The high cost of commercial feeds, around 60% on production cost of tilapia in Region 02, has prompted the bureau to undertake research study on duckweeds as alternative fish feed.
Duckweeds (Lemna spp.) are small free floating plants with reported 18-42% crude protein (CP) content depending on the nutrient added on the culture media. Fertilization is necessary in order to ensure high CP content. The plant is very easy to grow and can in fact thrive on waste water. Other positive attributes are:
* Inexpensive to produce, can be produced with almost no cost at all
* Fish produced is palatable, safe and nutritious for human consumption
* It is used / digested very efficiently by tilapia and carp, it can be fed to poultry
* Easily reproduces and can easily double its weight within 16 hours to 2 days thereby volume production from minimal area is possible
* It has balanced essential amino acids and has a highly digestible dry matter which results to minimal waste from the fish, optimum metabolism on the use of nutrients and better feed conversion ratio
* Has carotene and xantophyll
Site Selection
Duckweeds thrive on slow moving or still bodies of water, it can be grown in tanks, ponds or any other area provided the site is protected from strong winds and intense sunlight.
Planting Method
Planting simply entails transferring seed plants into the planting area. Seed plants can be acquired at BFAR Agricultural Pilot Center Fish farm at Iguig, Cagayan for free. Two (2) kilos planting material is enough for 100 square meters.
Production area must be fertilized at rate of 100 to 200 kg 16-20-0 per hectare or 1,000 – 2,000 kg chicken manure per hectare for favorable result. If you intend to produce duckweeds at same area with fish, the pond must be apportioned appropriately. Install net as division and protection of the plant from the fish.
Harvesting
When the seed plants have sufficiently multiplied, harvest plants every two days to prevent overcrowding. Feed the plants directly to the fish at designated feeding schedule and at appropriate ratio.
The research conducted at APCFF has determined that a feed combination consisting 50% fresh duckweeds and 50% commercial feed as the optimum mixture. The stocks fed with the combination even attained higher growth rate / weight gain than stocks fed with pure commercial feeds.
Using Duckweeds as Alternative Fish Feed
Proper site selection and pond preparation must be followed, likewise proper pond care and maintenance must be observed in any fishpond venture like How to raise Tilapia in the backyard.
When using duckweeds as alternative diet, simply divide the Daily Feed
Ration (DFR) by 2, such that feed composition will be 50% commercial feeds and 50% fresh duckweeds.
Feeding Rate and Schedule*
BW- Body Weight
* Semi intensive culture system
Simple Cost Analysis
a) Duckweeds production In 1,000 sq. m. pond (1 – year production cycle)
(this is just an example, scale duckweed production according to your actual requirement)
Projected annual duckweed production – 15,000 kilos.
Production cost per kilo duckweeds – 75 centavos -per kilo fresh duckweeds
15,000 kilos duckweeds is enough to supply partial feed requirement of 3 hectares fishpond under semi-intensive culture management (5 pcs fingerings per square meter).
b) 1,000 square meter fishpond project* using duckweeds as alternative feed
Income Estimate
Projected production (80% survival rate)= 666.67 kgs @ P75/kg.
Gross sales= 50,000
Less production expenses= 17,987
Net income= 32,013
ROE=- 178%
Source: trc.gov.ph
Photo: digitalnaturalhistory.com
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