• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.177-184
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• 2021

Sex identification in day-old chicks is essential in the poultry industry. Currently, the feather-sexing using a sex-linked inheritance is a chick sexing method used extensively in the poultry industry. For chicks produced by feather-sexing, all females are early-feathering (EF) chicks and all males are late-feathering (LF) chicks. Therefore, investigating the effects of EF and LF phenotypes on production traits of chickens is critical. The purpose of this study was to analyze and compare the production performance between EF and LF chickens in Korean native commercial chickens. The results showed that the survival rate of the EF chickens was significantly higher than that of the LF chickens, from hatching to 12 weeks of age (P<0.05), with the highest difference observed in females. However, no significant difference was observed in body weight between the EF and LF chickens at almost all ages. In addition, no significant difference was observed between in feed utility, such as average daily feed intake and feed conversion ratio, between the EF and LF groups. In conclusion, although the survival rate of early-feathering chickens was superior to that of late-feathering chickens, no significant difference was observed in growth performance and feed utility among Korean native chickens. The results suggest that production capacity is not influenced by feathering type in the establishment of a breeder structure and production system for feather-sexing Korean native chickens, which is valuable for the practical application of feather-sexing in the poultry industry.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.380-387
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• 2023

Stocking density is associated with Paralichthys olivaceus growth; thus, fish should be rapidly reared at high densities for commercial reasons. Studies have reported that high stocking density retards growth; however, few have investigated the malformations caused by stocking density stress. This study compared the growth and malformation rates of P. olivaceus at different densities and stress- and immune-related gene expression between malformed and normal fish. Forty days post-hatching, fish (total length, 1.49±0.02 cm) were reared at 800 (low density; LD), 1500 (medium density; MD), and 4000 (high density; HD) fish/m², and the growth rate was measured weekly. On day 30, RNA was extracted from the kidneys, and the expression of stress-, immune-, and malformation-related genes was analyzed using qRT-PCR. The malformation rate in the HD groups was approximately three times higher (62%) than that in the LD and MD groups (approximately 20%), and growth was lower regarding length and weight. The stress-related (HSP70 and GPX) and immune-related (PIR and IgM) genes showed higher mRNA expression in the HD group and malformed fish than in the LD group and normal fish. However, TLR3 showed the opposite results. In summary, high stocking density suppressed growth and increased malformation risk in P. olivaceus.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.292-304
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• 2024

This study compared and evaluated the antioxidant activities of Symphoricarpos albus(S. albus) extract and fermented extract. Antioxidant activity was measured by DPPH radical scavenging, FRAP, and ABTS. Concentrations were measured at 200, 100, 50, and 10 ㎍/mL, and antioxidant activity increased in a concentration-dependent manner. S. albus leaves fermented extracts had the highest antioxidant activity. And this study evaluated the safety and tail regeneration of S. albus extract using zebrafish model embryos. Zebrafish are in the spotlight as an alternative animal and can be used for cosmetic research. Zebrafish embryos were collected and evaluated for coagulation rate, hatching rate, and cardiotoxicity. As a result, it was toxic at concentrations above 100 ㎍/ml. The tail was cut and the regenerative effect was observed for 3 days. As a result, from 72 hours, S. albus 200ug/ml leaf extract showed a 17% regenerative effect compared to the control group. These results suggest that S. albus can be used as a natural material for antioxidant and regeneration for skin improvement.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.241-248
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• 2014

This study was carried out to evaluate the effects of embryonic stage, cryoprotectant, and freezing-thawing method on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Two to eight cell embryos were obtained from oviducts of mated $F_1$ hybrid female mice superovulated by PMSG and hCG. Two-step EG, DMSO and 4-step EG, DMSO were used as cryoprotectant and dehydration and rehydration method of embryos, and slow-cooling or rapid-cooling method was used as frozen program. The survival rates of embryos were measured after thawing and rehydration, and the developmental rates of embryos were compared and observed during culturing embryos for 24, 48, 72, 96 hrs. As for the survival and development rates of embryos according to embryonic stage, the survival rate of 2 cell stage in EG and DMSO was significantly higher than 4~8 cell (65.4% versus 61.2%, 81.1% versus 72.5%) (p<0.01, p<0.01), but the development rates of 4~8 cell embryos in EG and DMSO were significantly higher than 2 cell embryos for whole culture period (p<0.01) and the development rates of 4~8 cell embryos in EG were significantly higher than 2 cell embryos in DMSO (p<0.01). As for the survival and development rates of embryos according to cryoprotectant, the survival rate of 2 cell embryo in DMSO was significantly higher than that in EG(77.0% versus 64.4%) (p<0.01), whereas the development rate of embryos was not differ till 24 hrs. The development rate from morular to hatching blastocyst, however, was sinificantly higher in EG than in DMSO during 48 hr (p<0.01). The survival rate of 4~8 cell embryo was 62.5% in EG and 73.3% in DMSO. The development rates of embryo in EG were significantly higher for whole culture periods (p<0.01, 0.05). In respect to the effect of freezing and thawing program on the survival and development rates of embryos, method of slow cooling and rapid thawing was more effective than that of rapid cooling and rapid thawing. The survival rate of embryo in 2 cell stage was higher than in 4~8 cell stage, and EG appears more effective cryoprotectant than DMSO because EG showed better development rates of embryos in 2 and 4~8 cell stage. Moreover, slow cooling and rapid thawing method was considered as the best cryopreservation program.

• Journal of Embryo Transfer
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• v.19 no.2
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• pp.133-145
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• 2004

Serum-contain is commoly used for the production of in vitro-derived bovine embryos. However, were biological activity of serum varies from lot to lot, time consuming to choose better serum with good quality and risks of virus, bacteria and mycoplasma infection. This study established serum-free culture systems of in vitro embryo development to efficiently obtain a large number of blastocysts from ovaries of Hanwoo and oocytes maturation, cell number, tlerance of cryopreservation. Secondly, serum-contain medium is suspected of contributing to the large calf size, dystocia, cersarean sections, calf mortality and confirmed these blastocysts are high quality in terms of cyotolerance, high rates of pregancy and normal birth. For these reasons, Culture media (IVMD101 and IVD101) designed specifically for the preimplantation bovine embryo are rather simplistic, being based on salt solutions with additional energy substrates and growth factors. An improved serum-free medium (IVMD101) was developed for bovine oocytes maturation in vitro. Proportions of embryos developing to the blastocyst stage cultured in both IVD101(32.4%) and IVD101(34.5%) serum-free media were higher than in TCM199+10% FBS(12.4%) serumcontaining medium. Futhermore, the cell numbers per blastosyst obtained in the serum-free media were superior to those of blastocysts developed in serum-supplemented medium. Also, cell numbers of blastocysts obtained in the serum-free media were similar with blastocysts derived in vivo. Survival rate blastocysts after 24 hr incubation after thawing, the blastocysts cultured in both IVD101(94.5%) and IVD101(95.8%) serum-free media were higher than in TCM199+10% FBS (52.5%) serum-containing medium. After 72 hr incubation after thawing, hatching rates of blastocysts developed in IVD101(78.4%) and IVMD101(83.7%) were sighnificantly higher than that developed in the serum-supplemented medium(32.0%). The pregnancy rates almost not different between fresh blastocysts(38.2%) and frozen blastocysts(34.9%). The results suggested that the improved serum-free media(IVMD101 and IVD101) offer several advantages over culture in serum-cotaining medium, including increased rates of blastocyst formation and high cel numbers. Additionally, the survival and hatching rates of embryos product in serum-free media after post-thaw culture were superior to those of embryos produced in the serum-containg medium and useful for the production of high quality bovine embryos for cryo-preservation. These improved serum-free media are beneficial not only for the study of the mechanisms of early embryogenesis but also for mass production of good quality embryos for embryo transfer, cloning and transgenesis.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.97-107
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• 2007

The multicolored Asian ladybird beetle (Harmonia axyridis) has been commonly used with biological control agents for control of several kinds of aphids in agroecosystems. Also, environment friendly agricultural materials have been commonly applied in crop fields because the government held down pesticide application and environment friendly agricultures are gradually increased with consumer's desires. The multicolored Asian ladybird beetles may be directly or indirectly under the influence of environment friendly agricultural materials In crop fields. The insecticidal environment friendly agricultural materials (IEFAMs) might be saff against each developmental stage of multicolored Asian ladybird beetle. Fungicidal environment friendly agricultural materials (FEFAMs) had a miner effect to each developmental stage of multicolored Asian ladybird beetle with the exception of FEFAM A. Environment friendly agricultural materials contained useful soil microorganisms (EFAMSMs) C and H might be down the hatching rate of eggs, and EFAMSM A and F had a killing effect to 1st instar of lady beetles. Environment friendly agricultural materials contained plant extracts (EFAMPEs) A and D might be suffered effect a deathblow of egg hatching with lady beetles. Otherwise, there was a miner effect to lady beetles with the rest of tested environment friendly agricultural materials.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.119-126
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• 1996

This study was carried out to determine the optimal condition for successful and efficient c cryopreservation of zygotes, 1-cell embryos, using EFS40 which was 40% (v/v) ethylene glycol diluted in DPBS medium containing 30% Fic-oll (w/v) and 0.3 M sucrose. After mouse zygote produced by IVF was vitrified by two freezing methods, the post-warming survival rates of 1-cell zygotes were assessed as cleavage to the 2-cell stage and development into the hatching blastocysts at 5 day. In the one-step method, when embryos were directly exposed to the vitrification solution at 25$^{\circ}C$ for 1 min., survival and development rates of zygotes were 85.5% and 31.9% In the two-step method, embryos were equilibrated with a dilute 20% EG for 1, 3, 5 min. before 1 min. exposure to EFS40, re-spectively. However, the rates of development (17.7, 3.3, 0%) were lower than that of one-step method. The highest survival rate (95.9%) was obtained by one-step method which exposes embryos in EFS40 for 30 sec. In this condition, 63. 8% of cleaved 2-cell developed into hatching blastocysts. In the cell number of Total and ICM using differential labelling technique, there are no significant differences in the cell number of Total and ICM between blastocysts devel oped in vitrified-thawed embryos (63.2${\pm}$16.9, 1 13.5${\pm}$4.0) and control balstocysts (54.0${\pm}$15.2, 1 12.3${\pm}$4.6). Therefore, these results show that mouse zygotes can be successfully cryopreserved by a simple vitrification method although developmental rates of vitrified embryos were reduced. In conclusion, this proposed vitrifi cation procedures can be useful in the cryopreservation of mouse IVF zygotes.

• Journal of Aquaculture
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• v.8 no.3
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• pp.195-207
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• 1995

In order to study the embryonic development and hatching of wild long shanny, Stichaeus grigorjewi, were caught with the gill nets in the East Sea of Korea, and stocked at indoor tanks to induce natural spawning in February 25, 1994 and February 16 to 24, 1995. They were already matured when stocked, and average body length (50.66 cm) and body weight (1,192.74 g) of 57 females and average body length (48.62 cm) and body weight (612.58g) of 43 males were recorded. Before stocking, they were inserted with identification tags(ID tags) in the dorsal muscle, and spawning was traced by the portable reader (Destron/lDl Ltd.) Forty females among 57 spawned successfully in the average of 4 days after stocking. Females spawned almost all eggs contained in the ovaries at one time in the form of an egg mass and averaging 227,200 eggs Per egg mass. The egg mass was oval in shape, translucent milky in color, 20.32cm long axis and 14.57cm short axis in size, and 803.7g in weight. Male parents guarded their egg masses and circulated water with the tail part of the body. Fertilized egg was spherical in shape, and their average diameter was 1.54 mm. Each egg had a containing single oil globule, and it's average diameter was 0.37 mm. The average water temperature was $13.2^{\circ}C$ and incubation times after fertilization were 5 hours 25 minutes up to 2-cell stage, 13 hours up to morula stage, and 66 hours 35 minutes up to embryo formation stage. Hatching rate was approximately 10 percent in 368 hours 50 minutes after fertilization, and approxionateoly 90 percent of eggs were hatched in 425 hours 30 minutes after fertilization.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.15-24
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• 2006

This experiment was conducted to investigate the effects of dietary safflower seed (SFS) powder and chitosan on hatching egg production and eggshell qualify in aged egg-type breeder hens. A total of four hundred 54-week-old Hy-Line Brown breeder hens were divided into five the groups and fed experimental diets either with addition of 0.25 and 0.50% SFS powder or 0.10 and 0.20% chitosan or devoid of all for 6 weeks. There were no significant differences in feed intake and laying performances among the groups. The rate of sellable egg in the groups fed diets containing SFS powder or chitosan was significantly increased compared to that of control (P<0.05), irrespective of dose-dependent manner. The addition of SFS powder or chitosan significantly improved the eggshell strength (P<0.01). Eggshell thickness was also significantly increased in the groups 134 diets containing chitosan as compared with that of control (P<0.01). Fertility and hatchability of egg set were significantly improved by dietary chitosan that those of control (P<0.05). ike contents of tibial Ca and P were significantly increased in the groups fed diets containing 0.5% SFS powder, 0.1 and 0.2% chitosan as compared with those of control. The levels of blood estrogen, calcitonin and parathyroid hormone were not affected by the dietary treatments. The overall results indicated that the proper use of some feed additives such as safflower seed powder and chitosan might provide means of improving eggshell quality and reproductive performances in aged egg-type breeder hens.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.149-157
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• 2003

This study focused on relationships between Pb and Cd concentrations and the difference of success reproductive progress in urban (Seoul) and industrial complex (Ansan) areas. Results of the Pb analysis for the feral pigeons from Seoul (egg contents:1.64 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 29.5 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan industrial complex (egg contents: 1.13 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 10.5 $\mu\textrm{g}$ wet g-1) showed that the Pb level of eggs and adults is significantly different between the two colonies (p<0.05). Cd concentrations in liver and kidneys of adult pigeons were also significantly different between Seoul(liver: 0.24 ${\mu}g$ wet $g^{-1}$, kidney: 1.05 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan (liver: 0.14 $\mu\textrm{g}$ wet $g^{-1}$, kidney: 0.43 $\mu\textrm{g}$ wet $g^{-1}$ colonies (P<0.05). Clutch size of Feral Pigeons living in Seoul was similar between the two colonies, 1.9$\pm$0.3 in Seoul and 2.0$\pm$0.0 in Ansan. The length, breadth, and thickness of eggs were not significantly different between the two colonies (p>0.05). Incubation period in Seoul (17.8 days) did not differ from the Ansan (17.4 days). No difference in growth rate (body weight, wing length, and tarsus length) was found between the two test groups (p>0.05). In Seoul, 65.2% were hatching, and 42.1% fledging. The Proportion of hatching and fledging in the Ansan was 60.7% and 45.0%, respectively. The significant differences between the two colonies for reproductive sucess were not found (p>0.05). With regard to the reproductive effects to the heavy metals, the Pb and Cd concentrations feund in the two colonies were not as high as those considered in results of toxic effects in other species.