Ecotoxicity, hematological and biochemical aspects and efficacy of antibiotics and of ectoparasiticides in pacu (Piaractus mesopotamicus)

• Grant number: 10/09888-6
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): September 01, 2010
• Effective date (End): January 31, 2014
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal researcher: Maria José Tavares Ranzani de Paiva
• Grantee: Silvia Patrícia Carraschi de Oliveira
• Home Institution: Centro de Aquicultura (CAUNESP). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The gram-negative bacteria and the parasites are the most common pathogens in aquaculture, causing economic losses and may be manifest in interaction in the fish. The antibiotic enrofloxacin (EF) and florfenicol (FFC) can be used to treat bacterial diseases and the antiparasites thiamethoxan (TH) and toltrazuril (TOL) are pharmaceutical chemicals with therapeutic potential for use in aquaculture. The objectives of this project are: 1) estimate the 50% lethal concentration (LC50, 48h) of EF; of the FFC, of the TOL and of the TH separately and the interaction of EF with the TOL and of the FFC with TH for pacu (Piaractus mesopotamicus), 2) determine the effective concentration of EF and TOL in the control of Aeromonas hydrophila and Ictiophitirius multifiliis and FFC and TH in control of A. hydrophila and Monogenea in pacu, 3) evaluate the histopathological changes, hematological and blood chemistry before and after treatment and 4) validate the methodology for quantification of cortisol by ELISA for the pacu. For acute toxicity tests the animals (weighing between 0.5 and 1.0 g) are exposed to increasing concentrations of each pharmaceutical chemicals and controls. For efficacy trials, the fish are kept in poor conditions (low oxygen, no food, captures and excess organic matter), for development of parasites and then, with decreasing immunity, will be infected with the bacteria. After onset of clinical signs, start the treatment with a concentration of each pharmaceutical chemicals, a control without infection and other with infection. These concentrations and exposure time are previously adjusted in preliminary tests to adjust the concentration-response in the laboratory. At the end, the surviving fish will be quantified and the number of parasites exists still. Will be collected blood samples for hematological and biochemical analysis of blood samples and gill, liver, skin and kidney histopathology before and after treatment with pharmaceutical chemicals. With blood samples will also be measured cortisol, in which the methodology will be validated by the Elisa method for the species. The variables of water quality will be measured (pH, temperature, conductivity, dissolved oxygen and ammonia) during tests of acute toxicity and efficacy during the experiments. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

OLIVEIRA, Silvia Patrícia Carraschi de. Ecotoxicidade, segurança clínica e eficácia de fármacos em jovens de pacu (Piaractus mesopotamicus). 2014. Doctoral Thesis - Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal Jaboticabal.