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Genetic variation for resistance to WSS, AHPND in Pacific white shrimp | The Advocate

Genetic variation for resistance to WSS, AHPND in Pacific white shrimp | The Advocate | Aquaculture Directory | Scoop.it

White spot syndrome (WSS) and acute hepatopancreatic necrosis disease (AHPND) have become the main causes of economic loss in shrimp production worldwide. Prevention of these diseases is very difficult to achieve, and efforts to control them have often seen inconsistent results. Moreover, some intensive production systems seem to favor their rapid spread.

In such scenarios, breeding for disease resistance is a viable option to deal with this issue in commercial shrimp culture. Breeding shrimp for disease resistance is worthwhile when there are no other simple, cost-effective control measures, and there are genetic differences for resistance to the pathogen.


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John Bostock's curator insight, October 4, 2015 5:34 AM

Good to see this research ongoing - clearly challenging though.

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Identification of Genes Involved in Taura Syndrome Virus Resistance in Litopenaeus Vannamei

Identification of Genes Involved in Taura Syndrome Virus Resistance in Litopenaeus Vannamei | Aquaculture Directory | Scoop.it

Boube et al (2014). Identification of Genes Involved in Taura Syndrome Virus Resistance in Litopenaeus Vannamei. Journal of Aquatic Animal Health: Vol. 26, No. 3, pp. 137-143.

 

The goal of the present research was to identify the genes that are differentially expressed between two lineages of Pacific white shrimp Litopenaeus vannamei displaying different susceptibilities to Taura syndrome virus (TSV) and to understand the molecular pathways involved in resistance to the disease. An oligonucleotide microarray was constructed and used to identify several genes that were differentially expressed in the two L. vannamei lineages following infection with TSV. Individual L. vannamei from either resistant or susceptible lineages were exposed via injection to TSV. Individuals were removed at 6 and 24 h postinfection, and gene expression was assessed with the in-house microarray. The microarray data resulted in the selection of a set of 397 genes that were altered by TSV exposure between the different lineages. Significantly differentially expressed genes were subjected to hierarchical clustering and revealed a lineage-dependent clustering at 24 h postinoculation, but not at 6 h postinoculation. Discriminant analysis resulted in the identification of a set of 11 genes that were able to correctly classify Pacific white shrimp as resistant or susceptible based on gene expression data.


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John Bostock's curator insight, September 1, 2014 1:32 PM

This looks like useful progress for future management of TSV

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Proceedings of the Expert Consultation on Genetic Erosion Risk Analysis for Shrimp Diseases in Asia - Publications

Proceedings of the Expert Consultation on Genetic Erosion Risk Analysis for Shrimp Diseases in Asia - Publications | Aquaculture Directory | Scoop.it
Proceedings of the Expert Consultation on Genetic Erosion Risk Analysis for Shrimp Diseases in Asia, 2013

 

Shrimp aquaculture in tropical regions is facing a disease-induced catastrophe of lost production.  It is estimated that more than 40% of tropical shrimp production is lost to disease annually. The devastating impacts of disease on lost incomes, livelihoods, increased operational costs, trade restrictions and loss of consumer confidence has been a subject of many consultations and policy dialogues.  Discussions of disease crisis have to date been largely focused on identification of pathogens, guidelines and standards for disease detection and surveillance, regulations to limit trans-boundary movement of animals, and adoption of better management practices. 

There is reason to believe that current broodstock management practices may induce genetic erosion that increases susceptibility to disease and vulnerability to epizootics:

 

The basic tenet for this Expert Consultation is that an important aggravating factor in the disease crisis is an agro-economic system that locks shrimp breeders, hatcheries and farmers into behaviour that induces high levels of inbreeding.  If inbreeding does increase the severity and frequency of epidemics, this disease crisis will only get worse over vast areas of Asia, Central and South America, Africa and the Middle East until  it is addressed.


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John Bostock's curator insight, February 9, 2014 6:56 AM

A very important issue for aquaculture health management 

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Drug resistance in sea lice: a threat to salmonid aquaculture: Trends in Parasitology

Drug resistance in sea lice: a threat to salmonid aquaculture: Trends in Parasitology | Aquaculture Directory | Scoop.it

New paper from Stian Mørch Aaen, Kari Olli Helgesen, Marit Jørgensen Bakke, Kiranpreet Kaur and Tor Einar Horsberg; Norwegian University of Life Sciences, School of Veterinary Science, Sea Lice Research Centre, Oslo, Norway Drug-resistant sea lice are emerging in several salmonid-producing countries.Of the five compound groups available, resistance has been reported towards three.Efforts are being put into investigating genetic markers, physiology and biochemistry.The sensitivity status of sea lice populations could thus be monitored more easily.

 

Sea lice are copepod ectoparasites with vast reproductive potential and affect a wide variety of fish species. The number of parasites causing morbidity is proportional to fish size. Natural low host density restricts massive parasite dispersal. However, expanded salmon farming has shifted the conditions in favor of the parasite. Salmon farms are often situated near wild salmonid migrating routes, with smolts being particularly vulnerable to sea lice infestation. In order to protect both farmed and wild salmonids passing or residing in the proximity of the farms, several measures are taken. Medicinal treatment of farmed fish has been the most predictable and efficacious, leading to extensive use of the available compounds. This has resulted in drug-resistant parasites occurring on farmed and possibly wild salmonids.


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John Bostock's curator insight, January 31, 2015 12:07 PM

Further useful insights into the problems of drug resistance when combating parasites

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The surveillance programme for resistance to chemotherapeutants in L. salmonis in Norway 2013

The surveillance programme for resistance to chemotherapeutants in L. salmonis in Norway 2013 | Aquaculture Directory | Scoop.it

Grøntvedt RN, Jansen PA, Horsberg TA, Helgesen K, Tarpai A. The surveillance programme for resistance to chemotherapeutants in L. salmonis in Norway 2013. Surveillance programmes for terrestrial and aquatic animals in Norway. Annual report 2013.Oslo: Norwegian Veterinary Institute 2014


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John Bostock's curator insight, April 10, 2014 9:48 AM

Useful work from the Norwegian Veterinary Institute

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Method for detection of drug resistance in sea lice.

Method for detection of drug resistance in sea lice. | Aquaculture Directory | Scoop.it
Just as they have a method for detecting drug resistance in bacteria against antibiotics, researchers have found a way of doing the same for this parasite, the sea louse, that plagues the salmon industry in the north.

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John Bostock's curator insight, September 11, 2013 9:32 AM

This could help to avoid ineffective and costly treatments