• Journal of Embryo Transfer
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• v.13 no.1
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• pp.77-86
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• 1998

A combined technology of transvaginal ovum pick-up(OPU) system with in vitro-oocyte manipulation technique can be used for improving reproductive efficiency in the cattle. The objective of this study was to establish a newly-conceived breeding program using OPU in the pregnant cows. The OPU trial was performed in pregnant cows every 10 days from 40 through 90 days of artificial insemination (Al), and number of follicles in ovary, number of retrieved oocytes and embryo development following in vitro-fertilization, were evaluated. Reduced number of follicles in the ovaries of pregnant cows was firstly detected from 70 days after A' and a significant (P<0.05) decrease in the follicle number (5.4 follicles /donor) was found at 90 days than at 40, 50, 60 and 80 days after Al (8.0~9.2). A similar pattern was also observed in the number of oocytes retrieved by OPU apparatus during experimental period. When retrieved oocytes were matured and inseminated in vitro with frozen bull semen, development of the oocytes to the blastocyst stage was not significantly affected by the retrieval time. Four embryos (morula or blastocyst stage) derived from oocytes retrieved from pregnant cows were nonsurgically transferred to four recipient cows on day 7 of estrus cycle. For the first time in Korea, three of four transferred embryos developed to live calves with normal physiological parameters. In conclusion, an effective breeding program employing pregnant cow can be developed by use of OPU trial and in vitro culture techniques of oocytes ; OPU system could be repeated in pregnant cows with no risk of abortion and viable offsprings were borne after transfer to the recipients.

• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.309-314
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• 2005

This study was carried out to obtain the basic informations on the flowering habit, pollination patterns and seed setting in Hosta plantaginea Aschers. Flowers came out in the night with white color. Almost fertilization seemed to be out by wind in early and full flowering. But bearing pods by insects and fertilization rate by wind were increased by interval of flowering and particular scent slowly decreased in after flowering. Bearing pods and seeds setting rate were $65.0\%,\;40.9\%$ per peduncle after artificial pollination, and also $33.3\%,\;24.3\%$ in natural pollination, respectively. The flowering times was all around seven to eight o'clock at night and optimum temperature for pollination was $25{\sim}28^{\circ}C$.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.265-270
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• 2018

Up-to-date artificial insemination (AI) using frozen sperm consider as the most widely using technology for improvement of Korean Native Cow (Hanwoo) embryo production. However, it is time consuming, required at least 15~20 years to make more than 6 generations, and their offspring number is limited. To overcome such limitations, superovulation and in vitro fertilization have been developed. For superovulation, the number of produced embryos are not enough for commercialization and donor cows need rest period. This led to use of slaughterhouse ovary for in vitro fertilization, but it is impossible to repeat the collection from the same individual and it only can improve the genetic merits of offspring for one generation. Production of embryos using Ovum Pick-Up (OPU) technique, where oocytes can be repeatedly collected from living elite donor, might overcome these limitations. In this study, we investigated the possibility of using OPU technique from donors at different age and different session periods for mass-embryo-production. Oocytes were collected from 26 donor cows twice per week, 3 - 4 months per year, between 2013 and 2016. Results showed that, the average number of embryo produced in first year used donor was significantly higher than that in second year used donor ($3.89{\pm}2.85$ vs $3.29{\pm}2.70$), however, there was no significant difference between third year used donor ($3.51{\pm}3.32$) and other groups. Taken together, our data showed that repeated using of donor up to three years is possible for in vitro embryo mass-production. Moreover, OPU can be used as suitable embryo producing technique for livestock breed improvement.

• Korean Journal of Ichthyology
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• v.32 no.3
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• pp.130-135
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• 2020

Male gonadal development of the yellow catfish, Pseudobagrus fulvidraco, one of the most popular fish species in Korean aquaculture performance, was investigated by histological observation of monthly collected specimens to make comparisons between wild and cultured individuals. Their reproductive cycle was classified into the successive developmental stages as follows: a growing stage (April), a spawning stage (May), a degeneration stage (June to July), and a resting stage (August to October) in the wild and outdoor-cage individuals; a growing stage (April to June), a spawning stage (July to August), a degeneration stage (September), and a resting stage (October) in the indoor-cage ones. Values of gonadosomatic index (GSI) of wild and outdoor cages peaked in May, followed by a sudden decline in August~September and June~August, respectively. In contrast, GSI values of the indoor-cage individuals peaked in September and were followed by a sudden drop. Remarkable seasonal variation in condition factor (CF) was undetectable, peaking in June in the wild-cage individuals and November in the wild ones. Overall, our results suggest that it is suitable to use the male of the outdoor-cage individuals for artificial fertilization and that it is efficient to perform artificial fertilization in May, such as reproductive cycle of wild.

• Applied Microscopy
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• v.41 no.2
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• pp.123-128
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• 2011

The micropyles on the prefertilized and artificial fertilized eggs of Epinephelus fasciatus were investigated using scanning electron microscope (SEM). The micropyles ($6.6{\pm}0.41\;{\mu}m$) of E. fasciatus eggs were found in the animal pole and theirs shape were observed as a flat crateriform of cylindrical shape. The micropylar vestibule arranged by 6~7 thickened spiral annuli on the ridge and contributed to differentiate and form fertilization cone for blocking to polyspermy by presenting swollen vestibule structure. As E. fasciatus eggs was pelagic, so chorionic surface was an uneven structures such as circular and fillar form nodules. Especially, various pores (0.15~0.55 ${\mu}m$, 230~270 pores) distributed at the only around micropyles, those pores radiately exhibited regular projection structures showing gill filament-shape. These ultrastructural characters of E. fasciatus eggs can be utilized in a taxonomical cue of grouper species.

• Korean Journal of Animal Reproduction
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• v.16 no.1
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• pp.63-76
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• 1992

This study was carried out to investigate the appearance time of the second polar body for producing Gynogenesis or Triploid which could be obtained by arresting the second polar body by cold shock, and then blastoderm was used to measure fertility that revealed the nature of oogenesis, the effects of water temperature on fertility, hatchability, abnormality, viability and growth rate, and the water temperature and the breeding methods to prevent early death of larvae in Korean loach(Misgurnus anguillicaudatus) ; the results obtained in this study were summarized as follows. The second polar body was observed ont he surface of plasma disc close to micropyle within 10~40 min after fertilization at 29$^{\circ}C$. Artificial inseminatin had to be done immediately after the egg spawning because the spermatozoa of loach their mobility within 2 minutes when they were exposed to water. The amount of time needed to reach at blastoderm stage was 12 hours if fertilized eggs were incubated at 16$^{\circ}C$, 8 hours at 19$^{\circ}C$, 6 hours at 21$^{\circ}C$, 5 hours at 23$^{\circ}C$, 4 hours at 26$^{\circ}C$ and 3 hours 30 min at 29$^{\circ}C$ showing the shorter time for development of eggs at higher temperature. Fertilization rates in water temperatures of 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$, and 26$^{\circ}C$ were higher than those of water temperatures, 16$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 19$^{\circ}C$, 21$^{\circ}C$, and 23$^{\circ}C$ showed higher hatching rates that those of 16$^{\circ}C$, 26$^{\circ}C$, and 29$^{\circ}C$, while abnormal rates in 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$ and 23$^{\circ}C$ were lower than that of 26$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$ and 26$^{\circ}C$ respectively, were more different than 29$^{\circ}C$ in survival rates. The embryos were hatched at 72 hours after fertilization in 16$^{\circ}C$ water temperature, 48 hours in 19$^{\circ}C$, 40 hours in 21$^{\circ}C$, 32 hours in 23$^{\circ}C$, 25 hours in 26$^{\circ}C$, and 16 hours in 29$^{\circ}C$. Within three days after hatched out, the larvage grew 3mm in total length, the yolk granules were entirely consumed and the head and the trunk became thicker. Within 45 days after hatched out, the larva grew 25mm at 29$^{\circ}C$, 21mm at 26$^{\circ}C$, 16mm at 23$^{\circ}C$, 15mm at 21$^{\circ}C$, 12mm at 16$^{\circ}C$ in a 30 litreglass aquarium.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.167-173
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• 2011

This study was performed to describe the effect of water temperature, salinity and density on the eggs development of the hard clam, Meretrix petechialis. Eggs of Meretrix petechialis were turned out to be demersal isolated eggs of $82.3-86.1{\mu}m$ in an average diameter after spawning. The hatching rate of D-shaped larvae by elapsed time after spawning was the highest in fertilization immediately after spawning and distinguished decrease from 1 hour of spawning. The optimum water temperature for development of D-shaped larvae from fertilization was ranged between $25^{\circ}C$ to $27^{\circ}C$. However, D-shaped larvae was not developed at $33^{\circ}C$ of water temperature. The required time from fertilization to D-shaped larvae were 37.3 hours in $20^{\circ}C$, 20.8 hours in $25^{\circ}C$, and 15.3 hours in $30^{\circ}C$. Biological minimum temperature for the egg development was estimated to be $12.4^{\circ}C$ in average. The range of salinity for the development of eggs were 20.0-37.5 psu, optimum range was estimated to be 27.5-32.5 psu.

• Journal of Aquaculture
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• v.7 no.3
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• pp.159-164
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• 1994

All-female diploid Paralichtlrys olivaceus populations were produced by the artificial fertilization with the normal eggs and gynogenetic diploid males sperms. All-female triploids were also conducted to the fertilized eggs by cold shock. Floating, fertilization and hatching rates of the all-female diploid eggs were not significantly different from that of the diploid control eggs (P>0.05). All-female triploids were also not significantly different from their diploid controls or all-female diploid groups (P>0.05) in the floating and fertilization rates of eggs. However, hatching rates of all-female triploid groups were lower than that of the control (P<0.05). Induction of the triploids were confirmed by the measurement of erythrocyte sizes and by the chromosome counts. The volumes of erythrocytes and nucleus of triploid were larger than those of diploids, respectively. Percent incidences of triploid were $92.6\%$ in this experiment. The chromosome number of diploids and triploids showed 2n=48 and 3n=72, respectively, and their karyotypes were consisted of all acrocentric chromosomes. The gonads of 4-month-old triploids were histologically sterile.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.1071-1086
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• 2003

Reproductive biotechnologies continue to be developed for genetic improvement of both river and swamp buffalo. Although artificial insemination using frozen semen emerged some decades back, there are still considerable limitations. The major problem appears to be the lack of efficient methods for estrus detection and timely insemination. Controlled breeding experiments in the buffalo had been limited and similar to those applied in cattle. Studies on multiple ovulation and embryo transfer are essentially a replica of those in cattle, however with inherent problems such as lower number of primordial follicles on the buffalo ovary, poor fertility and seasonality of reproduction, lower population of antral follicles at all stages of the estrous cycle, poor endocrine status and a high incidence of deep atresia in ovarian follicles, the response in terms of transferable embryo recovery has remained low with 0.51 to 3.0 per donor and pregnancy rates between 15 to 30%. In vitro production of buffalo embryos is a valid alternative to recovery of embryos by superovulation. This aspect received considerable attention during the past decade, however the proportion of embryos that develops to the blastocyst stage is still around 25-30% and hence the in vitro culture procedures need substantial improvement. Embryo cryopreservation procedures for direct transfer post thaw need to be developed for bubaline embryos. Nuclear transfer and embryo cloning is a technique that has received attention in various species during recent years and can be of immense value in buffaloes as they have a low rate of embryo recoveries by both in vitro and in vivo procedures. Gender pre-selection, genome analysis, gene mapping and gene transfer are a few of the techniques that have been studied to a limited extent during recent years and are likely to be included in future studies on buffaloes. Very recently, reproductive biotechnologies have been applied to feral buffaloes as well, but the results obtained so far are modest. When fully exploited they can play an important role in the preservation of endangered species.

• Animal cells and systems
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• v.11 no.2
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• pp.117-124
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• 2007

The present study demonstrates the changes in body weight (BW) and plasma sex steroid hormone profiles during artificial maturation induced by human chorionic gonadotropin (HCG) or salmon pituitary extract (SPE) injections in cultured eel, Anguilla japonica, kept in seawater for 3 months. In the weekly SPE-injected female group, BW was relatively stable during vitellogenesis. Following induction of vitellogenesis, females exhibited a rapid increase of BW, and the oocytes were observed to be in the migratory nucleus stage at the end of the experiment. Plasma testosterone (T) and $estradiol-17{\beta}$ ($E_2$) levels increased slightly during vitellogenesis and peaked at an average of 5.82 ng/mL and 4.76 ng/mL, respectively, at the end of the experiment. In the weekly control and HCG-injected female groups, BW slowly decreased during the experimental period, and the oocytes of the two groups were observed to be at the primary yolk globule stage. In the weekly HCG-injected female group, plasma T and $E_2$ levels increased slightly during vitellogenesis and decreased afterward. In the control female group, however, plasma T and $E_2$ levels were not altered during the experimental period. Furthermore, plasma $17{\alpha},20{\beta}-dihydroxy-4-pregnen-3-one$ (DHP) was not detected in all experimental groups. Fertility and hatching rates of SPE-injected females were significantly higher in those that ovulated 15 h after DHP injection than 18 h. These results indicate that long rearing in seawater increases responsiveness to SPE in ovarian maturation of the Japanese eel, resulting in shortened period from completion of vitellogenesis by sex steroid hormone production.