Shrimp Diseases

AHPND on Shrimps and Its Signs

Chandrika Agustiyana
Chandrika Agustiyana
26 October 2023
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The productivity of shrimp farming is closely related to the cultivation production and is affected by the survival rate (SR). Disease is one of the causes that leads to low SR. One of the diseases with a high mortality rate, causing decreased production and financial losses in the aquaculture industry is AHPND. 

AHPND or Acute Hepatopancreatic Necrosis Disease is caused by Vibrio parahaemolyticus. It is also known as Early Mortality Syndrome (EMS). EMS disease affects post-larval stadia and can cause up to 100% death within 20-30 days after stocking.

Vibrio parahaemolyticus is a halophilic gram-negative bacterium that prefers high salinity environments. The AHPND strain of Vibrio parahaemolyticus can be detected by real time PCR (RT-PCR) with a high level of accuracy and short identification time. However, farmers can do initial screening for symptoms of infection.

This disease attacks shrimp in their early stages of cultivation, causing hepatopancreas damage (acute hepatopancreatic necrosis). Shrimp affected by AHPND has the following signs:

  1. During nursery stage, the movements of the larvae become weak, and the hepatopancreas become wrinkled and pale
  2. Sudden death of larvae and post-larvae occurs by more than 30%
  3. Empty intestines because it is not filled with feed
  4. Soft carapace
  5. Shrimp swimming in circles
  6. Dying shrimps sink to the bottom of the pond

Below is the comparison of normal and AHPND-infected vannamei shrimp:

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Source: https://www.agriculture.gov.au/sites/default/files/documents/acute_hepatopancrea tic_necrosis_disease.pdf

Under normal conditions, the vannamei shrimp has a filled intestine and a brown hepatopancreas. Vannamei shrimp infected with AHPND have an empty stomach and pale, shrunken hepatopancreas.

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:

  1. Ponds with high stocking density, which is more than 100 shrimp/m2
  2. Ponds with high salinity, which is more than 20 ppt
  3. Poor deep water quality
  4. Improper pond preparation
  5. Poor feed quality
  6. Dissolved oxygen (DO) levels are too low

Prevention is not easy, but it is much better than being infected with AHPND.

Sources

Azhar F. 2018. Aplikasi Bioflok yang dikombinasikan dengan Probiotik untuk Pencegahan Infeksi Vibrio parahaemolyticus pada Pemelihaaran Udang Vaname (Litopenaeus vannamei). Journal of Aquaculture Science. 3 (4): 128 &ndash; 137.

Fajriani B, Budiharjo A, Pujiyanto S. 2018. Isolasi dan identif ikasi molekuler bakteri antagonis terhadap Vibrio parahaemolyticus patogen pada udang Litopenaeus vannamei dari produk probiotik dan sedimen mangrove di Rembang. Jurnal Biologi. 7(1) : 52-63.

Hamzah, Herawaty, Hasmawati. 2021. Uji daya hambat madu, bawang merah, dan jahe terhadap beberapa jenis bakteri Vibrio sp.. SIGANUS: Journal of Fisheries and Marine Science. 2(2): 118-125.

Han JE, Tang KFJ, Pantoja CR, White BL, Lightner DV. 2015. qPCR assay for detecting and quantifying a virulence plasmid in acute hepatopancreatic necrosis disease (AHPND) due to pathogenic Vibrio parahaemolyticus. Aquaculture. 442:12&ndash;15.

Lightner DV, Redman CR, Pantoja BL, Noble LM, Nunan, Loc Tran, 2013. Documentation of An Emerging Disease (Early Mortality Syndrome) In SE Asia & Mexico. OIE Reference Laboratory For Shrimp Disease, Department of Veterinary Science & Microbiology, School of Animal And Comparative Biomedical Science.

Muchtar M, Farkan M, Mulyono M. 2021. Productivity of vannamei shrimp cultivation (Litopenaeus vannamei) in intensive ponds in Tegal City, Central Java Province. Journal of Aquaculture and Fish Health. 10(2):147&ndash;154.

Nainggolan RKS, Yuhana M, Sukenda S, Sariati WNE. 2020. Deteksi Vibrio parahaemolyticus menggunakan marka gen PirA pada udang vanname (Litopenaeus vannamei) dengan real time PCR. Jurnal Riset Akuakultur. 15(2). 111 - 119.

About the author

Chandrika Agustiyana is an Aquaculture Sciences student at the Bogor Agricultural Institute (IPB).

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