AHPND is one of the diseases that threaten shrimp. This disease is caused by bacteria and has a high mortality rate, leading to decreased production and financial losses in the aquaculture industry. What are the signs of AHPND in shrimp and how to overcome AHPND? Read on to discover the full explanation!
What Is AHPND in Shrimp?
AHPND or Acute Hepatopancreatic Necrosis Disease is a shrimp disease that is caused by the Vibrio parahaemolyticus bacteria. AHPND is also known as Early Mortality Syndrome (EMS) which affects shrimp in the post-larval stadia and can cause up to 100% mortality within 20-30 days after stocking.
Symptoms of Shrimp with AHPND
AHPND attacks shrimp at the beginning of cultivation and is signaled by damage in the hepatopancreas. Shrimp with AHPND will have an empty gut as it does not store food and its hepatopancreas will shrink and look pale.
Some other signs of AHPND are:
- During the nursery stage, the movements of the larvae become weak, and the hepatopancreas become wrinkled and pale
- Sudden death of larvae and post-larvae occurs at more than 30%
- Empty gut because of the absence of feed
- Soft shell
- Shrimp swimming in circles
Mortality can occur 10 days after stocking, and dying shrimp will sink to the bottom of the pond.
Characteristics of Ponds with a Higher Risk of AHPND
The spread of AHPND disease varies, whether through water, broodstock, or feed. Spread through the broodstock occurs when the broodstock is contaminated with AHPND, which then spreads to the eggs they produce. Spread through feed occurs because the feed source is contaminated with AHPND pathogenic bacteria, which is then transferred to the shrimp feed produced.
There are several characteristics of ponds that are at high risk of contracting AHPND disease. Make sure your pond does not have the following criteria:
- Ponds with high stocking density, more than 100 shrimp/m²
- Ponds with high salinity, more than 20 ppt
- Poor deep water quality
- Improper pond preparation
- Poor feed quality
- Ponds with high concentrations of organic matter
- Dissolved oxygen (DO) levels are too low
- Ponds with less plankton diversity
How to Treat AHPND in Shrimp?
After learning about the characteristics of AHPND and the characteristics of ponds at risk of being infected with AHPND, let's learn how to overcome AHPND if it has already infected the shrimp in your pond.
1. Disinfect dead shrimp
First, shrimp that have died due to contracting AHPND should be disinfected with 100 ppm of chlorine for 3-7 days, then buried. This step ensures AHPND will not spread to other shrimp or ponds.
2. Give supplements to shrimp
The remaining shrimp which have not contracted AHPND need to be given immunostimulants and probiotics to strengthen their immunity and reduce the risk of AHPND. Also, bacteriophages can be given. However, make sure all supplements are given based on the recommended dose.
3. Monitor water quality
A water quality that is below ideal conditions increases the risk of emergence or spread of AHPND in shrimp. Monitor water quality regularly, especially temperature, pH, DO, and salinity. If these parameters fluctuate or fall outside the ideal range, make necessary adjustments to prevent shrimp from being stressed or susceptible to diseases.
4. Clean the bottom of the pond
Additionally, the bottom of the pond should be cleaned by siphoning to remove remains of shrimp molting, feed, and mud. Then, disinfect the pond using 100 ppm of chlorine, which also helps eliminate any remaining pathogens.
5. Clean pond equipment and channels
Aside from the pond itself, the equipment as well as inlet and outlet channels should also be cleaned to prevent them from being the source of diseases. Disinfect equipment such as paddle wheels, feeding trays, and others with 100 ppm of chlorine. Dry out inlet and outlet channels, then provide them with 2 ton/ha of quicklime.
6. Recheck pond condition
Before the pond is used for the next cycle, recheck the bottom and walls as well as the water source to ensure everything is clean. For the next cycle, control stocking density to match the environmental carrying capacity and use high-quality shrimp fry with SPF or SPR certification. During cultivation, maintain the quality and quantity of feed and continue to routinely monitor water quality.
Conclusion
AHPND in shrimp is caused by the Vibrio parahaemolyticus bacteria and can cause acute hepatopancreatic damage which leads to mortality.
Shrimp that has contracted AHPND will show the following signs:
- Empty gut
- Shrunk and damaged hepatopancreas
- Soft shell
- Black spots on hepatopancreas
- Swimming in circles
To overcome AHPND, you can carry out the following steps:
- Disinfect dead shrimp
- Give supplements to remaining shrimp
- Monitor water quality
- Clean the bottom of the pond
- Clean pond equipment and channels
- Recheck pond condition before the next stocking
By routinely monitoring your farm, you can recognize signs of AHPND early on before it’s too late. The shrimp farm management application, JALA App is #HeretoHelp you record and monitor your farm anytime and anywhere. Haven’t joined JALA App? Register yourself now on app.jala.tech and download the mobile version from Google Play Store or App Store!
Resources
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About the author
Chandrika Agustiyana is an Aquaculture Sciences student at the Bogor Agricultural Institute (IPB).
