Gene expression in Nile tilapia vaccined and challenged with patogenic bacteria

• Grant number: 18/06012-4
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 03, 2018
• End date: November 02, 2018
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Maria José Tavares Ranzani de Paiva
• Grantee: Said Ben Hamed
• Supervisor: Miguel Angel Moriñigo Gutierrez
• Host Institution: Instituto de Pesca. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). São Paulo , SP, Brazil
• Institution abroad: Universidad de Málaga (UMA), Spain
• Associated to the scholarship: 16/19816-9 - Mono and trivalent vaccines of pathogenic bacteria Aeromonas hydrophila, Streptococcus agalactiae e Francisella noatunensis subsp. orientalis to Nile Tilapia, BP.PD

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. 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). For vaccines preparation, pathogen bacteria growing on their appropriate mediums, will be killed by adding 1% formaldehyde. A 0.05ml of vaccine with 109 cells / ml 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. Blood and organs will be extracted from fish before and after challenge test. Results exploration will be performed by measuring the Relative Percent Survival (RPS), executing a complete hemogramme, checking of the bactericidal activity of the serum. Gene expression of genes implicated in the immune response will be evaluated. The variation of gene expression will be evaluated in the liver, spleen and intestine. The data will be submitted to ANOVA and Tukey's test. Using this vaccine, we expected to enhance the immune system of reared fish and induce the development of self-fish defense. Consequently, the aquaculture's consumption of antibiotics and the environmental impact of drug use will significantly decrease. Likewise, the survival rate of tilapia and fish weight gain will increase and then improve the fish producers' economy.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

BEN HAMED, SAID; TERESA TAPIA-PANIAGUA, SILVANA; ANGEL MORINIGO, MIGUEL; TAVARES RANZANI-PAIVA, MARIA JOSE. Advances in vaccines developed for bacterial fish diseases, performance and limits. AQUACULTURE RESEARCH, v. 52, n. 6, FEB 2021. (19/07683-2, 18/06012-4, 16/19816-9)