• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.232-238
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• 1998

The distributions and relative frequencies of bovine chromogranin(BCG)-, serotonin-, and bovine pancreatic polypeptide(BPP)-immunoreactive cells in the pancreas of the duck(Anas plaryrhynchos plaryrhyncos, Linne) were studied immunohistochemically on 23 days of incubation, at hatching, 1 week, 2 weeks, 3 weeks, 5 weeks, 6 weeks, 7 weeks, 9 weeks, 10 weeks, and 32 weeks after hatching. In the exocrine portions, the relative frequencies of BCG- and serotonin-immunoreactive cells tend to decrease according to ages. BPP-immunoreactive cells first appeared 1 week after hatching, and thereafter decreased. These cells were mainly observed in the exocrine pancreas and marginal region of the pancreatic islets. In the endocrine portions, BCG-, serotonin- and BPP-immunoreacteve cells disappeared 2 weeks, 9 weeks and 5 weeks after hatching, respectively.

• Development and Reproduction
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• v.21 no.1
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• pp.79-91
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• 2017

The aim of this study was to compare the efficacy of cryopreservation methods for ex situ conservation of spermatozoa from far eastern catfish, Silurus asotus. The spermatozoa activity index (SAI) and hatching rates were higher in spermatozoa stored in Alserver's solution than those of spermatozoa stored in glucose solution. The SAI and hatching rates in all experimental groups gradually decreased with increasing duration of storage. Additionally, the SAI and hatching rates gradually decreased with increasing thawing temperatures at all storage durations (P<0.05). Based on the SAI and hatching rates, our results suggest that the optimal cryopreservation conditions of catfish spermatozoa involve storage in Alserver's solution with 15% ethylene glycol, and thawing at $25^{\circ}C$. Cryopreservation of spermatozoa is a useful and reliable technique for conserving gene resources and for artificial propagation of far eastern catfish.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.461-466
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• 1998

The histological profiles and endocrine cells in the bursa of Fabricius of the duck (Anas platyrhynchos platyrhyncos, Linne) were studied at 23 days of incubation, at hatching, 1 week, 2 weeks, 3 weeks, 5 weeks, 6 weeks, 7 weeks, 9 weeks, 10 weeks and 32 weeks after hatching. Histologically epithelium of bursa Fabricius were pseudostratified columnar and simple columnar epithelium. Numerous lymphatic follicles and well developed plica were observed in this study. The sections were reacted immunohistochemically using antisera specific to bovine chromogranin(BCG), serotonin and somatostatin antisera using immunohistochemical methods. A few number of BCG-immunoreactive cells were detected from 23 days of incubation to 5 weeks after hatching and serotonin-immunoreactive cells were also observed from 23 days of incubation to 3 weeks after hatching. No somatostatin-immunoreactive cells were detected in this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.332-337
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• 2018

The Pacific cod Gadus macrocepahlus, lays demersal eggs and the hatching larvae rise toward the surface layer of the ocean to feed. The change in the specific gravity of eggs and larvae was investigated to examine their vertical distribution and movement in the water column. The specific gravities of fertilized eggs and various size classes of larvae were measured using a density gradient apparatus. In total, the instantaneous specific gravity of 146 eggs and 225 larvae were measured. To prevent any disturbance in the gradient water column due to larval movement, 0.004% MS222 was used for anesthesia. Due to their high specific gravity, eggs spawned were deposited over the sea-bed of the spawning ground. The specific gravity of hatching larvae decreased abruptly. However, Pacific cod larvae still had a comparatively high specific gravity at hatching ($1.03655{\pm}0.00146g/cm3$, n=4, mean SL=3.62 mm) and their specific gravities tended to decrease as they grew. The specific gravity stabilized 6 days after hatching ($1.02590{\pm}0.00212g/cm3$, n=15, mean SL=4.67 mm) and the cod larvae were eventually able to float in the water column.

• Environmental Analysis Health and Toxicology
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• v.19 no.3
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• pp.271-278
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• 2004

Epoxy resins are mostly used as a molding material for drinking water tank. Bisphenol A is used at a constituent material for epoxy resins and is widely suspected to act as an endocrine disrupter. In this study, we investigated embryo hatching in zebrafish reared in water undergone leaching process of expoxy resin, and found a decreased survival rate. Bisphenol A eluted from epoxy resin in drinking water tank was completely degraded by TiO$_2$ photocatalysis. We detected 7.8 ng/ml of bisphenol A in epoxy resin tank, and observed that the concentration was undetectable after 48h photocatalysis over TiO$_2$. There was no toxicity in hatching rates in zebrafish and morphogenesis after photocatalysis. The effect of TiO$_2$ photocatalytic reactions on the catalase activities in the f]y stage of zebrafish was also examined. At 1 week post hatching, cataiase activities were higher both in the group of epoxy resin with 48 h TiO$_2$ photocatalysis and in the TiO$_2$ photocatalysis for 48 hours were higher than control group. However catalase activities of the treatment group of epoxy resin by TiO$_2$ photocatalysis for 48 hours were similar to control in 5 weeks post hatching fries. In conclusion, the toxicity of TiO$_2$ photocatalysis was not observed in this zebrafish.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.113-119
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• 1999

The most common cause of death is ostrich chick fading syndrome(OCFS), which is due to bacterial infection during artificial incubation and hatching. Six farmed ostrich chicks aged 3 and 10 days in Chonbuk province, were submitted to Chonbuk Livestock Development and Research Institute for necropsy, Clinically, birds showed hair loss, ocular exudate, lethargy, diarrhea, and subsequently died 3-5 days after onset of clinical signs. Grossly, umbilicus was enlarged. White-yellowish purulent nodules were scattered on the lung and the membrane of air-sac was thickened and had inflamed exudate on the surface in two chicks that died 3 days after hatching. In 10 days-old chick, intestine was shown rodding segmentally. Yolk sac was still retarded and its surface was partially hemorrahgic. The synovial fluid of the leg was yellowish. Microscopically, multifocal purulent exudates were scattered on the lung. Capillary microthrombi in the glomerulus were prominent and tubular epithelia were necrotic. Necrotic hepatocytes were scattered and intestine were congested. Microbiologically, Pseudomonas sp and/or E coli were isolated from air-sac, lung and/or liver. This case suggests that poor hygiene during artificial incubation, hatching or in the first week after hatching may cause high mortality of the ostrich chicks.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.292-299
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• 2008

The purpose of this study was to investigate the teratological effects of enrofloxacin, a veterinary antibiotic, on the embryos and fetus of hatching chicken eggs. A control group and four experimental fertilized egg groups were set up. The four experimental groups were injected with 0.05 ml, 0.1 ml, 0.2 ml, and 0.3 ml enrofloxacin ($50{\mu}g/ml$) respectively. During the hatching period, the weights of total eggs, inside material(yolk and white) and embryos or fetuses, embryo growth, and teratological effects were investigated. In the experimental groups (fertilized eggs injected with 0.05 ml, 0.1 ml, 0.2 ml and 0.3 ml enrofloxacin), the weights of total eggs were decreased, but the yolk and white weights were increased by the higher amount of antibiotics. The weights of embryos (fetuses) in experimental groups were 86.1%, 78.6%, 65.6% and 61.4% of the control, respectively. Retarded growth, deformity and embryo loss were observed in experimental groups. Teratological effects such as undeveloped eyes, wings and legs, and deformed head and bill were also detected. In conclusion, we found that veterinary antibiotics, enrofloxacin have made teratological effects on the embryos and fetus of hatching eggs.

• 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.

• Development and Reproduction
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• v.24 no.4
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• pp.307-316
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• 2020

The purpose of this study is to observe the early life history of Korean Lefua costata and use the result as basic taxonomic research data for balitorid fish. The fertilized eggs were light green color with completely circle shape and mean size was 1.21±0.06 mm (n=30). Immediately after hatching, the size of the larvae was 2.81±0.11 mm (n=5) in mean length, with egg yolk. On the 3rd day after hatching, the preflexion larvae had a mean length of 4.64±0.09 mm (n=5), and their mouth was opened to start feeding. On the 8th day after hatching, a mean length of the postflexion larvae was 9.43±0.46 mm (n=5), the distal part of the notochord was bent to 45°, and 16 fin rays were developed on the caudal fin. On the 31st day after hatching, a mean length of juveniles was 22.3±0.85 mm (n=5), and the number of fin rays was the same as that of adult fish with (iv8) dorsal fins and (iii8) anal fins.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.415-424
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• 2015

This research was conducted to reveal the characteristics of breeding ecology of oriental scops owl (Otus sunia stictonotus) inhabiting in South Korea according to the nest types during the breeding season from march to October for two years (2011 and 2012). Oriental scops owl nested in woodpecker's nest holes (46.1%), natural tree holes (38.5%), and artificial wood boxes (15.4%). These nests were located on following trees: Zelkova serrata, Paulownia coreana, Celtis sinensis, Salix chaenomeloides, Salix babylonica, Fraxinus rhynchophylla, Robinia pseudoacacia and Platanus occidentalis. The hatching success was 91.4%, fledging success was 83.0%, and breeding success was 75.9%. The factors of the breeding failure were falling (57.1%), abandonment (28.6%), hatching failure (7.1%), and others with unknown cause of death (7.1%). According to nest types, the fledging success (69.2%) of woodpecker's nest holes were low and the hatching success (79.2%) of natural tree holes were also low due to hatching failure and abandonment. However, hatching success, fledging success, breeding success were high in the artificial nests as all the eggs hatched and succeeded in fledging. Therefore, we suggested that artificial nests can cover the weaknesses of natural nests as well as increasing the breeding success. However, long-term research on installation place, height, and hole sizes of the artificial nest are required in order to clearly reveal the effects on the breeding success of oriental scops owl.