• Korean Journal of Veterinary Research
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• v.15 no.2
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• pp.177-180
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• 1975

This study was undertaken to obtain more detailed knowledge of the oxygen consumption rate of chick embryos, of the relationship between the increasing rate of embryo weight and that of oxygen consumption, of the daily increase of oxygen consumption by that of embryo weight, and of the metabolic rate of the White Leghorn eggs. The results obtained are summarized as follows. 1. The average oxygen consumption rate of the chicken embryo at the 3rd day of incubation is 0.8ml/h, STPD. It is strongly suggested that this value can used as a physiological criterion to classify the fertilized and unfertilized eggs, on the other hand oxygen consumption rate of the fertilized eggs reaches a plateau between the 18th and 20th days. 2. There exists a parallel relationship between the increasing rate of embryo weight and that of oxygen consumption rate during the incubation period. 3. There are not exist a parallel relationship between the daily increase of embryo weight and that of oxygen consumption during the whole incubation period. 4. The metabolic rate of chicken embryo(ml/h/g) is highest in the early stage of incubation and it started to decrease sharply until the 8th day follow by slow decrease thereafter.

• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.2
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• pp.63-72
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• 2006

Parthenogenesis, the development of unfertilized ovum opens new perspectives in silkworm breeding in the development of homozygous breeds. In order to improve induction of artificial parthenogenesis in the excised unfertilized eggs of different breeds of the silkworm, Bombyx mori L., a new method was devised and the results were compared with the routine method. General and specific combining abilities and hybrid vigour of newly developed bivoltine breeds were analyzed utilizing bivoltine breeds viz., $CSR_2,\;CSR_4,\;CSR_{17}\;and\;NB_4D_2$ Estimation of GCA revealed superiority of the breeds, $DNB_1$ for eight characters followed by $DNB_4$ for five characters. Among the testers, $CSR_2$ was found good general combiner for seven characters followed by $CSR_{17}$ for four characters. A great deal of variations was observed among the hybrids studied. Five hybrids namely, $DNB_1{\times}CSR_2,\;DNB_4{\times}CSR_4,\;DNB_4{\times}NB_4D_2,\;DNB_6{\times}CSR_2\;and\;DNB_7{\times}CSR_2$ showed significant SCA effects for 5-6 characters. The hybrid, $DNB_4{\times}CSR_4$ showed its superiority by expressing significant hybrid vigour over BPV for 7 characters. Majority of the hybrids exhibited significant hybrid vigour for survival rate, yield/10,000 larvae by weight, cocoon weight, cocoon shell weight, filament length and denier.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.262-270
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• 1983

The newly hatched nymphs of brown planthopper(BPH) were reared individually for two generations in test tubes, where young rice seedling was planted on agar solution, at $30^{\circ}C,\;25^{\circ}C\;and\;20^{\circ}C\;with\;95\%,\;75\%,\;65\%\;and\;35\%$ R.H. Effects of $30^{\circ}C$ on the development of BPH when compared with those of $25^{\circ}C$ are followings. Egg period, nymphal period, and adult longevity were shortened. Nymphal mortality was increased and the number of oviposited eggs was decreased. Hatchability was zero per cent because the eggs were either unfertilized or died before finishing the development. At the low temperature of $20^{\circ}C$, in comparision with $25^{\circ}C$, the developmental period of nymphs and eggs was considerably lengthened, and adult longevity was shortened, the number of oviposited eggs was decreased. The nymphal mortality was higher at high relative humidity $(above\;75\%\;RH)$ than that at low relative humidity $(under\;65\%\;RH)$. Under the condition of high relative humidities, the adult longevity was shortened, and the number of oviposited eggs was decreased.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.91-94
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• 2003

Artificial insemination of cryopreserved semen is not practiced in broiler breeder industry although its benefit has been recognized for years. Thus, the present study explored the possibility of artificial insemination with cryopreserved semen in Ross broiler breeders. Sixty Ross female broiler breeders were artificially inseminated either with fresh or with cryopreserved semen pooled from five male Ross broiler breeders. On.e hundred eighty eggs were collected from each semen treatment and hatched. Fertility and hatchability of fertilized eggs collected from hens artificially inseminated with cryopreserved semen were 68.0 and 47.1％, respectively, compared to 88.3 and 87.2％ with fresh semen. Both unfertilized eggs and dead embryos during hatch were significantly (P<0.05) higher in the cryopreserved semen­treated group by approximately 2.7­ and 3.2­fold than the fresh semen­treated counterparts. the moderately low fertility and markedly low hatchability of fertilized eggs obtained from cryopreserved semen observed in this study may be of practical interests in broiler breeder industry and deserves further study.

• The Korean Journal of Malacology
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• v.15 no.2
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• pp.115-119
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• 1999

We investigated the processes of egg and larval developments for aquaculture technique development of seedling production fo the flat oyster, Ostrea denselamellosa. Teo flat oyster of larviparous type was different from the pacific oyser (ovivarous type) because their larvae (trochophore and prodissoconch larvae) in the gill released into the seawater. The process of egg development was observed by artificial fertilization at $25^{\circ}C$, using a dissecting method. The sizes of Unfertilized eggs ranged from 80 to 90 $\mu\textrm{m}$ and fertilized eggs with globule-shape was 90-100 $\mu\textrm{m}$. The Polar body appeared after fertilization and egg cleavage began within 1 hour, reaching the blastula stage after 10 hours. The trochophore in the gill appeared 2-3 days after fertilization and grew to the prodissoconch larvae (130 140 $\mu\textrm{m}$) having a complete shell after 1-2 days. The shell of prodissoconch larvae grew to 205 220 $\mu\textrm{m}$ after 10 hours, and then they became umbo stage larvae showing oval in shape. The velum of umbo stage larvae was degenerated about 17-20 days after fertilization and grew into a pediveliger with a developed foot, at this time, the shell length size was 320 360 $\mu\textrm{m}$.

• Journal of Embryo Transfer
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• v.4 no.1
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• pp.41-45
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• 1989

Total thirty of flushing were attempted on day 4 to 15 of estrus cycle with S heifers and 9 cows by nonsurgical method. The flushed or recovered rate among flushings was 86.7% (26/30) or 88.5% (23/26), respectively. There was no difference in the recovered rate between heifers (85.7%,6/7) and cows (89.5%, 17119). The embryo was recovered on day 4 to 15 of estrus cycle from the donors in natural heat without any technical difficulties.The I2FG Foley catheter used for pubertal heifers had sometimes plug in it with uterine mucus during flushing of uterine horn. But the problem could be overcomed by pumping the catherter with fluthing solution or by changing the catheter. Three normal embryos were recovered from 3 pubertal (10-11 month old) heifers. The rate of normal and abnormal eggs was 60.9% (14123) and 39.1% (9/23), respectively. The abnormal eggs were on degenerating except one unfertilized egg and were mostly recovered from heifers or cows flushed consecutively during the estrus cycle. The developmental states of normal embryos were l6-cells on day 5, 32-cells on day 6, compacted-morula on day 7, early-to expanded-blastocyst on day 8-to 9, and hatching-to hatched-blastocyst on day 10 to 11 of estrus cycle. The stage of embryos on day 8 to 10 showed varities among donors. On day 8 to 9 of estrus cycle hatching-blas tocyst was recovered from some donors.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.283-283
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• 2004

The eggs of most animal species are surrounded by an extracellular matrix known as chorion, egg envelope, egg coat, or zona pellucida. Development of fish embryo usually takes several days in an aquatic environment. During embryonic development, the chorion must protect embryo from physical damage and microbial infection in the exposed aquatic environment. (omitted)

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.281-286
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• 2005

The ripe unfertilized eggs of Acheilognathus signifer were elliptical shape and baggily swollen toward animal pole. The size of fertilized eggs were $2.19{\pm}0.01$ mm in long axis and $1.85{\pm}0.08$ mm in short axis and oil globe were not observed. The zona radiata of A. signifer had the structure of regular fibrilar net and the diameter of outer opening micropyle was about $2.5{\mu}m$ and that of inner opening micropyle was about $1.5\sim2.0{\mu}m$. Development of fertilized eggs in A. signifer was proceeded in inclining position of animal pole and hatched in 49 hours under $20{\pm}1^{\circ}C$. The yolk sac was absolutely absorbed in 21 days after hatching.

• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.280-289
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• 1998

Voltage-sensitive ion channels contribute to establishment of the cell excitablity and the generation of the cellular function. At hamster oocytes in the primitive stage during developing process, an inward current elicited by voltage pulses was found to be carried mainly by $Ca^{2+}$. Even at present, $Ca^{2+}$ channels serve as the most probable route to pass this inward current but there is no evidence of the presence of this channels in eggs. To date, both the characteristic properties and the physiological role in the early stage of development remain unclear. Here we examined the characteristic properties of the inward current and changes in this currents at unfertilized oocytes, fertilized zygotes and two-cell embryos using whole-cell voltage clamp technique. The inward current carried reportedly by $Ca^{2+}$ was remained following removing external $Ca^{2+}$ but completely abolished by further replacement of impermeants such as tetramethylammonium ion ($TMA^+$) or $choline^+$ instead of $[Na^+]_0$. Tetrodotoxin did not affect on this inward current remained at $[Ca^{2+}]_0$-free condition. Removal of $Na^+$ ion out of the experimental solution clearly decreased the current. After adding 2mM $Ca^{2+}$ to the $Na^+$-free media, the inward current was restored. Interestingly, this current carried by either $Ca^{2+}$ or $Na^+$ was decreased by the reduction of intracellular $Cl^-$ concentration, or by $Cl^-$ channel blockers such as niflumic acid, DIDS and SITS. When $Cl^-$ concentration was lowered without changes in other ionic components, this inward current was reduced. At fertilized oocytes and two-cell embryos, the inward current carried by $Ca^{2+}$ and $Na^+$ was severely reduced. Also $Cl^-$ component could not be observed. From these results, the inward current is composed of $Ca^{2+}$, $Na^+$ and $Cl^-$ component, suggesting that the channel carrying this inward current is not selective specifically to $Ca^{2+}$. During early stage of development, the voltage-sensitive ion current seems not to contribute essentially to the cell cleavage and differentiation. The loss of $Cl^-$ component after fertilization suggests that $Cl^-$ may play a role in maintaining the viability of unfertilized ova.

• Development and Reproduction
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• v.6 no.2
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• pp.71-76
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• 2002

Present study was aimed to summary the recent reports of chromosomal technology such like a polyploidv, sex differentiation, gynogenesis, transgenic fish and gene manipulation. Triploid cells for rainbow trout and channel catfish were induced through thermal shocks of varying temperature levels and produced as a industrial use. A monosex fish with homogametic females of 15 species of high valued fish were produced by exposing to irradiation. It seemed that different irradiation was suitable to inactivate the sperm and block the formation in producing the gynogenetic diploids. Since 1985, transgenic fish have been successfully produced by microinjecting or electroporating desired foreign DNA into unfertilized or newly fertilized eggs using about 40 fish species. More recently, transgenic fish have also been produced by infecting newly fertilized eggs with pantropic, defective retroviral vectors carrying desired foreign DNA. These transgenic fish can serve as excellent experimental models for basic scientific investigations as well as in marine biotechnological applications.