Pronuclear embryo yield in Caninde and Saanen goats for DNA microinjection.

摘要

The objective of this study was to examine the effect of donor breed on pronuclear-stage embryo yield to be used for DNA microinjection in a transgenesis goat program. Twelve Caninde' and twelve Saanen goats were heat synchronized using a progestagen-cloprostenol treatment. Forty-eight hours before the sponge removal, superovulation was induced with a total administration of 4.4 mg/kg bodyweight NIH-FSH-P1, given twice daily in decreasing doses over 3 days. In addition, goats received 100 micro g of GnRH and they were hand-mated at 36 and 48 h after progestagen removal. Embryo recovery was performed by oviduct flushing at 72 h after sponge removal. Embryos were microinjected with a DNA construct and noticeable swelling of the nuclei was the criterion for successful microinjection. The total diameter, cytoplasm diameter, zona pellucida thickness and pronuclei diameter were measured for each microinjected embryo. A higher (p<0.05) percentage of fertilized ova was observed in Caninde (89.9%) than Saanen (36.2%) goats. In addition, Caninde donors produced a higher percentage of pronuclear embryos when compared with Saanen: 72.5% vs 20.6% (p<0.05), respectively. Successful microinjection was verified in 96.7% and 73.3% of times in Caninde and Saanen embryos, respectively (p<0.05). Significant differences were observed for all morphometric parameters except for cytoplasm diameter. In conclusion, under our study experimental conditions, Caninde were more efficient than Saanen goats concerning the pronuclear embryo yield and manipulation. The use of Caninde goats in transgenesis programs could be increase the interest in their breeding and could be contribute to saving them from extinction.