Embryo collection in prepubertal gilts and attempts to develop an improved embryo transfer technique

Wallenhorst, S.; Holtz, W.

doi:10.1136/vr.150.24.749

Cited by 13 publications

(8 citation statements)

References 14 publications

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“…On the other hand, the number of ovulations differed among gilts. There was a large variation in our study (6 to 72 oocytes per gilt) and in a previous study [6]. From these facts, it seems that control of the ovulation rate by eCG treatment is difficult.…”

Section: Discussionmentioning

confidence: 46%

“…Expanded blastocysts just before hatching, and hatched blastocysts, are available at 171 h. Previous reports have shown the efficacy of combined eCG and hCG treatment [2][3][4][5][6][7], but no reports have described methods of collecting embryos efficiently at the appropriate stage. Our results clearly show that the developmental stage of the collected embryo progresses with the increase in time elapsed after hCG administration.…”

Section: Discussionmentioning

confidence: 99%

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

Fujino¹,

Nakamura²,

Kobayashi³

et al. 2006

Journal of Reproduction and Development

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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.

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Section: Discussionmentioning

confidence: 46%

Section: Discussionmentioning

confidence: 99%

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

Fujino¹,

Nakamura²,

Kobayashi³

et al. 2006

Journal of Reproduction and Development

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“…To develop a practical and effective protocol for zygote collection, we decided to use in vivo derived zygotes and post-weaning multiparous sows as embryo donors by two main reasons: firstly, although the production of porcine zygotes in vitro may be a good alternative with lower costs and shorter time compared with in vivo collection, the current IVF systems remain sub-optimal; and secondly, although zygotes can be obtained in vivo from prepubertal and pubertal gilts, we chose multiparous sows firstly because superovulation treatments in prepubertal gilts and synchronized mature gilts produced high proportions (25-50%) of poor quality embryos, unfertilized oocytes and degenerated embryos [20][21][22][23] as well as increased embryonic losses post-implantation [24,25]. It was suggested that a percentage of ovulated oocytes in synchronizedsuperovulated females remains in the germinal vesicle stage (immature) and would not be fertilized [26,27].…”

Section: Discussionmentioning

confidence: 99%

Three-to-5-day weaning-to-estrus intervals do not affect neither efficiency of collection nor in vitro developmental ability of in vivo-derived pig zygotes

et al. 2020

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An efficient system to collect large numbers of vital zygotes is a pre-requisite for application of zygote genome-editing technology, including development of efficient models for xenotransplantation using pigs. Owing to the sub-optimal in vitro production of zygotes in pigs, efficient collection of in vivo developed zygotes is required. Timing of ovulation is a key factor to sustain efficiency since the interval between pronuclear formation and the first division is very short in pigs. The weaning-to-estrus interval can, due to its inverse relation with length of estrus and time of ovulation, interfere with ovulation and make it asynchronous, which reduces the probability of obtaining zygotes. This retrospective study compared the effects of three weaning-to-estrus intervals of 3, 4 or 5 days on zygote collection efficiency in a total of 17 trials over a 3year period including 223 sows. Donor sows in groups of 10-15 animals were superovulated with eCG 24 h after weaning and those in estrus at 48-72 h post-eCG were immediately treated with hCG, followed by insemination 6 and 24 h thereafter.Collected structures during laparotomy on Day 2 (Day 0: onset of estrus) were morphologically evaluated and only those with a single cell and two visible polar bodies were considered as zygotes. Zygotes were injected with CRISPR-Cas9 editor mixture and cultured for 6 days to evaluate their developmental ability against non-injected control zygotes. Of all recovered structures (N=5,468), 67.4%, 30.8% and 1.8% were zygotes, 2-cell embryos and oocytes-degenerated embryos, respectively. The different weaning-to-estrus intervals did not affect either the percentages of collected zygotes (range: 64.1% to 70.0%) or the percentages of sows with zygotes at collection time (range: 69.0% to 73.3%). The weaning-to-estrus intervals did not affect the in vitro developmental ability of zygotes. After 24 h of culture, 78.1±2.0% and 95.1±0.6 (P<0.05) of injected (N=2,345) and non-injected (N=335) zygotes, respectively, developed to 2-to-4-cell embryo stage. The total efficiency of the system was 64.1±2.2% and 85.8±1.5% (P<0.05) for injected and non-injected zygotes, respectively.In conclusion, the results indicate that neither the efficiency of collecting in vivo derived porcine zygotes from superovulated sows nor the zygote ability to develop to blastocyst after cytoplasmic genome-editing injection were affected by a weaning-to-estrus interval between 3-to-5 days.

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“…Unlike in sows Martinez et al, 2014), superovulation treatments in prepubertal gilts and synchronized mature gilts yield high proportions (25% to 50%) of unfertilized oocytes and degenerated embryos (Guthrie et al, 1974;Holt and Schlieper, 1991;Wallenhorst and Holtz, 2002;Ziecik et al, 2005), which makes the use of this these females as embryo donors inadvisable. We had only selected multiparous sows due to their high accessibility on-farm and because they usually have farrowing rates and litter sizes higher than those in primiparous sows.…”

Section: Discussionmentioning

confidence: 99%

Factors of importance when selecting sows as embryo donors

Nohalez

Martínez

Reixach³

et al. 2017

Animal

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The improvement in porcine embryo preservation and non-surgical embryo transfer (ET) procedures achieved in recent years represents essential progress for the practical use of ET in the pig industry. This study aimed to evaluate the effects of parity, weaning-to-estrus interval (WEI) and season on reproductive and embryonic parameters at day 6 after insemination of donor sows superovulated after weaning. The selection of donor sows was based on their reproductive history, body condition and parity. The effects of parity at weaning (2 to 3, 4 to 5 or 6 to 7 litters), season (fall, winter and spring), and WEI (estrus within 3 to 4 days), and their interactions on the number of corpus luteum, cysts in sows with cysts, number and quality of viable and transferable embryos, embryo developmental stage and recovery and fertilization rates were evaluated using linear mixed effects models. The analyses showed a lack of significant effects of parity, season, WEI or their interactions on any of the reproductive and embryonic parameters examined. In conclusion, these results demonstrate that fertilization rates and numbers of viable and transferable embryos collected at day 6 of the cycle from superovulated donor sows are not affected by their parity, regardless of the time of the year (from fall to spring) and WEI (3 or 4 days).Keywords: pig, embryo donor, parity, season, weaning-to-estrus interval Implications A key factor that has received very little attention in the field of porcine embryo transfer (ET) is the selection of embryo donors. Results hereby showed that donor parity (2 to 7), season (fall, winter or spring) and weaning-to-estrus interval (WEI) (3 to 4 days) does not influence embryo quantity or quality. The ability to use donor sows with a wide range of parity and over a long period of time simplifies the application of the ET programs in donor farms, as these types of sows are highly available in nucleus farms.

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Embryo collection in prepubertal gilts and attempts to develop an improved embryo transfer technique

Cited by 13 publications

References 14 publications

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

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

Three-to-5-day weaning-to-estrus intervals do not affect neither efficiency of collection nor in vitro developmental ability of in vivo-derived pig zygotes

Factors of importance when selecting sows as embryo donors

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