In vivo survival rate of transferred Zaribi Goat embryos cryopreserved by open pulled straw-vitrification technique

الملخص EN

The aim of the present study was to examine in vivo survival rate of goat embryos, exposed to vitrification solution or vitrified with OPS, recovered from Zaraibi does (Egyptian local breed) superovulated by PMSG.

This research work was carried out at the International Livestock Management Training Center (ILMTC), Sakha, belonging to the Animal Production Research Institute.

Agricultural Research Center during the period from March to June 2010.

Six non-lactating multiparous goat does were used to examine in vivo and in vitro survival rate of goat embryos, exposed to vitrification solution or vitrified with OPS.

All embryos were recovered from Zaraibi does (Egyptian local breed) superovulated by PMSG in the breeding season.

Mating was carried out with Zaraibi bucks on the first and second day of estrus.

Sex days post-mating the embryos were surgically collected from treated does fasted for 24 h.

Before embryo recovery, ovaries of donors were examined by laparoscopy to determine degree of ovarian response to the PMSG.

After recovery, embryos at morula and blastocyst stages were exposed to vitrification solution or vitrified with open pulled straws method (OPS).

Fresh, vitrified- or exposed-thawed embryos were transferred surgically into uterine horns on day 6 after estrus of synchronized recipients.

Results revealed that total superovulatory response donor was 19.16 in terms of 11.83 CLs and 7.33 unovulated follicles.

Ovulation rate was 61.74 % and average number of recovered total embryos /donor was 10.5 in terms of 9.0 transferable embryos and 1.5 unfertilized ova or degenerated embryos, with recovery rates of 88.76 and 85.71 %, respectively.

Embryo viability was higher for exposed than vitrified embryos in terms of recovery rate (100 vs.

85.7 %) and survival rate (95.3 vs.

76.2 %).

Percentage of pregnant recipients on day 60 of embryo transfer was lower (P < 0.05) for vitrified or exposed embryos than fresh embryos (71.4 % for each vs.

100 %).

However, percentage of kidded recipients was higher (P < 0.05) for fresh embryos as compared to exposed and vitrified embryos based on total number of recipients (85.7 vs.

57.1 and 42.9 %) or number of pregnant recipients (85.7 vs.

80.0 and 60 %), respectively.

In conclusion, vitrification of Zaraibi goat embryos by OPS technique provided acceptable pregnancy and in vivo embryo survival rates as a method of cryopreservation of caprine embryos.