• Journal of Sericultural and Entomological Science
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• v.20 no.2
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• pp.6-9
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• 1978

This experiment was attempted to investigate the effect of the specific gravity of silkworm eggs on the hatching and the practical hatching ratio depend upon six egg production companies for two silkworm races and their reciprocal crosses. 1. The hatching and the practical hatching ratio in the specific gravity of medium and heavy eggs were higher than in the specific gravity of light eggs. 2. Compare with Japanese or Chinese mother races each other, it was inclined that the former seems to be higher than the latter on the hatching ratio in the specific gravity of light and medium eggs, but the practical hatching ratio was high only in the specific gravity of light eggs. 3. Chinese mother races were different in the practical and the hatching ratio between the specific gravity of eggs. On the contrary in case of Japanese mother races were no difference for the hatching ratio but difference in the practical hatching ratio between the specific gravity of eggs. 4. On the egg production company, in case of the specific gravity of medium and light eggs, the hatching and the practical hatching ratio were high significance, but no difference in the specific gravity of heavy eggs.

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.59-62
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• 1969

It is very important physiological and economical problems to hatching within a day by increasing hatching-ratio of silkworm eggs in sericulture, and modified dark incubating method was experimented in Japan. The author studied on the economical problems of that rather than physiological study. Hatching was induced and accelerated by illumination before hatching 5 days which incubated in the dark room after eye spot pigmented eggs emerged 10-20 percentage. It was increased by 80-90％ in hatching-ratio, but the hatching was delayed a day. In autumn silkworm, newly hatched silkworms were hatched silkworms were hatched in the dark room because of high temperature period tough modified dark incubation was passed only 4 days. The author wonder which is more effective between effect of increasing the hatching-ratio and the health of silkworms.

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.57-58
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• 1969

Artificial silkworm eggs must do washing the acid completely after soaking HCl. Author experimented following deacidification times: 30 minutes, 1 hour, 2 hours, 6 hours soaking and 12 hours soaking eggs in the fresh water after artificial hatching, and incubated room temperature. There was no difference 1 hour's with control but more than 1 hour deacidification influenced badly in hatching ratio. Especially above than 6 hours deacidification was not only delaying 1 day in hatching date but also decreasing in practical hatching ratio.

• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.443-451
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• 1997

These studies were conducted to determine the sex of preimplantation Hanwoo embryos produced in vitro using polymerase chain reaction(PCR). Y chromosome specific and bovine speicific DNA primers were synthesized and tested for embryo sexing. Bovine IVF embryos were produced in TCM 199 and CR1aa medium, and classified by developmental stages on Day 7 to 9. The effects of developmental rates to bovine IVF blastocysts on sex ratio were also investigated using PCR methods. The results obtained in this study were as follows; 1. Developmental rates to blastocyst from IVM/IVF embryos in TCM 199 and CR1aa medium for 9 days were 23.5 and 30.2%, respectively, and there was significant difference between the media(P<0.05). 2. Male to female ratio of early, mid, expanded and hatching balstocyst produced on Day 7 were 0.7:1, 1.4:1, 2.2:1, and 2.5:1, respectively, and male embryos was significantly higher proportion in expanding and hatching blastocysts(P<0.01). 3. On Day 8, male to female ratio of early, mid, expanded and hatching blastocysts were 0.6:1, 1:1, 2.5:1, and 2.7:1, respectively. Both expanded and hatching blastocysts obtained a significantly higher proportion of males(P<0.01). 4. The male : female ratio of early, mid, expanded and hatching blastocyst produced on Day 9 was 0.6:1, 0.8:1, 1:1, and 2.2:1, respectively. Hatching blastocysts had a significantly higher ratio of males(P<0.01). The developmental rate of IVM/IVF embryos to blastocyst for 9 day culture was higher in CR1aa than that in TCM 199 medium. For the sex ratio by developmental stages of IVF embryos, male ratio was higher in expanded blastocyst but female in early blastocysts.

• Journal of Sericultural and Entomological Science
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• no.11
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• pp.55-57
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• 1970

There are many reports concerning to the restoring times, and the range of times are very wide. Author restored the artificial hatching silkworm eggs 1 ice pit (5$^{\circ}C$) two different method; one restored in directly after protected following different times 24 hours, 48 hours and 72 hours of room temperature (24$^{\circ}C$), another protected above suggested times and room temperature then indirectly keeping medium temperature (1$0^{\circ}C$)6 hours. It was incubated in $25^{\circ}C$ temperature after about 20 days of restoring. Pure line and hybrid silk warm eggs are no difference hatching ratio in 72 hours blocks by restoring. Especially good hatching ratio obtained by the medium temperature treatment rather than directly restoring.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.948-953
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• 2021

To find the optimal eggs to larvae transforming temperature of walleye pollock Theragra chalcogramma, we investigated their hatching pattern, mortality, and larval deformities. Results showed that the hatching quality decreased as the water temperature increased and dropped sharply above 13℃. The highest hatching rate was achieved at 7℃, whereas the lowest was at 15℃. Dead eggs were not observed at 7℃; however, dead egg ratios were significantly high at 4.5℃ and above 13℃ (P<0.05). Mortality of larvae after hatching was not observed at 4.5℃, but was significantly high above 13℃. The DNA content of the larvae did not show any significant difference at all water temperatures; however, RNA content was the highest at 7℃ and was significantly low above 11℃. In addition, RNA/DNA ratio was the highest at 7℃. Larval deformities after hatching were low at 7-11℃ and higher at higher or lower water temperature. Therefore, the hatching index and larval health index of Walleye pollock eggs in this study show that 7℃ to 11℃ seems to be the optimal transforming water temperature range.

• Clinical and Experimental Reproductive Medicine
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• v.41 no.2
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• pp.68-74
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• 2014

Objective: In search of an ideal method of assisted hatching (AH), we compared the effects of conventional micropipette-AH and laser-AH on the blastocyst formation rate (BFR) and blastocyst cell numbers. Methods: Four-to five-week-old ICR female mice were paired with male mice after superovulation using Pregnant mare's serum gonadotropin (PMSG) and hCG. The two-cell embryos were flushed from the oviducts of female mice. The retrieved two-cell embryos underwent one of five AH procedures: single mechanical assisted hatching (sMAH); cross mechanical assisted hatching (cMAH); single laser assisted hatching (sLAH); quarter laser assisted hatching (qLAH); and quarter laser zona thinning assisted hatching (qLZT-AH). After 72 hours incubation, double immunofluorescence staining was performed. Results: Following a 72 hours incubation, a higher hatching BFR was observed in the control, sMAH, cMAH, and sLAH groups, compared to those in the qLAH and qLZT-AH groups (p<0.05). The hatched BFR was significantly higher in the qLAH and qLZT-AH groups than in the others (p<0.05 for each group). The inner cell mass (ICM) was higher in the control and sMAH group (p<0.05). The trophectoderm cell number was higher in the cMAH and qLAH groups (p<0.05). Conclusion: Our results showed that the hatched BFR was higher in groups exposed the the qLAH and qLZT-AH methods compared to groups exposed to other AH methods. In the qLAH group, although the total cell number was significantly higher than in controls, the ICM ratio was significantly lower in than controls.

• Journal of Sericultural and Entomological Science
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• v.14 no.2
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• pp.113-123
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• 1972

The authors studied on the effect of silkworm eggs collected from the whole silkworm egg producers in Korea to know the cocoon crops, and the results are as follows. There was no remarkable correlation on the effect of silkworm eggs quality for the cocoon crops but can be concluded as follows. 1) There was a weak correlation between the hatching ratio and economical hatching ratio but no correlation between economical hatching ratio and cocoon crops. In other word, hatching ratio couldn't be influenced for the silkworm health. 5) Non-hybrid ratio (miss-crossing ratio) influenced to the amount of reelable cocoons and pupation ratio but on this experiment, there was a little influence for the cocoon crops. The authors found that there is no difference between origin and its F$_1$crops under the more suitable conditions. Non-hybrid ratio can be determined the silkworm eggs quality, but notice that the ratio decrease only when used pure origin. 3) There is some correlation between harvesting amounts of reelable cocoon and pupation ratio. In general, the eggs which harvest small amounts of reelable cocoon are lower on the pupation ratio. 4) The influence of cocoon layer ratio is based on the variety absolutely but cocoon crops also has a little influence on the cocoon layer ratio.

• Development and Reproduction
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• v.17 no.3
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• pp.247-255
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• 2013

The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 cm in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at $8^{\circ}C$, $13^{\circ}C$, $18^{\circ}C$, water temperature (12.8 to $24.2^{\circ}C$), and the best hatching temperature was $18^{\circ}C$. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate.

• 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