Following a high occurrence of reports in Bangladesh districts close to West Bengal regarding incidences of Acute Hepatopancreatic Necrosis Syndrome in shrimp, also known as AHPND or previously named as EMS, authorities have increased the alert. An emergency response team under the National Surveillance Program for Aquatic Diseases will undertake surveillance in the area. The State Government advised that in case of confirmation of the AHPND incidence, all stock at the affected farms will be destroyed and disposed of and the whole farm will be disinfected.
All other coastal states in India are requested to be vigilant and to monitor the shrimp aquaculture farms for prevention and control of any incidence.
The disease is a newly emerging threat but has already done serious damage to shrimp production and the shrimp aquaculture industry worldwide. It was first detected in China in 2009 and moved in the region, later crossing the Pacific with several reports from Latin America in recent years. Notable symptoms of affected shrimps include an empty gut and pale hepatopancreas. AHPND has been discovered to be caused by toxic strains of Vibrio parahaemolyticus that have acquired a »selfish plasmid«, encoding the deadly binary toxins PirAvp/PirBvp. Morbidity can reach 100%, and lead to 100% mortality within 20 to 30 days after a pond gets stocked with shrimp postlarvae.
Studies have revealed that phytogenic products can have anti-bacterial activity and have the capability to improve immune response. Therefore they have a high potential to improve the survival rate of some aquatic organism. A specific group of plant extracts called polyphenols has many biological effects including antioxidative, anti-inflammatory, and antimicrobial qualities, making them valuable ingredients for health promotion.
Recent studies performed in cooperation with the Faculty of Fisheries at Kasetsart University, Thailand, revealed how including Anta®Ox FlavoSyn (by Dr. Eckel Animal Nutrition GmbH & Co. KG, Germany) in the shrimp diet leads to excellent results. This was demonstrated under laboratory conditions when the animals were challenged with Vibrio spp. as well under commercial farm conditions in large ponds affected by AHPND.
Pacific White Shrimps that were fed with Anta®Ox FlavoSyn not only showed better growth parameters (1.35.1 vs. 1.55:1 FCR in the control group) but also improved histomorphology of the hepatopancreas, with no signs of atrophy and bacterial infection. In contrast, the control group showed 20–80% of hepatopancreatic cells damaged. All these benefits allowed for an improved survival rate of 91% in the product group, compared with only 63% in control.
Figure 1: Lower Vibrio counts in the hepatopancreas of Pacific White Shrimp
Figure 2: Hepatopancreas of Pacific White Shrimp. Top: 20-80% with cell necrosis. Bottom : Healthy hepatopancreas