How is Chitosan Benefited to Shrimp Farming ?

Last 10 years chitosan is initially manipulated in aquaculture industry particularly in shrimp farming applying chitosan to coat shrimp feed.  It is believed that chitosan is a natural biopolymer that is safe to human and nature.  

In the past, shrimp feed has low durability and easy to be dissolved in the water.  Within 2 - 3 hours , shrimp feed soaked in the water is quickly dissolved and too soft that shrimp cannot consume.  With this feature, the leftover shrimp feed at the bottom of the pond generates problem of water quality in the pond that increase ammonia and nitrite quickly causing toxic to shrimp.  If there is no problem solving, shrimp in a large number will be weaken and died finally.  However, if chitosan with 3 - 5 % w/v concentration is applied to coat shrimp feed and let dry for 30 minutes to have chitosan film cover shrimp feed pellet, and after that, the coated shrimp feed are scattered into shrimp pond, the chitosan coated shrimp feed can be endured 5 - 8 hours in the water without decomposing into powder.  It is still in pellet form and touchable similar to fish ball.  Chitosan will cover shrimp feed to be remained last long in the water that shrimp can easily consume and make better water quality in the pond due to no decomposed shrimp feed to spoil water.

When using chitosan coating shrimp feed for a time, shrimp will start molting out because chitosan will enhance chitin that is an important substance shrimp utilizing to generate shrimp shell and tissue.  Basically, shrimp in nature get enough chitin from other aquaculture shell such as small shrimp and crab, mollusks, squid that causes shrimp in nature has normal molting.  On the other hand, shrimp in farming receives not enough chitin to help molting due to a large number of shrimps in the pond eventhough shrimp itself can synthesize chitin from shrimp feed but it is not enough.

Shrimp molting is caused from the complete accumulation of all nutrients and generating adequate chitin.  After perfect molting, shrimp has larger size and will eat its shell scrap to reserve chitin for next molting.  However, shrimp will not be able to have another molting in the short time due to it has to accumulate nutrients and create enough chitin.

Before molting period, shrimp will resume minerals and store in hepatopancrease which is the most important organ for shrimp.  Hepatopancrease is responsible to digest nutrients, generate enzymes and accumulate nutrients and minerals for shrimp.  After molting, shrimp will resume those nutrients and minerals stored in hepatopancrease to create shell structure and absorb other minerals from water through shrimp gill to generate hard shell.

Basically, shrimp keeps chitin in hepatopancrease and tissue and resumes it when molting.  If shrimp receives chitin supplement such as chitosan, it helps shrimp to create chitin more efficient to have easy and perfect molting with high survival rate.  The supplement of chitosan into shrimp feed and shrimp consumes regularly is beneficial to shrimp and farmer.  Shrimp grows well and strong and farmer has success farming.  Since chitosan is a natural substance extracted from shrimp shell, it is much appropriate to apply for shrimp without any residue or prohibited substance and is proved more than 10 years that is useful for aquaculture farming.