Teste de letalidade de peixes da espécie Rhamdia quelen (QUOY; GAIMARD, 1824) submetidos a diferentes concentrações de extrato de acículas de Pinus elliottii (ENGELM, 1880)

Abstract

The continental pisciculture come expanding exponential mode the last years. Although, the absence prophylaxis care, management and projection and sanitation condicion of the production, in the ill success. In Laranjeiras do Sul - PR, went seen the present fish parasite call Lernaea cyprinacea, and on species of fish affected went the Rhamdia quelen. This parasite when fix in the host, acts directly by providing injuries, and indirectly as a vector of bacterial and viral secondary diseases. Therapeutics proceding utilizing leaf extract of the P. elliottii like active principle went recommend like alternative for utilization for chemist products in the control this disease. Although, yet no exist study in the security of the quantity for this proceeding. This work has like objective to identify the medium lethal concentration (CL-50) for aqueous brute extract for P. elliottii. The extract of the P. elliottii, in concentration 0.07, 0.7, 0.8, 1.1, 1.2, 2.2, 3.2, 4.2, 6.7 g/L went prepared with immersion of maceration in water by 24 hours. The extract went introducet in the aquariums and this went accompanied by 24 hours, checking the present of the dead fishes. The end this period, the animals were euthanized in eugenol 100 mg/L for collecting gills, liver and kidney for histological analysis. The total of dead were used CL-50 for analysis of Probit. To make the histological analysis, the organs collected passed for procedures of dehydration, alcoholic series, diaphanization in xylol, paraffin embedment, microtome cuts, blade coloring with Hematoxylin of Harris and Eosin and microscope analysis. The CL-50 estimaded was of 0,963 g/L, with confidence interval of 0,802 g/L and 1,125 g/L. Analysing slides of organs, it was observed drastic changes of animals servivors, as desorganization in the branchial structure with epithelial cell hypertrophy. In the kidneys were found tubular regions with cellular degeneration presenting pale cytoplasm, vacuolated, tubule hemorrhages, leukocyte infiltration, remmants of inflammatory reactions and dilated glomeruli. In the liver was found leukocyte migration and hematological disturbances. Despite the histological alterations found, the lethal dose was 48 times higher than recommended for treatment, indicating relative safety in treatment concentration.