• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.3
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• pp.279-286
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• 1996

Cultivated tilapia (Oreochromis niloticus) in the fresh water were acclimated to the sea water to improve palatability of the fish meat. Physicochemical properties in the rigor mortis of those fish meats were investigated during storage at $0^{\circ}C,\;10^{\circ}C\;and\;20^{\circ}C$. The faster onset of rigor mortis was occurred in acclimated meat than fresh water cultivated meat. Both meats stored at $0^{\circ}C$ showed faster figro mortis than at $10^{\circ}C\;and\;20^{\circ}C$. Significant difference was not observed between the breaking strength and the rigor index. The breaking strength reached maximum over 12hrs after death and then gradually declined, and the rigor index was slowly increased and reached maximum over 18hrs after postmortem. Low temperature and acclimation to the sea water affected the degradation of adenosine triphosphate (ATP), accumulation of inosine monophosphate (IMP) or lactate. These results suggest that the palatability of tilapia muscle cultivated in the fresh water could be improved by acclimation to the sea water which induces the prerigor at the early state of postmortem and the physical changes of fish muscle.

• Journal of fish pathology
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• v.31 no.2
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• pp.115-122
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• 2018

The Houttuynia cordata has been utilized for various beneficial purposes in humans mainly because of its potent antioxidant principle quercitrin present in this plant. This study examines the possibility of producing a functional sea food commodity containing active principle quercitrin by feeding H. cordata for a extended period. Spotted sea bass (Lateolabrax maculatus) were fed a diet containing H. cordata at 0.1-1.0% levels for 1 month and tissue concentrations of quercitrin were analyzed in serum, hepatopancreas and muscle. It was observed that quercitrin was found in the ranking order of hepatopancreas>muscle>serum. After a bolus administration of quercitrin (20 mg/kg, oral) to spotted sea bass and Nile tilapia (Oreochromis niloticus), idential rank order was observed after 48 hr. In contrast, the order was liver>serum>muscle in rat and mice, indicating that higher quercitrin distribution occurs to the muscle in fishes compared with in mammals tested. High residue concentration of qeurcitrin in the edible tissue can be an advantageous property in terms of functional food production. High level H. cordata extract inclusion of 1.0% seems to have detrimental effects in spotted sea bass leading to growth retardation and hepatic damage. It was concluded that incorporation of H. cordata extract into diet can be a way of producing healthy foods. However the level of active extract needs fine tuning to avoid toxicity to fishes.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.15-16
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• 2003

이제 바다로부터 식량을 얻는 방법이 어선을 통해 포획하는데서 점점 연근해에서 양식을 통해 생산하는 쪽으로 선회를 하는 것이 세계적인 추세가 되어가고 있다. 이와 같은 양식업의 점진적 발전은 해수 환경을 보전하고 생산 비용을 절감할 수 있는 새로운 형태의 먹이(사료)를 요구하고 있다. 그러나 물고기의 먹이로 적합한 어분 및 잡어의 생산과 공급은 해마다 어족 자원의 고갈로 감소되고 있다. 이런 가운데 양식어종의 사료로 어분이나 잡어를 대체할 수 있는 단백질 공급원을 개발하고 활용하는 연구가 활발히 진행되고 있다. 역사적으로 대두는 약 5000년 전 중국에서 재배되기 시작했다. 사람들은 본격적으로 19세기 초부터 대두에 대한 연구를 시작하여 대두가 사람에게 중요한 단백질과 기름을 제공할 수 있다는 것을 깨달았다. 1950년대 초반에 이르러 대두박이 값싸지만 단백질이 풍부한 사료원료로서의 가치가 입증되면서, 축산업이 오늘의 전성기를 구가할 수 있는 계기가 마련되었다. 그렇지만 바다에서 식량을 생산하는데 있어서도 육지에서 가장 많이 재배되는 두류작물인 대두와 대두제품을 활용하기 시작한 것은 먼 오래전의 일이 아니다. 우리나라뿐만 아니라 세계 여러 나라에서도 담수어종인 잉어, 뱀장어 및 틸라피아등에서 대두박의 영양학적 우수성이나 경제성이 이미 입증된 바 있다. 앞으로 해산어 양식기술의 발달은 해산어용 전문 배합사료의 개발과 보급 없이는 불가능하기 때문에, 미국, 일본, 노르웨이등 해산어 양식 선진국들일수록 이 부문에 대한 연구 개발 노력이 특히 활발하다. 식생활은 물론이고 심지어는 친환경적 산업 제품에 이르기까지 대두와 대두제품이 우리의 각광을 받고 있는 것은 결코 콩이 지닌 물리적 성상, 영양학적 및 경제적 가치의 우수성 때문만은 아니다. 미국은 자국의 대두 생산자들이 생산해 낸 대두를 판매하면서 조성한 자조금을 모아 대두의 생산성을 향상시키기 위한 연구 개발과 국내외 시장을 확대하기 위한 마케팅 활동에 쓰고 있다. 이런 자조 노력은 비단 미국의 대두 농민들에게만 국한된 것이 아니다. 가깝게는 일본의 수산업과 해산어 양식산업의 발전은 중앙 및 지방 정부, 수협과 같은 어민 조합 및 연근해 수산업 종사자들이 출연한 기금을 통해 이루어지고 있음을 지난 8월 북해도의 양식산업을 시찰했을 때 확인할 수 있었던 사실이다. 이제 우리나라도 국민소득 1만불 시대를 넘어 2만불 시대를 열기 위한 청사진을 그릴 만큼 모든 경제의 규모가 확대되었을 뿐 아니라 질적으로 고도화되었다. 우리에게 필요한 것은 성숙된 산업사회에 걸맞는 각 산업 주체들의 의식이다. 한국의 양식산업도 자조 정신을 갖추어 생산성 향상에 초점을 맞춘 양식기술의 개발, 환경 보전을 고려한 양식장 관리 및 소비를 확대하기 위한 유통시스템의 선진화에 스스로 투자를 해야 할 시기에 와 있다.

• Journal of fish pathology
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• v.8 no.2
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• pp.119-134
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• 1995

To induce an overpopulated melanomacrophage centers(MMCs) within spleen and kidney in tilapias, two methods were applied through the intraperitoneal inoculation of V. anguillarum FKC with a repeated dose of saline(the 1st induction group), and of colloidal carbon (the 2nd induction group). In the 1st group, both number and size of MMCs were slightly increased in spleen and head kidney. However in the 2nd group the two hemopoietic tissues were nearly occupied with quite a large number of MMCs. Regardless of induction groups, many of MMCs were confined within the walls of blood vessels in the spleen. Especially in the 2nd group, the MMCs without fibrous capsules often had concentrically or eccentrically located, thin-walled lumens of vessels, which strongly suggests to be ellipsoids. In head kidney, nearly all MMCs were located within or just around the lymphocytic areas but the precise relationship to blood vessel wall was not obvious. Despite of such overpopulated MMCs, no histopathological degenerative findings in hemopoetic parenchymas of both organs were recognized. To evaluate the effect on defensive function, tilapias of the 2nd group were challenged with E. tarda. Susceptabilities to E. tarda were never increased but rather significantly decreased compared to control. Weekly antibody titres in sera were determined for all induction groups, in which the titres in the 1st and 2nd groups were 4 or 8 times higher than in the control, and then remained high until the 4th week. Also with the hemopoietic function, cellular compositions of peripheral blood were analyzed at weekly intervals but no significant changes resulted. From those results, it is suggested that overcrowding of MMCs would not lead to any morphological as well as functional deteriorations of spleen and head kidney but have an intimate association with enhancement of protective immune system in tilapias.

• Journal of fish pathology
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• v.1 no.1
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• pp.5-30
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• 1988

This is a comprehensive study for considering the effective treatment and control program of bacterial disease occurring in common carp, israel carp, color carp, crucian carp, eel and tilapia by clarifying the causes, mechanism of infection and onset and the diagnostic criteria. As a first step, the authors investigated the external views, gross and histopathologic findings of diseased fish using 450 infected fishes obtained from various farmer of Korea. This infection was characterized by hyperemia, hemorrhage and swelling of body surface and fins, congestion of liver, spleen, kidney, inflammation of intestine, hemorrhagic inflammation of various tissues, and necrosis and ulcer of various tissues were accompanied in serious cases. Bacteriologically, Aeromonas hydrophila and Edwardsiella tarda were isoiated from these fishes. Particularly in the regular check on 222 eels, 177 strains were isolated as 29.94% of Aeromonas hydrophila, 48.58% of Edwardsiella tarda and 21.47% of Flexibacter columnaris. Hexibacter columnaris was isolated from corroded gill of eels. The identical disease was occurred by innoculating the isolated Aeromonas hydrophila and Edwardsiella tarda and the identical strains were isolated from infected experimental fishes. The eels which were diagnosed Aeromonas disease from Kwangju, Pusan accompanied hemorrhage, swelling of body surface and fins, inflammation of stomach and intestine containing mucous fluids mixed with the pathogens. Color carp and crucian carp which were innoculated with the isolated 5 strins of Aeromomas hydrorphil died within 3 or 4 days accompanying with the characteristics of Aeromonas disease. Edward disease was characterized by abscesses of body surface, pus formation with concentration on phagocytes. The size of absecsses increased with progression elf disease. There were also various abscesses at internal organ and white nodules appeared in kidney. Histologically, various progressive granuloma were examined without inflammation of intestine. Columnaris disease of eels showed no hemorrhage except slight white body color. In autopsy, most of internal organs appeared normal and there were no septic odors. The only character was corrosion of gills. In order to treat these bacterial diseases, infected fishes must bathe in 20ppm chloramphenicol or kanamycin solution for 1 hour. Besides, medication program in oral ingestion of 75mg/kg chloramphenicol per day continuing for 5 to 7 days. After injecting the formalin treated Aermonas hydrophila antigen into carp, relatively high agglutination titer showed between 3 weeks and 6 weeks. Though this titer decreased from that time, it was continued for 18 weeks. In the case of injecting the formalin treated Edwardsiella tarda antigen into tilapia, the titer also increased. But tilapia which were immersed in the suspension fluid of the formalin treated Edwardsiella tarda showed no increase of the titer.