• ALGAE
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• 제24권4호
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• pp.257-265
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• 2009

Marine microalgae are a key diet component in finfish and shellfish aquaculture. Cryopreservation of the microalgae is suggested by many other studies as the best method for long-term storage. To test cryopreservation efficacy, 19 taxas of marine microalgal species were examined. In the first experiment we compared dimethylsulfoxide ($Me_2SO$) and glycerol, which are most widely used as cryoprotectant agents (CPAs). The cryopreservation comprised two freezing procedures. Firstly, the samples containing the CPAs were kept at $4^{\circ}C$ for 10 min before being plunged into liquid nitrogen ($-196^{\circ}C$). Secondly, samples containing CPAs were pre-cooled ($-1^{\circ}C$ $min^{-1}$ to $-80^{\circ}C$ before being plunged into liquid nitrogen. Most of the species were successfully cryopreserved using $Me_2SO$, whereas the Prasinophyceae (T. striata and T. suecica) were successfully cryopreserved using glycerol. In general, the cooling method had no influence on the survival of the microalgae except in the case of the Tetraselmis species. In the second experiment, the cultured solution was divided before cryopreservation into concentrated and non-concentrated groups to identify the effect of cell density during cryopreservation. After 12 months of storage, the samples were again divided into centrifugation and non-centrifugation groups to learn the effect of $Me_2SO$ on the culture. Viability and growth of the microalgae were not influenced by cell density or the centrifugal removal of the $Me_2SO$ after thawing.

• 한국어병학회지
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• 제18권3호
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• pp.205-214
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• 2005

최근 2년간 동해안 지역 넙치 양식장의 양식 넙치에 피해를 일으키는 P. damselae 균을 분리하였으며, 분리된 P. damselae의 16s rRNA 염기 서열은 P. damselae subsp. damselae ATCC 33539와 99%의 상동성을 나타내었다. 분리 균주는 Pedersen et al.(1997)의 biotype과 비교한 결과, biotype No 8과 동일하게 나타났으며, P. damselae subsp. damselae ATCC 33539의 LPS와 동일한 단백질 패턴을 나타내었다. 넙치의 병어로부터 P. damselae와 Vibrio 속 세균의 감염 상태를 조사한 결과, P. damselae가 가장 높은 감염율을 나타내었고, 그 다음으로 V. anguillarum, V. splendidus, V. harveyi와 V. ordalii순으로 감염율이 나타났다.

• 한국어병학회지
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• 제18권3호
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• pp.239-245
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• 2005

오배자는 한방에서 지사제 또는 지혈제로 이용되는 약재로 화학요법제와 유사한 효능을 갖는다. 또한 한의학에서는 항암제로서의 가능성에 대한 연구, 의학 분야에서 항산화 성분, 항혈전 효과에 대한 연구가 활발히 진행되고 있다. 어류 질병 분야에서도 이런 특성을 적용하여 치료가 어려운 세균성 질병이나 바이러스성 질병을 예방하고 치료하기 위한 기초 연구로 추출 농도별, 추출 용매별 및 칼럼크로마토그래피법에 의해 얻어낸 분획물의 항균력을 시험하여 다음의 결과를 얻었다. 어병 원인 세균에 대한 오배자 열수 추출액의 농도별 항균력은 1,250 ${\mu}g$/disc가 8균주, 2,500 ${\mu}g$/disc가 9균주, 5,000 ${\mu}g$/disc가 9균주, 10,000 ${\mu}g$/disc가 12균주에 항균력을 나타내어 농도 의존적으로 나타났다.오배자 추출 용매별로는 에탄올 추출물이 15균주, 에틸아세테이트 추출물이 16균주, 부탄올 추출물이 12균주, 그리고 헥산 추출물이 7균주에 항균력을 나타내어 에틸아세테이트로 추출하였을 때 가장 항균력이 좋은 것으로 나타났다.에틸아세테이트 추출물의 실리카겔 칼럼 크로마토그래피법을 실시하여 얻어낸 8개의 분획물로 Streptococcus iniae KCTC3657에 대한 항균력을 시험한 결과, 분획물 4와 5가 가장 우수한 활성을 보였다.

• 한국양식학회지
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• 제10권4호
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• pp.457-462
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• 1997

1997년 9월 1일과 2일 심한 적조가 발생된 해역의 가두리 양식어장에서 적조원인 생물인 Cochlodinium polykrikoides의 주야 수직이동을 세포수와 Chlorophyll a로 분석한 결과 낮에는 표층에서 4 m까지 농밀층이 분포하고 있었으나 저녁에는 저층 10 m, 15 m층에 주로 분포하였다. 이로 볼 때 황토를 이용한 적조방제는 저녁 18시부터 20시까지, 아침 8시부터 10시까지가 눈에 보이지 않는 위험시기이다. 조사 당시 가두리 주위에 황토를 12시부터 18시까지 연속적으로 뿌려 적조를 방제하였으나 가두리 주위에서 용존산소의 분포는 정상이었다. 이때 수질환경 중 pH는 8.45로 정상치보다 높았으며 영양염 중 암모니아와 인산은 군집유지에 효율적으로 이용되었고, 질산염과 규산염은 정상보다 다소 높은 농도를 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.681-698
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• 2022

The Nile tilapia Oreochromis niloticus, Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss, olive flounder Paralichthys olivaceus, common carp Cyprinus carpio, grass carp Ctenopharyngodon idella and rohu carp Labeo rohita are farmed commercially worldwide. Production of these important finfishes is rapidly expanding, and intensive culture practices can lead to stress in fish, often reducing resistance to infectious diseases. Antibiotics and other drugs are routinely used for the treatment of diseases and sometimes applied preventatively to combat microbial pathogens. This strategy is responsible for the emergence and spread of antimicrobial resistance, mass killing of environmental/beneficial bacteria, and residual effects in humans. As an alternative, the administration of probiotics has gained acceptance for disease control in aquaculture. Probiotics have been found to improve growth, feed utilization, immunological status, disease resistance, and to promote transcriptomic profiles and internal microbial balance of host organisms. The present review discusses the effects of single and multi-strain probiotics on growth, immunity, heamato-biochemical parameters, and disease resistance of the above-mentioned finfishes. The application and outcome of probiotics in the field or open pond system, gaps in existing knowledge, and issues worthy of further research are also highlighted.

• 한국수산과학회지
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• 제56권4호
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• pp.473-483
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• 2023

This study was conducted to better understand the impact of marine fish farming by estimating mass balances of carbon and nitrogen. According to the results, 94.55% of carbon and 95.66% of nitrogen inputs were from the feed supplied in the farm. Of the total carbon emissions in the farm, 47.28% was due to fish respiration, which was subsequently released into seawater. Advection and diffusion in the farm contributed to 30.29% of the carbon released. In the case of nitrogen, 50.70% of the nitrogen released into the seawater was produced by fish excreta, and 31.37% was advected and diffused into the system. The sedimentary environment received 3.82% and 3.10% of the carbon and nitrogen released from the farm, respectively. The fish feed used for healthy growth contained 11.64% carbon and 9.17% nitrogen. Since the feed type was floating pellets, the load released into the sedimentary environment was relatively lower than that released into the marine environment. These findings suggest that the identification of an optimal fish feed that respects fish physiology and preserves a healthy ecology is critical for the future of aquaculture. Furthermore, ecosystem-based aquaculture systems that decrease environmental burden, while endeavoring to improve environmental health, are required.

• Fisheries and Aquatic Sciences
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• 제25권12호
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• pp.589-600
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• 2022

Longline fishery targeting tunas and tuna-like species is known to produce a significant amount of catch not only for the target species, but also for ecologically related species like sharks, marine turtles, sea birds and marine mammals. Recognizing this seriousness, tuna related regional fisheries management organizations (t-RFMOs) have established conservation and management measures (CMMs) to reduce bycatch and/or interaction with ecosystem vulnerable species including sea turtles and are obliged to implement bycatch mitigation measures and guidelines on safe release to their member countries. Along with development and strengthening of those measures, various case studies have been conducting to verify the effectiveness of bycatch mitigation for ecologically related species. This study examines the background and progress on developing CMMs of t-RFMOs and regulation programs of the United States related to sea turtles, which have recently become one of the main issues, and reviews case studies on sea turtle bycatch mitigation measures to find out the effectiveness of reducing bycatch rate and impacts to the fisheries. In order to respond the consultation process on certification determination with the United States, it was confirmed the current status of implementation on related measures conducted by Korean tuna longline fishery based on scientific observer data and survey for captains. Even though all Korean tuna longline fleets belong to the deep-set longline fishery (100-300m), which is not subject to the obligation of those mitigation measures, they are voluntarily implementing both measures, use of circle hook and whole finfish bait, regardless of which RFMO's Convention area they operate. And the national regulatory and management programs for sea turtle bycatch prevention adopted by Republic of Korea seems to be comparable in effectiveness to that of the United Stated. However, Korea needs to take preemptive measures in establishing sustainable fisheries, including the protection of the marine ecosystem and environment, as stronger requests are anticipated to be made by the international community on this matter.

• 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.

• 한국양식학회지
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• 제18권4호
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• pp.287-292
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• 2005

본 연구는 넙치 육성용으로 실험 부상배합사료와 시판사료 및 생사료의 효능을 비교하기 위해 평균 체중 43.5 g의 넙치를 8주 동안 사육하였다. 실험사료로 4종류의 부상배합사료(EPl-EP4), 시판사료 4종류(EP5-EP8)및 습사료(MP)를 준비하여 1일 3회 만복으로 공급하였다. 사육실험 결과, 생존율은 모든 실험구에서 $85\%$ 이상으로 양호하였으며, 증중률은 EP2-EP4 실험구에서 가장 높은 값을 보였으며, EP6 실험구에서 가장 낮았다. 사료효율과 단백질효율은 MP 실험구에서 가장 낮은 값을 보인 반면, 일일 사료섭취율과 일일 단백질섭취율은 MP 실험구에서 가장 높은 값을 보였다. 어체의 단백질 함량은 실험구간에 유의한 차이가 없었으나, 수분, 지질 및 회분 함량은 사료에 따라 유의한 차이를 보였다. 혈액의 총 단백질은 모든 실험구간에 유의한 차이가 없었으며 , 중성지방은 EP3 실험구에서 높은 값을 보이긴 하였지만, EP7 실험구를 제외한 모든 실험구간에 유의한 차이는 없었다. 이상의 결과들로 보아 평균체중 42 g${\~}$108 g인 넙치의 성장을 위해 EP2-EP4를 공급하여도 좋을 것으로 판단된다.

• 한국양식학회지
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• 제19권1호
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• pp.47-51
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• 2006

다양한 희석액과 보존온도에 따른 강도다리 (Platichthys stellatus) 정자의 냉장보존 효과가 검토되었다. 강도다리 어미로부터 채정된 정액의 spermatocrit와 정자농도는 각각 $72{\pm}5$와 $6.00{\pm}0.98{\times}10^8/mL$였으며, 정장의 삼투질농도와 pH는 각자 $337{\pm}g\;mmol/kg$과 $7.7{\pm}0.1$이었다. 강도다리 정자의 냉장보존을 위해 희석액으로 인공정장(artificial seminal plasma, ASP), Stein's solution (SS), 해산어류용 생리식염수(marine fish Ringer's solution, MFRS)를 이용하여 각각 $0^{\circ}C,\;2^{\circ}C,\;4^{\circ}C$에서 30일간 보존하면서 정자의 활성을 검토하였다. 강도다리 정자의 냉장보존을 위해서 희석액으로는 SS가 가장 효과적이었으며 보존온도는 $0^{\circ}C$에서 정자의 활성이 가장 좋아 30일 동안 높은 운동성을 유지하였다.