Relationship between Time Elapsed after Human Chorionic Gonadotropin Administration and Developmental Stage in Porcine Embryos Collected from Prepubertal Gilts

Abstract

Abstract. We examined the relationship between the time elapsed after human chorionic gonadotropin (hCG) administration and developmental stage of porcine embryos after collection. Prepubertal gilts, 7 to 8 months old, were given 1500 IU equine chorionic gonadotropin (eCG) intramuscularly, followed by 500 IU hCG 72 h later. The treated gilts were inseminated artificially on Day 1 (Day 0=the day of hCG administration) and on Day 2. Embryos were collected surgically on Day 6 (140, 144, and 147 h after hCG administration) or on Day 7 (164, 168, and 171 h), and the developmental stages of the collected embryos were examined. From 75.2% (276/367) of the prepubertal gilts treated with hormones, we collected an average of 20.7 embryos per gilt with normal morphology. At 140 h after hCG administration, morulae (54.4%) could be collected. At 144 h, morulae and early blastocysts (57.7% and 28.9%, respectively) were collected. By 147 h, the proportion of embryos at the blastocyst to expanded blastocyst stages had increased (10.0%). From 164 h to 171 h, expanding or expanded blastocysts of more than 200 µm in diameter and hatched blastocysts could be collected. The proportion of hatched blastocysts increased from 3.2% (164 h) to 41.0% (171 h). These results suggests that although the number of ovulations differed among gilts, porcine embryos at the appropriate stages can be collected efficiently by controlling the time elapsed between hCG administration and embryo collection.

The quality after culture in vitro or in vivo of porcine oocytes matured and fertilized in vitro and their ability to develop to term

“…Estrus synchronization was carried out (Fujino et al . ) by intramuscular injection of 1000 IU of eCG (Peamex), followed 72 h later by 500 IU hCG (Puberogen). The IVM/IVF oocytes were transferred to NCSU‐37 supplemented with 4 mg/mL BSA and 25 mmol/L HEPES, after adjustment of the osmolarity to 280 mOsm/kg.…”

“…Embryo transfer (ET) and in vitro culture of IVM/IVF oocytes We used 7-8-month-old prepubertal crossbred gilts (Landrace, Large White and Duroc breeds) as recipients of IVM/IVF oocytes. Estrus synchronization was carried out (Fujino et al 2006) by intramuscular injection of 1000 IU of eCG (Peamex), followed 72 h later by 500 IU hCG (Puberogen). The IVM/ IVF oocytes were transferred to NCSU-37 supplemented with 4 mg/mL BSA and 25 mmol/L HEPES, after adjustment of the osmolarity to 280 mOsm/kg.…”

Fixed-time artificial insemination protocols on brazilian locally adapted breed gilts on ovulatory response and embryo production

“…The use of eCG, in this study, served the propose to induce superovulation, as the animals that received eCG showed a higher number of ovulations, compared to the other treatment groups, and since Brazilian Piau breed has average of 11.1±2.4 in ovulation rate, number of total pigs born (9.3±2.7) and pigs born alive (7.9±2.6) (Silva et al, 2011). Also seen in other studies with averages of more than 20 ovulations in commercial breeds, when the dosage applied was equal to or greater than 1000 IU (Besenfelder et al, 1997;Hazeleger et al, 2000;Rátky et al, 2001;Fujino et al, 2006;Kauffold et al, 2007;Sommer et al, 2007;Martinat-Botté et al, 2010). Given that eCG activity is similar to FSH and LH (Brüssow et al, 2009;Soede et al, 2011;Driancourt et al, 2013;De Rensis and Kirkwood, 2016), a dosage of 1000 IU triggers greater follicular growth, stimulating greater numbers of follicles to grow and develop LH receptors and, subsequently, to ovulate, resulting in a larger amount of CL.…”

Utilization of porcine in vitro‐produced parthenogenetic embryos for co‐transfer with vitrified and warmed embryos

“…In vivo-produced morulae were collected and vitrified according to the method reported by Fujino et al (2006). Briefly, 7-to 8-month-old prepubertal Landrace gilts were given an intramuscular injection of 1500 IU of eCG, followed 72 h later by 500 IU hCG to induce superovulation.…”

“…Estrus synchronization was carried out by intramuscular injection of 1000 IU of eCG, followed 72 h later by 500 IU hCG (Fujino et al 2006). The in vitro-produced parthenotes and vitrified-warmed morulae were transferred to NCSU-37 supplemented with 4 mg/mL BSA and 25 mmol/L HEPES, after adjustment of the osmolarity to 280 mOsm/kg.…”