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Automatic Feeders and Feeding Trays

 

 

Billy Setio (surijo_setio@yahoo.com): Hi Listers, are any of you using automatic feeders?  How do you set them up?  Do you use feeding trays with them?  How far from the automatic feeders should the feeding trays be placed?  I’ve been getting the same results with automatic feeders that I got with manual feeding.  I don’t know when to feed less or more, or how aggressive I should be when I make a change.

 

Jorge Cordova (seabizec@yahoo.com): Hi Billy, we use automatic feeders during growout in ponds stocked at 10-12 juveniles per square meter.  We place trays in areas where the feed will fall so we can see how much feed is left over after we feed.  You could also use a fairly large diameter pipe with glass over one end to scan the bottom of the pond the morning after you feed.  We feed from 11:00 a.m. to 11:00 p.m.

 

We begin using automatic feeders after we have a good idea of how much feed the pond is taking, which usually occurs soon after stocking and after the first round of mortalities when the juveniles are around five grams.  After that, not much additional feed is necessary, but more automatic feeders may be needed as the biomass increases.  We found that we can support two metric tons of shrimp with one automatic feeder.

 

• Make sure the automatic feeders throw the feed at least 11 or 12 meters.

• Your automatic feeders should be 40 to 50 meters away from each other.

Extruded feeds seem to work better than pelleted feeds.

• Your return on investment should go up once you start using automatic feeders.

 

Billy Setio (surijo_setio@yahoo.com): Hi Jorge, our stocking density is 130-150 PLs per square meter, and we use 60-hp of paddlewheel aeration per hectare, combine with a touring turbine aerator.  With manual feeding, we produce 20-gram shrimp in 85 to 90 days, with survival rates of around 85 to 95%, a feed conversion ratio of 1.05 to 1.15, and no partial harvests.

 

With manual feeding, we use four feeding trays per pond, checked twice per feeding to decide when to slow down, hold steady or increase the feeding.  Our concept is usually to increase feeding or hold steady, so the feeding graph we get is usually up.

 

With automatic feeding, we use a day timer, an interval timer and a feed-duration timer.  We set the day timer for 24 hours, and the other two timers are adjusted daily, according to what the feeding trays tell us, which we place about two meters from the automatic feeders.  We use two automatic feeders in our 2,000-square-meter ponds and one our 1,000-m2 ponds.

 

We turn all the automatic feeders on at 30-35 days of culture.

 

We believe in many small feedings, rather than one large feeding, which results in very little wasted feed and fresher, more nutritious feed for the shrimp.

 

We feel our automatic feeder and tray placement is still not quite right because currents from our paddlewheels affect the sinking feed.

 

Are there any rules of thumb on placing the automatic feeders and how to “read” the feeding trays?

 

Enrique Manuel Niño Cordero (enriquemlnino@gmail.com): Hi Billy, I have a lot of experience working with feeding trays on 1,450-hectare, 214-hectare and 80-hectare farms.  All our feeding was done with feeding trays—no feed casting or automatic feeders.  We made 35,000 of them using 20 per hectare in ponds stocked at 20 PLs per square meter and got FCRs of 1.05.  We mixed the feed with molasses and fed the shrimp twice a day, which was a lot of work and hand labor, but the results were good.  We saved money and kept the pond bottoms clean.  The weekly growth was never less than one gram per week, pumping costs were reduced, and we got better survivals because we based our feeding rate on our feeding-tray observations.  When you use feeding trays, the shrimp eat all the time, and the small shrimp have a better chance to eat and grow larger.

 

Billy Setio (surijo_setio@yahoo.com): This is the first time I’ve used automatic feeders, and I’m still not as comfortable with them as I am with manual feeding because I still don’t know how to “read” the feeding trays.  That’s why I still need more information.  Is there a rule of thumb on the distance the feeding trays should be from the automatic feeders?

 

Jorge Cordova (seabizec@yahoo.com): Hi Billy, there’s no set rule of thumb for placing automatic feeders and feeding trays.  Just make sure that you use one or two trays within the area where the feed is falling.

 

The type of automatic feeder you use can affect the amount of feed that lands in the feeding trays.  On our farm, we have tried an acoustic feeding system and various arrangements with automatic feeders.  With the acoustic feeding system, we have observed that it is possible to grow close to 1,400,000 shrimp with four feeders in an area close to 2,000 m2.

 

We disperse small amounts of feed from the automatic feeders around the clock with no big impact on biological oxygen demand.

 

Based on our observations, between 5 to 7 metric tons of shrimp can be obtained without a decrease in shrimp performance (growth rate).  We use an automatic feeder that can disperse close to 35 grams of feed per second.

 

Feed demand seems to vary seasonally because of changes in temperature and the lunar cycle, but it always seems to be greatest between 4 and 8 pm.  If you’re only using one automatic feeder, it’s more difficult to estimate feed demand.

 

Billy Setio (surijo_setio@yahoo.com): Hi Jorge, we don’t use an acoustic feedback system.  I have just finished our first harvest using automatic feeders.

 

From my historical data, we have a feeding program based on average body weight and daily feed amount, and we feel comfortable using it because it prevents overfeeding.

 

I have to evaluate our first results with automatic feeders.  Thank you for your valuable comments.  We will be patient and experiment with different ways of using automatic feeders and feeding trays.

 

Saji Chacko (chacko.saji@gmail.com): I’m from India and have been using automatic feeders on my farm for the last five years.  My annual production of Penaeus vannamei is over 1,000 metric tons from a 100-hectare farm.

 

I use one automatic feeder per hectare with a daily ration of 200 to 250 kilograms of feed.

 

We harvest shrimp varying in size from 15 to 50 grams, depending on the market conditions and the weather.

 

During the first month of culture, feed crumbles are distributed by manual broadcasting, and after that we use automatic feeders.

 

Our automatic feeder throws feed up to 16 meters, but the distance can be programed for shorter distances.

 

We keep two feeding trays within the feeding zone of the feeder and monitor them at least three times a day.  To get an idea of the feed demand, we check the trays for uneaten pellets and the appearance of the fecal strands.

 

Automatic feeders are becoming more popular in India.

 

Jorge Cordova (seabizec@yahoo.com): Hi Saji, what biomass can you harvest from one feeder?

 

Saji Chacko (chacko.saji@gmail.com): We have done up to 12 metric tons from one automatic feeder.

 

Jorge Cordova (seabizec@yahoo.com): Hi Saji, that’s an excellent yield.  How many grams of feed does your automatic feeder deliver per second?

 

Saji Chacko (chacko.saji@gmail.com): Hi Jorge, about 12 grams per second.  Soft ware controls the feeder.  We define the start time and end time.

 

Sources: 1. The Shrimp List (a mailing list for shrimp farmers).  Subject: Autofeeder.  August 7 to 11, 2017.  2. Bob Rosenberry, Shrimp News International,  October 2, 2017.

 

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