SURVIVAL AND INTEGRATION RATE OF CHANNEL CATFISH AND COMMON CARP EMBRYOS MICROINJECTED WITH DNA AT VARIOUS DEVELOPMENTAL STAGES

Channel catfish, Ictalurus punctatus, and common carp, Cyprinus carpio, were microinjected with DNA at early, intermediate or late one-cell stage, two-cell stage or four-cell stage to determine the most appropriate developmental stage for maximizing the production of transgenic individuals, a product of survival X integration rate. Survival (hatching rate) decreased (P < 0.05, r= -0.81) when channel catfish embryos were microinjected at later stages compared to earlier stages. Survival relative to non-microinjected controls was 65.0, 43.6, 38.5, 27.4, and 35.9% and integration rate was 2. 1, 1.5, 15.2, 12.5 and 7.7% for early one-cell, intermediate one-cell, late one-cell, two-cell and four-cell stages, respectively. Cell stage at time of microinjection did not affect (P > 0.05, r = -0.52) survival in common carp and survival of microinjected common carp embryos was higher (P < 0.01) than survival for channel catfish embryos. Survival relative to non-microinjected controls was 88.9, 85.3, 91.5, 85.3, and 83.4% and integration rate was 8.3, 1.0, 0.0, 11.5 and 1.7% for early one-cell, intermediate one-cell, late one-cell, two-cell and four-cell stages, respectively, of common carp. The late one-cell and the two-cell stage were the most appropriate stages for maximizing production of transgenic channel catfish and common carp, respectively.