Abstract
This study assesses of efficiency of oocyte recovery and in vitro development for during the non breeding season in goat. Thirty-four matured goats, maintained in a pen under natural day length and fed hay ad libitum, were pretreated with progestagen implanted CIDR for 10 days. Superovulation treatment of the goats received twice daily intramuscular injections of a total of 70 mg FSH for 3 days from Day 8 of CIDR. All the gonadotropin treated goats were injected with 10 mg $PGF_2{\alpha}$ on Day 8 and 400~600 IU hCG in the afternoon on Day 10. Oocytes were recovered by follicle aspiration or oviduct flushing at 35 to 40 h after hCG injection through mid-ventral incision. The in vivo matured oocytes were activated by ionomycin (5 min) and 6-DMAP (3.5~4 h). The activated oocytes were cultured in mSOF medium containing 0.8% BSA at $38.5^{\circ}C$ in an atmosphere of 5% $CO_2$, 5% $O_2$, 90% $N_2$ for 7~8 days. There was no significant difference in the mean number of CL and in vivo matured and follicular oocytes recovered. But, quality of I+II grade follicular oocytes was lower (p<0.05) in the prepubertal goat (25.0%) than the adults (52.4%). The same results were also observed in the cleavage and blastocyst rate of activated oocytes. The clavage and blastocyst rate from prepubertal derived oocytes were lower (p<0.05) in the prepubertal goat (54.5%, 23.3%) than the adult goat (86.8%, 46.6%). Considering overall these results, we suggest that maturation of donor goats is a major factor affecting recovered oocytes quality and in vitro development of activated goat oocytes. There was no significant difference in oocyte quality between seasonal treatments.
본 연구는 연중 비번식기에도 효율적인 재래산양 난포란의 확보가능성을 검토하고자 비번식기에 과배란 처리를 실시하여 체내 성숙난자 및 난포란을 회수하였으며, 회수란의 활성화를 유도하여 체외발달율을 조사하였다. 비번식기에 과배란 처리에 의한 배란점은 각각 $13.9{\pm}6.5$개로서, 번식의 $13.0{\pm}3.8$개와 차이가 없었다. 난관에서 외과적 관류방법으로 체내성숙난자를 회수하였을 회수율은 43.9%로서 번식기의 67.1%보다 낮았다(p<0.05). 공란 산양 두당 회수 난자수는 비번식기가 $5.9{\pm}5.2$개로서, 번식기의 $8.8{\pm}3.2$개보다 적었다. 공란 산양으로부터 체내 성숙난자 회수 후 난소의 난포로부터 주사기로 흡입하여 채란 시에 공란 산양 두당 난포수는 비번식기가 $5.8{\pm}4.6$개로서 번식기의 $7.5{\pm}3.9$개보다 적었으며(p<0.05), 회수율은 각각 68.7 및 54.7%로서 차이가 없었다. 공란 산양 두당 회수난자 수도 $3.9{\pm}3.2$ 및 $4.1{\pm}3.4$개로서 차이가 없었다. 회수한 난포란의 등급도 비번식기와 번식기간에 차이가 없었다. 비번식기에 회수한 체내성숙 난자를 단위발생을 유도하였을 때 분할율은 76.4%로서 번식기의 83.6%와 차이가 없었으며, 배반포기로의 발달율은 비번식기가 23.8%로서 번식기의 43.5%보다 유의적(p<0.05)으로 낮았다.