• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.144-149
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• 2018

The eggs are incubated for 18 days through the generator and incubated in the developing incubator. During the developmental period, the weight loss of the fetus is correlated with the ventricular formation, and the proper ventricular formation is also associated with the healthy embryonic hatching and the egg hatching rate. However, in the incubator period of the domestic hatchery, it is a reality to acquire the resultant side by the Iranian standard weight measurement with the experience of the hatchery and the person concerned and the development period without the apparatus for measuring the present weight. As a result, prevalence of early mortality, hunger and illness during hatching are frequent. Monitoring the reduction of weaning weight is crucial to obtaining chick quality and hatching performance with weight changes within the development machine. Water loss is different depending on the size of eggs, egg shell, and elder group. We can expect to increase the hatching rate by measuring the weight change in real time and optimizing the ventilation change accordingly. There is a need to develop a real-time measurement system that can control 10 to 13% reduction of the total weight during hatching. The system through this study is a way to check the one - time directly when moving the existing egg, and it is impossible to control the measurement of the fetal water evaporation within the development period. Unlike systems that do not affect the hatching rate, four load cells are connected in parallel on the Arduino sketch board and the AT-command command is used to connect the mobile phone and computer in real time. The communication speed of Bluetooth was set to 15200 to match the communication speed of Arduino and Hyper-terminal program. The real - time monitoring system was designed to visually check the change of the weight of the fetus in the artificial incubator. In this way, we aimed to improve the hatching rate and health condition of the hatching eggs.

• Development and Reproduction
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• v.17 no.4
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• pp.369-377
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• 2013

The fertilized eggs of E. septemfasciatus are spherical and transparent with buoyancy at 790 to $890{\mu}m$ (average $821.8{\pm}2.0{\mu}m$) in diameter with 170 to $230{\mu}m$ oil globules (average $192.9{\pm}0.93{\mu}m$). Hatching began approximately 46 and 35 hours after fertilization at $22.0^{\circ}C$ and $25.0^{\circ}C$ water temperature, respectively. The average total length of newly hatched larvae was $1.75{\pm}0.03mm$. Most of the yolk and oil globules were absorbed within 3 to 4 days after hatching. The larvae reached 2.48 to 2.72 mm in total length, and their mouths and anuses opened at 3 to 4 days after hatching. In this time, the mouth diameters of the larvae were 0.209 to 0.238 mm. The larvae reached 3.24 to 4.15 mm in total length at 11 to 17 days after hatching, and began to metamorphose at the time the second dorsal and pelvic spines appeared and elongated. The abdominal cavity was densely lined with melanophores. The larvae reached 5.12 mm in total length at 24 days after hatching.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.2
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• pp.90-94
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• 2018

In the present study, we investigated the effects of temperature and photoperiod on oviposition of Protaetia brevitarsis. The effects of long- and short-day cycles on oviposition and egg hatching of P. brevitarsis were investigated at different temperatures. Three male-female pairs were confined to oviposition chambers maintained at $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, and $35^{\circ}C$, with 16L:8D and 8L:16D photoperiod. Oviposition was observed at all temperatures. The total number of eggs laid per female was between 46.8 and 110.8, and the optimal temperature for oviposition and fertility was between $20^{\circ}C$ and $30^{\circ}C$. Furthermore, it was difficult for the eggs to hatch at $35^{\circ}C$. Fewer eggs were laid under short photoperiod than under long photoperiod at all temperatures. Hatching success was 93.5% at $20^{\circ}C$, 90.9% at $25^{\circ}C$, 71.5% at $30^{\circ}C$ and 37.3% at $35^{\circ}C$ under long-day(16L:8D) condition and Temperature had a strong effect on the time to hatching. Neither oviposition nor subsequent egg hatching was influenced by photoperiod and temperature. The information obtained will be useful for mass rearing P. brevitarsis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.2
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• pp.170-179
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• 2021

This study was conducted to identify taxonomic differences in the characteristics of Acheilognathus majusculus and A. yamatsutae during their initial life history via an interspecific hybridization experiment. Hatching time required 36 h for MY and 49 h for YM at 21.5℃, showing a significant difference of 13 h between the hybrids. The hatching rates of the cross-bred eggs were 30% for cross MY (A. majusculus♀×A. yamatsutae♂) and 40% for cross YM (A. yamatsutae♀×A. majusculus♂). The hatching larvae size was total length 3.13-3.43 mm in MY and total length 3.89-4.22 mm in YM, which was larger in YM. The hybridization test between A. yamatsutae and A. majusculus that live in the same water stream confirmed that no interspecific reproductive isolation occurred.

• Journal of fish pathology
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• v.14 no.1
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• pp.11-15
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• 2001

For the production of healthy shrimp(Penaeus chinensis, Penaeus japonicus) seedlings free from the white spot baculovirus(WSBV), we tried to disinfect shrimp eggs with iodine. A relative hatching rate of over 50% has resulted from the treatments of fertilized eggs of fresh shrimps(P. chinensis) with an effective povidon-iodine concentration of 20-200 ppm for 30 seconds and 60 seconds, respectively. The 60 sec treatment group with a 20 ppm effective povidon-iodine concentration showed nearly a 50% relative hatching rate. The over 50 ppm treatment group, however, did not result in hatching show a relative hatching rate. These hatching rates were similar to those in the fertilized eggs of kuruma prawns treated with povidon-iodine solutions. In case of washing fertilized eggs with UV-irradiated seawater 33.3% relative hatching rate in fresh shrimps was much lower than 55.2% in kuruma shrimps. Treatment fertilized eggs of 2 species of shrimp with 200 ppm iodine for 30 sec did not affect the survival rate of the larvae until the early stage of the post larvae even though the hatching rates were low. In order to produce healthy shrimp seedlings non-infected by WSBV, the shrimp eggs should be washed with UV-irradated seawater and sterilized with a low povidon-iodine concentration for a short time.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.155-161
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• 2008

The inhibitory effect of herbal extracts using methanol and hexane collected from Sudan and Korea was evaluated on egg hatching of Meloidogyne incognita. The concentration of herbal extracts were 10,000, 1,000 and 100 ppm, respectively. They were treated to Meloidogyne incognita eggs after 3, 7, and 21 days of hatching. All herbal extracts inhibited egg hatching significantly compared to the control. The degree of inhibition was directly related to the concentration of the extracts. At 10,000 ppm, very fewer individuals were hatched at all the periods of exposure with the exception of the extract of fruits of Quisqalis indica which gave 84.4 and 54.5% at 7 and 21 days, respectively. Egg hatching was completely ceased, especially after 7 days for most of the extracts. While at 1,000 ppm relatively high numbers of eggs were hatched compared to the higher concentration, as well the extracts Q. indica reported many number of hatched eggs compared to others, especially at 21 days. On the other hand, the extract from pods of Cucumis mello var agrestis gave the least hatching number of eggs at all periods of exposure which gave 2, 8, and 3% at 3, 7, and 21 days, respectively in comparison to the control. Whereas at 100 ppm, inhibition increased with exposure time. However, the extract leaf of Desmodium caudatum represented the fewer hatching eggs at 3 and 7 days.

• Development and Reproduction
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• v.18 no.3
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• pp.173-178
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• 2014

In order to monitor the developmental features of embryos, larvae, and juveniles of Oryzias latipes (Temminck and Schlegel), Oryzias latipes was caught in river of Shinduck-dong, Yeosu-si, Jeollanam-do, on May 2011, and experiments were carried out in Ichthyology laboratory at Chonnam National University. The blastodisc step was the first level for natural spawning. The optic vesicle, Kupffer's vesicle, myotome began to appear 75 hours 57 minutes later. After blastodisc development, the pectoral fins were made at 143 hours 37 minutes and the tail was separated started at the same time. Hatching was observed at 167 hours 27 minutes after blastodisc. The total length of the hatched larvae was 4.95~5.10 mm (mean, 5.01 mm), the mouth and anus were opened. Larvae used yolk completely after 3 days after hatching. The total length larvae was 5.45~5.56 mm (mean, 5.52 mm) after 8 days after hatching, and appeared the stems for tail. The stems pectoral, anal fin were showed after 14 days and the stems dorsal, ventral fin were appeared after 19 days. For 35 days after hatching, the total length of larvae 13.95~15.30 mm (mean, 14.64 mm), and at this time, fins and body were transferred like the adult Oryzias latipes.

• Development and Reproduction
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• v.8 no.1
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• pp.11-17
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• 2004

The larvae and juvenile development of haddock Melanogrammus aeglefinus which is significant commercial fish living north Atlantic Ocean are described here. Larvae were reared in laboratory and sampled periodically for developmental study until 67 days after hatching. An increase in total length(TL) of fish indicated continuous growth, described by the growth expression Y=4.07 $e^{0.037}$( $R^{2}$=0.9978). The newly hatched pre-larvae was 4.9 mm in TL with ellipsoid yolk. In 16 days after hatching, larvae attained 6.8 mm in TL, and absorbed the yolk completely to become post-larval stage, but first heterotrophic food could be in 7 days after hatching already. Post-larval stage continued during 16~52 days after hatching with development of organs attachment. In 61 days after hatching with 41.3 mm in TL, the fries became a juvenile stage respectively having small teed lateral line, and a black blotch on the flank same as adults, but chin barbel was not developed yet. It was presumed that haddock changed food and ecological behavior after metamorphosis ken this time.e.

• 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.

• Animal cells and systems
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• v.12 no.4
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• pp.297-304
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• 2008

Morphology and distribution of the minute tubercles projected on the skin surface of larvae with its development were observed in the Korean bitterling, Acheilognathus somjinensis. The minute tubercles appeared to be two distinct morphologies, hemispheric or scaly and vestigial structures. Just after hatching, the epidermis of the larvae consists of a thin single cell layer having smaller basophilic flat or round-flattened basal cells. As the larvae grow, the epidermis contains more small flat cells and large epidermal cells which are round and hemispheric, or scaleshaped, called minute tubercles. They are distributed over the anterior part and most part of yolk sac, posterior region of yolk sac and the body region. Vestigial epidermal cells, another minute tubercle, occur only in the caudal fin-fold region, which they are shrunken and flattened, causing the cell boundary to be unclear. They increase in number and height from just to 5 days after hatching, but they become reduced as the larvae develop gradually. The required time for those disappearance was different each by regional body: at day 20 after hatching in the anteriormost part of yolk sac, and day 11 after hatching in the posterior part of yolk sac and the body, and day 21 after hatching in two regions such most part of the yolk sac and the caudal finfold regions.