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The use of drugs in aquaculture is necessary to combat pathogens responsible for causing the high rate of mortality in fish farming, such as infection by ectoparasites. The aim of this research was to evaluate the efficacy: (A) of toltrazuril (TOL) treatment against Ichthyophthirius multifiliis, Trichodina heterodentata and Anacanthorus penilabiatus; (B) of thiamethoxam (TH), in treating fish infected by A. penilabiatus and (C) of enrofloxacin (ENR) and florfenicol (FFC) against Aeromonas sp. and Streptococcus sp. The drugs TOL and TH were administered in therapeutic baths while ENR and FFC were mixed with the fish food. The drug concentrations were adjusted according to the experimental conditions (laboratory, microcosm or mesocosm). The drug TOL presented a treatment efficacy rate of 100% against I. multifiliis in microcosm and T. heterodentata in mesocosm. Moreover, ENR presented an efficacy rate of 100% in treating fish infected by Aeromonas sp. and Streptococcus sp. in mesocosm. Finally, TH efficacy rate in controlling A. penilabiatus infection was 81.86% in mesocosm and FFC decreased the overall bacterial load in infected fish. Aeromonas sp. and Streptococcus sp. strains were found in the samples collected for microbiological analysis. In conclusion, TH presented a high efficacy in treating fish against A. penilabiatus infection while TOL was better in controlling T. heterodentata. The antibiotics used in mecoscosm condition presented potential to be used against bacterial infection in aquaculture. [ABSTRACT FROM AUTHOR]

In this study we describe the anti- Trichodina effects of teflubenzuron (TFB) for Oreochromis niloticus and for Piaractus mesopotamicus . We also evaluated the acute toxicity, for both species, by using TFB in the concentrations of 700.0, 800.0, 900.0 and 1000.0 mg L −1 and a control, without the drug. To assess the efficacy of TFB against Trichodina spp., we used the concentrations of 30.0 or 50.0 mg L −1 for one hour exposure in tilapia, and the concentration of 30.0, 50.0 and 80.0 mg L −1 for one hour and 50 mg L −1 for two hours exposures in pacu. Teflubenzuron did not present significant toxicity in either species, with LC50;48h > 1000.0 mg L −1 . The drug effectiveness was observed against four identified Trichodina species: T. magna, T. heterodentata , T. compacta and T. centrostrigeata , with 87.9% parasite reduction with one hour exposure to 50.0 mg L −1 TFB on O. niloticus and 96.1% with two hours exposure to 50.0 mg L −1 TFB on P. mesopotamicus . Teflubenzuron is a drug with potential to be used in Brazilian aquaculture; it attends to important requirements, such as low toxicity and high efficacy in controlling Trichodina spp. infection in O. niloticus and P. mesopotamicus . [ABSTRACT FROM AUTHOR]

Tendo em vista o papel biológico da histamina sobre a permeabilidade vascular e a escassa literatura deste autacóide em peixes teleósteos, este estudo propõe avaliar a participação da histamina na reação inflamatória aguda em tilápias do Nilo desafiadas com Aeromonas hydrophila, tratadas com anti-histamínico prometazina, através da análise da atividade respiratória dos leucócitos. O método determinou as espécies reativas de oxigênio (ROS) produzidas pelo "Burst" respiratório por meio do ensaio colorimétrico baseado na redução do corante Nitroblue Tetrazolium (NBT). Os resultados demonstram evidências de que a histamina participe da inflamação das tilápias com aumento de ROS na fase mais aguda pós-tratamento com prometazina intra-celomática e com 6 e 12 horas em peixes tratados via intramuscular (efeito tardio), sugerindo aumento na atividade celular de neutrófilos e monócitos no sangue resultantes da diminuição da diapedese por alteração na permeabilidade vascular. [ABSTRACT FROM AUTHOR]