THE PHILIPPINES used to enjoy an abundance of shrimps as the third top producer and exporter in the world during the 1990s. However, in 2003, viral diseases started to destroy the shrimp population, bringing down the country’s ranking to No. 11.
The decline in the country’s shrimp industry promptedMary Beth Maningas, a professor at the College of Science, to conduct research on how to control the spread of the virus.
Maningas’ study titled Ribonucleic acid interference (RNAi) technology to elucidate shrimp-virus interaction is part of a joint project by the Bureau of Fisheries and Aquatic Resources (BFAR) of the Department of Agriculture, University of the Philippines in the Visayas (UPV), and the Tokyo University of Marine Science and Technology (TUMSAT). Titled Biotechnology for Shrimp: Utilization of molecular technologies to elucidate shrimp immunity and develop disease diagnostic methods, the joint project focuses on the interaction between the shrimps and the infective viruses to devise ways to control the diseases.
Maningas’ research studied the white spot virus (WSV) that causes the white spot syndrome, said to be the most widespread and devastating infectious agent to hit the shrimp aquaculture industry worldwide.
“The virus is known for causing massive [destruction] among shrimps quickly.In the Philippines, the BFAR has already modified routine fry quality assessment to include WSV in local farms and hatcheries to prevent this,” Maningas said.
Maningas’ study also noted the substantial lack of effective means to control the effects of the WSV.
“WSV is still a big problem because there has not been any significant advance in finding effective means to control the virus’ spread and effects. Part of the reason for this is that the mechanism of shrimp response to viral infection is poorly understood,” she said.
RNAi is a gene silencing process that causes a change in the arrangement of viral genes.Recent studies have shown that it is possible to block viral disease progression by injecting shrimp with double stranded RNA (dsRNA) specific to viral genes.
“RNAi was proven to be very efficient in the study of gene function and [its role] in mounting antiviral responses,” Maningas said. “Here we aim to determine the efficiency and potency of dsRNA interference among crustaceans like shrimps.”
The study was done in four steps. The first involved identification of three genes that have critical function against WSV. It was then combined with the extracted deoxyribonucleic acid (DNA) to produce the needed dsRNA injected into the shrimps. The shrimps were observed, and the mortality rate and related data were recorded for further analysis.
“Through our study, we hope to optimize materials for gene functional studies that can be used by other laboratories or scientists on their own studies, by identifying the needed genetic material to standardize protocols in the production of dsRNA for the viral genes,” Maningas said.
After making the protocols for producing the dsRNA of the virus, Maningas said it was equally important to distribute the information to the scientific and industrial communities.
“Workshops, publications of manuals for fish health or diagnostics technicians and peer-reviewed journals are essential in promoting awareness of the existence of biotechnological methods of diagnosis in the country,” she said.
But she stressed that the local shrimp industry would be the biggest beneficiary of the resesarch.
“The improved protocols in the gene silencing can be used to improve stock quality by using it as an alternate to antibiotics, because it can already combat the infection and stop its replication at the genetic level.Also, these protocols, particularly with the publication of how-to-manuals,can provide helpful information to diagnostic laboratories since they can be applied in the Philippine setting,” she said. Julienne Krizia V. Roman
