HEALTH
Sustainable solutions to support shrimp natural defenses: How plant extracts can be an effective asset against AHPND Amine Chaabane, Laboratoires Phodé AHPND: A global issue in shrimp farming Marine shrimp aquaculture has become a worldwide industry with farms mostly located in Asia and Latin America, ranging in several latitudes from Mexico to Peru, and from China to Australia. Despite different environments, farming systems and technology, the expansion of shrimp farming came with its diseases, which today are also widespread. Among pathogens involved, bacteria from the Vibrio genus are very common in seawater. Different strains from different species are known for causing pathologies like Early Mortality Disease (EMS), currently known as Acute Hepatopancreatic Necrosis Disease (AHPND) and caused by the species Vibrio parahaemolyticus (Tran et al., 2013). Outbreaks of AHPND naturally occur in the first 30 days after stocking a freshly arranged shrimp pond, and mortality rate can reach 100%. Firstly reported in southern China in 2010 and subsequently in Southeast Asia, this disease is now ubiquitous in shrimp farms worldwide.
Dealing with AHPND requires a multi-layer strategy, which generally involves environment control (although depending on the farming system and limited as Vibrio bacteria are native and ubiquitous in waters), antibiotics, genetics, or probiotics. Shrimp are fragile animals, that do not possess a proper acquired immunity system and rely on innate immunity with unspecific response to any external agent. Then, besides previously mentioned strategies, solutions are being sought by the shrimp farming industry to stimulate their natural defenses and limit the impact of this disease on ponds.
Plant extracts: A wide range of benefits Among sustainable candidates, plant extracts have shown promising results to limit Vibrio infection in aquaculture. Most of the active compounds from plants used today are secondary metabolites, which are molecules naturally synthesized by plants to enhance their fitness, for example, when fighting parasites and/
Table 1. In vitro assays in different Vibrio species
Identified name
Origin
Minimum Inhibitory Concentration (MIC, ml/kg)
Vibrio alginolyticus
Ninh Thuan, VN
2.84
Vibrio fluvialis
Ninh Thuan, VN
0.71
Vibrio harveyi
Hawaii, USA
0.71
Vibrio parahaemolyticus
Thailand
0.71
Vibrio parahaemolyticus
Ecuador
1.42
Vibrio parahaemolyticus
Vung Tau, VN
1.42
Vibrio rotiferianus
Ninh Thuan, VN
2.84
30
Aquafeed: Advances in Processing & Formulation Vol 15 Issue 3 2023