• Korean journal of applied entomology
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• v.51 no.4
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• pp.371-376
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• 2012

This study was conducted to predict the hatching time of eggs of Lycorma delicatula, to select an effective environmentally-friendly agriculture material (EFAM) and to evaluate the attraction effect of brown sticky traps for controling of Lycorma delicatula nymph and adults. Eggs hatched 55.9, 26.8, 21.6 days after incubation at 15, 20, $25^{\circ}C$ with 14L:10D condition and the hatching rates of egg were 61.9, 57.8, 30.4%, respectively. At high temperature conditions, egg development periods were shorter and the hatching rate was lower. The relationship between temperature and developmental rate was expressed by the linear equation Y=0.0028X-0.0228, $R^2$=0.9561. The low temperature threshold of eggs was $8.14^{\circ}C$ and the thermal constant required to reach larva was 355.4 DD. According to this relationship, the mean estimated hatching date was $22^{nd}$ May. The effective EFAM was natural plant extract, sophora extract, derris extract to nymph and natural plant extract, pyrethrum extract, sophora extract to adult. Among three colors of sticky trap : brown, blue and yellow, the brown sticky trap was the most attractive to nymphs and adults of L. delicatula over a 2 weeks trial period. It suggested that the brown sticky trap could be a very useful and environment-friendly control method for nymphs and adults of L. delicatula.

• Clinical and Experimental Reproductive Medicine
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• v.41 no.3
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• pp.115-119
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• 2014

Objective: This study was designed to investigate the survival rate of vitrified mouse blastocysts depending on the presence or absence of sucrose in vitrification solution. Methods: Mouse two-cell embryos were collected and cultured to blastocysts. Two vitrification solutions were prepared. The control solution was composed of 25% glycerol, 25% ethylene glycol, and 0.5 M sucrose (G25E250.5S) containing 2.5 mL glycerol, 2.5 mL ethylene glycol, 2 mL SSS, and 0.855 g sucrose in 5 mL PB1. The experimental solution was composed of 25% glycerol and 25% ethylene glycol (G25E25) and contained 2.5 mL glycerol and 2.5 mL ethylene glycol in 5 mL PB1. Artificial shrinkage was conducted by aspirating the blastocoelic fluid using an ICSI pipette. To examine the effect of sucrose in the vitrification solution on the survival rate of mouse blastocysts, the shrunken-equilibrated blastocysts were rehydrated or vitrified after being exposed to one of the two vitrification solutions. After exposure and the vitrification-thawing process, the re-expansion rate and hatching rate were evaluated after 6 hours of in vitro culture. Results: The re-expansion rate of mouse blastocysts exposed to vitrification solution with and without sucrose were not different in the experimental solution (without sucrose) (98%) and the control solution (with sucrose) (92%) (p>0.05). The hatching rate was higher in the experimental solution (95%) than in the control solution (88%), but did not differ across two treatments (p>0.05). The re-expansion rate of mouse blastocysts vitrified in the control solution was 92% and 94%, respectively (p>0.05), and the hatching rate was higher in the experimental solution (90%) than in the control solution (74%) (p<0.05). Conclusion: Sucrose need not be added in vitrification solution for freezing of artificially shrunken mouse blastocysts.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.762-763
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• 2002

Recently, automatic control or application of measuring instrument with computers is rapidly increasing. In this paper we designed automatic incubation system that has functions of control and monitoring of measuring instrument, analysis of measured data, and automatic control by using LabVIEW graphic program that can easily collect, control, analyze, and apply data. Then to inspect the system we produced Incubator. Internal environment is measured by a sensor and each device is setting and controlled to create the optimum environment after finding hatching environment of selected individual from Database file for incubation. Through this functions, problems of hatching rate and quality that were affected by minute change of hatching environment are dealt successfully with, and retrenchment of labor and cost is expected as well.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.59-64
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• 1998

This study was designed to evaluate the influence of pronuclear age on the survival and post-thawing development after cryopreservation of mouse embryos. Freezing and thawing were performed in the different pronuclear stages of mouse embryos after IVF. Embryos were obtained from $F_1$ hybrid mice and classified into 4 groups according to the pronuclear stage (6hr, 9hr, 12hr and 15hr after insemination). Pronuclear ova were slowly cooled in a biological freezer using 1.5M 1,2-propanediol and 0.1M sucrose as cryoprotectant. Thawing was done at room temperature and 1,2-propanediol was removed by multi-step dilutions. Both frozen-thawed embryos and control fresh embryos were cultured in vitro in Ham's F-10 medium supplemented with 4mg/ml BSA. In control group, the development rate after 48hr was 99.3%, and the complete hatching rate after 144hr was 61.3%. In experimental groups, the survival rate after thawing was 95.4% in 6hr, 88.7% in 9hr, 75.2% in 12hr and 62.4% in 15hr after insemination, the development rate after 48hr was 61.1, 77.0, 67.0 and 79.6%, respectively, and the complete hatching rate after 144hr was 25.7, 43.7, 42.2 and 60.0%, respectively. The survival rate in 15hr was significantly lower (p<0.05) compared with other groups. In vitro development rates after 48hr were similar in all groups, but complement hatching rate was significantly lower (p<0.05) in 6hr group. In conclusion, cryopreservation of mouse pronuclear ova with 2 distinct pronuclei (9hr and 12hr groups) showed better results after thawing compared with early (6hr group) or late pronuclear ova just prior to cleavage (15hr group).

• Clinical and Experimental Reproductive Medicine
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• v.45 no.3
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• pp.129-134
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• 2018

Objective: In frozen and thawed embryos, the zona pellucida (ZP) can be damaged due to hardening. Laser-assisted hatching (LAH) of embryos can increase the pregnancy rate. This study compared thinning and drilling of the ZP before frozen embryo transfer (FET). Methods: Patients were randomly allocated into two groups for LAH using thinning or drilling on day 2 after thawing. Twenty-five percent of the ZP circumference and 50% of the ZP thickness was removed in the thinning group, and a hole $40{\mu}m$ in diameter was made in the drilling group. Results: A total of 171 in vitro fertilization/intracytoplasmic sperm injection FET cycles, including 85 cycles with drilling LAH and 86 cycles with thinning LAH, were carried out. The thinning group had a similar ${\beta}$-human chorionic gonadotropin-positive rate (38.4% vs. 29.4%), implantation rate (16.5% vs. 14.4%), clinical pregnancy rate (36.0% vs. 25.9%), miscarriage rate (5.8% vs. 2.4%), ongoing pregnancy rate (30.2% vs. 23.5%), and multiple pregnancy rate (7.0% vs. 10.6%) to the drilling LAH group. There were no significant differences in pregnancy outcomes between subgroups defined based on age (older or younger than 35 years) or ZP thickness (greater or less than $17{\mu}m$) according to the LAH method. Conclusion: The present study demonstrated that partial ZP thinning or drilling resulted in similar outcomes in implantation and pregnancy rates using thawed embryos, irrespective of women's age or ZP thickness.

• Journal of Aquaculture
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• v.20 no.4
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• pp.260-264
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• 2007

We investigated egg collection and the effects of water temperature (4, 7, 10, 13 and $16^{\circ}C$) on egg development, hatching and larval growth of Pacific cod Gadus macrocephalus under laboratory conditions. Fertilized eggs were round in shape ($1.01{\pm}0.03\;cm$) and adhesive to nylon nets. Fertilization rate was 68% by wet method. The time of egg development was negatively proportional to water temperature with the range of $4^{\circ}C$ to $13^{\circ}C$. Eggs hatched only at $7^{\circ}C$ after 288 hours of fertilization and $10^{\circ}C$ after 192 hours. Hatching rate was highest as 65% at $7^{\circ}C$ followed by $34.4^{\circ}C$ at $10^{\circ}C$. Survival rate was 18.3% at $7^{\circ}C$ and 5.2% at $10^{\circ}C$.

• Journal of Aquaculture
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• v.10 no.2
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• pp.179-187
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• 1997

Early development growth and sexual phenomena of the hybrid between male spotted flounder (Verasper variegatus) and female olive flounder (Paralichthys olivaceus) were investigated. The hybrid produced was newly called the "Bumnupchi" in Korean name, "Mottled flounder" in English name. Fertilization rate, hatching rate and early survival rate of the mottled flounder were 56.9~72.3%, 86.7~92.5% and 89.1~96.0%, respectively. At 50th day and 240th day after hatching, they were 2.1$\pm0.2cm\;and\;22.9\pm2.1cm\;in\;total\;length, \;0.10\pm0.002g\;and\;179.0\pm38.5g$ in body weight, respectively. Eye position of the mottled flounder was mixed with both dextral (77.7%) and sinistral type (22.3%). Gonads were differentiated into ovarian type and testis type at 80th day after hatching, and its ratio was 1:1 (P>0.05). Most Gonads seemed to be sterile without having germ cell, whereas only 3.6% of investigated indiciduals turned out to have oocytes in the gonad. When the induction of sex reversal were attempted by daily oral administration of $17\beta$-methyltestosterone (0.5mg/kg fish) andestradiol-17$17\beta$(0.5mg/kg fish)from 40th to 100th day after hatching, both testis and ovary type were induced 81.9% and 87.7% of each hormone-treated fish, respectively.fish, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.669-673
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• 1999

The effect of delayed initial feeding (1, 3, 5, 7 days) and starvation on morphological change, mortality and cannibalism on larvae of Siniperca scherzeri was examined by laboratory rearing. The larvae of S. scherzeri began to feed on Artemia nauplii at 4 days after hatching. In case of unfed and 7-days delayed groups, all of the larvae died at 12 days after hatching. The larvae of 1 day delayed feeding survived and grew as almost same as the control group, and 3-days delayed groups showed $33\%$ survival rate at the end of experiment (12 days after hatching). In case of the unfed group, total length of the starved larvae showed lower growth rate than the control group, and they did not reached at the same size of the larvae of the control group. Cannibalism were more common in the unfed group and the delayed fed group than the control group. The highest rate of daily mortality caused by cannibalism in the delayed fed group was $23\%$ at 8 days after hatching.

• Journal of Aquaculture
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• v.18 no.2
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• pp.107-114
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• 2005

Clownfish are important and very popular fish in the ornamental aquarium industry. Demand for the fish is increasing dramatically. The present study was conducted to verify methods of broodstock management, patterns of spawning, rates of egg hatching and estimates of larval growth fur the saddleback clownfish, Amphiprion polymnus. Spawning occurred 8 times between August 2002 to June 2004 with 2 females and 1 male participating. Fertilized eggs were separated by an adhesive matrix and were oval in shape. The eggs were $2.46{\pm}0.13mm$ in size as measured along the longest axis. The percentage of fertilized eggs was 96.7%. Hatching was observed seven days post-spawning and hatching rate was 85.5%. The sizes of the newly-hatched larvae were $4.58{\pm}0.21mm$ TL (total length). Larvae had an open mouth and anus, and an oval yolk sac. At the 1 st day after hatching, the sizes of the larvae were $4.90{\pm}0.35mm$ TL. The larvae began to eat rotifers after complete yolk absorption. On the 5th day post-hatch, larvae were $5.88{\pm}0.31mm$ TL with complete fins and the survival rate was 48.6%. At 8 days after hatching, a band began to appear on head and back of the larvae indicating the beginning of metamorphosis. Metamorphosis was completed at an average TL of $15.00{\pm}2.12mm$ on the 23rd day after hatching. By the 45th day after hatching, juveniles averaged $22.76{\pm}3.22mm$ TL and survival rate was 28.4%.

• Fisheries and Aquatic Sciences
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• v.20 no.11
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• pp.29.1-29.7
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• 2017

The objective of this study was to determine a simple and reliable ploidy identification protocol for the rainbow trout (RT), Oncorhynchus mykiss, in the field condition. To evaluate the ploidy level and compare different detection protocols, triploid RT and gynogenesis were induced by UV irradiation and/or heat shock. The hatching rate at day 30 was 85.2% and the survival rate at day 90 was 69.4% (fingerling). The sex ratio of female RT was 93.75% in the gynogenesis group, illustrating that the UV irradiation inactivated the sperm DNA. The hatching rate and survival rate were 82.0 and 74.7%, respectively, in the triploid-induced group. The triploid induction rate by heat shock procedure was 73.9%. Cytogenetic protocols for ploidy identification such as chromosome counting, erythrocyte nuclear size comparison, and analysis of nucleolar organizing regions (NORs) by silver staining were compared. Silver nitrate staining showed the greatest success rate (22/23 and 32/32 for the triploid-induced group and gynogenesis group, respectively), followed by erythrocyte nuclear size comparison (16/23 and 19/32 for the triploid-induced group and gynogenesis group, respectively) and, lastly, chromosome preparation (2/23 and 6/32 for the triploid-induced group and gynogenesis group, respectively) with the lowest success rate. Based on our findings, silver staining for RT ploidy identification is speculated to be highly applicable in a wide range of research conditions, due to its cost-effectiveness and simplicity compared to other numerous ploidy detection protocols.