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June 3, 2015

The World

Making Small Batches of Shrimp Feed

 

Lorenzo M. Juarez (lorenzojuarez@yahoo.com): For a test, I’m looking for a procedure to re-make small batches of shrimp feed.  The idea is to grind the feed, add extra ingredients (medication, immune boosters, probiotics and vitamins) and a binder and re-extrude the mix using a meat grinder or similar devise.  I don’t want to topcoat the feed because I want all the ingredients to be part of the mash.  Does anyone have a procedure for this?

 

Durwood M. Dugger (ddugger@biocepts.com): Years ago we used a meat grinder with blades that cut the pellets.  Pellet length was controlled by the number of blades—one, two or four—and to some degree by the ingredient consistency.  We were using pretty standard shrimp feed formulations and typical standard commercial commodity ingredients.  We built a 4x4x8-foot, “solar oven dryer” out of grooved T-111 plywood.  It had a gabled roof and chimney on its peak.  The chimney had a baffle to control the airflow and temperature of the “oven”.  This little solar “out house” had 2x4 studding on its exterior that we covered with clear plastic to collect passive solar heat on the sides.  The plastic covered walls had a small fan that forced outside air down the wall and into the oven through small holes in the bottom of the interior wall and into the oven to create an upward hot air flow out of the chimney.  The T-111 plywood grooves were used to support screened trays where thin layers of feed would have hot air passing up through them, carrying away moisture.  On a sunny days it took about 24 hours to dry about a 100 pounds of feed pellets.  I can send you pictures of the oven and the grinder.  Not very elegant, but very functional.  The whole building/box was painted flat black, following Kirchhoff’s Law of thermal radiation.

 

Greg C. Lutz (glutz@agcenter.lsu.edu): Here is a summary, more or less, of how the folks in our nutrition lab accomplish this.  The original commercial extruded diets are ground in a hammer mill, and then mixed with the desired quantities of the new ingredients.  We use one of those “V” shaped rotating powder mixers.  In our work here with alligator diets, if a non-digestible filler is needed (say, to reduce the crude protein and lipid contents) powdered cellulose is added to the mix.  However, when diluting the diet like this, it is necessary to obtain the original vitamin and mineral premixes and add enough to match the original concentrations of vitamin and mineral supplementation.  Re-pelleted diets also include 1% carboxymethylcellulose (CMC) in the mix, as a non-nutritive binder.  We re-pellet using a simple ½-horsepower meat grinder with a series of different size dies that yield a spaghetti like product that gets broken into more or less uniform pellets.  You may need different dies or different equipment altogether depending on the pellet size and characteristics you are trying to produce.  I like Durwood’s (above) modification of this approach using blades attached to the shaft to cut the pellets more uniformly.  We dry our re-pelleted diets indoors overnight (using simple 110v fans) to approximately 10 percent moisture, to avoid any breakdown of nutrients due to heat or even sunlight.  Then we store them at -20 C until needed.

 

Source: The Shrimp List (a mailing list for shrimp farmers).  Subject: Feed Re-Making.  June 1–2, 2015.

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