• 한국수산과학회지
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• 제47권6호
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• pp.796-800
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• 2014

A feeding trial was conducted to investigate the growth and body composition of juvenile sea cucumber Apostichopus japonicus in integrated culture with abalone Haliotis discus hannai or rockfish Sebastes schlegeli. Triplicate groups of sea cucumber averaging $1.2{\pm}0.05g$ were cultured alone or with abalone or rockfish for 12 weeks. Survival of sea cucumber was not affected by co-culturing (P>0.05). Weight gain of sea cucumber cultured with rockfish was significantly higher than that of sea cucumber cultured alone (P<0.05), and did not differ from that of those cultured with abalone (P>0.05). These findings indicate that co-culturing sea cucumber with rockfish effectively improves the growth of sea cucumber.

• 한국수산과학회지
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• 제49권2호
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• pp.161-167
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• 2016

The effects of fermented fecal solid diets on the growth of the sea cucumber Apostichopus japonicus was investigated in a recirculating aquaculture system (RAS) during a 90-day experiment at 16.5-17.5℃, 32±0.5 psu salinity, pH 7.9-8.2, and 5.2-7.1 mg/L dissolved oxygen. The aim was to determine the feasibility of RAS fecal solid waste as a renewable feed for A. japonicus. In this study, unfermented fecal solid (UF), fermented fecal solid (FF), and commercial feed (CF) diets were used. The results showed that the growth rate did not differ significantly (P>0.05) between A. japonicus fed FF and CF; however, the growth rates of A. japonicus fed FF and CF were ~50% higher than that of those fed UF. Thus, utilization of fecal solid by A. japonicus may overcome the problem regarding accumulation of RAS waste. Use of a fermentation process would improve utilization of fecal solid as a renewable food source for A. japonicus.

• 한국수산과학회지
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• 제49권3호
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• pp.343-350
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• 2016

The sea cucumber Apostichopus japonicus is a commercially valuable aquaculture species in Korea. Aquaculture species require specific nursery culture conditions to increase survival and growth rates. Sea cucumbers hibernate during the high temperatures of summer and during the low temperatures of winter, and suboptimal temperature conditions decrease sea cucumber growth and survival rates. The natural South Korean environment is very unfavorable for culturing sea cucumber; therefore, developing a recirculating aquaculture system (RAS) capable of breeding and growing sea cucumber year-round is necessary. The aim of this study was to investigate growth performance of juvenile sea cucumber in a RAS. Growth and survival rates of juvenile sea cucumber were high during our 24-week experiment. Sea cucumber survival rates were 87.8-93.3%, and specific growth rates were 0.4689-0.7846.

• 한국수산과학회지
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• 제47권6호
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• pp.785-789
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• 2014

An experiment was conducted to investigate the effects of feeding by different feed types (powder, crumble and pellet) of two different feed formulations with simple dried (D) or extruded (E) conditions on growth and body composition of juvenile sea cucumber Apostichopus japonicus. Triplicate groups of sea cucumber averaging $1.2{\pm}0.05g$ were fed each of the D1, D2, EP1 or EP2 diets for 12 weeks. Survival of sea cucumber fed D2-crumble was higher than that fed EP2-crumble diet (P<0.05). Weight gain of sea cucumber fed EP1-powder was higher than that fed EP1-crumble and EP2-crumble diets (P<0.05). These findings indicated that simple dried feed could use independently feed type for sea cucumber culture and powder type of extruded feed is also good for sea cucumber culture.

• 수산해양교육연구
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• 제28권5호
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• pp.1407-1416
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• 2016

12주 동안 육상 다단식 사육시스템을 이용하여 어린 돌기해삼의 성장, 생존율 및 적정 수용밀도를 알아보고자 하였다. 10 L 사육수조에 습중량 4.3~4.5 g의 어린 돌기해삼을 1, 2, 3, 4, 5 및 10마리씩 수용하여(각각 D1, D2, D3, D4, D5, D10으로 표기) 수용밀도별로 10단씩 쌓아 실험을 하였다. 체중성장과 생존율은 매 4주마다 조사하였다. 어린 돌기해삼의 수용밀도에 따른 성장은 수용밀도가 낮을수록 빠른 경향을 보였으며, 개시기부터 사육 8주까지는 수용밀도에 따른 성장의 유의한 차이는 없었다(P>0.05). 사육 12주째는 D1~D5 실험구간에는 유의한 차이가 없었으나(P>0.05), D1과 D10간에는 유의한 차이를 보였다(P<0.05). 생존율은 모든 실험구에서 12주째 72~100%로 수용밀도 D1~D5 실험구간에는 유의한 차이가 없었으나(P>0.05), D1~D5와 D10 실험구와는 차이를 보였다(P<0.05). 따라서 육상 다단식 사육시스템을 이용한 어린 돌기해삼의 적정수용밀도는 성장과 생존율을 고려할 때 0.05마리/$m^2$ 이내로 판단된다.

• 환경생물
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• 제33권4호
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• pp.433-440
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• 2015

The Apostichopus japonicus is an important species in some Asia countries including Korea, China and Japan. The purpose of the present study was to investigate the differential gene expression of heat shock protein90 (Hsp90) and ferritin as a biomarker for the thermal stress during water temperature rising in the sea cucumber, A. japonicus. The A. japonicus (1.4 g) was cultured in incubator of separate temperature ($15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$) for each 0, 3, 6, 12, 24, 48 hours. The mRNA expression levels of Hsp90 and ferritin were examined using RT-PCR assay. Results showed that, the expression of Hsp90 mRNA was not significantly changed at $15^{\circ}C$. The expression of Hsp90 mRNA was significantly increased at high temperature such as $20^{\circ}C$ and $25^{\circ}C$. Furthermore, Hsp90 mRNA was early increased at $25^{\circ}C$ than $20^{\circ}C$. The ferritin mRNA was similar expression pattern with Hsp90. But, Hsp90 mRNA was more sensitive than ferritin mRNA at high thermal stress. These results indicate that Hsp90 and ferritin mRNAs were involved in the temperature changes response and may be play an important role in mediating the thermal stress in A. japonicas.

• 한국수산과학회지
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• 제49권1호
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• pp.26-29
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• 2016

This study investigated the effects of dietary inclusion of sea mud on growth and body composition of juvenile sea cucumber Apostichopus japonicus. In experiment 1, three experimental diets containing sea mud at the level of 0, 30 and 60% were prepared. After feeding trial for 7 weeks, survival was not significantly different among groups. Final mean weight of sea cucumber fed the experimental diet without sea mud supplementation was significantly higher than that of sea cucumber fed the diet containing 30 and 60% sea mud. In experiment 2, three experimental diets containing sea mud at the levels of 0, 15 and 30% were prepared. After feeding trial for 19 weeks, survival was not significantly different among groups. Final mean weight of sea cucumber fed the diet without sea mud supplementation was not significantly different from that of 15%, but was significantly higher than that of sea cucumber fed the diet containing 30% sea mud. It was concluded that dietary inclusion of sea mud may inhibit growth of sea cucumber.

• 한국수산과학회지
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• 제49권4호
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• pp.474-485
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• 2016

This study compared the fatty acid composition of wild and cultured specimens of the sea cucumber Apostichopus japonicus. We extracted total lipids from the specimens and determined their fatty acid compositions through capillary gas chromatography, resulting in the identification of 53 fatty acids. We found that wild sea cucumbers were rich in palmitoleic (C16:1n-7) and eicosapentaenoic acid (C20:5n-3), whereas cultured specimens were rich in eicosenoic (C20:1n-9) and arachidonic acid (C20:4n-6). In both types of sea cucumbers, the highest percentage of polyunsaturated fatty acids (PUFA) consisted of polar lipids (PL), followed by total lipids (TL) and neutral lipids (NL). Cultured sea cucumbers contained a higher percentage of total lipids (TL) than wild sea cucumbers did, whereas there was no significant difference between the two groups in the percentages of neutral (NL) and polar lipids (PL).

• 한국수산과학회지
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• 제50권4호
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• pp.366-371
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• 2017

Six experimental diets for juvenile sea cucumbers Apostichopus japonicus were evaluated and compared with current commercial diets. Sea cucumbers (50 per tank; initial mean weight $2.3{\pm}0.1g$) in three replicates of seven groups were fed one of six experimental diets (ED1, 20% wild-harvested Sargassum thunbergii powder; ED2, 20% commercial S. thunbergii powder; ED3, 20% Undaria pinnatifida and Ascophyllum nodosum powders; ED4, 40% U. pinnatifida and A. nodosum powders; ED5, 10% brewer's yeast; and ED6, 10% sea shell powder) or a commercial diet (CD) for 28 weeks. The survival rate in all groups was 85-94%, with no significant difference among the experimental groups. The mean body weight of the sea cucumbers was significantly different among the experimental groups 6 weeks after the feeding trial. The final mean weight of the sea cucumbers was highest in ED1, ED3, and ED4, followed by ED6, ED5, ED2, and CD, in decreasing order. The results of this study suggest that U. pinnatifida and A. nodosum powders could provide a substitute for the S. thunbergii powder commonly used in commercial sea cucumber diets. Thus, the EP4 diet formulation, which contains no S. thunbergii, could be used as a practical feed for juvenile sea cucumbers.

• 한국수산과학회지
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• 제52권4호
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• pp.400-407
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• 2019

The optimum growth temperature of sea cucumber is $18^{\circ}C$, above $20^{\circ}C$, the appetite declines and the digestive tract is atrophied. At $25^{\circ}C$ or more, it is known that the digestive tract is degenerated as growth is stopped by minimizing metabolic activity. Because of these physiological and ecological characteristics, the growth period of sea cucumber Apostichopus japonicus is relatively short in the natural environment of Korea where four seasons are clear. Therefore, maintenance of water temperature in sea cucumber culture is very important. This experiment was conducted to investigate the growth and lipid compositions of sea cucumbers at high temperature. Results showed that the growth and survival rates of sea cucumber were not significantly different until $26^{\circ}C$ (P>0.01). The fatty acid compositions of total lipid of sea cucumber tended to increase with saturated fatty acid content and decrease with n-3 fatty acid content at higher water temperature.