• 수산해양기술연구
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• 제53권1호
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• pp.49-59
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• 2017

The objective of this study was to investigate the growth rate and the optimal stocking density of sea cucumbers. Grow-out was studied in situ by conducting a follow-up survey using visible implant elastomer (VIE) tags. The rearing systems were made of polypropylene pipe for the frames and netting. The experiment ran for 70 days near Yeosu, Korea in the water depth of about 7 m. A total of 576 sea cucumbers which have three groups of body sizes (small: 5.15, medium: 12.34 and large: 23.26 g) were used. The five groups of stocking densities (150, 300, 450, 600 and $850g/m^2$) in rearing system for sea cucumber were considered. Sea cucumbers were fed a mixed diet (mud, mineral, fish meal, etc.). The feed was supplied to 10% of their body wet weight once every 7 days. The survival rate (73%) of sea cucumber in $850g/m^2$ was lower than those of other density groups ($150g/m^2$: 89%, $300g/m^2$: 84%, $450g/m^2$: 78% and $600g/m^2$: 86%). The survival rate of medium size group was higher than those of small and large groups regardless of the density (P<0.05). Most of density groups have no significant difference except for $850g/m^2$ (P>0.05). The growth rate of small size group ($0.63%day^{-1}$) was higher than those of medium ($0.38%day^{-1}$) and large ($0.34%day^{-1}$) group regardless of the density (P<0.05). The threshold water temperature was $11.0^{\circ}C$ for sea cucumber growth in winter season.

• 수산해양교육연구
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• 제28권4호
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• pp.1006-1013
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• 2016

돌기해삼 종묘의 보관에 따른 외상, 부위별 움직임 및 생존율을 관찰하였다. 10, 15, 20 및 $25^{\circ}C$에 종묘를 3, 6, 12, 24시간 보관 후 회복과정을 통해 생존율을 관찰하였고, 이를 위해 외상정도와 네 가지 부위별 움직임 변화(촉수 움직임, 촉수를 제외한 몸의 움직임, 뒤집기, 이동)를 적용할 수 있는지 검증하였다. 외상정도는 $20^{\circ}C$에서 24시간 실험구와 $25^{\circ}C$의 12시간 실험구에서 각각 $2.2{\pm}0.8$, $2.6{\pm}0.7$로 낮게 나타났다. 부위별 움직임 변화는 촉수의 움직임과 이동 여부 항목에서 생존율 및 외상 정도와 관련성을 보였다. 생존율은 보관 온도 $10^{\circ}C$와 $15^{\circ}C$ 실험구에서는 24시간까지, $20^{\circ}C$는 12시간까지 그리고 $25^{\circ}C$에서 6시간까지는 변화가 없었다. 돌기해삼 종묘의 보관 온도에 따른 치사시간(LT10)은 $20^{\circ}C$의 경우 15.73시간 이었으며, $25^{\circ}C$의 경우 5.57시간 이었다. 본 연구결과는 방류종묘의 운송에 따른 생존율을 간접적으로 파악할 수 있는 지표로서 적용 가능할 것이다.

• 한국해양생명과학회지
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• 제7권1호
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• pp.29-36
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• 2022

돌기해삼 Apostichopus japonicus는 주요 양식 대상 무척추동물로서 우리나라 연안 해역에 서식하고 있다. 본 연구는 방류 방법에 따른 단기간의 생리학적 스트레스 정도를 평가하기 위하여 heat shock protein 90 (HSP90) 유전자의 발현 변화를 실시간 정량적 중합효소연쇄반응법으로 조사하였다. 어린 돌기해삼을 비닐봉지에 산소 포장하여 30분간 수송하거나 방류 해역의 간조기에 1시간 공기 중에 노출된 실험군의 HSP90 유전자 발현은 대조군의 HSP90 유전자 발현에 비하여 통계학적으로 유의미하게 증가하였다(수송 후 실험군 p=0.001; 간조기 실험군 p=0.032). 어린 돌기해삼을 방류 후 6시간까지 분석한 결과, 선상에서 씨뿌림 방식으로 방류된 6시간째의 개체 및 호스를 통과하여 수중으로 방류된 2~6시간째의 HSP90 유전자 발현율은 대조군에 비하여 약간 감소하는 경향을 보였다(씨뿌림 실험군 p=0.069; 호스 방류군 p=0.093). 한편, 잠수부에 의해 수중에서 방류된 어린 돌기해삼은 방류 후 시간이 경과할수록 HSP90 유전자 발현율은 증가하는 패턴이 관찰되었다(p=0.061). 이상의 결과는 방류된 어린 돌기해삼의 단기간 스트레스 반응 연구와 효과적인 방류 방법의 개발에 HSP90 유전자 발현이 유용하게 사용될 수 있음을 시사한다.

• 수산해양교육연구
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• 제25권6호
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• pp.1360-1365
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• 2013

다양한 염분 농도에 따른 어린 돌기해삼의 생존과 피부계의 구조적 이상을 관찰하였다. 돌기해삼의 크기 및 수는 습중량 $1.0{\pm}0.2g$, 250 개체였다. 실험농도는 0, 5, 10, 15, 20, 25, 30, 35 및 40 psu 였으며, 96시간 노출 후 7일간 일반해수에서 회복과정을 통해 생존을 관찰하였다. 그 결과 25-35 psu에 노출된 개체들은 모두 100%의 생존율을 보였으며, LC50은 21.05 psu로 나타났다. 돌기해삼의 피부계는 20 psu 이하의 염분 농도에 노출된 개체들의 경우 상피층 두께 감소, 상피세포 핵 응축, 점액세포 감소 및 진피층 결합조직의 성긴 배열 등이 주로 관찰되었다. 하지만 이와는 반대로 40 psu의 염분 농도에 노출된 개체들은 상피세포 핵의 비대, 점액세포 증가 및 진피층 결합조직의 치밀배열 등이 나타났다. 진피층에서 관찰된 alcian blue(pH 2.5) 양성 분비세포들은 20 psu 이하에서는 노출 24시간 내에 대조구에 비해 급격한 증가 및 감소폭을 보였다. 40 psu 에서는 노출시간이 길어질수록 증가한 후 회복일수에 따른 감소경향을 보였다.

• Fisheries and Aquatic Sciences
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• 제12권3호
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• pp.203-208
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• 2009

A factorial feeding trial of different levels of three carbohydrate sources (wheat flour, $\alpha$-potato starch, and sodium alginate) was conducted to determine proper sources and levels of dietary carbohydrate for juvenile sea cucumbers. Three replicate groups of juvenile sea cucumbers (770 mg average weight) were fed the experimental diets once a day for 10 weeks. After feeding trial, survival of sea cucumbers was not significantly different between diets. The body weight of sea cucumbers was significantly (P<0.01) affected by both source and level of dietary carbohydrate, tending to decrease as dietary carbohydrate level increased. Body weight of sea cucumbers fed a 25% wheat flour diet was the highest but was not significantly different from that of sea cucumbers fed diet containing 10% wheat flour with 15% sodium alginate (P>0.05). No significant differences were observed in contents of moisture, crude protein, crude lipid and ash of sea cucumbers among dietary treatments. These results suggest that sea cucumbers utilize wheat flour and sodium alginate more efficiently than they do $\alpha$-potato starch, and that a formulated diet containing 43-60% carbohydrate may be suitable for juvenile sea cucumber culture.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.127-132
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• 2010

A study was conducted to investigate the effects of dietary lipid sources on the growth and fatty acid composition of juvenile sea cucumber. For 12 weeks, three replicate groups of sea cucumber (average weight 1.4 g) were fed one of three diets, containing squid liver oil (SLO), soybean oil (SO), or linseed oil (LO) as a dietary lipid source, or a control diet (CON) without added lipids. Sea cucumber survival was not significantly different among dietary treatments (P>0.05). The highest weight gain was observed in sea cucumber fed the SLO diet, whereas the weight gain of sea cucumber fed the SO diet was the lowest among dietary treatments (P<0.05). No significant differences were found in the moisture, crude protein, crude lipid, and ash contents of whole sea cucumber body among dietary treatments (P>0.05). Concentrations of 20:5n-3 and 22:6n-3 were significantly higher in sea cucumber fed the SLO diet than in those fed on the other diets. The highest 18:2n-6 and 18:3n-3 contents were observed in sea cucumber fed the SO and LO diets, respectively. The results of this study suggest that squid liver oil could be used as a good lipid source in formulated diets for juvenile sea cucumber.

• 수산해양기술연구
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• 제50권2호
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• pp.202-213
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• 2014

The sea cucumber, Apostichopus japonicus, is becoming an important aquaculture species in China, Japan and Korea. The purpose of this study is to evaluate the biological performance of a tubular type of subsurface cage for sea cucumber grow-out by in-situ tests. The cage structure was constructed of PP (polypropylene) frames and PP tubes (${\phi}130mm{\times}24pieces$). A set of tests were conducted at a depth of 15 m near Seosaeng, Ulsan, Korea for 295 days (23 July, 2012 to 13 May, 2013). A total of 155 sea cucumbers were used and fed a mixed diet containing mud, mineral, wheat, fish meal, etc (3% of their body weight). At the end of the experiments, sea cucumber showed a higher survival rate in feed shelter (77.14%) rather than no feed shelter (64.71%). The specific growth rate (SGR) of sea cucumbers in feed condition (0.04% $day^{-1}$) was higher than that of no feed culture animals (-0.49% $day^{-1}$) during total experimental periods. The result was able to find a no significance difference in survival rate but a significance difference in SGR under feed and no feed treatments.

• Fisheries and Aquatic Sciences
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• 제25권5호
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• pp.264-275
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• 2022

A non-destructive environmental DNA protocol for the genetic analysis of sea cucumber (Apostichopus japonicus) resources DNA was established. Among the several commercial DNA extraction kits, the DNeasy^® Plant Mini Kit was selected as the best choice to obtain the high-quality genomic DNAs from the mucous sea cucumber. As the temperature and incubation time increased, the amount of extracted environmental DNA was also large, but it was judged that the increased amount did not affect as much as 2-3 times. Therefore, these conditions were not considered to be the main factors to consider in actual environmental DNA extraction. However, the amount of seawater relative to the size of the sample was judged as a major consideration, and a sufficient amount of environmental DNA for analysis was secured when stored within 1 min while stirring the volume of seawater corresponding to the total sea cucumber weight (g). In securing the environmental DNA of sea cucumbers, the mortality rate of sea cucumbers in all experiments was 0, and it was judged that the effects of sea cucumbers were not significant through this treatment. Through the results of this study, sea cucumber DNA research, which has been conducted in a destructive method, can be conducted non-destructively through environmental DNA analysis. Through this study, we have secured a standard protocol that can successfully extract the sea cucumber DNA through environmental DNA. It is not only excellent in terms of time and cost of traditional DNA analysis method currently used, but it is completely non-destructive in the ecosystem of the survey area. It is believed that the system can be transformed in a way that does not affect it. However, it is thought that various standard protocols should be established considering the characteristics of each type.

• 한국수산과학회지
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• 제50권5호
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• pp.494-499
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• 2017

This study evaluated the abundance of fecal coliforms in oysters Crassostrea gigas, sea squirts Halocynthia roretzi and sea cucumbers Apostichopus japonicus in fisheries along the coast of Korea in 2014, and investigated the prevalence of antimicrobial resistance in Escherichia coli isolated from these fishery products. The ranges of fecal coliforms found in oysters, sea squirts and sea cucumbers were <18-20, <18-330 and <18-3,300 MPN (most probable number)/100 g, respectively. Sea squirts contained the greatest range of E. coli (<20-140 MPN/100 g), followed by sea cucumbers (<20-130 MPN/100 g) and oysters (<20-20 MPN/100 g). A total of 26 strains of E. coli were isolated from 34 sea squirt, 25 sea cucumber and 13 oyster samples. Strains thus isolated were tested for their susceptibility to 22 antimicrobial agents used in Korea for medical or veterinary therapy. E. coli isolates showed the greatest resistance to ampicillin (84.6%), followed by trimethoprim (34.6%), nalidixic acid (34.6%), tetracycline (30.8%), pipemidic acid (26.9%), streptomycin (23.1%), chloramphenicol (23.1%), trimethoprim/sulfamethoxazole (23.1%), and gentamicin (15.4%). Resistance to at least one antimicrobial agent was present in 88.5% of E. coli isolates. Of the 26 isolated, six strains (23.1%) were resistant to multiple antimicrobial agents.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1753-1762
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• 2017

Sea cucumber (Apostichopus japonicus) is a popular seafood source in Asia, including South Korea, and its consumption has recently increased with recognition of its medicinal properties. However, because raw sea cucumber contains various microbes, its ingestion can cause foodborne illness. Therefore, analysis of the microbiota in the whole body of sea cucumber can extend our understanding of foodborne illness caused by microorganisms and help to better manage products. We collected 40 sea cucumbers from four different sites in August and November, which are known as the maximum production areas in Korea. The microbiota was analyzed by an Illumina MiSeq system, and bacterial amounts were quantified by real-time PCR. The diversity and bacterial amounts in sea cucumber were higher in August than in November. Alpha-, Beta-, and Gammaproteobacteria were common dominant classes in all samples. However, the microbiota composition differed according to sampling time and site. Staphylococcus warneri and Propionibacterium acnes were commonly detected potential pathogens in August and November samples, respectively. The effect of experimental Vibrio parahaemolyticus infection on the indigenous microbiota of sea cucumber was analyzed at different temperatures, revealing clear alterations of Psychrobacter and Moraxella; thus, these shifts can be used as indicators for monitoring infection of sea cucumber. Although further studies are needed to clarify and understand the virulence and mechanisms of the identified pathogens of sea cucumber, our study provides a valuable reference for determining the potential of foodborne illness caused by sea cucumber ingestion and to develop monitoring strategies of products using microbiota information.