Development of pathogenic bacteria vaccines for Nile tilapia (Oreochromis niloticus): immunological and hematological analysis

• Grant number: 17/05183-7
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2017
• End date: July 31, 2019
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Maria José Tavares Ranzani de Paiva
• Grantee: Maria José Tavares Ranzani de Paiva
• Host Institution: Instituto de Pesca. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Carlos Massatoshi Ishikawa ; Danielle de Carla Dias ; Leonardo Tachibana ; Said Ben Hamed
• Associated scholarship(s): 18/18658-6 - Development of pathogenic bacterias vaccines for Nile tilapia (Oreochromis niloticus): Immunological and hematological analysis, BP.TT

Abstract

Wild fisheries harvesting is currently in a state of decline because of over-fishing, climate changes, pollution and marine habitat destruction among other factors. Aquaculture is rising significantly around the world. Drug supplemented feeds are often used to keep farmed fish free from diseases such as Streptococcosis, Francisellosis and others. Unfortunately, the use of antimicrobials in aquaculture industries and aquatic environments can select pathogen resistant strains and accumulate residual antibiotic in fish and aquatic environment. The antimicrobial-resistant bacteria, or their resistance genes, can be transferred to humans. Preventive measures using vaccination seems to be necessary in order to avoid diseases outbreak, but the vaccines are not always efficient because it is based on foreign variants of the pathogenic bacteria and under other fish growth conditions. This project aimed to develop and test a custom-made monovalent and trivalent vaccines for tilapia using three pathogens bacteria from Brazil (Francisella noatunensis orientalis, Streptococcus agalactae and Aeromonas hydrophila). Thus, four groups of 50 tilapia of 10 g will be reared at temperature of 25 ± 2 ºC and at a photoperiod of 12 h light/12 h darkness. For vaccines preparation, pathogen bacteria growing on their appropriate mediums, will be killed by adding 1% formaldehyde. A 0.05mL-1 of vaccine with 109 cells mL-1 concentration will be injected into fish visceral cavity, after 20 days the booster with the same quantity will be injected and finally challenge test four weeks later. Results exploration will be performed by measuring the bactericidal effect of plasma in vitro and the ELISA for determination of the antibodies triter. The data will be submitted to ANOVA and Tukey's test. (AU)