Tag - hepatopancreas

Dietary organic acids for farmed shrimp and fish

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Organic acids supplement in diets have recently been applied very common in aquaculture, because their benefits on the growth performance, nutrient utilization, immune response and disease resistance of farmed aquatic animals. Organic acids have a specific antimicrobial activity, which is pH dependent. Organic acids improve protein and energy digestibilities by their impact on the gastrointestinal microflora and reducing microbial competition, thus farmed shrimp/fish fed organic acid diet has significantly higher survival and growth. Furthermore, the use of formic acid is highly [...]


Characterization of a new member of Iridoviridae, Shrimp hemocyte iridescent virus (SHIV), found in white leg shrimp (Litopenaeus vannamei)

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A newly discovered iridescent virus that causes severe disease and high mortality in farmed Litopenaeus vannamei in Zhejiang, China, has been verified and temporarily specified as shrimp hemocyte iridescent virus (SHIV). Histopathological examination revealed basophilic inclusions and pyknosis in hematopoietic tissue and hemocytes in gills, hepatopancreas, periopods and muscle. Using viral metagenomics sequencing, we obtained partial sequences annotated as potential iridoviridae. Phylogenetic analyses using amino acid sequences of major capsid protein (MCP) and ATPase revealed that it is a new iridescent [...]


Four AHPND strains identified on Latin American shrimp farms

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AHPND is a major global disease of farmed shrimp that seriously affects the industry in many countries in Asia and Latin America. Photo by Darryl Jory. Acute hepatopancreatic necrosis disease (AHPND), also commonly known as Early Mortality Syndrome (EMS), is a serious, major global disease of farmed shrimp that causes hepatopancreas dysfunction and secondary Vibrio infections and can result in 100 percent mortality in the animals’ juvenile stages. The disease started in China in 2010 and has currently spread to aquaculture facilities in [...]


Massachusetts – John Sackton on EHP

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At the Global Aquaculture Alliance’s GOAL shrimp session in Vancouver, British Columbia, Canada (October 2015), a panel of shrimp experts talked about the microsporidian Enterocytozoon hepatopenaei, a spore-forming fungal parasite, and how it might affect the global shrimp supply.  John Sackton, Editor and Publisher at Seafood.com (an online, subscription-based, fisheries news service) prepared the following report based on interviews with a number of the shrimp experts, who spoke on the condition that they would not be quoted by name. When [...]


What do we know about EHP?

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• Tissue specific for HP unlike most other microsporidians which affect muscle • Transmitted orally between shrimp with no need for an intermediate vector very unusual and very worrisome • Very difficult to visualize with normal histology • Requires practice and patience • Once spores are in ponds very difficult to eradicate HP with EHP spores Control of EHP • Two fold approach to possible control – Broodstock carriers shed spores in feces which contaminate egg and nauplii surfaces. – Farmed animals shed spores into ponds which in [...]


How to Manage the New Microsporidian Disease

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The March/April 2015 issue of The Global Aquaculture Advocate (“The Global Magazine for Farmed Seafood”) contains an excellent article by Dr. Stephen Newman on how to manage the new microsporidian disease caused by Enterocytozoon hepatopenaei (EHP), a parasite widely found in Asia and other areas that severely retards the growth of farmed shrimp. EHP infects the tubules in the shrimp’s hepatopancreas and damages the organ’s ability to gain nutrition from feed. Total elimination of EHP may not be possible. [...]


Four reasons why India’s shrimp exports are booming

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For years it seemed nearly impossible for another country to outpace Thailand’s shrimp exports to the United States, the world’s biggest market for shrimp. Early mortality syndrome (EMS) saw an end to that. The disease, which attacks the shrimp’s hepatopancreas, an organ crucial to digestion, proved to be a major setback for Thailand and other producing nations in Southeast Asia starting in 2009. The stunning downturn in production, estimated at more than 30 percent in the region, opened the door [...]


Mexico – Research on EMS

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Moribund shrimp affected by acute hepatopancreatic necrosis disease (AHPND) from farms in northwestern Mexico were sampled for bacteriological and histological analysis.  Bacterial isolates were molecularly identified as Vibrio parahaemolyticus by the presence of the tlh gene.  The tdh-negative, trh-negative, and tlh-positive V. parahaemolyticus strains were further characterized by repetitive extragenic palindromic element-PCR (rep-PCR), and primers AP1, AP2, AP3, and AP and an EMS2 IQ2000 detection kit (GeneReach, Taiwan) were used in the diagnostic tests for AHPND.  The V. parahaemolyticus strains were used in immersion challenges with shrimp, and farmed and challenged shrimp presented the same clinical [...]


How can you control Vibrio bacteria?

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After Dr. Lightner confirmed its virulence using Koch’s postulate, it was found that some strains of Vibrio parahaemolyticus that is the cause of EMS in Asia. Most recently it has also been found to cause EMS in Mexico, which is far away from Asia. It is possible that someone brought brooder shrimp from an Asian country where EMS is prevalent into Mexico for breeding purposes and the weak postlarvae got EMS, or perhaps they used very fast-growing breeding stock [...]


“Black spot” on shrimp

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Regulations prohibit the use of many chemicals and antibiotics in U.S. shrimp aquaculture. The FDA in Silver Spring, MD publishes a list of drugs approved for aquaculture, USFDA URL: http://www.fda.gov/AnimalVeterinary/DevelopmentApprovalProcess/Aquaculture/ucm132954.htm. The main commercial operations in the U.S. claim that they use chemicals and antibiotics responsibly and only when necessary. Although unsubstantiated, this claim is reinforced by limited or no disease occurrences in recent history in the U.S., negating the need for chemical use. Agricultural lime is used to control algal blooms [...]