THE KEY to protecting the Philippines’ high-value prawn industry from disease and antibiotic resistance may be living inside the prawns themselves.
UST-Ebi Team researchers Kristelle Tardecilla, a microbiology master’s alumna, and Prof. Mary Beth Maningas of the Department of Biological Sciences have succesfully “primed” the immune systems of freshwater prawns using Weissella confusa C6, a probiotic strain isolated from the species’ digestive tract.
Their 2024 study, titled “Evaluation of inhibitory, immunomodulatory, survival, and growth effects of host-derived Weissella confusa on Macrobrachium rosenbergii challenged with Vibrio parahaemolyticus,” found that the host-derived probiotic helped prawns fight infections, survive longer and use food more efficiently.
According to Maningas, probiotics taken directly from the host species are more effective because they are already naturally adapted to survive inside the organism.
The probiotic works by strengthening the prawns’ immune system before infection occurs.
“We all know from layman’s terms, na umiinom tayo ng Yakult, ganyan din ‘yong mga hipon. They also need something na pwedeng mag-boost ng kanilang immune system, and we are fortunate that we were able to isolate this,” Maningas told the Varsitarian.
Researchers monitored hemocytes, the shrimp equivalent of immune blood cells, to measure how the probiotic improved the prawns’ defenses against disease.
“Ang maganda is we were able to prove scientifically that it does improve ‘yung hemocytes. We also look at other parameters, and we have proven that it does boost the immune system of shrimp,” Maningas said.
The team exposed treated prawns to Vibrio parahaemolyticus, a harmful bacterium that commonly affects shrimp farms. Untreated prawns died within days, while those given the probiotic showed much higher survival rates.
“We were able to improve survival. Without the probiotic addition, the shrimps will die 100% in 10 days or in a week’s time. We were able to observe significant survival in the utilization of W. confusa C6,” Maningas said.
The probiotic also improved feed conversion ratio (FCR), which measures how efficiently prawns convert food into growth. Lower FCR means farmers can produce healthier shrimp using less feed.
Aside from bacterial infections, the probiotic may also help prawns defend themselves against White Spot Syndrome Virus (WSSV), one of the most destructive viral diseases in shrimp farming.
Maningas said the research came at a critical time as the aquaculture industry faces growing concerns over antimicrobial resistance (AMR), a problem caused by the overuse of antibiotics.
“I think it’s very urgent because I think you are also aware of the danger of AMR. In fact, hindi lang siya problema sa aquaculture, even in the livestock industry and human [population],” she said.
She said stricter international standards on antibiotic residues make probiotic-based alternatives increasingly important for Philippine seafood exports.
“Maswerte na tayo in the Philippines that I think wala pa tayong ganoong problema, but in other Asian countries, problema nila ‘yun. Hopefully, hindi ‘yun mangyari sa Pilipinas,” Maningas said.
The probiotic is mixed into shrimp feed, though researchers are also studying how it can be adapted to actual farming practices, where probiotic mixtures are commonly added directly into ponds.
The study has been tested only in laboratory aquariums, and researchers are looking to see if the probiotic will also work in commercial ponds and actual shrimp farms.
“We have proven it on a small scale, but we have to prove it on an industrial scale, the large pond. We’re looking if it will work in an uncontrolled environment, to see if it’s really robust for the farmer to adopt,” Maningas said.
The researchers also hope to apply the same probiotic approach to other important aquaculture species such as tilapia and milkfish.
Beyond probiotics, the UST-Ebi Team has developed easy-to-use diagnostic tools that can help shrimp farmers quickly detect diseases on-site before outbreaks spread.
Maningas credited the project’s beginnings to Tardecilla, a microbiology graduate student who initiated the study during the Covid-19 pandemic despite limited access to shrimp samples and strict border restrictions at the time.
“For scientists, especially those in the academe, learn to laymanize. Learn to convert or transition your technology to the layman people. It’s about making sure that the science we do in the lab actually reaches the hands that need it the most,” she said.
Tardecilla and Maningas received the Dr. Elvira O. Tan Award for Outstanding Published Paper in the Aquatic Sciences Category during the DOST-Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development (PCAARRD) Science and Technology Recognition and Awards Ceremony in November 2025.
