• Fisheries and Aquatic Sciences
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• 제22권8호
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• pp.18.1-18.5
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• 2019

The development of sex-specific genetic assays in a species provides both a method for identifying the system of sex determination and a valuable tool to address questions of conservation and management importance. In this study, we focused on the identification of single nucleotide polymorphisms (SNPs) that differentiate genetic sex in burbot Lota lota. Burbot are the only true freshwater representative of the cod family and a species of conservation and management importance throughout Eurasia and North America. To identify sex-specific SNPs, we utilized restriction site-associated DNA sequencing (RADseq) to interrogate thousands of SNPs in burbot samples of known phenotypic sex. We discovered 170,569 biallelic SNPs, none of which fit the pattern expected under female heterogamety. However, we identified 22 SNPs that fit the pattern expected under male heterogamety (males heterozygous XY, females fixed XX) and, from these, developed two genetic assays that robustly (~ 97% genotyping success) and accurately (> 99% correct) sexed burbot samples. These sex-specific genetic assays will benefit growing conservation aquaculture programs for this species and allow future assessments of sex-specific migration, growth, and mortality.

• 한국수산과학회지
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• 제3권1호
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• pp.52-64
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• 1970

1969년 5월 21일에 채란하여 부화시킨 후 월동 사육중에 있는 자주복의 치어 사육 과정에 있어서 우선 150일간이 되는 10월 25일까지의 시험 결과를 요약하면 다음과 같다. 1. 자주복의 인공 수정 란은 수온 $15.9\~17.4^{\circ}C$에서 163시간만에 최초의 부화를 볼 수 있었고, 부화율은 $61.56\%$ 였다. 2. 부화 후 $6\~7$ 일경에 후기 자어에 달하나 이 때에 1차 대량 폐사가 일어나서 부화 치어의 $57.26\%\~68.0\%$가 감소되었다. 3. 부화 후 16일경부터는 전장 6.7mm의 것이 4.6mm의 치어를 공격하는 것을 볼 수 있었다. 4. 부화 후 $25\~28$ 일 경에는 식성의 변화가 생기게 되며, 이 때는 다시 제 2차 대 량 폐사가 일어나서 부화 수량의 $90.7\%\~90.9\%$가 감소되었다. 5. 치어기 이후의 공식 현상은 체장에 관계없이 적정 먹이의 부족에서 일어나며 식해당하는 위치는 꼬리지느러미쪽에서 시작된다. 6. 46일간 사육한 유어기(체장 $53\~68$mm)의 먹이 종류별 증육 계수는 바지락 5.5, 지렁이 8.5, 잠어 8.7이었다. 7. 부화 후 $53\~63$일 경부터는 제 3차 폐사가 일어나서 부화 수량의 $95.76\~97.34\%$가 감소하였으나 주원인은 영양실조에 의한 구루병(곱추병)이었다. 8. 성장 결과는 부화 직후의 것은 전장이 2.68mm이나 부화 후 10일째는 전장 3.84mm, 25일째는 전장 7.96mm 40일째는 전장 20.96mm, 체중 130mg, 80일째는 전장 73.65mm, 체중 9.06g, 150일째는 전장 123mm 체중 31.8g로 성장하였다. 9. 이 때의 전사육 기간 중의 수온은 $15.7\~28.4^{\circ}C$(평균 $22.10^{\circ}C$)범위였고 염분 농도는 $25.53\~34.50\%_{\circ}$ (평균 $32.07\%$) 범위였다. 10. 자주복의 유어는 저염분 농도에 대한 저항력이 높아서 $5\%_{\circ}$까지의 급변에도 잘 견디었으나 $3\%_{\circ}$이하부터는 폐사율이 많은 편이었다. 11. 정상 해수에서 담수로 바로 옮긴 것은 9시간 40분 후에 폐사했는데 비하여 저염분 농도($5\%_{\circ}$)에서 54일간 단련시킨 것은 60시간 40분이나 더 생존할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권11호
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• pp.1598-1608
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• 2013

An optimum dietary carbohydrate content is important for maximum fish growth. In this study, we fed Wuchang bream (Megalobrama amblycephala) with either control diet (30.42%) or high carbohydrate diet (52.92%) for 90 d. Fish were fed to apparent satiation three times daily in an aquarium with automatic temperature control and circulated water. Growth performance, plasma biochemical parameters, hepatic morphology and enzyme activities were determined. It was shown that compared to fish fed control diet, fish fed high carbohydrate diet had higher plasma triglyceride and cortisol levels for d 90, and lower alkaline phosphatase level for d 45, lower hepatic superoxide dismutase and total antioxidative capacity for d 90, higher malondialdehyde for d 45 and glycogen content for d 45 and 90 (p<0.05). Histological and transmission electron microscopy studies showed that hepatocytes of fish fed high carbohydrate diet contained large lipid droplets, causing displacement of cellular organelles to periphery of hepatocytes. The relative level of hepatic heat shock protein 70 (HSP70) mRNA of Wuchang bream fed high carbohydrate diet was significantly higher than that of fish fed the control diet for 90 d (p<0.05). These changes led to decreased specific growth rate and increased feed conversion ratio (p<0.05). Upon hypoxia challenge, fish fed high carbohydrate diet had higher cumulative mortality than those fed the control diet (p<0.05). These results suggested that high dietary carbohydrate (52.92%) was detrimental to the growth performance and health of Wuchang bream.

• 한국어병학회지
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• 제7권2호
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• pp.105-112
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• 1994

1993년 전북도 관내에서 순환여과식으로 사육중인 한국산 메기에 세균성 질병이 발생하여, 이 질병에 의한 폐사율이 4개월 동안에 30%에 달하였다. 병어는 양어지의 가장자리에서 두부를 위로 한채 힘없이 물표면을 헤엄치거나 때로는 회전 발광유영을 하는 개체가 많았다. 외견상 특정적인 증상은 두부와 가슴지느러미의 기부에 궤양 병소가 형성되거나 아랫턱 주변의 출혈을 주증상으로 하고 있었다. 병어의 뇌, 신장, 비장 및 간장으로부터 원인균을 분리하여 생화학적 특성과 생물학적 특성을 조사한 바, Edwardsiella ictaluri로 동정되었다. 분리균을 한국산 메기, 차넬메기 및 잉어에 복강주사하여 병원성을 조사한 결과 한국산 메기와 차넬메기에는 병원성이 있었지만, 잉어에 대한 병원성은 없었다.

• 한국수산과학회지
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• 제43권5호
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• pp.457-461
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• 2010

To estimate the effect of selective breeding on the improvement of growth in olive flounder Paralichthys olivaceus, we compared the growth of a strain selected for rapid growth to that of an unselected strain from a commercial hatchery. The fish strains were fed with either moist pellets (MP) (dry matter, 59.8% crude protein; 14.1% lipid) or extruded pellets (EP) (dry matter, 50.4% crude protein; 13.8% lipid) for 190 days and were reared under similar conditions. The mortality rates were less than 2% and were not significantly different among the experimental groups. The growth rate of the selected fish was significantly greater than that of the unselected fish regardless of the diet type, and both strains fed MP grew significantly faster than those fed EP. The selected fish consumed more feed than the unselected fish. However, there was no significant difference in the feed efficiency between the selected and unselected fish. These results demonstrate that the selected fish exhibited superior growth rates, and that this was associated with a greater intake of food. Thus, selective breeding may be useful for improving the growth of commercial olive flounder.

• 한국수산과학회지
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• 제54권5호
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• pp.617-623
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• 2021

The study was conducted to investigate the dietary supplementation of citrus by-product (CBP) and CBP fermented with Bacillus subtilis (BS) or B. pumilus (BP) on growth performance, feed utilization, innate immune responses and disease resistance of Korean rockfish Sebastes schlegelii. Triplicate groups of juvenile fish (initial weight of 22.9 g) were fed one of five experimental diets which were formulated to replace a synthetic vitamin C (L-ascorbyl-2-polyphosphate, LAPP) with CBP or fermented CBP. A basal diet without LAPP and CBP was used as the control diet (Con). At the end of the 13 weeks feeding trial, growth performance, feed utilization and survival of fish fed the Con were significantly lower than those of fish fed the LAPP, CBP and fermented CBP diets. Fish fed the Con were significantly lower in lysozyme activity than fish fed LAPP, CBP and fermented CBP diets. In a challenge test against Edwardsiella tarda, cumulative mortality of fish fed LAPP, CBP and fermented CBP diets was significantly lower (20-30%) than that of the Con (60%). The findings in this study indicate that the CBP and/or fermented CBP can be a promising vitamin C source for LAPP replacement in diet for Korean rockfish.

• Fisheries and Aquatic Sciences
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• 제22권10호
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• pp.21.1-21.7
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• 2019

Background: Lactococcus garvieae is one of the most important risk factors in the rainbow trout culture. Therefore, the purpose of this study was to identify and detect strains isolated from rainbow trout suspected of having Lactococcus garvieae using biochemical characteristics and PCR and determination of the degree of severity of isolated strains. Methods: In this study, the cause of lactococcosis in selected rainbow trout farms in Kohkilooieh and Boyerahmad province was assayed. Gram-positive and catalase-negative bacterial isolates were first obtained from selected trout fish farms using conventional biochemical tests and PCR assay. The 10-day LD₅₀ method (concentration causing 50% mortality in 10 days) was used to determine the severity of the isolated bacteria. Results: One bacterial isolate was detected from all sampled fish which confirmed as Lactococcus garvieae using a specific PCR assay based on the 16S rDNA gene by producing a single band of 1107 bp. Analysis of the rate of mortality showed that the 10-day LD₅₀ was 4.6 × 10⁵ CFU/fish. The results of this study showed that isolated bacteria had high severity for rainbow trout. The presence of bacteria in internal organs of suspected fish showed a severe systemic infection in challenged fish. Antibiogram assay also indicated that the isolated Lactococcus garvieae were resistant to some mostly used antibiotics in rainbow trout. Conclusions: According to current research, it can be concluded that the condition of lactococcosis in the studied area is not suitable, and despite the presence of disease, there is no proper action to control and prevent the disease. Unfortunately, isolated bacteria from the studied area have a very high severity compared to bacteria isolated from other regions of the country or other countries. Therefore, further investigation is needed to determine the cause of this difference and possibly in the design of the vaccine.

• Toxicological Research
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• 제32권3호
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• pp.215-223
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• 2016

This study is to investigate the biological, biochemical and cytotoxic effects of puffer fish (Arothron stellatus) toxin extracts under in-vitro condition. Extracted toxins from various organs of puffer fish were purified by using active charcoal column, and Bio-gel-P2 column chromatography. The lethality of toxin was tested in crabs, which consists of neurotoxic compounds. The degree of the brine shrimp lethality assay was found directly proportional to the concentration of the toxin extracts, which was well supported by hemolytic assay. The experimental results suggested that the gonad was found higher toxins than the liver and muscles. The mortality rate of brine shrimp nauplii was increased with the raise of concentrations of toxin level. Among the different doses and time dependent cytotoxic effect of human cervical carcinoma (HeLa) cells were showed $4.0{\mu}g/mL$ of toxin, which was effectively inhibited cancer cell proliferation. HPLC and TLC analysis was revealed that the A. stellatus toxin contains tetrodotoxin (TTX), related compounds 4-epi TTX and anhydro-TTX. The present results suggested that the A. stellatus contain TTX as a major and anh-TTX as a minor toxin. It could be the potential candidate in the field of anticancer drug discovery against human cervical cancer cells. The present data is confirming that the puffer fish toxin as an interesting source of novel bioactive natural compounds with potent applications in pharmacology.

• 한국어병학회지
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• 제24권3호
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• pp.279-287
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• 2011

Transcriptional response patterns of mud loach (Misgurnus mizolepis; Cypriniformes) hepcidin, a potential ortholog to human hamp1, in response to experimental challenges with non-pathogenic and pathogenic bacterial species were analyzed based on the semi-quantitative reverse transcription-PCR assay. Mud loach hepcidin transcripts were much more preferentially induced by pathogenic bacterial species (Edwardsiella tarda and Vibrio anguillarum) causing apparent pathological symptoms than by non-pathogenic species (Escherichia coli and Bacillus thuringiensis) displaying neither clinical signs nor mortality. However in overall, the induced amounts of hepcidin transcripts were positively related with the number of bacterial cells delivered in both pathogenic and non-pathogenic bacterial species. Inducibility of hepcidin transcripts were variable among three tissues examined (liver, kidney and spleen) in which kidney and spleen were more responsive to the bacterial challenge than liver. Time course expression patterns of hepcidin mRNAs after challenge were different between groups challenged with pathogenic and non-pathogenic species, although the overall pattern of hepcidin expression was in accordance with that generally observed in battery genes appeared during early phase of inflammation. Fish challenged with E. coli (non-pathogenic) showed the significant induction of hepcidin transcripts within 24 hr post injection (hpi) but the level was rapidly declined to the basal level either at 48 or 96 hpi. On the other hand, hepcidin transcript levels in E. tarda (pathogenic)-challenged fish were continuously elevated until 48 hpi, then downregulated at 96 hpi, although the level at 96 hpi was still significantly higher than control level observed in non-challenged fish. This expression pattern was consistent in all the three tissues examined. Taken together, our data indicate that hepcidin is tightly in relation with pathological and/or inflammation status during bacterial challenge, consequently providing useful basis to extend knowledge on the host defensive roles of hepcidin under infectious conditions in bony fish.

• 한국어류학회지
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• 제28권3호
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• pp.141-146
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• 2016

본 연구에서는 넙치 유래 VHSV (genotype IVa)에 의한 무지개송어의 영향을 조사하기 위하여 다양한 조건에서 감염 실험을 실시하였다. 3개의 다른 로트의 담수 무지개송어 치어에 VHSV ($10^{6.3-7.3}TCID_{50}$/fish)를 복강 주사한 결과, 15% 이하의 누적 폐사율이 관찰되었다. 무지개송어 (in vivo)를 사용하여 VHSV를 계대 배양한 후 감염 실험을 실시한 결과, VHSV를 5회 계대 배양하여도 독력의 변화는 관찰되지 않았다. 해수에 사육 중인 송어 (성어)에 넙치 유래 VHSV ($10^{5.3}TCID_{50}$/fish와 $10^{6.3}TCID_{50}$/fish)를 복강 주사한 결과, 폐사어는 관찰되지 않았고, 어체 내에서도 VHSV는 검출되지 않았다. 이상의 결과, 해수 송어 (성어)에서는 넙치 유래 VHSV의 병원성이 확인되지 않았으나 담수 무지개송어 치어에서는 낮은 독력을 나타내었다.