The coasting time affects the quality of cumulus-oocyte complexes in superstimulated ewes.

We hypothesized that the coasting time may be beneficial to the quality of cumulus-oocyte complexes recovered from live ewes, as reported in cattle. The present study assessed the effect of coasting times on the quantity and quality of cumulus-oocyte complexes (COCs) in sheep. All ewes were subjected to the "Day 0 protocol", followed by an ovarian stimulation (80 mg of pFSH in three decreasing doses), varying only the coasting time [12 (G12), 36 (G36), or 60 h (G60]. In Experiment 1, data regarding follicular population was assessed. In Experiment 2, the COC quality was checked by their morphology, brilliant cresyl blue (BCB) test, evaluation of chromatin condensation pattern, and oocyte diameter. In Experiment 3, genes related to oocyte developmental competence were evaluated in BCB + COCs. The oocytes in the G60 group had more (P < 0.05) large follicles than the other groups and oocytes with a greater diameter than the G12. Oocyte morphology was similar (P > 0.05) among groups, as well as the BCB + COCs quantity. The G60-oocytes presented a better (P < 0.05) configuration of chromatin condensation compared with the other groups and a greater (P < 0.05) gene expression of BMP15, MATER, ZAR1, and PTGS2 compared with G12, and PTGS2 and HAS2 compared with G36 group. In conclusion, 60 h of coasting time positively affects the quality of COCs recovered after subjecting ewes to the "Day 0 protocol" and ovarian superstimulation. Implementing the appropriate coasting time to a given protocol can positively impact the in vitro embryo production outcomes in sheep.

Embryo development is impaired in goats that are treated for hydrometra and subsequently subjected to superovulation.

BACKGROUND: Reproductive efficiency after hydrometra (HD) treatment is usually unsatisfactory. METHODS: To identify mechanisms involved in low reproductive efficiency of HD-treated goats, pluriparous dairy goats treated for HD (n=10, HD) or with no reproductive disorders (n=11, control: CONT) were induced to oestrus and superovulated. Goats were mated with fertile bucks and seven days after oestrus, non-surgical embryo recovery was performed. Embryos were evaluated and gene expression was performed. RESULTS: There were no differences (P>0.05) in sexual behaviour parameters, superovulation response, mean number of retrieved structures and viable embryos between groups; although embryo recovery rate was higher (P=0.01) in CONT group. Structures in delayed stage (8-16 cells) were more frequent (P<0.05) in HD (29 vs 1 per cent) goats, as well as the percentage of advanced embryos was greater (P<0.05) for CONT (59.3 vs 33.3 per cent) goats. However, the expression of genes related to apoptosis (BAX and Bcl-2), trophectoderm differentiation (CDX2) and pluripotency maintenance (NANOG) was not affected (P>0.05) in embryos that reached the morulae and blastocyst stages. CONCLUSION: Although the HD embryos that developed to morula and blastocyst stages showed no change in the expression of genes related to their quality and implantation capacity, overall, embryo development was impaired in HD-treated goats.