2010 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research project is to identify mechanisms and develop tools and methods to improve reproductive and growth efficiency of catfish. 1b.Approach (from AD-416) Continued collaborative research will be conducted to identify mechanisms for targeted enhancement of catfish reproduction and growth in order to fulfill the unit’s data collection, publication, and catfish improvement efforts. 3.Progress Report Xenotransplantation of spermatogonial germ cells in catfish Xenotransplantation of testicular germ cells from blue catfish to otherwise sterile channel catfish provides a unique alternative to current production methods for hybrid catfish. ARS and Cooperator co-advised a post-doc to conduct research on the xenotransplantation of spermatogonial germ cells in catfish. Blue catfish testicular cells were isolated and injected into several hundred channel catfish cohorts on day 1, 2, 3, and 4. Survival was assessed at each age, with days 2, 3, and 4 yielding the highest survival. To date, approximately 200 xenotransplanted fish exist. Means of verifying success prior to reproduction are being evaluated. If successful, these fish and technology can be transferred to the hybrid catfish industry. Migratory capabilities of isolated testicular cells are critical to gonadal development and success of xentransplantation of germ cells. Two genes, Vasa and Dnd, both involved in germ cell migration and reproductive development have been cloned and partially sequenced. These genes may prove useful in developing methods to monitor transplanted cell colonization and catfish gonadal development.