Hormonal Management for the Induction of Luteolysis and Ovulation in Andalusian Jennies: Effect on Reproductive Performance, Embryo Quality and Recovery Rate.

Two prostanglandins (luprostiol, LUP, and dinoprost, DIN) and two ovulation-inducing agents (human Chorionic Gonadotropin, hCG, and deslorelin, DES) were evaluated for luteolysis and estrus induction, and for ovulation induction, respectively, in embryo donor jennies. Twenty-six fertile Andalusian jennies were used. In Experiment 1, jennies (n = 112 cycles) were randomly treated with either LUP or DIN after embryo flushing. In Experiment 2, donors (n = 84 cycles) were randomly treated with either hCG or DES to induce ovulation. No differences were found between prostaglandins for all variables studied (prostaglandin-ovulation interval (POI), interovulatory interval (IOI), embryo recovery rate (ERR), positive flushing rate (PFR) and embryo grade (EG)). The ovulation rate was similar for hCG and DES (60.9% vs. 78.7%). However, the interval to ovulation (ITO) was affected (62.61 ± 7.20 vs. 48.79 ± 2.69 h). None of the other variables studied (ERR, PFR and EG) were affected (p > 0.05), except for embryo quality (p = 0.009). In short, both prostaglandins evaluated are adequate to induce luteolysis and estrus. Both ovulation-inducing agents hastened ovulation, but DES seems to be more effective than hCG. Follicular diameter affected the interval from treatment to ovulation, and high uterine edema was related to low embryo quality.

One-step warming does not affect the in vitro viability and cryosurvival of cryotop-vitrified donkey embryos.

The objective of this study was to compare the effects of two warming protocols (three-step vs. one-step dilution) on embryo quality, post-warming embryo survival and embryo cell viability of donkey embryos vitrified by the Cryotop method. Twenty, Day 7-8, grade 1-2 donkey embryos were measured, morphologically evaluated and vitrified using the Cryotop technique. Embryos were then randomly warmed using two different warming procedures: (i) W3 (three-step dilution; n = 11): embryos were warmed in 1 M, 0.5 M and 0 M sucrose, and (ii) W1/0.5 (one-step dilution; n = 9): embryos were warmed directly in 0.5 M sucrose. After 3 and 24 h of warming, the embryos were measured and evaluated for their morphology, developmental stage and viability (Propidium Iodide-Hoechst 33,342 dyes). Although both treatments decreased embryo quality after warming (P < 0.05), no significant differences (P > 0.05) were observed between protocols in terms of post-warming embryo quality, diameter and embryo survival. Greater percentages of dead cells (P < 0.001) were observed when embryos were warmed directly in 0.5 M sucrose (one-step dilution) when compared to the three-step protocol. The percentage of ruptured embryos was 27.3% and 0% in W3 and W1/0.5 protocols (P = 0.0893), respectively. In conclusion, warming Cryotop-vitrified donkey embryos directly in 0.5 M sucrose had no negative effects on embryo quality and post-warming embryo survival. Moreover, one-step protocol may help to prevent rupture when donkey embryos warmed directly in 0.5 M sucrose. These results observed in vitro must be verified by embryo transfer.