• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.156-157
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• 2003

In teleost, vitellogenin (Vtg) is synthesised in the liver in response to estrogens and transported by the blood to the growing oocytes where it is incorporated by micropincytosis (Selman and Wallace, 1982). Generally, Vtg is not induced in normal male fish but male fish are capable of synthesis Vtg in reponse to exogenous estrogen and xenoestrogens. (omitted)

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.486-492
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• 2013

Recently, a new disease showing symptoms such as epidermal exfoliation and muscular necrosis occurred in cultured Korean catfish. Although the mortality of fishes was low but the economic damages owing to loss of commercial value were severe. The authors isolated the causative agent from diseased fish and observed pathological changes both in naturally and artificially infected fish. The causative bacteria was identified as Aeromonas veronii. Subsequently we observed the daily death and pathological symptoms of artificially infected fish with Aeromonas veronii. Symptoms of artificially infected fish were similar to those of naturally infected fish and all fish died within 7 days after infection. Histopathological changes on the naturally infected fish revealed severe congestion and necrotic degeneration in the liver, spleen and kidney. Some bacterial aggregates with inflammatory degeneration were observed in the heart, and congestion and fibrosis in the lamina propria of digestive tube were predominant. In artificially infected fish, skin erosion and necrotic degeneration of muscle tissue around injected region were particularly manifested. Degeneration of hepatocytes in liver and hyalic degeneration around ellipsoids in spleen were partially observed. However, there were no predominant signs in digestive tube in artificially infected fish.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.419-432
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• 2016

The aim of this study is to assess the influence of effluent discharge from a sewage treatment plant by evaluating oxidative stress and histopathological alterations in freshwater crucian carp Carassius auratus collected from the Eungcheon stream, located in Korea. Catalase activity in the gills, liver, and kidneys of C. auratus was collected from mixing zones; the downstream site was notably higher of fish than that of the upstream site. In addition, the activity of glutathione-S-transferase in the gills and liver was significantly higher in samples from the mixing zone than in those from the upstream site (p < 0.05). In addition, significantly elevated lipid peroxidation levels were observed in fish livers sampled from the mixing zone than in those from the upstream site (p < 0.05). Significant histopathological alternations were also observed in C. auratus, with the order of magnitude changes being liver > kidney > gills. These findings suggest that the liver is most affected by effluent discharge. The degree of tissue changes (DTC) indicate that the highest level occurred in samples from the mixing zone (30.98 ± 5.40) followed by those from the downstream site (19.28 ± 4.31) and was the lowest in samples from the upstream site (4.83 ± 2.67). These findings indicate that fish collected from the mixing zone are most affected by effluent discharge and both oxidative stress and histopathological indices are useful tools for monitoring contaminated rivers and streams.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.216-217
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• 2002

Vitellogenin (VTG) is a Precursor form of egg yolk Proteins, which appear only in the blood circulation of female fish and its synthesis in the liver is considered to be regulated by several hormones. It has been reported that in addition to estradiol-17 $\beta$ (E2) several hormones are also involved in the production site of VTG, the liver (Peyon et al., 1996; Mori et al., 1998). (omitted)

• Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.4.1-4.9
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• 2020

Growth of fish is controlled by various environmental factors, including water temperature (WT). WT is also a major factor that affects the eating behavior of fish. In this study, we studied the relationship between WT and expression profiles of factors involved in appetite regulation and digestion in red spotted grouper. Fish were divided into three groups with 30 fish per group and reared for 2 weeks in a recirculating system at three different WT (natural WT, 20 ℃, and 25 ℃). After 2 weeks, they were sacrificed immediately after food intake (+ 0 h), 3 h after (+ 3 h), 6 h after (+ 6 h), and 3 h before being fed the next day (- 3 h). Fish samples were obtained for analysis of mRNA expression levels of cholecystokinin (CCK), leptin A (LepA), leptin B (LepB), and neuropeptide Y (NPY) in the brain, liver, and intestine. Expression of CCK and NPY mRNA was significantly higher at 25 ℃ compared to that at natural WT and 20 ℃, but no difference was observed for leptin. This suggests that the red spotted grouper shows characteristics typical of subtropical fish and has higher levels of feeding and digestion when reared at 25 ℃ water temperature condition.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.331-339
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• 2009

This study evaluated the potential human health risk on the basis of the level of bioaccumulation and EDI (Estimated Daily Intake) of microcystin-LR, one of hepatotoxic, in organs, including liver, muscle, viscera and gill, of fish from Lake Yeongeheon and Lake Daecheong when the cyanobacterial water-blooms broke out. The result has confirmed that Carassius cuvieri from Lake Yeongcheon contains higher level of microcystin-LR in its organs including liver. In Lake Daecheong, omnivorous Hemibarbus labeo and phytoplanktivorous Carassius cuvieri have shown high microcystin-LR level on average, especially higher for viscera, and Carassius cuvieri has appeared to contain higher level of microcystin-LR in the liver and the gill compared with other species. As a result of comparison between EDI of microcystin-LR from each organs and TDI (Tolerable Daily Intake) of WHO (Chorus and Bartram, 1999) to evaluate human health risk, the EDI levels from Carassius cuvieri's organs except museles have exceeded TDI level at the both lakes. Consequently, the study has proved that microcystin was bioaccumulated in the various parts of fish, and it can be ingested by human resulting in risking human health. Continuous monitoring and reducing consumption of fish, especially Carassius cuvieri, during the cyanobacterial water-blooming period will be needed to protect human health.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.521-528
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• 1986

In this paper, proteolytic activity of the tissue extracts from the internal organs such as alimentary canal, pancreas, pyloric caeca, stomach, liver and spleen of mackerel, Scomber japonicus, and sardine, Sardinops melanosticta, was compared with each other under the optimum reaction condition. The proteinases distributed in alimentary canal, pancreas, pyloric caeca and spleen were active in alkaline pH range, but those in stomach were shown the activity in acid pH range, furthermore those in liver were exhibited the activity in acid, neutral and alkaline pH range. The proteinases distributed in the internal organs of both fish were stable at the heat treatment of $45^{\circ}C$ for 5 minutes. The proteinases from stomach and pyloric caeca of the two fish and those from pancreas of sardine were less stable than those from any other internal organs of both fish. Whereas the proteinases from spleen and neutral proteinases from liver were shown to be stable by the heat treatment at $55^{\circ}C$ for 5 minutes. The proteinases from pyloric caeca of both fish, and stomach, pancreas and spleen of mackerel were stable during the whole storage days at $5^{\circ}C$, but the other proteinases were slowly inactivated after 14 days of storage. The enzymes were seemed to be more stable in the storage at $-15^{\circ}C$ than at $5^{\circ}C$.

• The Korean Journal of Zoology
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• v.27 no.2
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• pp.85-92
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• 1984

The effect of copper ion on the lactate dehydrogenase isozyme patterns in the heart, liver, kidney, skeletal muscle, and ovary of catfish, Parasilurus asotus, was studied by cellulose acetate gel electrophoresis. 1. The LDH-1 and LDH-2 of heart type appeared in the heart muscle of control fish. When the fish were exposed to copper ion, however, the LDH-1, LDH-2, LDH-3, and LDH-4 appeared. The amount of LDH-1 was decreased and those of LDH-2, LDH-3, and LDH-4 were increased. 2. There was one band of LDH-4 in the liver of normal fish. But the amount of LDH-4 was decreased and additional new LDH-5 appeared by exposure to copper ion. 3. There were LDH-1, LDH-2, and LDH-4 in the kidney tissue of both control and experimental groups. The LDH-1 was increased, whereas LDH-2 and LDH-4 were decreased after exposure to copper ion. 4. There was broad band of LDH-5 in the skeletal muscle of the control fish. However, the LDH-4 and LDH-5 with M sub-band appeared by the exposure to copper ion. 5. There was LDH-3 band only in the ovary of control, wheras all five LDH isozymes appeared in the ovary of the fish exposed to copper iion. 6. During the period of exposure to copper ion, the LDH isozyme of heart type which associated with aerobic metabolism was decreased, but the LDH isozyme of muscle type of anaerobic metabolism was increased in most of heart, liver, and skeletal muscle. It seems that these organs are related to some of important functions for anaerobic metabolism during the copper poisoning period.

• Journal of Aquaculture
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• v.19 no.4
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• pp.254-260
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• 2006

A 6-week feeding trial was conducted to determine apparent protein and phosphorus digestibilities in order to evaluate nine different dietary protein sources in growing olive flounder, Paralichthys olivaceus. Nine diets containing fish meal analog ($BAIFA-M^{TM}$), white fish meal (WFM), flounder muscle powder (FMP), squid liver powder (SLP), leather meal (LM), soybean meal (SM), corn gluten meal (CGM), poultry by-product (PBP) or egg albumin(EA) were prepared by mixing a basal diet (BD) with one of nine test ingredients at the ratio of 7 to 3. Apparent protein digestibilities of FMP, SLP, WFM, SM, CGM, LM, PBP, $BAIFA-M^{TM}$, and EA were 94%, 92%, 86%, 82%, 75%, 72%, 72%, 71%, and 30%, respectively. Apparent phosphorus digestibilities of FMP, SLP, $BAIFA-M^{TM}$, LM, WFM, PBP, CGM, EA and SM were 77%, 72%, 65%, 55%, 54%, 50%, 20%, 20%, and 17%, respectively. Weight gain of fish fed FMP ($323^a$) was significantly higher than those of fish fed the other diets, and those of fish fed basal diet ($302^b$), SLP ($305^b$) and WFM ($308^b$) diet were significantly higher than those of fish fed SM ($274^c$), $BAIFA-M^{TM}\;(268^{cd}),\;PBP\;(261^{de}),\;LM\;(251^e),\;CGM\;(254^e)$ and EA ($181^f$). Based on the results of apparent protein digestibilities, apparent phosphorus digestibilities and weight gain, SLP, SM and $BAIFA-M^{TM}$ could be one of good protein source to replace fish meal in flounder diets.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.282-293
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• 2020

This study investigated a long-term variation trend of water quality, fish compositions, and ecological health conditions in the Gwanpyeong stream located in the nearby Daejeon metropolitan city to understand the impact of urban development projects on the aquatic ecosystem. The sampling was made in four surveys (2009, 2010, 2016, 2019) before and after urbanization. The urban development was conducted in 2008, resulting in the stream's ecological disturbance, and the stream restoration was conducted in 2012. Thus, stream monitoring was conducted to analyze the ecological trends before and after the restoration. The multi-metric models for Fish Assessment Index(FAI) and necropsy-based Health Assessment Index(HAI) were applied in the fish community and organ-level, respectively, to assess the ecological health of the stream. Minimum turbidity and chlorophyll-a(Chl-a) occurred in the mid-stream(St. 2), and this was probably due to rapid current velocity in the riffle zone. We collected 18 fish species, and the dominant species was Zacco platypus (40.6%). In 2016 immediately after the stream restoration, the relative proportions of sensitive species and insectivore species were the highest along with highest values in the species diversity and species richness index, resulting in the best condition in the ecological health, based on FAI model values. However, the ecological health, based on the FAI, became worse in the latest survey conducted in 2019. The analysis of the HAI model based on the organ-level approach showed skin erosion in the fish of upper stream, kidney defects in downstream, and the liver and gill defects observed in all sites, indicating that the anatomical health was also affected.