tilapiaMANILA — Aquaculture expert Virgilio Marzo has warned fishpond and fish cage owners to go slow in using rice bran for their milkfish and tilapia, saying that that while rice bran may contain Omega 6, it also has high arsenic levels.

Marzo, who trained at the University of the Philippines College of Fisheries (UPCF), told attendees at a seminar on “Fish Nutrition and Probitics” on the final day of AgriLink, FoodLink and AquaLink Exposition at the World Trade Center (WTC) in Pasay City that by boosting aquafeed with rice bran, they are also increasing the ingestion of arsenic by consumers.

The expert, who has been into the business of developing aquafeed with more organic content and even less fishmeal, said that his formulation avoids the use of rice bran but also contains a higher crude protein content from fishmeal and other substances that are high in Omega 3 fatty acid.

Marzo said that unless the high arsenic content is reduced substantially, consumers run the risk of developing cancer of the liver and kidney.

In his discussion, Marzo stressed that the many of the commercial aquafeed brands sold in the country contain less crude protein, which makes the growing period for fish last longer.

He claims that for aquaculturists to harvest their fish quicker, their feed should have a protein content in the range of 35 percent to 45 percent.

For his own operations, Marzo claims that he is batting for a crude protein content at a maximum of 50 percent, much higher than international standards, which is at 35 percent.

The expert also surprised many officials of the Department of Agriculture (DA) by claiming that practically all the tilapia consumed in Metro Manila are genetically modified organisms (GMOs) because these are sex-reversed using methyl testosterone (MT) and are transformed into all-male tilapia that grow bigger and faster than females.

Seventy percent of all the freshwater fish consumed in Metro Manila come from Laguna de Bay, which is now 40 percent dominated by fishponds and fish cages. The lake has a total area of 94,900 hectares.

Marzo also recently surprised Agriculture Secretary Proceso J. Alcala that the lobed river mullet, locally known as “ludong,” can be bred successfully in captivity, eventually making the current closed season for the fish normally caught in the Abra and Cagayan Rivers unnecessary.

The rare “ludong” (Cestraeus sp.) actually lays its eggs in the sea and eventually swim upstream, where they are caught. A 45-day closed season in the Cagayan and Abra Rivers will have the net effect of raising the price of “ludong” much higher than the current P8,000 a kilo, making it the most expensive freshwater fish in the Philippines, much like the “pigek” in Cotabato.