ISSN 2094-2818

Editors: Eduardo A. Padlan and
Gisela P. Padilla-Concepcion
VOLUME 7 NUMBER 2 (July to December 2014)

Phil. Sci. Lett. 2014 7 (2) 309-316
available online: September 10, 2014

*Corresponding author
Email Address:
Received: August 12, 2014
Revised: June 30, 2014
Accepted: July 4, 2014
Published: September 10, 2014
Editor-in-charge: Eduardo A. Padlan

Keywords: loop-mediated isothermal amplification, polymerase chain reaction, white spot syndrome virus, Vibrio spp., shrimps

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Utilization of loop-mediated isothermal amplification (LAMP) technology for detecting White Spot Syndrome Virus (WSSV) and Vibrio spp. in Litopenaeus vannamei in selected sites in the Philippines

by Amalea Dulcene D. Nicolasora1, Benedict A. Maralit4, Christopher Marlowe A. Caipang3, Mudjekeewis D. Santos4, Adelaida Calpe5, and Mary Beth B. Maningas*1,2

1Research Center for the Natural and Applied Sciences, Thomas Aquinas Research Complex
2Biological Sciences Department, College of Science, University of Santo Tomas, Philippines 1008
3School of Applied Science, Temasek Polytechnic, Singapore
4Genetic Fingerprinting Laboratory, National Fisheries Research and Development Institute, 101 Mother Ignacia St. Quezon City 1103 Philippines
5Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development - Department of Science and Technology, Los Baños, Laguna

Shrimp disease outbreaks in the Philippines remain to be uncontrollable. This is compounded by the inaccessibility of disease diagnostics to most shrimp farmers. The loop-mediated isothermal amplification (LAMP) is a new technology that is used as a practical alternative for rapid detection of viral and bacterial pathogens. The method proves to be rapid, highly sensitive, and cost-effective compared to other detection assays. In this study, LAMP protocols for the detection of the two most common shrimp pathogens, white spot syndrome virus (WSSV) and Vibrio spp., in the Philippines were developed. A temperature range of 550C to 680C for WSSV detection and 590C to 670C for Vibrio spp., and incubation periods of 45 minutes to 1 hour, were proven to be the suitable conditions for the LAMP assay. Using these conditions, asymptomatic Litopenaeus vannamei samples from selected sites (Iloilo, Batangas, Bulacan, Laoag, and Leyte) were tested for WSSV. Samples which indicated WSSV infection were from Iloilo (89.47%), Batangas (30.00%), Bulacan (43.33%), and Leyte (75.00%), while shrimps from Laoag City (0.00%) tested negative. Likewise, the occurrence of Vibrio spp. was determined in shrimps sampled in Pangasinan and six bacterial DNA isolates of Vibrio spp. were identified. Moreover, conventional PCR and microbiological methods were performed along with the LAMP reaction for comparison and further confirmation. The results showed that the LAMP assay was faster and 10 times more sensitive than polymerase chain reaction in detecting WSSV and was more efficient than the traditional microbiological method in diagnosing vibriosis. Overall, the results indicated that a LAMP protocol, which is more convenient, highly sensitive, faster, and more practical, has been effectively utilized to detect WSSV and vibriosis in selected Philippine shrimp farms.