Acute Hepatopancreatic Necrosis Disease (AHPND)
Animal model: Whiteleg shrimp
Applications: Functional feeds, environmental treatments, system modification, immersion and in feed treatments, benchmarking commercial treatments, genetic selection/phenotyping
Type of model: per os
Clinical Signs of Disease in our Model: Pale Hepatopancreas, empty stomach and midgut
Challenge conditions: 25-30ºC, 22-28ppt
Starting Fish Size: 0.5 - 5 grams
Shrimp aquaculture is a 38 billion dollar (USD) global industry, which produced 6.0 million tonnes of shrimp and prawn in 2018. Accounting for approximately 80% of production is whiteleg shrimp, Litopenaeus vannamei, which as a warm-water species is primarily cultured in Asia and Latin America. Due to the intense nature of shrimp aquaculture, disease outbreaks are of major concern. Vibrio parahaemolyticus is the aetiological agent of acute hepatopancreatic necrosis disease (AHPND), a widespread disease impacting all major shrimp farming regions, with mortality that can range up to 100% within a month of stocking depending on the strain of V. parahaemolyticus and species of shrimp.
The disease is transmitted primarily via ingestion, typically through cannibalism of infected individuals, and can be exacerbated by environmental or other stressors. Two toxins pirA and pirB associated with bacterial infection are the primary cause of pathological damage and mortality. Current treatment for AHPND relies mostly on antibiotics, however, reduced efficacy due to the development of resistance, as well as a negative market opinion based on the environmental and human health impact, means that alternative treatments are being sought.
The disease model at CAT is executed via per os exposure to the bacteria. The growth and processing of the bacterial stock are primary to mortality elicited and thus are carefully tailored to the specific study being carried out. In addition, the model can be carried out with shrimp being held in individual units or using larger cohabiting populations.