Breakthrough in natural feeds to make tilapia culture cheaper

TUGUEGARAO CITY, Cagayan – Cagayan Valley’s tilapia growers no longer need to content themselves in shouldering the ever-rising price of feeds and other inputs in their fishponds. 

This came as a result of a successful farm trial in Iguig town here which showed duckweeds to be an effective alternative diet of tilapia, also known as Saint Peter’s fish, in lieu of commercial feeds.

The results of this experiment conducted by the Bureau of Fisheries and Aquatic Resources (BFAR) in Iguig’s experimental farm would redound to some 50 percent savings for tilapia growers in the region which is slowly becoming the tilapia capital of the country.

Duckweeds (scientific name: Lemma spp) are small floating plants in fishponds which contain 40-45 percent of crude protein and are ideal as alternative feeds for tilapia, said researchers from the BFAR regional office here led by Dr. Jovita Ayson.  

Romeo Pizarro, farm manager of the experimental farm, said that after a series of experiments involving different mixtures of dry and wet duckweeds with commercial feeds, it was seen that a mixture of 50 percent fresh duckweeds and 50 percent commercial feeds was the most economically viable mix for tilapia growers.

“Repeated experiments showed that a 50-50 mix of fresh duckweeds and commercial feeds offered the best possible economic return for fish farmers,” Pizarro said.

Pizarro said that the said combination offered an even higher growth rate for tilapia than those grown purely on commercial feeds, signifying much greater revenue for the farmers in five to six months.

He said the production expense using duckweeds is only 76 centavos per kilogram including labor costs compared to P25 per kilogram for commercial feeds. 

Moreover, Pizarro said those interested in propagating duckweeds as alternative feeds for their tilapia in Cagayan Valley can just visit their experimental farm in Iguig to obtain for free the plant’s so-called propagules, or seedlings from the BFAR staff. 

Propagation of duckweeds, Pizarro said, merely means transferring them to the planting site, whether this is a pond, tank or secured body of water. Five kilograms planting material can be enough to cover 1,000 square meters.

Duckweeds propagate rapidly, doubling their volume in only two days, meaning one has to harvest them every now and then.

Pizarro also said that when producing duckweeds in ponds, the water must be fertilized at a rate of 100 kilograms of chicken manure and 10 kilograms of ammonium phosphate (16-20-0) per month per 1,000 square meters for best results. Water must be totally changed every month.  

Pizarro said that although duckweeds can be produced in the same pond with fish, this is not very efficient since any form of mechanical aeration of the water (i.e. paddle wheel, aerators) disturbs the growth of the plants. Likewise, their photosynthetic activity blocks oxygenation of the water which the fish need.