• 한국수산과학회지
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• 제50권4호
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• pp.372-377
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• 2017

A feeding trial was conducted to evaluate the effects of partial replacement of fishmeal (FM) protein in a practical diet for rockfish Sebastes schlegeli juveniles with mealworm Tenebrio molitor meal (WM), in terms of growth performance, feed utilization, whole body composition and hematological parameters. Four isonitrogenous and isoenergetic diets were formulated to contain 8, 16, 24 and 32% WM (designated as WM8, WM16, WM24 and WM32). A FM-based diet without WM inclusion was used as a control. Triplicate groups of rockfish ($2.6{\pm}0.07g$) were hand fed one of the experimental diets to visual satiation twice a day for 8 weeks. Weight gain of fish fed the WM32 diet was lower than that of control. No significant differences were found in daily feed intake, feed efficiency and protein efficiency ratio. The whole-body protein content of fish fed WM0 and WM8 diets were significantly higher than that of fish fed WM32 diet. No statistical differences were observed in hematological parameters. These results indicate that WM has potential as alternative to FM in practical diets for juvenile rockfish and can be used at an inclusion level of up to 24% without having a significant negative effects on growth and feed efficiency.

• Ocean and Polar Research
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• 제23권3호
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• pp.285-290
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• 2001

The strength of juvenile black rockfish, Sebastes schlegeli, raised in different hatcheries for wild stock enhancement was evaluated in terms of resistance to an anesthetizing agent, tricaine methane-sulfonate (MS-222), and exposure to drying. The working dosage of MS-222 varied significantly with fish size and hatchery population. Smaller fish were less resistant to the chemical than larger ones. MS-222 effects also differed with fish growth history. The fish cultured in embanked populations showed stronger resistance, earlier recovery, and lower mortality, compared to those cultured in land-based tanks or collected from wild stocks. Similar results were seen in juveniles challenged to dry exposure. These results suggest that an embanked population of black rockfish is more resistant to anesthetic stress, expressed as anesthesia recovery and mortality, and that this population is healthier than others.

• 한국양식학회지
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• 제18권2호
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• pp.92-97
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• 2005

This study examined the partial replacement of the fish meal with meat meal in practical diets for juvenile rock-fish. Five isonitrogenous (48% CP) diets were prepared to contain meat meal at 0% (control), 10%, 20%, 30% and 40% with substituting the mackerel meal in the control diet. Three replicate groups of fish (initial average weight, 4.1g) were hand-fed to visual satiety two times daily for 8 weeks. Survival (>93%) and daily feed intake were not significantly different (P>0.05) among treatments. The best weight gain, feed efficiency and protein efficiency ratio were obtained from fish fed the diets containing 0% and 10% meat meal, and were not significantly different (P>0.05) to those of fish 134 diet containing 20% meat meal. Condition factor, visceralsomatic index and hepatosomatic index were not influenced by dietary meat meal levels. The contents of crude protein and ash of whole body were not significantly affected (P>0.05) by dietary meat meal levels, whereas crude lipid content of fish fed the diets containing 30% and 40% was lower than that of fish fed the control diet. Proximate composition of liver was not influenced by dietary meat meal level (P>0.05). The data obtained in this study indicate that a diet containing $10{\sim}20%$ meat meal could be used for least-cost formulation in juvenile rockfish diet.

• 한국양식학회지
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• 제22권1호
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• pp.112-117
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• 2009

배합사료에 생약재 첨가가 치어기 및 육성기 조피볼락의 성장, 사료이용성 및 체조성에 미치는 영향을 조사하기 위하여, 14가지 생약재 혼합물 및 약쑥과 삼지구엽을 혼합 첨가한 배합사료로 치어기(3.6 g) 및 육성기(166 g) 조피볼락을 8주간 사육실험 하였다. 치어의 생존을, 증중량, 사료 효율, 일일사료섭취량, 단백질 효율, 비만도 및 간중량지수는 사료 침가제에 영향을 받지 않았다(P>0.05). 육성어의 증중량, 일일사료섭취량, 비만도 및 간중량지수는 사료 첨가제에 영향을 받지 않았지만 (P>0.05), 사료 효율과 단백질 효율은 생약재 첨가구가 대조구보다 높은 값을 보였다. 사육실험 종료 후, 치어와 육성어의 등 근육, 간, 장 및 전어체의 일반성분 및 지방산은 모든 실험구간에 통계적인 차이가 없었다(P>0.05). 이상의 결과로부터 조피볼락 치어의 성장 및 사료이용효율이 사료 첨가제에 영향을 받지 않았지만, 육성어의 경우에는 생약재 첨가가 사료이용효율을 개선시킬 수 있을 것으로 판단되며, 어류의 성장단계에 따라 그 효능이 달라질 수 있음을 알 수 있다.

• Fisheries and Aquatic Sciences
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• 제6권2호
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• pp.81-87
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• 2003

Experiments were carried out to investigate the accumulation and the histopathological changes in liver of juvenile rockfish, S. schlegeli, after sub-chronic dietary Cu (0, 50, 125, 250 and 500mg/kg) exposure for 60 days. Cu accumulation in liver was significantly increased with dietary exposure period and concentration for 60 days, and has a linear relation with dietary exposure days. After 60 days of Cu dietary exposure, the Cu concentration in the liver was $75.9\pm12.05,\;126.29\pm22.11\;and\;360.44\pm45.26\;{\mu}g/g$ dry weight and was approximately 11-fold, 18-fold and 51-fold higher than in the control diet group at 125, 250 and 500 mg/kg Cu diet group. The accumulation factors were increased with the dietary exposure period in liver of rockfish. In the primary exposed stage, the effect of hepatic tissue in the rockfish exposed to dietary Cu observed enlargement of hepatocytes nuclei, activity of hepatic cells and the swelling of hepatic cells. While exposed time and concentration were increased, the distinct granulation, irregular shape and necrosis of hepatic cells were observed. It was observed that granule degeneration and necrosis showed a part of cells in hepatic tissue after 60 days at 500 mg/kg.

• Fisheries and Aquatic Sciences
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• 제7권3호
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• pp.115-121
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• 2004

Experiments were carried out to investigate Cd accumulation, elimination and cell response in juvenile rockfish (Sebastes schlegeli) exposed to sub-chronic dietary Cd (0, 0.5, 5, 25 and 125 mg/kg) for 60 days and depuration periods of 30 days. Cd accumulation in the kidney of cock fish increased with exposure periods and concentrations for the 60 days of dietary Cd exposure. After the end of the dietary Cd exposure, Cd accumulation values in the kidney were $52.9{\pm}9.94\;{\mu}g/g$ and $90.6{\pm}15.7\;{\mu}g/g$ for those exposed to 25 mg/kg and 125 mg/kg Cd, respectively. The accumulation factors increased with the exposure period in the kidney. Cd elimination in the kidney of rockfish did not vary significantly and remained constant after the cessation of the dietary Cd exposure. In the primary exposure periods, the effect of kidney tissue in the rockfish exposed to dietary Cd was observed the swelling of capillary of the glomerulus. In addition, there was also hydropic swelling within the pyknotic nuclei, some of hyaline droplet accumulation and the microvilli showed a positive reaction to alcian blue in the tubular cells. While exposure time and concentrations were increased, there was a lot of hyaline droplet accumulation and the microvilli showed a positive reaction to alcian blue in the tubular cells. Fused renal tubule and its necrosis were observed after 60 days at l25 mg/kg.

• Fisheries and Aquatic Sciences
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• 제1권1호
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• pp.42-47
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• 1998

The chemiluminescent (CL) response of phagocytes from juvenile rockfish, Sebastes schlegeli, which were administered orally with levamisole was investigated. The fish intubated with doses of levamisole either at 0.5mg $kg^-$ or 1 mg $kg^-$body weight showed significant increase in CL responses at two weeks after the administration. The increased extent of CL in the fish exposed to 0.5 mg $kg^-$ body weight was considerably lower than that in the fish exposed to 1 mg $kg^-$. The fish exposed to 5 mg $kg^-$ body weight showed a steady and significant increase of CL response after the intubation. The fish intubated with 10 mg of levamisole $kg^-$ body weight, however, showed no significant differences in CL response after the administration. In the experiment of feeding experimental diet, a lower dose of levamisole induced immunostimulation of phagocytes, but higher doses of levamisole induced immunosuppression of phagocytes. At one week after marking and blood sampling, plasma glucose level was significantly increased in the control group and the group intubated 0.5 mg levamisole/kg body weight. However, the fish in another groups, which were administered higher levels of levamisole, showed no significant difference in glucose level after marking and blood sampling. The result of the present study suggests that levamisole can be used as a potent immunostimulator in rockfish by oral administration, and the immunomodulating activity of levamisole depends on the dosage used.

• 한국양식학회지
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• 제11권3호
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• pp.303-310
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• 1998

난황형성 단계에 있는 암컷 어미에게 갑상선 호르몬인 3,5,3'-triiodo-L-thyronine ($T_3$)를 20 mg $T_3$/kg 체중으로 주사하여 출산된 조피볼락 자어를 대조구인 sham구 및 control구 자어와 함께 30일간 사육하면서 성장과 생존율을 비교하였다. 자어에게는 출산후 5일째까지 rotifer를 공급하였고, 6~15일까지 rotifer와 Artemia nauplii를, 이후 30일까지 Artemia nauplii와 넙치용 배합사료를 혼합공급하였다. 출산후 자어의 성장은 대조구들에 비해 $T_3$구에서 유의하게 빨랐으며, 생존율 역시 T하(3)구가 대조구들 보다 유의하게 높았다. 실험종료시 치어의 비만도는 $T_3$구가 control구에 비해 다소 낮았고, sham구에 비해서는 유의하게 낮았다. 이상의 결과, 조피볼락에 대한 $T_3$의 모체주사는 모체에서 유래된 외인성$T_3$가 초기 출산자어의 생리활성을 증진시켜, 자치어의 성장과 생존율 향상에 도움을 줄 수 있는 것으로 평가되었다.

• Fisheries and Aquatic Sciences
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• 제17권2호
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• pp.229-247
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• 2014

Seven feeding trials were conducted to determine the effects of feeding rate and frequency in the Korean rockfish Sebastes schlegeli at seven different water temperatures. Two feeding-rate experiments for 5-g Korean rockfish at $17^{\circ}C$ and $20^{\circ}C$; three feeding rate experiments for 16-g Korean rockfish at $16^{\circ}C$ and $24^{\circ}C$; and finally, two feeding frequency experiments for 93- and 100-g at $15^{\circ}C$ and $20^{\circ}C$ were conducted. Twenty fish averaging $5.5{\pm}0.2$ g ($mean{\pm}SD$) were randomly distributed into 18 indoor tanks containing 40-L seawater from a semi-recirculation system. Fish were fed a commercial diet for 4 weeks at water temperatures of $17^{\circ}C$ and $20^{\circ}C$. Two feeding trials were conducted to determine the optimum feeding frequency in growing Korean rockfish reared at temperatures of $15^{\circ}C$ and $19^{\circ}C$. Broken line regression analysis of weight gain (WG) indicated that the optimum feeding rates of 5-g growing Korean rockfish were 4.48% (BW/day; BW, body weight) at $17^{\circ}C$ and 4.83% (BW/day) at $20^{\circ}C$. Broken line regression analysis of WG showed optimum feeding rates of 16-g juvenile Korean rockfish of 3.41% (BW/day) at $16^{\circ}C$, 3.75% (BW/day) at $20^{\circ}C$, and 3.34% (BW/day) at $24^{\circ}C$. The biological performance, results, along with morphological indices and serological characteristics, suggest that a feeding frequency of 1 meal/day was optimal to improve WG in growing Korean rockfish grown from 93 to 133 g at a water temperature of $15^{\circ}C$, and 100 to 132 g at $19^{\circ}C$.

• Fisheries and Aquatic Sciences
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• 제6권4호
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• pp.213-219
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• 2003

Experiments were carried out to investigate the accumulation and elimination changes in the tissue of juvenile rockfish (Sebastes schlegeli) after sub-chronic dietary Cu (0, 50, 125, 250 and 500 mg/kg) exposure for 60 days and depuration for 30 days. The profile of Cu accumulation in the tissue of rockfish was dependent on the exposure periods and Cu concentration. Liver of rockfish is a more important storage tissue than other tissues, and the order of Cu accumulation in tissues was liver > intestine > kidney > gill > muscle. The accumulation factors were increased with the exposure period in gill, intestine, liver, kidney and muscle. An inverse relationship was observed between the accumulation factor and the exposure concentrations in the gill, kidney and muscle. Cu elimination in tissues of rockfish were decreased with periods for the 30 days of depuration except kidney and muscle. The order of Cu elimination in organs during depuration was intestine > liver > gill.