Development and viability of bovine preplacentation embryos treated with swainsonine in vitro

This study investigated the effects of swainsonine (a locoweed toxin) on bo vine preplacentation embryo development using in vitro procedures. We exami ned and confirmed the viability and developmental potential of swainsonine- treated embryos by transfer to synchronized recipient heifers. Oocytes (n = 6338) were aspirated from ovaries collected from the abattoir and subjecte d to in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro c ulture (IVC). Swainsonine was added to IVM, IVF, IVC media spatially and IV M/IVF/IVC continuously, at 0 ng/ml (TRT1, control), 200 ng/ml (TRT2), 400 n g/ml (TRT3), and 800 ng/ml (TRT4). Embryo development was evaluated with re spect to oocyte cleavage rate and the rates of morula and blastocyst format ion. There was no difference (P > 0.05) among treatments. The average numbe r of nuclei per blastocyst at Day 7.5 of culture (Day 0 = IVF) was 85.9 +/- 4.3 (n = 47) and 89.3 +/- 4.4 (n = 44) for swainsonine-treated embryos (80 0 ng/ml) and control embryos, respectively. Pregnancy rate as determined by ultrasonography on day 35 to 40 post embryo transfer was 43.8% and 38.3% f or swainsonine-treated (800 ng/ml) and control embryos, respectively. Nine (9.4%) healthy calves were delivered from heifers receiving swainsonine-exp osed and nine (9.6%) from control embryos. Mo difference: (P > 0.05) was de tected in number of calves developing from TRT and control embryos. We conc lude that swainsonine does not have an adverse effect on the development an d viability of preplacentation bovine embryos. (C) 1999 Elsevier Science B. V. All rights reserved.