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The project will, test genetic families for resistance to TSV and NHP-B. evaluate reservoir hosts of NHP-B, characterize the quasi-species of TSV, test the effect of temperature and salinity on TSV basic reproduction number, characterize shrimp growth and survival in a closed shrmimp growout system, characterize the nutrient cycle in closed shrimp growout system, characterize the microbial community in the closed shrimp growout system.
Non-Technical Summary: Disease in shrimp aquaculture is a constraint to industry expansion in the US. Selective breeding of shrimp for resistance to TSV and NHP-B offers one way to deal with these devastating pathogens. TSV is an RNA virus and as such has a very high rate of mutation. The high rate of mutation allows the development of a genetically diverse population with in a host called a quasi-species. The quasi-species provides the genetic variation that natural selection works on and allows for rapid evolution of the pathogen. Understanding the course of the evolution of virulence of TSV is necessary to design farming methods that do not select for TSV genotypes with increased virulence. Profitable and environmentally sustainable shrimp production systems will be closed. In order to maximize profit in such systems we must understand the cycling of nitrogen and the role that the microbial community plays in the health of the systems. <P> Approach: TSV and NHP-B resistance will be evaluated by a common garden design. TSV quasi-species will be characterized by cloning and sequencing a number of particles at the CP-1 region of the TSV genome. Temperature and salinity effect on R-naught will be done as described in Lotz et al. 2003. Shrimp will be grown at 500 and 250 per cubic meter in eight 80 cubic meter raceways. The nitrgen cycling will be evalated by stable isotopes and the commnity structure of the microbes will be done by DNA profiling.