• Fisheries and Aquatic Sciences
• /
• 제5권1호
• /
• pp.1-4
• /
• 2002

The modulatory effects of oxytetracycline treatments at high concentrations on the infection potential of scuticociliates in cultured juvenile olive flounder (Paralichthys olivaceus) and density of the ciliates in culturing water were investigated. The groups bathed with 400 and 500 ppm of oxytetracycline showed significantly lower intensities of scuticociliates on the fish and considerably lower number of the ciliates in culturing water when compared with the control group. However, the intensity of scuticociliates on the fish in the group bathed with 300 ppm of oxytetracycline was not significantly different with that of the control group in spite of considerably lower number of scuticociliates in culturing water than in that of the control group. Although the intensities of scuticociliates on the fish intubated orally with 400 and 500 mg/kg of oxytetracycline were lower than that of the control group, there were no statistical significances. In contrast, the fish fed 300 mg/kg of oxytetracycline showed significantly lower intensity of scuticociliates when compared with other groups. The results of this study suggest that oxytetracycline treatments can modulate occurrence of scuticociliatosis in fish farms probably through change of bacterial density, damaging to scuticociliatosis and immuno-suppression of fish.

• 한국어병학회지
• /
• 제18권1호
• /
• pp.29-37
• /
• 2005

스쿠티카섬모충이 사육중인 자주복에 침입하였을 때 감염어의 외부증상, 행동특성 및 피부, 아가미 그리고 혈관내 충체의 분포 양상을 조사하였다. 스쿠티카섬모충에 감염된 개체는 초기에 체색 변화나 유영행동 등의 외부증상을 인지할 수 없었으나, 몸체에 감염부위가 병리적인 진행에 따라 표피와 지느러미에 발적과 부식, 그리고 궤양증상을 보였다. 또한 감염어는 정상개체와 달리 무리에서 이탈하여 선회 또는 저면에 멈춰 있거나 수면 위로 입올림 하였으며, 일부 개체에서는 돌발적인 유영도 보였다. 사육중인 자주복에 침입한 스쿠티카섬모충은 타원형으로 크기가 20-40 ${\mu}m$ 범위였고, 몸체의 미부에 수축포와 10-12 ${\mu}m$되는 하나의 긴 섬모가 개재되어 있으며, 생식방법은 이분열로 증식하여 형태분류학적인 측면에서 막구충아강 채찍섬모충목의 특색을 나타내었다. 아가미에 스쿠티카섬모충이 감염된 경우에는 아가미 새판상피의 비대로 새엽이 곤봉화 되는 병리적 현상이 있었다. 혈관 속에 침입한 스쿠티카섬모충들은 혈관의 직경 크기에 따라 1-2마리에서 많게는 9-10마리씩 산재하였고, 그들 중 일부 개체에서 적혈구 세포를 섭취한 스쿠티카섬모충이 관찰되었다.

• Journal of Species Research
• /
• 제10권2호
• /
• pp.184-190
• /
• 2021

The diversity of scuticociliates (subclass Scuticociliatia Small, 1967) had previously been superficially investigated in Korea and only 10 species were reported according to the National Species List of Korea published in 2019. Here, we identify four scuticociliates, collected from three coastal water samples, by observing protargol-impregnated specimens. As a result, the present species belong to the order Pleuronematida Fauré-Fremiet in Corliss, 1956 and their lower taxonomic classifications are as follows: family Eurystomatellidae Miao et al., 2010 - Eurystomatella sinica Miao et al., 2010; family Pleuronematidae Kent, 1881 - Pleuronema grolierei Wang et al., 2008, P. setigerum Calkins, 1902, and Schizocalyptra aeschtae Long et al., 2007. The family Eurystomatellidae and the genus Schizocalyptra Dragesco, 1968 are reported for the first time in Korea. Considering that the scuticociliates are a species-rich group and very common in most habitats(including freshwater and terrestrial habitats), our findings indicate that we are far from understanding the complete diversity of Korean scuticociliates.

• 한국어병학회지
• /
• 제31권2호
• /
• pp.109-113
• /
• 2018

The purpose of the present study was to determine whether the scuticocidal activity of olive flounder (Paralichthys olivaceus) head-kidney leucocytes can be enhanced by stimulation with polyinosine-polycytosine [poly (I:C)]. The growth of Miamiensis avidus was not affected by exposure to unstimulated or poly (I:C)-stimulated leucocytes alone, heat-inactivated immune serum alone, or unstimulated leucocytes plus heat-inactivated immune serum. However, leucocytes stimulated with poly (I:C) showed clearly high scuticocidal activity against M. avidus in the presence of heat-inactivated immune serum. Furthermore, numerous poly (I:C)-stimulated leucocytes occupied the surface of scuticociliates in the presence of the heat-inactivated immune serum, which led to lysis of scuticociliates. These results suggest that both of the stimulation of leukocytes and the immobilization of scuticociliates are necessary to kill scuticociliates by leukocytes.

• 한국어병학회지
• /
• 제18권1호
• /
• pp.99-103
• /
• 2005

스쿠티카섬모충에 감염된 자주복의 장, 비장, 신장, 정소, 뇌, 연골 그리고 육질부에 충체의 분포를 조사하였다. 실험어는 사조 CS(주)에서 사육중인 자주복 중 스쿠티카섬모충에 감염된 자주복을 이용하였다. 스쿠티카섬모충은 장, 비장, 신장, 정소, 뇌, 연골, 육질부의 기관을 덮는 결합조직에 분포하고 있다. 뇌에 감염되었을 때 막성조직과 시엽피질 사이가 벌어지는 증상이 있었다. 비장에서 hemosiderin이 과다 침적되는 증상을 제외한 다른 내부 조직과 기관에서는 병리적 증상을 볼 수가 없었다.

• 한국어병학회지
• /
• 제16권2호
• /
• pp.135-138
• /
• 2003

The research was carried out to know the occurrence trend of scuticociliatosis and mortality of fingerlings in flounder. The diseased fish were collected from on-land rearing farms lind hatcheries of flounder in Jeju Island from January 1991 to December 2001. Occurrence of scuticociliatosis was about 10% of total occurred diseases from 1991 to 1996, but increased to 34.5% in 2001. Although monthly occurrence of scuticociliatosis was not related to season from 1999 to 2001, the highest occurrence was revealed in July and August. Mixed infections of bacteria including Vibrio sp. Edwardsiella tarda, Streptococcus sp., and Flexibacter sp. with scuticociliates were observed. Among the bacteria, Vibrio sp. was the highest frequency(40.1%), and the lowest one(10.1%) was Streptococcus sp., Mortality of fingerlings by scuticociliates was different sharply according to size of fish. Mortality of infected fingerlings below 7 cm of total length was 53.8%, while that of normal fingerling above 7 cm of total length was 13.2%. When fish were grown above 25 cm, mass mortality by scuticociliates infection was decreased markedly.

• 한국어병학회지
• /
• 제23권3호
• /
• pp.303-311
• /
• 2010

이전의 연구에서 참가리비(Patinopecten yessoensis) 인공종묘생산 중 수질관리를 위해 주기적으로 실시하는 환수(전량환수)가 scuticociliates 감염을 촉진 할수 있다는 가능성을 제기하였다. 본 연구에서는 수질과 scuticociliates 감염을 고려한 최적 환수 횟수를 결정하고자 하였으며, 유생성장, 생존, scuticociliates 발생을 1차 기준으로 하였으며, 부가하여 중간 육성장으로 이동하여 성장 및 기형 발생율을 2차기준으로 조사하였다. 5일 간격의 환수(3T)가 가장 좋은 결과를 보였다. 잦은 환수(5T)는 수질 개선에도 불구하고 성장 둔화가 확인되었으며, 이것은 scuticociliates의 감염과 연관이 있는 것으로 보였다. 9일간격의 환수(1T) 역시 성장둔화를 보였으며, 5T 실험구와 더불어 중간육성이후 성장 둔화(통계적 유의성 없음)와 비정상 발생을 유발하였다. 본 연구결과 최적 환수간격은 5-7일 사이로 나타났다.

• 한국어업기술학회:학술대회논문집
• /
• 한국어업기술학회 2001년도 춘계 수산관련학회 공동학술대회발표요지집
• /
• pp.538-539
• /
• 2001

자주복(Takifugu rubripes)은 높은 부가가치의 양식품종인 어류이나 이빨이 날카로워 그물을 절단하거나 서로 깨물어 상처를 입히고, 사육시에 공식현상이 타 어종에 비해 심하기 때문에 치어사육 및 양성시 2∼3회에 걸쳐 이빨을 절단하여 사육하는 양식이 까다로운 종이다. 자주복 양성 중에 스쿠티카섬모충(scuticociliates)의 감염에 대한 피해가 확인되었으며, 최근에 들어 양성중인 다른 해산어류에서도 스쿠티카섬모충의 감염이 대량폐사 원인으로 되어 있어 이들 섬모충에 관한 연구가 절실히 필요한 시점이다. (중략)

• 한국수산과학회지
• /
• 제47권1호
• /
• pp.45-51
• /
• 2014

Scuticociliates are regarded as serious pathogens in marine aquaculture worldwide. In Korea, they cause mass-mortalities in fish such as the commercially important olive flounder Paralichthys olivaceus. In particular, mixed infections of scuticociliates with pathogenic bacteria have been commonly reported. During efforts to identify natural marine-algae derived products that possess anti-bacterial and anti-scuticociliate properties, we found that an 80% methanolic extract of the red alga Polysiphonia morrowii Harvey exhibits both anti-scuticociliate activity against Miamiensis avidus, which is a major causative agent of scuticociliatosis, and anti-bacterial activities against fish pathogenic bacteria. Activity-guided fractionation and isolation of the 80% methanolic extract of P. morrowii yielded three bromophenols, which were identified as 3-bromo-4,5-dihydroxybenzyl methyl ether (1), 3-bromo-4,5-dihydroxybenzaldehyde (2) and urceolatol (3) based on spectroscopic analyses. 3-bromo-4,5-dihydroxybenzyl methyl ether (1) showed the highest anti-bacterial and anti-scuticociliate activities, with a minimal inhibitory concentration (MIC) of $62.5{\mu}g/mL$ (against Vibrio anguillarum) and minimal lethal concentration (MLC) of 62.5 ppm (in seawater). Investigations of the anti-bacterial and anti-scuticociliate activities of seventeen bromophenol derivatives, including the three isolated natural bromophenols, showed that the existence of an electron donating group or atom with a non-covalent electron pair at $C_4$ of the 2-bromophenol structure may be important in anti-scuticociliate activity. These findings suggest that the extract and bromophenol derivatives of P. morrowii may provide useful alternatives in aquaculture anti-scuticociliate therapies.

• 한국어병학회지
• /
• 제16권1호
• /
• pp.13-21
• /
• 2003

The infection characteristics with scuticociliates at on-land rearing farms and hatcheries of flounder, Paralithys olivaceus was investigated during the year of 2001 by juvenile infection routes. When culture tanks for living food organisms such as chlorella, rotifer, and Artemia were searched, scuticocilates were detected both in live and dead rotifer, and at the dregs of culture tank bottoms at almost hatcheries. When rotifer infected with scuticocilates fed on fish larvae, lots of scuticocilate were inhabited at the bottom of fry rearing tanks. After feeding on scuticocilates-infected rotifer on fish larvae, first infection was detected at 10 days after bottom dwelling or 40 days old after hatching. By histopathological examination we confirmed the infection route of eyeball or brain contamination was that the ciliate worms digged through mouth and front part of the dosal fin cuticle, transferred into eyeball along the epithelium and muscle tissue, and reached finally into brain by the muscle and nerve tissue. The infection of internal organs was clarified into two routes. The first route was started from the infection at ventral and anal fin rays by the worms, and reached at the anus and rectum through the epithelium and muscle tissue. The second route was initiated from the infection at urinary organ and reached into the rectum epithelium cells, inner wall of intestine, abdominal cavity, pancreas, kidney, and pancreas. At seed production farms where fish larvae fed on scuticocilate-free rotifer, the worms were not detected not only at the food organisms culture tanks and juvenile rearing tanks but also larval flounder less than 7cm in total length.