Eficácia do florfenicol e da oxitetraciclina no controle de Aeromonas hydrophila em pacu (Piaractus mesopotamicus)

The effective concentration of antibiotics OTC and FFC in the treatment of Aeromonas hydrophila in pacu (Piaractus mesopotamicus). The pacus were subjected to capture twice daily (four days) and then were infected with A. hydrophila (2.4 x10 7 bacteria mL -1 ). The treatments were: control without infection (CSI), with infection control (CCI) and 110.0, 140.0 and 170.0mgOTC.kg -1 , and 5.0, 10.0 and 15.0mgFFC.kg -1 . The variables of water quality were monitored daily. After treatment, the CSI of the two experiments was 100% survival. In tests with OTC, the CCI was 29.17%, in 110.0mg.kg -1 , 37.5%, in 140.0mg.kg -1 , 29.17% and in 170.0mg.kg -1 , 50.0%. The FFC was effective with 10.0 mg kg -1 , and in the CCI the survival was 76.9%, in 5.0mg.kg -1 , 81.81%, in 10.0mg/L.kg -1 , 100% and in 15.0mg.kg -1 , 87.5%. The OTC in concentrations of up to 170.0 mg.kg -1 of ration is not effective in the control of A. hydrophila in pacu and the FFC is effective in the concentration of 10.0mg.kg -1 and this antibiotic does not change the variables of water quality.