Feed Palatability and The Alternative Protein Sources in Shrimp Feed
Department of Aquatic Science, Faculty of Natural Resources
Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
Feed intake is central to growth and general performance of animals. Intake is regulated by factors such as nutrient concentration and balance, level of toxins, and physical characters of feed such as texture that improves acceptance. Feed palatability in naturally carnivore aquaculture species have been crucially related to the presence of compounds that act as attractants. These attractants are commonly associated with the prey components under wild conditions. Shrimps provide a spectacular example in this category in terms of attractant- dependence. Thus nutritionally adequate and organoleptically-pleasing diet is essential to achieve satisfactory intake and growth in shrimps. Historically fishmeal has been an essential dietary component of intensive shrimp cultures. Besides its nutrient composition, fishmeal is thought to have been a source of a host of attractants within. However, in recent years the fishmeal supplies have been dwindling due to overfishing and diminishing natural fish-stock elevating price and market volatility. This has led to search for cheaper suitable protein sources as fishmeal substitutes. To improve the palatability of diets, various substances have been investigated for their effectiveness in aqua-feed including natural feed ingredients and synthetic flavor substances. For crustacean, attractants characteristically are of low molecular weight, water and ethanol soluble, and amphoteric or basic compounds that are released from potential prey items. Compounds such as free amino acids, especially taurine, hydroxyproline, glycine, arginine, glutamic acid and alanine have been identified to stimulate feeding in shrimps. The same has been identified with organic acids, nucleotides and nucleosides, betaine, and some small peptides. Palatabilityalso have been associated with animal’spastexperiencewiththefeed. Understandings of factors that regulate feed palatability are therefore primary for successful shrimp culture.
Keywords: Organoleptic, diet, crustacean, fishmeal and aquaculrture