Potential of plant-derived essential oils, antimicrobial peptides and combination of antimicrobials against fish bacterial pathogens

Author(s)

Inácio Mateus Assane

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2022-12-12.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2022-08-25
• Advisor: Fabiana Pilarski

Abstract

This thesis addresses the issue of the emergence of bacterial diseases in fish farming, in a scenario of limited availability of effective antimicrobials. The results are presented in five chapters (manuscripts) that correspond to the objectives. In the first manuscript, outbreaks of emerging bacterial disease are described in a fish farm and laboratory facility, respectively; denoting the ineffectiveness of antimicrobials approved for use in Brazilian fish farming. The second manuscript describes the genetic diversity, virulence, and antimicrobial resistance profile of one of the main pathogenic bacteria (group B Streptococcus, GBS) of the main fish species cultivated in Brazil (Nile tilapia, Oreochromis niloticus). The third and fourth manuscripts describe the synthesis, chemical composition, cytotoxicity, and antimicrobial activity of synthetic antimicrobial peptides (AMPs), plant-derived essential oils (EOs) and their combinations with conventional antimicrobials, respectively; highlighting their potential as an alternative to conventional antimicrobials against the main bacterial diseases of fish cultured in tropical regions. In the fifth manuscript, the pharmacokinetics of the combination of two conventional antimicrobials (thiamphenicol and florfenicol) in Nile tilapia is described. Our findings indicate that new effective therapeutic options against bacterial diseases are needed in Brazil and AMPs, EOs and combined therapy are good treatment options for bacterial diseases in aquaculture. (AU)

• FAPESP's process: 19/22775-0 - Combination of thiamphenicol with florfenicol: pharmacokinetics and therapeutic efficacy in the treatment of Streptococcosis in Nile Tilapia (Oreochromis niloticus)
• Grantee: Inácio Mateus Assane
• Support Opportunities: Scholarships in Brazil - Doctorate