• Journal of Aquaculture
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• v.19 no.4
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• pp.281-287
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• 2006

Intraspecific diploid androgenesis was achieved in mud loach (Misgurnus mizolepis) by the inhibition of the first mitotic division using combined thermal treatment. A combined thermal treatment (heat shock at $40.5\;^{\circ}C$ for 120 sec followed by cold treatment at $1\;^{\circ}C$ for 45 min) applied to the 1st metaphase of cell division (28 min post insemination at $25\;^{\circ}C$) successfully recovered viable androgenetic diploidy. Mean hatching success of the androgenetic diploid group was 29.6%, and the average yield out of total eggs taken was about 7% assessed at 1 week of age. However, relatively large variations in the yield of diploid androgenesis were observed among different egg batches used as cytoplasmic donors. Successful diploidization was confirmed by flow cytometric analysis, and parthenogenic reproduction in a paternal exclusive manner was verified with transgene dosage. Significant mortality was found in most androgenetic groups especially from hatch to 1 month of age, although such mortality was stabilized later.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.273-278
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• 1996

An epidemiologic survey along the several sites of southern coastal areas of Korean peninsula was performed to know the infection status of Pcnlotremc app. metacercariae in Tapes phiLlppirlawm. The clams were purchased from 13 coastal areas in Kyongsangnam- do alld Chollanam-do. in September, 1990. Each of them was digested with pepsin-HCI solution and examined under a stereomicroscope for the recovery of metacercariae. A total of 232 (77.3%) out of 300 examined clams were proved to have 1 to 273 Pawatrema app. metacercariae (54.7 in average). None of the clams from Samoan-myon Kosong-gun and Dolsan-up. Yochon-gun was infected with metacercariae. However, all of the clams from Yonghyon-myon, Sachon-guu, Dohwa-myon, Kohung-gun, Ahllyang-myon. Changhung- gun and Chiryang-myon. Kangiin-gun were infected with average 71, 31, 80 and 42 metacercariae respectively. Of the clams from Kohyon-myon, Namhae-gun, Doam-myon, Kangiin-gun and Kusan-myon. Uichang-guil examined, 97.5%. 95.0% and 90.0% were infected with about 117. 76 and 28 metacercariae. In other 4 surveyed areas. Seolchon rlyoll, Namhae-gun, Hwayang-myon. Yochon-gun Byollyang-myon, Sungju-gun and Bukpyong-myon, Haenam-gun. 55.0%-80.0% of clams were positive. and their average intensity of infection ranged from 6 to 25 metacercariae. From these results, it was confirmed that Tcpes philippincrum from southern coastal areas of Korea are highly infected by Parvatrema spp. metacercariae.

• Development and Reproduction
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• v.9 no.1
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• pp.7-13
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• 2005

The effects of various physicochemical stimuli in parturition induction were assayed on ovoviviparous freshwater melania snails, Semisulcospira libertina libertina and S. gottschei. Both of them did not respond to $NH_4OH$ and $H_2O_2$, but showed responses to the water temperature raising, serotonin and acetylcholine. S. gottschei showed stronger responses to the stimulants in parturition induction compared with S. libertina libertina. In case of S. libertina libertina exposed to $10^{-9}M$ acetylcholine, the number of newly born larvae and juveniles per adult and juvenile parturition rate were 68 individuals and 57.5%, which were the most among experimental groups, respectively. In the parturition induction with temperature raising of $9^{\circ}C$, S. gottschei bred 113 larvae and juveniles in which juvenile parturition rate was 56.3% and $10^{-12}M$ acetylcholine also induced very high juvenile parturition rate(61.7%) and 83 larvae and juveniles. It could be concluded that the treatment of acetylcholine has a high effectiveness in the parturition induction of S. libertina libertina and S. gottschei.

• Development and Reproduction
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• v.15 no.2
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• pp.133-141
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• 2011

The marine ornamental industry has become a multi-billion dollar industry these days. As developing, however, this industry has been criticized for the indiscriminate captures and the destruction of the surrounding environment. To circumvent these problems, it is suggested to breed the organisms artificially. While clownfishes Amphiprion sp. and Premnas sp. are the most famous ornamental organisms in the trade, few studies are yet available on the culture and commercial production of these fishes. These studies were performed to investigate the spawning periodicity, behavior and the habits during egg incubation, and to provide the information on the mass hatching system. The spawning periodicity and frequency were different in 4 pairs under the constant condition, temperature, salinity and photoperiod. On the contrary, the male's behaviors for egg incubation are almost same in the all. The egg-fanning activity of the male increased as the developing eggs reaching to the hatching day. Based on the above results, we designed a new artificial hatching system, the rotating type (RT), and compared it with the aeration type (AT) and spray type (ST) that were previously described. RT showed higher hatching rate of 87.3% than AT (74.4%) and ST (60.5%). Also, there were no significant differences in the hatching rate regardless of the number (2, 3, 5) of hatching plates. We suggest RT may accommodate various number of hatching plates and constitute a better hatching system for clownfishes.

• Development and Reproduction
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• v.14 no.2
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• pp.51-58
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• 2010

This research investigated that the effect of water temperature on egg developmental stages of largescale blackfish Girella punctata and smallscale blackfish Girella melanichthys. The required times from fertilized embryos to hatching for the G. punctata were 67.8~37.5 hrs from 15 to $21^{\circ}C$, shorter as the water temperature increased. But fertilized embryos were dead after Kuffer's vesicle appearance stage at $24^{\circ}C$ and morula stage at $27^{\circ}C$. Biological minimum temperature (starting point for embryonic development) of the egg development was estimated to be $7.6^{\circ}C$ in average. In G. melanichthys, fertilized embryos were hatched within 61.2~38.3 hr from 15 to $21^{\circ}C$, the times were shorter as the water temperature increased to hatching, but its were dead on above $24^{\circ}C$. Biological minimum temperature of the egg development was estimated to be $6.5^{\circ}C$ in average. Based upon these results, it is recommended that the range of optimum water temperature for embryonic development of G. punctata and G. melanichthys is $15{\sim}21^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.1
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• pp.16-23
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• 1987

The cyprinid loach, Misgurnus mizolepis $G\ddot{u}nther$, a freshwater teleost, is a member of the family Cobitidae and is known to distribute in Korea and China. This fish is considered to be an excellent food fish in Korea. This report is a description of the gross morphology of the embryos and larvae up to the development of juvenile period of life. The eggs were obtained by injecting gonadotropin and fertilized by wet method in the laboratory on July 10 in 1986. The inseminated eggs were rinsed with tap water and incubated at $25^{\circ}C$. Live, freshly laid eggs were separative, demersal, adhesive, light yellow and average 1.1mm in diameter. The hatching took place in about yellow and average 1.1mm in diameter. The hatching took place in about 24 hours after fertilization. The newly hatched larvae were average 2.7 mm in total length possessing yolk sac and 35-36 myotomes. Ten hours after hatching, the prelarvae attained 3.5 mm in total length. The first heart pulse and melanophores at the side of the body were observed at this stage. Yolk sac was completely reserved at four days after hatching. The larvae that was cultured 24 days after hatching, 15.4-16.4 mm in total length, entered the juvenile period of life. All the un rays were already peresent; D. III 6, A. III, 5, P.10, V. 4-5, C.14.

• Journal of Aquaculture
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• v.9 no.2
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• pp.125-132
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• 1996

A study was carried out to test sex ratio of the progeny that were induced by the artificial fertilization between normal female and gynogenetic diploid eggs and sex-reversed gynogenetic diploid male sperm. Sex reversed gynogenetic diploid males were produced successfully in gynogenetic diploid female by immersion treatment with $17{\alpha}$-methyltestosterone at the concentration of 10 pub from $13.5{\pm}0.22$ mm to $57.6{\pm}5.1$ mm in total length. In $F_1$ progeny test, matings between normal females and sex-reversed gynogenetic males were not produced all female, but matings between gynogenetic diploid females and sex-reversed gynogenetic males were produced all female populations in six out of eight groups and two lots produced $96.9\%$ and $95\%$ female. These data showed that all-female populations were produced by crossing between gynogenetic diploid female and sex reversed gynogenetic diploid male.

• Development and Reproduction
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• v.10 no.2
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• pp.135-140
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• 2006

The small octopus(Octopus minor), a species in the cephalopod class spawns the fewer eggs compared with its relatives such as Octopus vulgaris and Octopus ocellatus and exerts special efforts in nursing eggs hiding in the deep cave beneath the mud flat. Correspondingly, its embryogenic process had been hardly observed. In this study, we induced the small octopus to spawn its eggs in the artificial spawning tube and to nurse the developing embryos under the periodical observation. The early embryogenic change in the fertilized eggs was appearance of blastodisc on the animal pole at 4 days after spawning. A mass of rudiments of several organs developed in the middle of the yolk sac at 28-th day and it moved gradually toward the animal pole. At 38 days after spawning, two eyes appeared on the head and the trunk with heart developed on the apical part of the yolk sac. At 45-th day of embryonic development, the trunk and head occupied a half of the egg capsule and consequently the yolk sac was reduced to a half of its original size. Two eyes became prominent at the bottom of the trunk with several spots at day 60. Embryonic development was completed at about 80 days after spawning and the arms stuffed the lower half of egg capsule. The young fry squeezed out of the egg capsules with their long and slender arms first and mantles later. Soon after hatching, it swam actively and squirted ink.

• Korean Journal of Veterinary Research
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• v.36 no.3
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• pp.719-729
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• 1996

To investigate changes of estrus signs and genital organs in the bitch by hormonal induction of estrus, fourteen bitches of nulliparous and multiparous(2nd-5th) were grouped into diestrus and anestrus according to their estrus cycle. The hormonal treatments were divided into four groups: group A($PGF_2{\alpha}+PMSG+hCG$) and group B(PMSG+hCG) in diestrus bitches and group C(GnRH+FSH+hCG) and group D(PMSG+hCG) in anestrus bitches. The external signs of proestrus and estrus as well as the vaginal smear findings and natural breeding as estrus detection were investigated in all the experimental groups. Also, genital organs were examined at two months after the hormone treatment. The bitches in anestrus showed 100% of male attraction, vaginal bleeding and vulvar swelling as proestrus signs after the hormonal treatment for estrus induction and they showed higher numerical value of signs than the bitches in diestrus. The group A showed the lowest value in proestrous signs of all the groups. The bitches in anestrus treated with GnRH+FSH showed 100% of positive estrus by vaginal smear findings and 75% of natural breeding as estrus detection index and these values were the highest of all the groups. Pregnancy was recognized in only group C and the conception rate was 7.14% in al the experimental animals. Of the side effects after the hormone treatment, external findings of continous male attraction, continous external swelling and purulent exudate were recognized in all the experimental groups and the bitches in diestrus showed higher value of the findings than the bitches in anestrus. Of the changes of genital organs after the hormone treatment, hypertrophy of uterine horn, sanguineous exudate and purulent exudate as uterine findings were recognized in all the groups and these findings were shown more in the bitches in diestrus than in those in anestrus. These results indicated that group C showed the highest value of all the experimental groups in external signs of estrus and estrus detection and also pregnancy was recognized only in that group, consequently, that the hormonal treatment of group C would be the most effective for estrus induction, and also indicated that bitches in anestrus were more suitable than bitches in diestrus for the induction of estrus. In addition, side effects in external genital organs and uteri after hormone treatment were shown more in the bitches in diestrus than in those in anestrus, indicating that bitches in anestrus would be of choice for estrus induction.

• Journal of Embryo Transfer
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• v.18 no.2
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• pp.151-156
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• 2003

The objective of this study was to investigate response of corpus luteum, recovery rate of embryos and production of transferable embryos according to superovulation by PEG 30% FSH in Hanwoo. Cows were selected as recipient, subsequent were superovulated with a total of 400 mg NIH-FSH-P1(Folltropin-V, Canada) given by one shot subcutaneously. At the time of five days after Folltropin injection, 25mg of a PGF$_2$a was injected and cows were inseminated 12 and 24h after the onset of estrus. Seven days after insemination, embryos were collected non-surgically and were cryopreserved by direct transfer methods. The results are summarized as follows : 1. Response of corpus luteum following the superovulation in Hanwoo, right ovary were 52.8%(271/513) and left ovary were 47.1%(242/513), respectively (P<0.05). 2. Recovery rate of embryos following the number of corpus luteum were 83.0%(426/513). 3. Mean number of embryos recovered and transferable embryos were 7.74 and 6.43, respectively (P<0.05). 4. In the total number of transferable embryos per flush were collected 6.4 and all saved transferable embryos were 355.