Detection of the fish pathogen Saprolegnia spp. using LAMP from Recirculating Aquaculture Systems.

Session: Watershed and Lake Science Informing Management (1)

Satyaki Ghosh, Bowling Green State University, [email protected]
David Straus, Harry K. Dupree Stuttgart National Aquaculture Research Centre, [email protected]
Christopher Good, Freshwater Institute, The Conservation Fund, [email protected]
Gayathri Beligala, Bowling Green State University, [email protected]
Vipaporn Phuntumart, Bowling Green State University, [email protected]

Abstract

Saprolegniasis is a disease caused by oomycete pathogens of the genus Saprolegnia, which infect fish in both natural habitats and commercial aquaculture. It is estimated to cause economic losses of 10% in salmon production alone and 30% in fish production worldwide. In production and natural settings, a sudden drop in water temperature immunocompromises the fish host, while facilitating the virulence of the Saprolegnia spp. pathogens. This study aims to establish Loop Mediated Isothermal Amplification (LAMP) as a rapid and sensitive molecular tool for on-field detection and quantification of Saprolegnia spp. from water samples, specifically focusing on zoospore detection. This will facilitate informed decisions about the timing and extent of disease treatment. LAMP reactions are performed at a constant temperature, and results can be estimated visually within 30 minutes, making it suitable for field diagnostics. Our developed LAMP technique could detect as low as 10fg of Saprolegnia spp. DNA, and one zoospore of Saprolegnia spp. directly. Additionally, we have developed a simple strategy to filter large volumes of water through polycarbonate track etch (PCTE) membranes, followed by a simple heat-based DNA extraction strategy for LAMP. This procedure was successfully applied to detect Saprolegnia spp. in water collected from recirculating aquaculture systems.