African Journal of Water Conservation and Sustainability

African Journal of Water Conservation and Sustainability Vol. 1 (5), pp. 066-068, December, 2013. © International Scholars Journals
 
Full Length Research Paper

Evaluation of experimental infection with Aeromonas hydrophila in pacu (Piaractus mesopotamicus(Holmberg, 1887)*

Silvia Patrícia Carraschi1,2*, Claudinei da Cruz2, Joaquim Gonçalves Machado Neto3, Flávio Ruas de Moraes4, Oswaldo Durival Rossi Júnior5, Antonio Nader Neto2 and Neida Lucas Bortoluzzi4

1Centro de Aquicultura (Aquaculture Center) at Unesp – Jaboticabal Campus – São Paulo – Brazil.

2Núcleo de Estudos e Pesquisas Ambientais em Matologia (NEPEAM) (Weed Science Environmental Research Studies Centre) of the College of Agricultural and Veterinary Sciences at Unesp - Jaboticabal – São Paulo – Brazil.

3Laboratório de Ecotoxicologia dos Agrotóxicos e Saúde Ocupacional (Laborseg) (Pesticides Ecotoxicology and Ocupational Health Lab) of the College of Agricultural and Veterinary Sciences at Unesp - Jaboticabal –

São Paulo Brazil.

4Laboratório de Ictiopatologia (Fish Pathology Lab) of the College of Agricultural and Veterinary Sciences at Unesp - de Jaboticabal – São Paulo – Brazil.

5Departamento do Medicina Veterinária Preventiva (Preventive Veterinary Medicine Department) of the College of Agricultural and Veterinary Sciences at Unesp - Jaboticabal – São Paulo – Brazil.

*Corresponding author. E-mail: pacarraschi@yahoo.com.br. Tel: (+5516) 3209-2630.

Accepted 21 October, 2013

Abstract

The aim of this work is to determine the concentration of Aeromonas hydrophila to be inoculated in pacu (Piaractus mesopotamicus), so as to induce bacterial infection but not death during a period of at least ten days and, therefore, enable the development of treatment protocols. The tested concentrations were established through the Mac Farland scale and fish were subjected to three A. hydrophila infection concentrations (1.2 × 107, 2.4 × 107 and 1.5 × 108 UFC.mL-1) through intracoelomic, intramuscular and subcutaneous injections. The clinical exam was done 24 h after inoculation, and the clinical signs suggested aeromonosis in all three groups. In the lowest concentration, animals demonstrated few clinical signs of disease, and in the highest concentration, all animals died within 24 h of aeromonosis induction with acute infection. In the intermediate concentration (2.4 × 107 UFC.mL-1), all animals presented clinical signs of aeromonosis and kept living at the beginning of the time of treatment. Therefore, 2.4 × 107 UFC mL-1 concentration was defined as viable for the study of experimental infection in pacu by A. hydrophila, as the fishes were kept alive at the beginning of the time of treatment protocol with pharmochemicals.

Key words: Bacterial infection, fish, disease, antibiotics.


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