• 한국수산과학회지
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• 제56권6호
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• pp.861-869
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• 2023

This study aimed to evaluate the effectivity of full-fat black soldier fly Hermetia illucens (BSF) and defatted mealworm Tenebrio molitor (MW) larvae meal as a fish meal (FM) substitute in a low-fish meal (LFM) diet for juvenile olive flounder Paralichthys olivaceus. The LFM diet comprising 45% FM with tankage meal, poultry byproduct meal, soy protein concentrate and wheat gluten was the control diet. Three experimental diets were 10% FM in Con with BSF, MW and a mixture of both at the same ratio (designated as B10, M10 and B5M5, respectively). Four hundred and forty-fourth juvenile P. olivaceus (34.3±0.1 g) were randomly distributed into 12 tanks (425 L) in three replicate groups per treatment and fed the experimental diets for 15 weeks. At the end of the feeding trial, growth performance, survival, biological indices (condition factor, viscerosomatic index, hepatosomatic index), non-specific immune responses (lysozyme, myeloperoxidase) and intestinal histology (villi length and goblet cells) were not significantly affected by treatments. Feed utilization was significantly decreased in M10 compared to the control group. Alanine aminotransferase level was significantly higher in M10 than in the control group. Glucose level was significantly lower in B10 than in the control group. These results suggest that BSF and MW can be used as FM substitutes. However, considering feed conversion ratio and AST level, MW availability is thought to be lower than that of BSF, and feeding fish with a diet containing MW for an extended period is thought to adversely affect fish growth.

• 한국수산과학회지
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• 제33권5호
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• pp.469-474
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• 2000

넙치 배합사료의 어분 대체 단백질원으로서 대두박의 이용성을 조사하기 위하여 평균체중 359인 넙치를 각 수조마다 20마리씩 2반복 수용하여 대두박 함량을 $0{\%}, 10{\%}, 20{\%}$ 및 $30{\%}$로 조절한 사료로 45일간 사육실험하였다. 그 결과, 모든 실험구에서 $100{\%}$의 생존율을 나타내었으며, 증중량은 대조구와 대두박 $10{\%}$ 첨가구간에는 차이가 없었지만, 대두박 $20{\%}$ 및 $30{\%}$ 첨가구는 대조구보다 유의하게 낮았다 (P < 0.05). 사료효율과 단백질효율은 사료의 대두박 첨가수준이 높을수록 감소하는 경향을 보였으나, 대조구와 대두박 $10{\%}$ 및 $20{\%}$ 첨가구간에 유의한 차이를 보이지 않았다(P > 0.05). 이와 반대로, 일일사료섭취율과 일일단백질섭취율은 사료의 대두박 첨가수준이 높을수록 증가하는 경향을 보였다. 어체간의 일반성분은 각 실험구간에 유의차가 없었으나 (P > 0.05), 사료의 대두박 첨가수준이 높을수록 단백질과 수분함량은 증가하고, 지질함량은 감소하였다. 혈장 총 콜레스테롤 농도는 사료의 대두박 첨가수준이 높을수록 감소하는 경향을 나타내었으나, 대조구와 대두박 $10{\%}$ 첨가구간에 유의차가 없었다 (P > 0.05) 혈장 GOT는 사료의 대두박 첨가수준이 높을수록 증가하는 경향을 보였다. 이상의 결과로부터, 본 실험 사료 조성으로 넙치 치어를 사육하였을 때, 어분 대체단백질원으로서 대두박을 사료의 $10{\%}$까지 첨가할 수 있을 것으로 판단된다.

• 한국양식학회지
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• 제9권3호
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• pp.279-285
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• 1996

넙치의 전 암컷 집단의 생산을 위한 연구의 일환으로 실제 양식 어민이 손쉽게 이용할 수 있는 성전환 처리방법을 개발하고자, 부화 후 30일째부터 90일까지 60일간 $17{\beta}-methyltestoste-rone$ (MT)과 $estradiol-17{\beta}\;(E_2)$을 $1\~100$ ppb로 매일 2시간 동안 침지하여 성전환을 유도하였다. 부화 후 200일째의 실험군의 성비는 대조군에서 수컷이 $46.7\%$로 나타나 암수비가 거의 1 : 1이었으나, MT에 의한 수컷 유도율은 1 ppb 처리군이 $72.5\%$, 그리고 10 ppb 처리군이 $87.2\%$로 나타났고, 특히 100 ppb 처리군의 경우 $100\%$로 나타났다. $E_2$에 의한 암컷 유도율은 1 ppb 처리군에서 $75.5\%$ ,10 ppb 처리군에서 $91.9\%$였고, 가장 높은 농도인 100 ppb에서는 $97.2\%$로 나타났다. 호르몬 농도에 따른 각 처리군별 생존율 및 성장은 유의한 차이가 없었다(P>0.05).

• 수산해양교육연구
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• 제26권4호
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• pp.808-822
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• 2014

넙치 (Paralichthys olivaceus)로부터 elastase-like serine protease (PoElSp)를 암호화하는 cDNA를 클로닝하여 그 서열을 분석한 결과, PoElSp 유전자는 269 아미노산을 암호화하는 978염기쌍으로 구성되었다. PoElSp 유전자의 조직 특이적 발현 양상을 RT-PCR법으로 조사한 결과, 간, 비장 및 소장에서 그 발현이 크게 나타났다. lipopolysaccharide (LPS)로 인위적 세균감염을 유도한 후, 1시간째에 콩팥에서, 3시간째에는 근육에서, PoElSp 유전자의 발현이 크게 증가하였다. 또한, 이 유전자의 발현은 비장에서 LPS 주입 후 1-24시간동안 점차로 증가하였다. pro-mature PoElSp (proPoElSp)에 해당하는 cDNA를 pET32a 벡터 시스템을 이용하여 대장균에서 발현시켰다. 이 재조합 proPoElSp 단백질의 활성은 gelatin zymography 방법과 합성형광 Z-Phe-Arg-AMC의 분해법을 이용하여 측정하였다. 단백질 분해효소 활성을 위한 최적 pH는 7.5였다. 실험결과들을 종합하면, PoElSp 단백질은 면역 반응에서 중추적 역할을 하리라 판단된다.

• 한국수산과학회지
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• 제54권5호
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• pp.751-760
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• 2021

This study investigated the changes in water quality parameters and microbial colonies when ozone was applied to a semi-recirculating aquaculture system (semi-RAS) for the olive flounder Paralichthys olivaceus (500 g in average weight). Concentrations of ozone-produced oxidants (OPO) in rearing tanks were maintained at 0, 0.014, 0.025 mg/L as Cl₂ for 26 days. Except total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, chemical oxygen demand, and total suspended solids decreased significantly with increasing OPO concentration in daily and weekly monitoring (P<0.05). Colony forming unit (CFU) counts of heterotrophic marine bacteria decreased in an OPO concentration-dependent manner. Overall reduction rates of microbial colonies in the treatments were 80% higher than those of the control (P<0.05). During the experiment, the OPO concentration-driven ozonation was reliably practiced without any adverse effects on the animals cultured in semi-RAS. Considering the biohazard, operating cost, and stability of ozonation, an OPO concentration of 0.014 mg/L would be sufficient to control water quality parameters and microbial colonies in a semi-RAS.

• 한국수산과학회지
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• 제51권6호
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• pp.688-696
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• 2018

This study investigated the effects of ozone-produced oxidants (OPO) on the growth, hematology, and histology of olive flounder Paralichthys olivaceus (average weight 500 g), raised in an ozonated semi-recirculating aquaculture system. The system was ozonated to maintained OPO concentrations of 0.004 (Control), 0.014 (OPO15), and 0.025 (OPO25) mg $Cl_2/L$ in culture tanksfor 26 days. The specific growth rate, feed conversion ratio, and survival rate did not significantly differ among the groups (P>0.05), while the daily feeding rate decreased OPO-dose-dependently (P<0.05). OPO appeared to affect the gill, hepatopancreas, and kidney tissues of fish from ozonated tanks. Hematologically, OPO affected some blood indices. The levels of chloride, glucose, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase were significantly increased in the ozonated groups, while the total cholesterol and cortisol decreased dose-dependently. These results imply that long-term exposure of olive flounder to an OPO concentration ${\geq}0.014mg\;Cl_2/L$ might result in damage to the gill, hepatopancreas, and kidney tissues and cause physiological stress, albeit with no apparent short-term effects on growth or survival.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.70-70
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• 2003

This study was conducted to determine the effects of the dietary microbial phytase (P) supplementation on growth performance and bioavailability of phosphorus in juvenile olive flounder, Paralichthys olivaceus and juvenile Korean rockfish, Sebastes schlegeli fed soybean meal-based diets. Nine experimental diets were formulated to be isonitrogenous and isocalolic to contain 50.0%crude protein (CP) and 16.7kJ, 48.6% crude protein (CP) and 16.0kJ available energy/g without the dietary phytase supplementation for olive flounder and Korean rockfish, respectively : 100% fish meal (FM); 70% FM ＋ 30% soybean meal (SM); 70% FM ＋ 30% SM ＋ Phytase(P) 1000U/kg diet; 70% FM ＋ 30% SM ＋ P 2000U/kg diet; 70% FM ＋ 30% SM with phytase-treated (Ptre) P 1000U/kg diet; 60% FM ＋ 40% SM; 60% FM ＋ 40% SM ＋ P 1000U/kg diet; 60% FM ＋ 40% SM ＋ P 2000U/kg diet; 60% PM ＋ 40% SM with Ptre P 1000U/kg diet. After two weeks of the conditioning period, triplicate groups of 25 fish initially averaging 6.15$\pm$0.04g, was randomly distributed into the aquarium for olive flounder, and 20 fish initially averaging 7.25$\pm$0.04g was randomly distributed into the aquarium for Korean rockfish. After 8 weeks feeding trials, there was no significant difference on weight gain fish fed between 100% FM and 70% FM＋30%SM with Ptre P 1000U in olive flounder and Korean rockfish. Apparent phosphorus digestibility fish fed phytase supplemental diets were significantly higher than those of fish fed phytase non-supplemental diets in olive flounder and Korean rockfish. Therefore, these results indicated that pre-treated soybean meal with phytase 1000U could replace fishmeal up to 30% for the maximum growth of juvenile olive flounder and Korean rockfish. Phytase supplementation could improve apparent digestibility of phosphorus in olive flounder and Korean rockfish fed soybean meal based diets.

• 한국양식학회지
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• 제18권1호
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• pp.60-65
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• 2005

Effects of the commercially available or formulated extruded pellets (EP) and raw fish-based moist pellet (MP) on growth and body composition of flounder Paralichthys olivaceus L. were evaluated on commercial scale for 10 months. Survivals of flounder fed the MP, EP 1 and EP3 were not significantly different from those of fish fed the EP2 or EP5, but significantly (P<0.05) higher than that of fish fed the EP4. Weight gain of fish fed the MP was not significantly different from that of fish fed the EP3 and EP5, but significantly (P<0.05) higher than that of fish fed the EP1, EP2 or EP4. Improvement in weight gain of flounder fed the high lipid diets (EP1, EP2, EP3) compared to low lipid diet (EP4) in the $55\%$ protein level, and weight gain of fish fed the high lipid diet (MP) compared to low lipid diet (EP5) in the $61\%$ protein level indicated protein-sparing effect of lipid. FER for flounder fed the EP3. which was not significantly different from that for fish fed the EP1 or EP5 was significantly (P<0.05) higher thar. that for fish fed the EP2, EP4 and MP. FER significantly (P<0.05) changed over time. CF of flounder fed the MP was significantly (P<0.05) higher than that of fish fed EP1 or EP4. Moisture content of dorsal muscle in flounder fed the EP2 was significantly (P<0.05) higher than that in fish fed the EP1 or EP4. Crude protein content of dorsal. muscle in flounder fed the EP1, EP4 and EP5 was significantly (P<0.05) higher than that in fish fed the EP2. How- ever, crude lipid content of dorsal muscle, and moisture, crude protein and crude lipid content of liver in flounder was not significantly different among the diets. In considering performance of flounder, it can be concluded that the use of EP3 and EP5 is more recommendable than the MP, which commonly used in flounder farm.

• 한국수산과학회지
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• 제40권3호
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• pp.128-132
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• 2007

We identified a microsatellite marker, Poli121TUF, which appears to be significantly linked (P<0.001) with a lymphocystis disease virus (LCDV)-resistance gene in the olive flounder, Paralichthys olivaceus. The olive flounder is an economically important food fish, that is widely cultured in Korea, Japan, and China. Lymphocystis disease has spread in these countries and has seriously reduced the economic value of the fish. LCDV causes lymphocystis cells (LC) to form on the body surface, fins, gills, mouth, and intestine. Fish with LC lose commercial value due to their deformed appearance. The identified micro satellite marker can be used as a candidate locus for marker-assisted selection (MAS) in order to enhance the efficiency of selection for LCDV resistance in the olive flounder.

• 한국어병학회지
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• 제34권1호
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• pp.47-53
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• 2021

Scuticociliates are one of the serious parasitic threats faced by the marine aquaculturists worldwide. To date, Uronema nigricans, Philasterides dicentrarchi, Miamiensis avidus, Uronema marinum, and Pseudocohnilembus persalinus have been reported as the important culprit species causing scuticociliatosis in fish. The present paper reports the finding of an additional scuticociliate isolate from the gill of diseased olive flounder Paralichthys olivaceus in Korea. Based on the morphological characteristics, a scuticociliate in this study was identified as Paranophrys marina. Phylogenetic analysis placed P. marina as a sister lineage to three species of Pseudocohnilembus and Mesanophrys carcini within the order Philasterida.