• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.228-234
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• 2005

Despite the relatively high production of fingerlings of the olive flounder Paralichthys olivaceus, its larval rearing in terms of first feeding has not been fully analyzed. We evaluated the variations of amino acids and fatty acids of starved larvae over 96 hr after hatching. We also investigated depletion of the yolk and oil globule of starved larvae and those fed the rotifer Brachionus plicatilis. In addition, the optimum size of the rotifers according to the mouth size of the larvae, and the point of no return with delay of the first feeding, were also examined. The amino acids in the egg decreased abruptly during embryo development. At 48 to 72 hr after hatching, the amino acids of starved larvae decreased by $30-40\%$ from the level in newly hatched larvae. The concentrations of fatty acids in newly hatched larvae were lower than those of floating eggs and dropped sharply at 48 hr after hatching, when the yolk disappeared. The starved larvae depleted their yolksacs and oil globules earlier than the fed larvae did. At 84 hr after hatching, rotifers were detected for the first time in the guts of the larvae, which were about 3 mm in total length. The point of no return appeared to be close to the fourth day from the first feeding. For a high survival rate of P. olivaceus larvae, the first feeding should occur before the third day after hatching.

• The Korean Journal of Malacology
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• v.12 no.1
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• pp.47-51
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• 1996

Radix auricularia coreana, the intermediate host of Fasciola gigantica, is the most common pulmonate snail in Korea, This species is often found intermingled with Austropeplea ollula, the intermediate host of F. hepatica, in their natural habitats. In the present study. the life history of Radix auricularia coreana was examined under three different laboratory conditions. Egg-masses were taken from the field-collected adult R. auricularia coreana and incubated in the temperature ramges of 22-26$^{\circ}C$. The hatching began after 11 days from spawned eggs, and complete hatching took about 12 days. The hatching rate was about 88%. The juvenile snails were cultured at three different laboratory conditions. When the juvenile snails were cultured in the aquarium fed on lettuce leaves at 22-26$^{\circ}C$, the snails reached 20 mm in shell length at 86 days after hatching. The bottom of each aquarium was filled up with washed sand(1.5 cm) and decomposing ark shells were put on the sand. The aquarium was then filled with four litres of distilled water and continuously aerated. Most of snails (93%) survived until the experimenta period. The dggs are laid in 40 days after hatching; the averge number of eggs per egg-mass was 40.8.

• Journal of Embryo Transfer
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• v.20 no.2
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• pp.129-135
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• 2005

The present study examines the effects of kinds and concentrations of cryoprotectants, PVP and sucrose and trehalose on the survival rate of vitrified porcine embryos. 1. The developmental stages for the embryos used in vitrification were $245(23.0\%)$ for 2 cell stage, $256(24.1\%)$ for the blastocyst, $234(22.0\%)$ for the early blastocyst $221(20.8\%)$ from the expanded blastocyst and $107(10.1\%)$ from hatching blastocyst out of 1,063 embryos. 2 The survival rate of morula, early blastocyst and expanded blastocyst vitrification-thawed with EDT and EGS were $69.1\%,\;70.3\%,\;69.8\%\;and\;62.5\%,\;61.7\%,\;63.6\%$, respectively. The expanded blastocyst treated with EDS showed the highest survival rate compared with the other cryoprotectants. 3. The survival rate of early blastocyst, expanded blastocyst and hatching blastocyst vitrification-thawed with EDS diluted in $medium + 10\%$ FCS were $61.1\%,\;27.8\%,\;16.7\%$, respectively. This result were love. than the control of group $(92.3\%,\;71.2\%,\; 55.8\%)$. 4. The survival rate of embryos vitrified with EDS and EDT supplemented with $10\%\;and\;20\%$ PVP were $74.3\%,\;77.5\%\;and\;79.4\%,\;71.1\%$, respectively. The survival rate of vitrified embryos cultured for $24\~48$ hours were $37.1\%,\; 40.0\%\;and\;35.3\%,\;31.6\%$ which were significantly lower than that of non-cultured embryos. The survival rate of embryos vitrified with EDS and EDT supplemented between $10\%\;or\;20\%$ PVP did not have a significant difference. 5. The survival rate of embryos vitrification-thawed with EDS to morula, early blastocyst, expanded blastocyst and hatching blastocyst were $58.2\%,\; 36.4\%,\;14.5\%$ to morula, $62.5\%,\;45.8\%,\;20.8\%$ to early blastocyst, $74.1\%,\;61.1\%,\;29.6\%$ to expanded blastocyst and $60.0\%,\;40.0\%,\;14.0\%$ to hatching blastocyst.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.53-59
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• 2006

This study was carried out to obtain the biological studies on aquaculture fundamental data for the resources annexation of Miichthys miiuy in terms of the characteristics of the spawning and effect of salinity. The adults spawners in 5 years were TL $72.3\sim89.6\;cm$, BW $3,736\sim8,818\;g$ in female (n=39), TL $47.1\sim81.2\;cm$, BW $716.6\sim6,853\;g$ in male (n=24). The adults size which were suitable for a stable egg collection were $97.9\sim110.2\;cm$ in total length, $9,657\sim13,200\;g$ in body weight. Each egg contained $1\sim5$ oil globules. Also, the highest hatching rate was 96.7% at the one having an oil globules. The highest hatching rate was 87.0% at 30.0 ppt. The fastest time required from fertilization to hatching was 17 hours 24 minutes at 28.0 ppt.

• Development and Reproduction
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• v.5 no.1
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• pp.17-21
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• 2001

This study was conducted to investigate the expression pattern of Trypsin-like enzyme and the effect of a trypsin inhibitor(benzimidine) on hatching process during in-vitro culture of mouse preimplantation embryos. The Trypsin-like enzyme was identified by rhodamine-conjugated Trypsin substrate probe. The expression of trypsin-like enzyme was firstly detected at the late morula stage, and the enzyme was uniformly localized in the trophectoderm of late blastocysts. Especially, intense fluorescence was observed in the blebbing area of hatching blastocysts. Bisbenzamidine, contained in culture media, did not alter embryonic development from 4-cell stage to the expanded blastocyst but decrease the hatching rate in ImM concentration (15.8% vs 89.7%, p<0.02). In the treatment of bisbenzimidine (5mM) for 12 hours according to the embryonic stage of mouse, the hatching rate of control (83.0%) and treatment in late blastocysts (8.7%) were significantly (p<0.01) different. From these results, we suggested that the hatching enzyme having trypsin-like activity was localized from the late morula stage, and the hatching process by this enzyme was activated in the late blastocyst stage of mouse embryos.

• Korean Journal of Poultry Science
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• v.47 no.4
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• pp.237-245
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• 2020

This study investigated the effects of breed, laying age, and egg storage period on hatching performance. Eggs were collected from early laying period (27 to 29 weeks old) and late laying period (50 to 52 weeks old) in Hwanggalsaek Jaeraejong, Korean Rhode Island Red, and Korean White Leghorn chicken breeds. Eggs laid for each period were stored for 3, 7 and 14 days and then hatched. Fertility, hatchability, and embryonic mortality were observed to determine the hatching performance. The results showed that hatching performance was affected by breed, laying age, and egg storage period with independently or interactively. The Korean Rhode Island Red breed had the lowest hatching performance. Hatchability and early embryonic mortality rate increased in early laying period eggs compared to the late laying period, but the late embryonic mortality rate increased in late laying period eggs. Additionally, hatching performance decreased as the egg storage period increased. Using breed-specific hatching management techniques, avoiding late laying period eggs, and shortening the egg storage period to seven days after laying may improve the hatching performance.

• 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).

• Korean Journal of Environment and Ecology
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• v.22 no.1
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• pp.59-65
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• 2008

This study is mainly focused on the mating of 9 couples of Eagle Owl Bubo bubo habitating in Paju, Ganghwa Island, Icheon, Sihwa Lake, Chungju. For this study, from 2005 to 2007, regular filming and mornitoring for the breeding ecology and copulation behavior of 9 couples of Eagle Owl in the nest and near area had been done. Clutches ranged in size from one to four eggs but averaged 2.27 eggs(n=15), hatching success rate was 71 %(n=34) and fledgling success rate was 83%(n=23). Through the filming and mornitoring, it was found that Eagle Owl continued to copulate each other even after hatching and kept its copulation until the chicks left their nest($7\sim8$ weeks after hatching). This copulation behaviour without fertilization seems to be done for confirming, maintaining and strengthening of pair-bond by the necessity of both male and female, and to aim at stable breeding of their chicks.

• Environmental Analysis Health and Toxicology
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• v.20 no.1
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• pp.57-65
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• 2005

Effects of five polycyclic aromatic hydrocarbon (PAHs) constituents (naphthalene, fluorine, fluoranthene, benzo(a)pyrene, pyrene) on fertilization and early development of sea urchin egg, sperm and fertilized egg were investigated. The eggs, sperm and fertilized eggs were exposed to several concentrations of PAHs (1, 10, 100, 1000 and 10000㎍/L). The rate of fertilization and hatching decreased when the eggs and sperm were exposed to aqueous solution of PAHs. Also, Exposure of fertilized eggs with each PAHs did decrease survival and hatching rate. Concentration-dependent toxic effects on the rate of fertilization, hatching, survival and abnormality in A. crassispina were observed following exposure to PAHs (1, 10, 100, 1000 and 10000㎍/L). These data show that PAHs exposure decreased in fertilization success of sea urchin egg and sperm and producted abnormal embryo. It is plausible to suggest that PAHs had the potential to significantly reduce coastal recruitment of sea urchin.

• Journal of Aquaculture
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• v.16 no.4
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• pp.262-266
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• 2003

In order to develop a method for the cryopreservation of fish embryos, the determination of optimal concentrations of dimethyl sulfoxide (DMSO), ethylene glycol and glycerol as individual cryoprotectants was performed by using the early embryos of black seabream, Acanthopagrus schlegeli. Optimal concentrations of cryoprotectants were assessed in terms of effects on mortality, median lethal concentration and hatching rate of embryos. The mortality of black seabream embryos immersed in cryoprotectants was related to the concentrations of cryoprotectants and immersion times. The toxicity to embryos was lower in order of DMSO, < ethylene glycol, < glycerol. The results from the mortality, median lethal concentration and hatching rate evaluations suggest that DMSO was the most effective cryoprotectant for black seabream embryos followed by ethylene glycol, and suitable concentrations of DMSO and ethylene glycol were 2.0∼2.25M and 1.0∼1.78M, respectively, with 20 minutes of immersion time.