Morphologic and histologic comparisons between in vivo and nuclear transfer derived porcine embryos

14-39625 MORPHOLOGIC AND HISTOLOGIC COMPARISONS BETWEEN IN VIVO AND Nuclear transfer (NT) is an inefficient but invaluable tool. This study examines abnormalities associated with NT porcine embryos at days 10, 12, and 14. Methods. 4 experimental groups were examined: non-pregnant, in vivo pregnant, NT recipients, and manipulation control (MC) recipients. Maternal blood samples were collected and assayed for insulin-like growth factor-1 (IGF-1). Embryos were evaluated for embryonic disc diameter, morphology, nucleoli density and mitotic figure index. Results. NT day 12 (P ≤ 0.03) and day 14 (P ≤ 0.01) embryos had increased nucleoli when compared to in vivo produced and MC embryos. NT day 14 embryos had an increased (P ≤ 0.03) mitotic index when compared to in vivo produced day 14 embryos. In vivo produced day 12 embryos had greater ( P ≤ 0.03) embryonic disk diameters compared to NT and MC embryos. In vivo produced day 14 embryos had increased (P ≤ 0.01) embryonic disk diameters when compared to NT day 14 embryos. In vivo produced day 14 embryos were morphologically more advanced (P ≤ 0.01) than NT and MC day 14 embryos. There were no significant differences between IGF-1 levels. Conclusions . Nuclear transfer embryos develop at a slower rate than in vivo embryos with abnormalities potentially affecting the cell cycle. The techniques used during nuclear transfer also appear to compromise embryo development.