8th week after treatment did not show inhibition zone. The HPLC test on enrofloxacin residual concentration in tilapia infected with A. salmonicida subsp, smithia （second group） at the 1st, 4th and 8th week after treatment showed the average of 33.0, 6.10 and 0.0021 μg/g of enrofloxacin residue level. While in tilapia infected with A. salmonicida subsp, achromogenes and treated with enrofloxacin intramuscularly （third group） showed the average of residue level 35.79, 2.18 and 0.00065 μg/g. In conclusion, the residue of enrofloxacin was still high concentration until the fourth week after treatment in the second and third groups. Based on Indonesian National Standards and Rules, the maximum limit of enrofloxacin residue is 0.01 μg/g. The concentration of enrofloxacine residue was very low and the concentration of enrofloxacin residue collected from tilapia using orally and intramuscularly method of treatment was not different.