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June 10, 2014

United Kingdom

Scotland—Salmon Hydrolysate as an Attractant in Shrimp Feed


Shrimp have poor eyesight and are attracted to feed by chemicals released into the surrounding water.  Chemoreceptors located on their antennae receive the signals and help gauge the distance to the food.  Chemoreceptors on their mouthparts and legs are involved in food seizure and ingestion.  Effective feed attractants are characteristically water soluble and closely related to the chemical compounds that are released from potential prey.  Thus, substances that elicit strong feeding behavior are protein derived amino acids such as taurine, proline, glycine, arginine, glutamic acid, and alanine, together with other organic compounds such as peptides and nucleotides.  In contrast, studies have shown that while fish oil tastes and smells fishy to humans, shrimp take a long time to detect it because oil does not mix with water.


So where do we find effective attractants that fit the above criteria and do not involve non-renewable resources from marine environments?  Fish by-products and trimmings left over from human consumption are the obvious answer.  Some of these are the very same raw materials that would be traditionally converted into fishmeal.  From a feed attraction stand point the most cost effective approach is to convert these fish by-products into fish protein hydrolysate to better mimic the attractant compounds found naturally in the shrimp’s diet.


Rossyew, Ltd., produces hydrolysates from farmed salmon by-products (mostly viscera and the liver).  They are first hydrolyzed using natural enzymes and then the excess oil is removed by centrifugation.  The hydrolyzed protein fraction is then concentrated by low temperature vacuum evaporation to produce a thick sticky liquid called “Salmon Pro Hydrolysate”.


Information: Rossyew, Ltd. (UK), phone +44-1684-566692, email,, webpage


Source: AQUA Culture AsiaPacific.  Editor/Publisher, Zuridah Merican (email  Salmon Boosts Shrimp Feed Attractiveness.  Ian Wright.  Volume 10, Number 3, Page 32, May/June 2014.

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