Chitosan has been used in aquaculture industry for a decade which has a lot of benefits to aquatic animals such as shrimp, fish and frog. Chitosan helps all aquatic animals growing fast and generating high immunes.

Chitosan is a natural biopolymer extracted from shrimp and crab shell. It consists of long molecular chains of amino sugar (glucosamine). Chitosan used for aquaculture should have good qualification with high degree of deacetylation (>95) and been through the purification process at high temperature to ensure that it is free from fungi, viruses and bacteria. 

1. Good raw materials.

2. Appropriate molecular weight of chitosan.

3. Suitable method of chitosan production and hygiene controlling process.

 

Good raw materials of chitosan is fresh shrimp and fresh crab shell that should be stored at the temperature of less than 4 celsius degree. All fresh shell should be extracted protein completely to avoid spoilage of chitosan when it is changed to chitosan solution. It should also be extracted calcium and minerals to have least residues in good chitosan. Good chitosan has DD (degree of deacetylation) more than 95. The value of DD implies that high DD chitosan can be completely dissolved with less residues and will have clear solution. On the contrary, the solutions of low DD chitosan will be turbid and cannot  be dissolved well. This solution is not suitable to the products for human food, aquacultures or plant immune promoting. The low DD chitosan solution can only be used for soil fertilizer or water treatment. Therefore, to choose good chitosan, it is recommended to choose high DD of chitosan which is produced from company that has expertise in chitosan industry and has high quality production process to have clear chitosan solutions without any residues.

 

Using chitosan to meet each objective is upon to various molecular weight of chitosan. Chitosan with low molecular weight has short chain but chitosan with high molecular weight has long chain. Generally, chitosan with various molecular weight derived from various parts of shrimp and crab shell. The shrimp and crab shell being stored at proper temperature will have stable molecular weight more than the shell begin dried under sunlight. The dried shell will have protein residues much more than fresh shell which is not suitable for some using objectives. Therefore, it is very important to choose appropriate molecular weight of chitosan to meet each objective. For example, chitosan with medium and high molecular weight are good for  fish and shrimp feed coating . Chitosan with low molecular is good for plants. However, using chitosan to coat fruits and vegetables to prolong life, it is recommended to use very high molecular weight chitosan (premium grade).

 

Each chitosan solution product has different qualification due to the following details;

1. Selected organic acid used to dissolve chitosan.

2. Chitosan dissolving process.

3. Temperature used during dissolving process.

4. Containers used for dissolving process.

5. Metal and lon control in chitosan solution.

6. Determination of bacteria and fungi in solution.

7. Production control by production specialist.

Good quality chitosan solutions comes from high standard of chitosan powder certified by FDA (Food and Drug Administration) During production process, chitosan powder dissolved by which is standard food grade organic acid will cause clear and hygiene chitosan solutions without residue. Good quality chitosan solutions shoud be processed at proper temperature in stainless container, dissolved with non-ionic water and determinate fungi and bacteria with high heat. Over all chitosan production process should be monitored and controlled by experts who have been in chitosan industry for many years.

Nowaday, there are many quality chitosan solutions product sold in the market. These products come from low DD chitosan which is less than 60-70. Low DD chitosan cannot be dissolved completely and present only 60-70 percent of chitosan value. The rest of them will be residue in the solutions that is worthless. Some chitosan products use low grade of organic acid from heavy industry. This kind of organic acid has strong sour smell and causes bad effect to chitosan solutions. When it is mixed with other supplements and medicine, it causes devaluation of supplements and medicine. On the contrary, chitosan solution produced from high quality process and control using food-grade of raw materials and organic acid to dissolve will be safe to human,animals and plants.

 

1. Coating shrimp feed and other aquatic animals’ feed

Results:keep feed stable and slow disintegrating in the water. Chitosan coating on feed works as binding agent to coat vitamins, medicines and other supplements to stick on feed tigthly. Chitosan solution can replace other coating oil such as squid oil, oyster oil, fish oil that cause swelling hepatopancrease and over fat on hepatopancrease of shrimp.

2. Enhancing shrimp health and generating shrimp shell

Results: use 25cc of chitosan solutions per 1 kilogram of feed coat on shrimp feed and leave it dry about 30 minutes. Continuously use chitosan mixing with shrimp feed at the beginning period of farming will help strengthening shrimp health. Shrimp has clear muscle, well-flipped body and perfect molting which causes hard and shiny shell and also free from viruses and bacteria. 

Is it necessary to use chitosan solutions in shrimp farming? 

Basically,shrimp always has continuous molting that has good management of farm with good water treatment and launchs shrimp at low density is not necessary to use chitosan. 

 

1. Launching shrimp densely populated (vannamei >100,000 per rai, black tiger shrimp >50,000 per rai)

2. Slow molting and slow growth in shrimp.

3. Shrimp has white muscle, not clear body.

4. After molting, shrimp shell is thin and slow of shell hardness.

5. Use vitamin and medicine and need them to be dissolved slowly.

6. During first 20 days of farming, shrimp is weak apparently.

7. Shrimp has black wound on shell and need molting to dump shell

When one of the above symptoms is found, chitosan can be used to help and protect the above problems. However, using chitosan at the beginning farming period will have better result due to shrimp need to absorb chitosan continuously from time to time to have enough chitosan to generate shell and muscle.

  To apply chitosan in shrimp farming, farmer has to be patient to wait for 1-2 weeks. Shrimp needs time to absorb chitosan enough to generate muscle and strengthen health. It is recommended to use chitosan at every feed time until shrimp absorbs enough chitosan and strong health then decrease chitosan when shrimp health is completely strong.

 

1. Shrimp

- Chitosan generates muscle and shell and stimulate complete molting and make shrimp grow quickly.

- Chitosan increases blood circulation and helps shrimp digestion.

- Chitosan enhances immune in shrimp.

- Chitosan as a coating agent causes feed stable and slowly disintegrated.

-  Chitosan enhances shrimp pigment.

- Chitosan continuously strengthens shrimp health.

- Chitosan as a binding agent to stick all supplements to shrimp feed tightly and shrimp can totally consume these supplements.

2. Fish

- Chitosan as a coating agent causes feed stable and slowly spoiled.

- Chitosan enhances fish pigment particularly red color on fancy carp fish.

- Chitosan enhances fish to consume more feed and have good digestion.

- Chitosan increases fish growth.

3. Frog

- Chitosan enhances frog consuming more feed and grow fast.

- Chitosan strengthens frog digestion system.

- Chitosan adjusts and improve water quality in frog pond.