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Abstracts
Workgroup: Genetics and Oyster Populations
Accelerated Selective Breeding to Develop Dermo Resistance Oysters in the Gulf of Mexico and Identification of Potential Mechanisms for Increased Disease Resistance
Principal Investigator(s):
Jerome F. La Peyre, Department of Veterinary Science, Louisiana State University, jlapeyre@agctr.lsu.edu
Co-Investigator(s):
John E. Supan, Office of Sea Grant Development, Louisiana State University
Funding Period: 10/1/2001-9/31/2003
In summer 2002, two oyster stocks (Grande Terre, Oyster Bayou) which showed high survival rate and low Dermo infection were selected. These oysters (i.e., designated F1 select stocks) are the progeny of large oysters collected from Dermo endemic areas and have undergone three years of field exposure to Perkinsus marinus. Control oysters were collected from Snail Bay (Barataria Bay, La) a low salinity area where P. marinus prevalence and intensity have historically been low. The F1 select and control oysters were spawned in summer 2002 and their progeny (i.e., designated as F2 select stocks and F1-02 control stock) were grown in up-welling systems at the Louisiana Sea Grant oyster hatchery in Grand Isle, until they reached about 25 mm in length. Oysters (2,500) from each stock were then transferred to floating cages in October 2002 for further grow out. In February 2003, 600 oysters from each F2 select stocks will be inoculated with wild parasites in the laboratory. When oyster mortality reaches 50%, the surviving oysters will be transferred back to floating cages in Grande Isle for field conditioning and will be spawned in summer 2003 to produce F3 select stocks. Control oysters from Snail Bay will be collected and spawned in summer 2003 and their progeny designated as F1-03 control stock. Each year, the mortality, P. marinus infection intensity and host defense responses of the remaining oysters of the F2 and F3 select stocks will be compared to control oysters (F1-02 and F1-03) following challenge with the parasite by natural exposure in the field as well as experimental challenge with the parasite in the laboratory.
IMPACTS AND/OR BENEFITS
This project will demonstrate the feasibility of speeding up the process of selective breeding to increase Dermo resistance in Gulf oysters by spawning, growing and challenging oysters to Dermo all within a year. This study is feasible in the Gulf of Mexico because of the high growth rates of oysters raised off-bottom in this subtropical region and because Dermo is the only serious disease affecting oysters in the Gulf, therefore simplifying and potentially enabling rapid selection against this single parasite. Information will also be obtained on the relationship between specific host defense parameters and infection intensities in control and select oyster stocks. Results from this project may validate the use of specific host defense traits as indirect selection criteria to facilitate and further hasten breeding resistance to Dermo in oysters.
PROJECT PUBLICATIONS
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