• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.185-192
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• 1999

The present study was performed to investigate the efficacy and safety of laser assisted hatching (AH) on mouse embryos. Non-contact $1.48{\mu}m$ diode laser system used to create a precise hole on zona pellucida. 2-cell embryos were collected from the mice (ICR) that had the coitus vaginal plug confirmed at 48 hours after hCG injection. Collected 2-cell embryos were cultured in the HTF medium supplemented with 0.4% BSA. For experiments, embryos at 8-cell stage were used after 18-22 hours in culture. After assisted hatching, the embryos were further cultured in HTF medium containing 0.1% PVP (anti-hatching system) for 3 days. For evaluate efficiency of laser on mouse embryo hatching, the effect of AH methods (acidic tyrode, pronase and laser), the number of artificial holes (1, 2 and 3 hole) and the irradiation time of laser (2, 4, 6, 8 and 10 ms) were examined. Hatching rates of laser AH group (95.2%) was significantly higher than that of control group (50.8%), but there was no differences among the laser (95.2%), acidic tyrode (100%) and pronase (98.5%) groups. Hatching rates of the number of zona pellucida opening by laser, there were no differences among the 1 hole (87.5%),2 hole (92.1%) and 3 hole (85.9%) groups. Developmental and hatching rates of embryos according to laser irradiation time were similar in the treatment groups. Therefore, these results suggest that laser AH using non-contact $1.48{\mu}m$ diode laser is a simple and accurate and effective procedure for AH. Based on these results, laser AH could be use safely for human ART program.

• Journal of Life Science
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• v.9 no.3
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• pp.333-340
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• 1999

The toxic effect of TBTO on Chlorella and Rotifer was observed. The value of 48hr-LC50 for Chlorella (3.3$\mu\textrm{g}$/L) estimated to be almost 500 times as high as that for Rotifer (6.7ng/L). A fertilized egg of olive flounder exposed in an embryo-formation stage was mostly influenced by TBTO toxicity when the fertilized egg at each stage until hatching was exposed to TBTO at the concentrations of 5 to 200ng/L. The values of LT50 were estimated to be 68.0, 41.0, 21.0, 13.0, 7.7 and 4.7 hours at 5, 10, 25, 50, 100 and 200ng/L of TBTO, respectively when the fertilized egg in a morula stage was exposed to TBTO, and the 48hr-LC50 was 8 ng/L. In case of TBTO treatment in an embryo-formation stage, the values of LT50 were 33.0, 12.5, 3.5, 1.3, 0.5 and 0.2 hours at 5, 10, 25, 50, 100 and 200ng/L of TBTO, respectively, and the value of 48hr-LC50 was 4ng/L. The values of LT50 were estimated to be 17.0, 11.0, 6.2, 4.0, 2.6 and 1.7 hours at 5, 10, 25, 50, 100 and 200ng/L of TBTO, respectively when the fertilized egg in a stage just before hatching was exposed to TBTO, and the 48hr-LC50 was below 1ng/L. The percentages of hatching were 46.2, 20.6, 21.9, 20.6 and 13.2% at 25, 50, 100, 250 and 500ng/L of TBTO, respectively when the fertilized egg in the stage just before hatching was exposed to TBTO and the measurement was done at second day after the completion of hatching. However no survival after the completion of hatching was found in all cases. With the treatment of 1, 5 and 10ng/L of TBTO, the percentages of hatching were 80.5, 70.0 and 44.1%, respectively. The percentages of survival until second day after the completion of hatching were 80.0, 63.3 and 9.1%, respectively. The percentages of hatching and survivability after the completion of hatching for the control were 84.5 and 82.5%, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.46 no.1
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• pp.16-23
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• 2023

The silkworm's dormancy and embryonic development are accomplished through the interaction of various genes. Analysis of the expression of several interacting genes can predict the embryonic stage of silkworms. In this study, we analyzed the changes in the expression level of genes at each stage during the embryonic development of dormant silkworm eggs and selected genes that can predict the hatching time. Jam123 and Jam124 silkworms were collected after egg laying, and the silkworm eggs were preserved using a double refrigeration method and expression analysis was performed for 23 genes during embryogenesis. There were 5 genes showing significant changes during embryogenesis: UDP-glucuronosyltransferases (BmUGTs), heat shock protein hsp20.8 (BmHsp20.8), Cytochromes b5-like proteins (BmCytb5), Krüppel homolog 1 (BmKr-h1), and cuticular protein RR-1 motif 41 (BmCpr41). As a result of quantitative comparison of the expression levels of these 5 genes through real-time PCR, the BmUGTs gene showed a difference between Jam123 and Jam124, making it difficult to see it as an indicator for predicting hatching time. However, the BmHsp20.8 gene had a common expression decreased at the imminent hatching stage. In addition, it was confirmed that the expression level of the BmCytb5 gene decreased to the lowest level at the time of imminent hatching, and the expression of the BmKr-h gene was made only at the time of imminent hatching. The expression of the last BmCpr41 gene can be confirmed only at the time of imminent hatching, and it was confirmed that it shows a rapid increase right before hatching. Taken together, these results suggest that expression analysis of BmHsp20.8, BmCytb5, BmKr-h1, and BmCpr41 genes can determine the stage of embryogenesis, predict hatching time, which facilitate better management of silkworm eggs.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1702-1707
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• 2002

The effects of dark-control (D) and continuous green light (GL) exposure of incubated meat-type breeder eggs (Hybro) on embryonic growth from 5 to 15 days of age, hatching time, hatchability per cent and chick hatching weight were investigated in three consecutive experiments at 33, 38, and 41 weeks of age. A total of 798 eggs were used in this study. Eggs were set in an incubator on trays either in the D or under two tubes of 20-watt green fluorescent light during the first 18 days of incubation. Eggs from both treatments were transferred to the dark hatching compartment at 19 days of incubation. The light intensity was in the range of 1,340 to 1,730 lux at the surface of the eggs. GL incubation of eggs significantly (p<0.01) increased weight (expressed as an absolute value) and daily weight gain of embryos at 11 and continued to 15 days of age, hatchability per cent by 4.8%, reduced dead embryos per cent and chick weight at hatch by 37 and 2%, respectively and accelerated hatching time by about 24 h when compared with the D-control incubation. Chicks hatched at 504 h of incubation had significantly (p<0.01) higher body weight, expressed as an absolute value or as a percentage of egg weight, than those hatched earlier at 456 h of incubation. It was concluded that the GL incubation of meat breeder eggs reduced incubation period and chick weight at hatch and increased embryonic growth and hatchability per cent.

• Fisheries and Aquatic Sciences
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• v.21 no.9
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• pp.23.1-23.8
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• 2018

Background: Russian sturgeon (Acipenser gueldenstaedtii) is an emerging candidate species in the Korean aquaculture domain owing to its highly valued caviar. Although the embryonic development of this species was previously described, the complete image data on the morphological differentiation of developing embryos have not been yet fully available. Further, with the viewpoint of larval production in hatchery, the effects of temperature on embryonic viability and the temporal window of hatching event have not been extensively studied. Hence, the objective of this study was to provide a complete set of photographic image data on the embryogenesis and also to examine the effects of incubation temperatures on embryonic viability and hatching event in farm-bred Russian sturgeon. Results: Typical characteristics of embryonic development including uneven, holoblastic cleavages with unequal blastomeres, followed by the formation of germ layer, neurulation, and organogenesis until hatching, were documented. Under different temperature conditions (12, 16, or $20^{\circ}C$), viability of embryos incubated at $12^{\circ}C$ was significantly lower as relative to those of 16 and $20^{\circ}C$ incubated embryos. Hatchability of embryos was higher, and the timing of hatching event was more synchronized at $20^{\circ}C$ than at 12 and $16^{\circ}C$. Conclusion: Data from this study suggest that the incubation of Russian sturgeon embryos at $20^{\circ}C$ would be desirable in the hatchery practice with respect to the good hatchability of embryos and the synchronization of hatching events. Additionally, the updated image data for complete embryonic development could be a useful reference guide for not only developmental researches but also artificial propagation of Russian sturgeon in farms.

• Korean Journal of Environment and Ecology
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• v.37 no.3
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• pp.192-197
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• 2023

This study was conducted to determine whether the difference in egg hatching temperature of Korea Reeves' turtle (Mauremys reevesii) at the artificial nursery of Seoul National Grand Park affects the incubation period and growth. A total of 201 eggs were incubated at 26 ℃ (n=89), 28 ℃ (n=75) and 32 ℃ (n=37). The incubation period of eggs showed significant differences according to the hatching temperature. In this study, the higher the hatching temperature, the higher the hatching rate. The incubation period of the eggs hatched at 26 ℃, 28 ℃ and 32 ℃ was 66.1 (±4.0, n = 52) days, 65.3 (±3.3, n = 44) days and 58.8 (±7.7, n = 31) days, respectively. Eggs incubated at 32 ℃ (83.8%) had a higher hatching success than those at 26 ℃ (58.4%) and 28 ℃ (58.7%). The body mass of 14-day-old hatchlings incubated at 32 ℃ was greater than those incubated at 26 ℃ and 28 ℃. However, there was no significant difference in the mean body mass of 180 and 270-day-old turtles hatched at these different temperatures. This study showed that the hatching temperature significantly affected the incubation period and body mass in the early life of the Korea Reeves' turtle (M. reevesii).

• Clinical and Experimental Reproductive Medicine
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• v.27 no.4
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• pp.345-351
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• 2000

Objective: Hatching of the blastocyst from the zona pellucida (ZP) is a key event in mammalian implantation. In vivo, two factors have been identified as possible mediators of hatching: lysis of the ZP by substances elaborated either from the embryo or female reproductive tract and pressure exerted on the zona by expansion of the blastocyst. Two methods of zona manipulation were already in use to enhance the ability of embryos to hatch: mechanical PZD and chemical ZD by acidic Tyrode's solution. But several controversies of each method have been reported. The purpose of this study was to investigate the effect of pronase for mouse embryo hatching. Methods: Mouse embryos were obtained following ovulation induction of $F_1$ animals. Fresh and cryo-thawed morula embryos were exposed to 0.5, 1.0, 2.0, 5.0 ${\mu}g/ml$ pronase in Ham's F10 for 72 hrs. Main outcome measures were the rates of partial hatching and completely hatched blastocysts, and cell number of it. Results: In fresh and cryo-thawed group, the rates of completely hatched blastocyst were significantly higher in 5 ${\mu}g/ml$ pronase treatment group than control group. There was no difference in completely hatched blastocyst total cell number between pronase treatment group and control group. This suggest that pronase treatment did not harmful in mouse embryo development. In pronase treatment group, zona pellucida were thinner than control group. Conclusion: The addition of pronase to culture media may accelerate the hatching of embryo. So, enzymatic treatment of the zona may provide a valuable and effective assisted hatching technique for human in-vitro fertilization-embryo transfer.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.133-139
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• 2016

The incubation time required for hatching of O. ocellatus were investigated through the processes of egg and embryonic developments by the dissecting microscopic and visual observations. And differences in ecological characteristics of the plankton mode of life or the benthic mode of life according to total numbers of the suckers on each short arm of the hatched juvenile larvae of O. ocellatus were studied by comparisons with other octopodidae species. Compared with the recent a few results reported by other researchers associated with the incubation time required for hatching by female adult mother of O. minor (73-90 days after spawning at $20.9-21.5^{\circ}C$ ranges), in this study, the incubation time required for hatching by female adult mother of O. ocellatus was 56-57 days after spawning at $11.0-20.4^{\circ}C$. Therefore, the incubation time required for hatching by female adult mother varied with Octopodidae species. In this studies, each ovarian egg laid by a female was connected to an egg string attaching to the surface of the wall or bottom of vacunt shell of Rapana venosa. Egg and embryonic developments of this species were studied in the indoor aquaria, in the specific gravity ranging 1.024-1.025. the hatched juvenile of O. ocellatus is 10.3 mm in the mean total length and 4.5 mm in mantle length, and each of its short arms has 18-20 suckers. The just hatched juvenile larvae of O. ocellatus enter the benthic mode of life (benthic larval stage) after hatching. In particular, regarding differences in ecological characteristics of the mode of life according to total numbers of the suckers, O. vulgaris may not need to have many suckers because they enter the planktonic mode of life after hatching, however O. ocellatus may need to have many suckers, because they should adapt to the benthic mode of life. And also the just hatched juvenile larvae of O. minor (bearing many suckers more than O. ocellatus) enter the benthic mode of life (benthic larval stage) after hatching. Therefore, the total number of the suckers on each short arm of the hatched juvenile larvae can be used for determining whether an octopus species has planktonic larval stages or benthic larval stage (benthic mode of life). In particular, The intracohort cannibalism phenomena appeared at the hatched juvenile larval stage because the larval stage of O. ocellatus and O. minor enter into the benthic larval stage in the early stage, unlike entering into the plaktonic larval stage in other Octopus species such as O. vulgaris: at this time, the early hatched larvae fed the late hatched larvae (they are the same species and almost same ages). Therefore, the intracohort cannibalism pheneomena occur in the just hatched juvenile stage of only O. ocellatus and O. minor.

• Korean Journal of Animal Reproduction
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• v.21 no.1
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• pp.61-69
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• 1997

The present study was carried out to investigate the effects of EGF and anti-EGF on early embryonic development and hatching in mice. Developmental and hatching rates of mouse em-bryos from 2-cell to morular stage which were cultured in Ham's FlO medium supplemented with EGF (1-1,000 ng/ml) or anti-EGF (whole serum diluted from 1:10 to 1:1,000) were compared to those of control When mouse early 2-cell embryos were cultured in the EGF supplemented medium, blastulation was accelerated compared with control. Hatching rate was also significantly (p

• Journal of Aquaculture
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• v.21 no.3
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• pp.176-180
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• 2008

This study clarified biochemical overripeness characterization of ovulated eggs of Anguilla japonica and suggested a method maintained overripeness after ovulation for high hatching rates. In maturated Japanese eel eggs, the relationships between fertilization rate and hatching rate, and fertilization and survival rates were measured. DNA contents showed the significantly low 0.653 pg/ug protein in 20% downward hatching rate trial with decrease of hatching rate(P<0.05), whereas RNA/DNA ratio showed the significantly high 1.058 in 20% downward hatching rate trial(P<0.05). And activities of total alkaline protease and ACPase according to the hatching rate groups did not show the significant difference(P>0.05). The protein contents were assayed the significantly high 186.16 ug/mg protein in 20% downward hatching rate trial(P<0.05). However, the overripened eggs had lowed hatching rate, because of stimulate the overripening of normal maturated eggs due to the continuous supplement of protein (vitellogenin). We suggested that need to reduce supplement speed or interception of vitellogenin produced in live for prevent overripeness of maturated eggs after ovulation