Xenogenesis has been accomplished previously in ictalurid catfish. However, spawning rates and fry production were inadequate for large-scale application to produce channel catfish, Ictalurus punctatus, female X blue catfish, I. furcatus , male hybrid catfish. A series of experiments were conducted to make stem cell harv est more efficient and productive, and stem cell transfer, colonization and proliferation more effective.
A hydrostatic pressure level of 7,000 psi 5 min after fertilization was needed to produce near 100% triploidy. Application of ROCK I at 50 µM yielded higher viability of spermatogonial stem cells (SSCs ) and oogonial stem cells (OSCs) during the isolation phase, and these cells had the highest viability in the first day right after being dissociated from the gonads. The optimal size for collecting blue catfish SSCs in regard to yield/kg was 25 to 39.9 cm. Optimal size for blue catfish OSC collection was 25 to 39.9 cm and 200 to 600 g based on the peak for OSC production in these females. Injecting the stem cells into triploid hosts 4-6 dph resulted in higher colonization and proliferation compared to time periods prior or after that time. Preliminary data indicates that higher transformation and spawning are associated with introducing cells during this time.
In the current study, xenogenic channel catfish and white catfish, Ameiuru s catus, harboring gametes from channel catfish and blue catfish were utilized to produce pure species and hybrid progeny. By utilizing the protocols above, xenogenic spawning with normal fry production is becoming more frequent. Preliminary results indicate that xenogenic common carp, Cyprinus carpio , might be used as blue catfish sperm factories as an alternative approach in the hybrid catfish embryo production technology.