Diseases in shrimp

Shrimp farming has been developing rapidly for many years, gradually becoming an important economic sector, mainly contributing to the overall growth of the fisheries sector. However, farmers are facing many difficulties and challenges regarding environmental pollution, disease outbreaks, overuse of antibiotics and chemicals in farming process, and product quality does not meet market requirements, causing economic losses to people.

Impact of environmental pollution and diseases
The expansion of production scale, increase in the level of intensive farming has led to the emergence and outbreak of many dangerous diseases that threaten the sustainable development of the shrimp industry, directly causing great losses to farmers. In addition, environmental pollution is also a problem of concern of not only the shrimp farming community but also the entire society in both directions. Farming activities are adversely affected by pollution and shrimp farming is also a source of self-pollution for ponds and the surrounding environment. Due to climate change, prolonged hot weather, sudden increase in salinity or decrease, disease outbreaks occurred more frequently, causing great damage to farming industry.

Quantity and quality of non-infected shrimp breeds, controlled from parents and reproductive stage; disease control processes in commercial farming have not yet met the development requirements of production. These shortcomings have caused some farmers to overuse chemicals and antibiotics in the culture process to treat the environment, prevent and treat diseases; Since then, the farming products made by these farmers have been supplied to the processing plants which have not yet ensured food safety, making the prestige of Vietnam’s shrimp industry to be affected accordingly.

Some diseases causing great damage
White Spot Disease
The WSSV (White spot syndrome virus) that causes white spot disease in brackish water shrimp was recorded in the 1990s in Taiwan and then spread in many places including Vietnam. WSSV is considered to be a special virus because it can survive in most crustaceans but only causes epidemic in brackish water shrimp (Dang Thi Lua, 2018).

Acute Hepatopancreatic Necrosis Disease
Early mortality syndrome (EMS) (also known as acute hepatopancreatic necrosis disease – AHPND) has caused an epidemic leading to damage of shrimp farming in Asia and Latin America and was recorded in Vietnam in April 2011. The disease caused rapid death of black tiger shrimp and whiteleg shrimp in the period of 15 – 45 days of age after stocking with a mortality rate of up to 100%. AHPND pathogens are thought to be caused by bacteria of the Vibrio group, such as Vibrio parahaemolyticus, V. harveyi and V. campbellii. Among the antibiotics allowed or recommended to limit use, Vibrio parahaemolyticus is sensitive to gentamicin, florfenicol, oxytetracycline, doxycycline and tetracycline.antibiotics. Feed, toxic algae, pesticides in shrimp ponds are not related to AHPND but ponds of shrimp with AHPND disease often show signs of organic pollution.

Infectious Hypodermal and Hematopoietic Necrosis Disease – IHHNV

The disease is caused by Infectious Hypodermal and Hematopoietic Necrosis virus (IHHNV). The most effective way to prevent disease is still to use high-quality, disease-free broodstock.

Yellow Head Disease – YHV

The disease is caused by a complex of Yellow Head Virus YHV and Gill-Associated Virus – GAV. Effective disease prevention can be done by checking disease-free breed and water treatment before stocking.

Enterocytozoon Hepatopenaei Disease – EHP

EHP disease in shrimp is caused by the Enterocytozoon hepatopenaei (EHP) parasite. This parasite parasites in the shrimp’s hepatopancreas and prevents the shrimp from absorbing nutrients leading to shrimp growth retardation. The best way is to limit the entry of EHP into the pond and control its infection in the pond to a minimum.

Solutions

There is a need for a new overall view in choosing the approach to find solutions to develop the shrimp industry to ensure food safety, environmental friendliness and disease restriction. Such an approach should be based on industry-specific production practices; research and training system; the system of input services, and the system of processing and commercializing products. In other words, it is the approach to the industry chain, where each stage should be aware of and perform its tasks towards the sustainable development of the shrimp industry from breed production, commercial farming, processing and supplying products to the domestic market as well as for export.

It is necessary to ensure the relationship between ensuring food safety in aquaculture production in general, shrimp production in particular from farming to processing. For aquaculture, it is necessary to ensure biosafety, where disease prevention is a cornerstone of good production practices (GAP) and is also a necessary condition to ensure food safety in aquaculture. It also corresponds to good manufacturing practices (GMP), sanitary control practices (SCP) as the basis for hazard analysis and critical point control (HACCP) in seafood processing.

The above challenges require the implementation of many synchronous solutions, including research and application of scientific and technological advances, training of science and technology human resources that are decisive for sustainable development of the industry. It is necessary to research to identify pathogens: Applying research methods from traditional ones (such as histology to modern ones such as using electron microscopes, PCR, etc.) to quickly and accurately identify the pathogens. Researching and developing preventive and treatment measures to ensure food safety and environmental friendliness such as production of vaccines, probiotics, nano products, herbal products, and restriction of antibiotic use. Developing and applying advanced farming technologies such as Bio-floc, Cope-floc, indoor farming; technology for using microorganisms which requires less water change; applying new achievements in informatics, new materials and biotechnology, automation in care, feeding, environmental and disease monitoring, traceability. Researching breed production, selecting disease-free breeds to increase the proportion of disease-free shrimps for commercial farming. Tightly managing the broodstock import and breed transport to limit the spread of diseases. Strengthening surveillance of farming areas, early detecting epidemic areas to limit spread. Developing large-scale production systems to facilitate the application of biosafety and food safety management, environmental management and product price reduction. Strengthening the linkage between the stages in the linkage chain between producers in the farming area to effectively prevent diseases. Applying the biosafety principle to the management of farming activities from broodstock fattening to grow-out in farms. Using probiotics in form of periodic microorganisms to improve water quality and improve waste management in the culture process. Limiting the use of antibiotics, absolutely avoiding using antibiotics in shrimp disease prevention. Gradually applying information technology to manage production activities.

Mai Van Tai – Research Institute for Aquaculture no. I
Source: www.thuysanvietnam.com.vn