1a.Objectives (from AD-416)
The objectives of this cooperative research project are to:. 1)Complete the development of rainbow trout breeding stocks that consist of true-breeding individuals for the cecropin gene, a gene which increases disease resistance;. 2)Complete the identification and characterization of genes in rainbow trout macrophage cells that are responsive to induction by cecropin B, and;. 3)Develop rainbow trout broodstock for aquaculture with enhanced muscle growth by down-regulating the MSTN-1 gene.
1b.Approach (from AD-416)
Bacterial and viral pathogens will be used to challenge F2 transgenic fish and those that exhibit resistance to one or more of the pathogens will be bred together as the initial stages for development of a true-breeding stock. In addition, the production of gynogens from the eggs of resistant animals will be attempted to shorten the time to make the genes completely homozygous. Rainbow trout macrophages will be treated with cecropins and the expression of genes will be monitored by the use of cDNA subtraction hybridization. This technique will allow the identification of the genes which play a role in the adaptive immune response in rainbow trout. Finally, the development of rainbow trout broodstock with increased muscle growth will be attempted by use of the RNAi gene constructs to down-regulate the MSTN gene. Preliminary results suggest that this approach will lead to strains with enhanced somatic growth rate, reducing the costs for care, feeding and rearing space.
This report serves to document research conducted under a specific cooperative agreement between ARS and the University of Connecticut. In FY 2007 this project has progressed to the second generation in several additional lines with targeted transgenes that appear to have enhanced disease resistance. Other groups of transgenic rainbow trout have been bred to the F2 generation. Monitoring was accomplished via telephone discussions and periodic written reports.