The funghi oomycete Saprolegnia sp. are of special atention in aquaculture because are secondary pathogens and increase the harshness of bacterial and parasitic diseases causing high mortality rates. The drugs used in funghi control have no register and the molecules prospection is essential for aquaculture. Thus, the aims this research are: to evaluate the acute toxicity (LC50;48h) of ketoconazole, fluconazole e itraconazole for pacu, Piaractus mesopotamicus; to evaluate the efficacy of the fungicides in Saprolegnia sp. control in vitro; to evaluate the efficacy in vivo, of fungicide that shows the best effectiveness in vitro and to evaluate the possible histopathological and hematological changes in pacu, after treatment in vivo. In the acute tests the fish will be to exposure at nominal concentration of fungicides and it will be to determine the LC50;48h. In the assays in vitro the funghu will be cultivated in yeast agar 2%, to add antibiotics and submitted at morphological identification. After agar homogenizing, a disk 9mm of diameter from oomycete cultivation will be spread in the central position of dish and will be incubated in bacteriological incubator at 25°C. The fungicides will be tested in the concentrations: 0, 10, 50, 100, 1000, 5000 and 10000 mg.L-1. In the in vivo assay, the fungicide that shows the best effectiveness in vitro will be tested in Saprolegnia sp control in pacu in microcosm (60 boxes liters). For this, the fish will be distributed follow: healthy control (HC), healthy control exposed at fungicide in the treatment form (ExC), infested control without treatment (InC) and the infested fish with treated with fungicide (Tr). The fungicide will be tested in terapheutic bath, with daily application and one exposure hour, and to add in the food, with seven days of administration at 2,5% body weight. In the end of treatment will be collected samples from kidney, liver, gills and blood to histopathological and hemathological analysis.
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