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September 1, 2015

Australia

Gold Coast Marine Aquaculture: FCRs, Feeding Frequency and Feeding Trays

 

   

 

Shrimp are usually fed five times daily, but Gold Coast Marine Aquaculture feeds shrimp only four times daily.  By providing more time for shrimp to rest between eating cycles, consistently lower feed conversion ratios (FCRs) have been achieved.  There is also more time for pond staff to properly deploy and check feeding trays, which reduces errors in feed management.

 

FCR is a measure of shrimp’s efficiency in converting feed mass into increased body mass.  FCR is defined as the mass of the food eaten divided by the body mass gain, over a specified period.  For Penaeus monodon, the typical feed-conversion ratio is 1.8.

 

FCRs are important because higher FCR values indicate uneaten feed that can leach out nutrients in ponds.  Leached nutrients impact water quality in growout ponds and potentially increase the nutrient load in the farm effluent.  In general, a high FCR means more feed waste and costs, which leads to lower profitability for the farm.

 

   

 

At Gold Coast feeding is applied using a vehicle with a feed blower, which spreads feed evenly across ponds.

 

• At the same time the feeding vehicle spreads the feed, 0.5% of the total feed is added to three feeding trays in every pond and checked after about three hours.

 

• If no feed is left in the trays, a 3-kg increase in feed volume is made during the next feeding for an average shrimp body weight up to 10 grams.  An increase of 5 kilograms is made for shrimp with average body weight greater than 10 grams.

 

• If feed is left on the trays, a 20 to 80% decrease is made in the next feeding.  Previously, Gold Coast Marine Aquaculture only decreased feeding by 10 to 30% when feed was left on the trays.  This was due to the belief that a large decrease in feed would lead to a higher rate of cannibalism in Penaeus monodon stocked at high density.  If the amount of feed is decreased, especially during molting periods, they thought it would will cause a decrease in biomass due to cannibalism.  Observations made by Gold Coast Marine Aquaculture show the opposite.

 

• Shrimp do require regular feeding due to their small stomachs and rapid digestion.  However, from previous observation, shrimp generally feed and rest periodically before returning to the water column in search of more food.

 

• Since the time gap between feedings is a constant six hours, there is enough time for shrimp to rest before resuming their eating cycle.  This allows the shrimp to properly digest their source of nutrients.  This simple act can help maximize molt cycle and growth performance.

 

 

Information: Bambang Julianto, Gold Coast Marine Aquaculture, Pty., Ltd., Marks Road, Woongoolba, Queensland 4207, Australia (email jbambang@bigpond.net.au, webpage http://www.gctigerprawns.com.au/contact.php).

 

Source: The Global Aquaculture Advocate (The Global Magazine for Farmed Seafood).  Editor, Darryl Jory (dejry2525@aol.com).  Feed Tray Management Lowers FCRs, Shrimp Production Costs in Australia.  Bambang M. Julianto and Darrel Herbst.  Volume 18, Issue 5, Page 38, September/October 2015.

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