Project Number: 3655-31320-002-01
Project Type: Specific Cooperative Agreement

Start Date: Jun 29, 2009
End Date: Jun 30, 2013

Objective:
Current ARS, and ARS partners’, efforts are directed at advancing aquaculture in the Great Lakes region. The Great Lakes region is home to approximately 32% of the U.S. population but produces less than 3% of the total U.S. aquaculture production. The Great Lakes region consumes 1.5 billion pounds of seafood annually (valued at $23 billion, 2004 dollars). Yellow perch are a high-value food fish ($16.00-$22.00/lb retail) and current ARS (and ARS partners) efforts are aimed at developing improved yellow perch broodstocks, and rearing/production practices, to advance aquaculture in this region. The emergence of viral hemorrhagic septicemia virus (VHSv) in the Great Lakes region of North America has led to multi-species epidemics in wild populations. This disease poses a serious threat to aquaculture production and profitability in this region and thus is the impetus for the scientific efforts of the ARS program. To address the needs of the Great Lakes region, we shall undertake the following objectives: 1) Continue genotype x environment trials on F3 progeny to evaluate growth and surival in commercial settings, 2) Identify F3 selects from on-site performance trial, PIT tag and photoperiod and temperature cycle to induce maturation, 3) Investigate use of specialty micro-diets and live-diets for production of high-quality perch fingerlings and initiate evaluation of diets for efficient grow-out of perch fingerlings, 4) Complete development of the STaRT-PCR assay for rapid detection of the VHS pathogen, and 5) Characterize innate immune response and pathogen recognition and response pathway(s) to VHSv (and subunits) in fish cell lines.

Approach:
1) Continue genotype x environment (GxE) studies on F3 progeny to evaluate growth and survival in commercial settings (Binkowski, UWM-SFS). Maintain and complete ongoing Genotype x Environment studies, which are essential to evaluating growth and survival of our genetically-improved (F3) progeny at commercial indoor farms. The information gained from the GxE studies will be used to improve genetic gain for growth and identify sources of genetic variation for survival and growth in our broodstock strains. 2) Identify F3 selects from on-site performance trial, PIT tag and photoperiod and temperature cycle to induce maturation (Binkowski, UWM-SFS). Select animals from the F3 generation will be identified, individually tagged, genotyped and photoperiod/temperature cycled to bring these animals into spawning condition to enable future crosses and development/testing of early life-history and grow-out diets. 3) Investigate use of specialty-micro-diets (SMD) and live-diets for production of high-quality perch fingerlings and initiate evaluation of diets for efficient grow-out of perch fingerlings (Binkowski, UWM-SFS). The early life-history dietary work will focus on the use of commercially-available larval diets to improve yellow perch larval and fingerling survival. The aim is to identify a substitution to live diets, which will have a direct impact on continued broodstock improvement efforts and to the yellow perch aquaculture industry. This work will be extended to a production setting by evaluating dietary nutrient requirements needed to sustain efficient grow-out of high-quality fingerlings. This work will also support activities of a new ARS post-doc who will be conducting nutritional research on yellow perch. 4) Complete development of the STaRT-PCR assay for rapid detection of the VHS pathogen (Stepien, UT; Willey, UT and Leaman, UT). Continued work is essential to completion of the STaRT-PCR assay. The final phases of this work are focused on validating platform specificity for the VHSv pathogen. When completed, this platform will be used as a means to verify and validate a TaqMan-based real-time PCR assay format that will make this detection technology more widely available and cost-effective. Cooperators will also disclose this technology to APHIS/USDA in an effort to obtain further direction/input that will enable this testing platform to meet requirements for Federal approval. 5) Characterize how VHSv structural and non-structural genes evade the host innate immune capacity to detect and respond to the VHS pathogen (Leaman, UT and Stepien, UT). In vitro studies, using newly developed reagents and fish cell-lines, will be aimed at understanding the molecular pathways involved with the viral recognition and response pathways in fish. Additionally, this work will result in a better understanding of how various VHSv genes influence virulence and pathogenicity in these cell-lines. This work is critical to developing new means to detect the pathogen and in identifying novel therapeutic approaches to interfere with the pathogen lifecycle as a means to prevent and/or treat this disease.