• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2003년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.201-202
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• 2003

Recently, probiotics is applied for aquaculture management as an alternative method of antibiotics. Probiotics is defined as a live microbial feed supplement which a good effect to the host animal by improving its microbial condition of gastrointestinal tract (Fuller, 1989). Generally, probiotics affect growth and survival of cultured fish, water quality, immune system and so on (Rengpipat et al, 2000, Robertson et al, 2000). (omitted)

• 한국수산과학회지
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• 제29권6호
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• pp.828-836
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• 1996

The histological changes of gill, liver, spleen and muscle, and respiration and blood variables and liver glycogen content were examined in black seabream, Acanthopagrus schlegeli. Fish were exposed to a high level of total ammonia nitrogen (10.4 mg/l) and recovered from exposure $(0.4{\pm}0.2mg/l)$ in a closed recirculating seawater system. In the process of exposure, mortality was $9\%$, and hyperplasia, necrosis or inflammation appeared in all tissues except for muscle. Oxygen consumption was decreased by $49\%$, and red blood cell (RBC) number, hematocrit and hemoglobin concentration were significantly decreased, while plasma glucose contents, activities of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) increased. Liver glycogen content significantly increased from $6.6\%\;to\;10.4\%$. A large amount of hemosiderin was observed in the splenic tissue. During the recovery period, RBC number, hematocrit, hemoglobin concentration, GOT and GPT activities were returned to the normal status. Histological status of liver tissue was returned to the normal, but liver glycogen content was not recovered. During the recovery period, spleen melanin-macrophages temporarily increased, but subsequently decreased to the normal status.

• 한국수산과학회지
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• 제15권1호
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• pp.47-51
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• 1982

1981년 여름 폐쇄식 순환사육 장치에서 붉은 Tilapia정어를 잉어정어와 혼합하여 45일간 사육 실험을 행하여 그 성신 결과를 비교 검토하고 또한 호적조건의 노지에서 성장한 붉은 Tilapia정어의 성장과도 비교하여 보았다. 탱크는 대 부분의 실험기각동안 심한 식물성 Plank-ton의 대량 번식으로 수색이 짙은 녹색으로 유가되었으며, 사육장치 일부에는 개구리밥 (Lemma Sp.)과 배옥잠 (Water hyacinth, Eichhornia crassipes)을 번식시켰다. 실험기간 동안 탱크내에서의 총암모니아농도는 최저 3.4ppm에서 최고 11.2ppm까지 나타났으나 대개 $5\sim7ppm$범위로 유지되었다. 실험탱크내에서의 Tilapia의 일일평균 성장률은 1미의 폐사도 없이 $6.51\%$를 나타낸 반면 같은 탱크에서 사육한 잉어는 약간의 폐사와 함께 $3.61\%$로 저조했고, 또한 노지에서 사육한 Tilapia는 $5.77\%$ 를 나타내었다. 이번 사육실험에 사용한 사료는 잉어사료를 주었으며, U. G. F. (Unknown growth factr)를 감안하여 보조사료로서 사육장치 일부에서 번식시킨 개구리밥을 매일 일정양을 공급했다.

• 한국수산과학회지
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• 제38권6호
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• pp.353-358
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• 2005

The present study investigated the feces production rate and fecal nitrogen production ratio of abalone, Haliotis discus hannai fed seaweed, Undaria pinnatifida. The abalone, with shell lengths of 3 cm, 5 cm, and 7 cm, were tested at temperatures of $12^{\circ}C$, $16^{\circ}C$, and $20^{\circ}C$ in a semi-recirculating aquaculture system. Under the given experimental conditions, the weight specific feces production rate (FPw) of the abalone increased with the decrease of shell length and the increase of temperature. The relationship of the FPw was. $FPw=-3.092+206.573/T - 1916.8/T^2+0.141L -0.037L^2(r^2=0.9412)$. In addition the abalone produced 17.8-22.5% of fecal material against ingested seaweed, Undaria pinnatifida, and $18.4-22.4\%$ of nitrogen ingested total nitrogen.

• Fisheries and Aquatic Sciences
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• 제8권3호
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• pp.128-131
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• 2005

The effects of alternate-week feeding strategies on growth and feed efficiency ratio of juvenile Nile tilapia were investigated in a recirculating aquaculture system. Twenty fish initially weighing 25.5 g were randomly distributed into each of 18 tanks to conduct three replicates for each of six different feeding strategies. Weight gain of fish in the control that were fed daily for 6-week feeding trial was significantly higher than those of fish subjected to various alternate-week feeding regimes. Weight gain of fish that were starved for 3 weeks and then fed daily for 3 weeks (3WS+3WF) was not significantly different from that of fish, starved and fed daily for alternate 1-week period during the trial (1WS+1WF), but was significantly higher than those of fish starved for 2 weeks, and fed for 2 weeks (2WS+2WF); fish starved for 4 weeks and fed for 2 weeks (4WS+2WF); and fish fed for 5 weeks and fed for 1 week (5WS+1WF.) The amount of feed supplied to fish in the groups of 1WS+1WF and 3WS+3WF was significantly lower than that fed to fish in the control group, but significantly higher than the amount feed supplied to fish in the other three groups. Feed efficiency ratio for fish in the control group did not differ from that for fish in the groups of 1WS+1WF, 2WS+2WF and 3WS+3WF, but was significantly higher than that for fish in the groups of 4WS+2WF and 5WS+1WF. In conclusion, juvenile Nile tilapia that were subject to starvation for 1 to 5 weeks did not exhibit compensatory growth sufficient to attain the same weight as fish fed daily for 6 weeks. In addition, fish subjected to starvation exhibited low feed efficiency ratio compared to fish fed daily, which were probably attributable to poor weight gain.

• Fisheries and Aquatic Sciences
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• 제24권6호
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• pp.219-227
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• 2021

The effects of various feeding ratios on the growth, body composition, and blood chemistry of the juvenile mandarin fish Siniperca scherzeri (initial body weight 9.6 g) were examined in recirculating freshwater system equipped with 21, 300 L tanks at 20 fish per tank. The triplicate groups of seven feeding ratios treatments were prepared: 100% (control), 95%, 90%, 85%, 80%, 75%, and 70% of satiation. The feed amount of control group was determined by supplying with apparent satiation and then the feed amounts of the other six feeding groups were determined based on the feed amount of the control group. Fish were hand-fed with test diet (55.4% crude protein) for 10 weeks. Weight gain (WG) and specific growth rate of fish fed to 100% satiation were not significantly (p > 0.05) different from those of fish fed to ≥ 80% satiation but were significantly higher than those of fish fed to 75% and 70% satiation. Feed efficiency, protein efficiency ratio, and protein retention of 100% satiation were not significantly different from those of 95% and 90% satiation but were significantly (p <0.05) lower than ≤ 85% satiation. Condition factor, hepatosomatic index, and coefficient variation were not significantly (p > 0.05) affected by feeding ratio. Whole body composition and contents of hematocrit, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, glucose, total protein, and high-density lipoprotein cholesterol in blood serum were not significantly (p > 0.05) affected by the feeding ratio; however, content of total cholesterol tended to decrease as the feeding ratio decreased. Using broken-line analysis of WG, it was suggested that the optimum feeding ratio of juvenile mandarin fish, ranging from 9.0 g to 37.0 g, appeared to be 87.7% of satiation without growth inhibition.

• 한국수산과학회지
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• 제34권1호
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• pp.51-56
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• 2001

염분변화에 따른 숭어와 틸라피아의 아가미 조직과 전어체의 일반성분을 조사한 결과를 요약하면 다음과 같다. 사육수의 염분조절은 담수로부터 1일만에 $33\%_{\circ}$의 해수가 되도록 사육수를 교환하였고, 이후 15일 후에 다시 담수로 사육수를 교환하여 15일간 담수로 유지하였다. 전 실험기간중 숭어의 아가미 조직상은 별다른 차이를 보이지 않았다. 그러나 틸라피아는 염분상승에 따른 조직의 손상이 관찰되었으며, 해수 2일째에는 아가미 2차 새변 (gill lamella)의 모세혈관들이 응혈 (bloodclot)되고 새변이 중첩되는 조직상을 보였다. 염분이 상승함에 따라 숭어의 아가미 염류세포는 개구부 (apical pit)가 뚜렷하였으며, 많은 수의 미토콘드리아를 가지고 있었다. 틸라피아에서는 실험개시시에는 염류세포 개구부가 거의 닫혀있는 형태를 나타냈으며, 미토콘드리아는 담수 보다 해수에서 증가되었다. 숭어 전어체의 수분 함량은 실험개시시 $74.0\pm0.6\%$, 해수사육 15일째 $73.6\pm0.5\%$, 담수사육 15일째 $74.5\pm0.3\%$로 서로간에 유의한 차이를 보이지 않았다. 그러나 틸라피아에서는 실험개시시 $72.2\pm0.1\%$였다가 해수사육 2일째에는 $70.2\pm0.2\%$로 유의하게 낮아졌다. 숭어의 전어체 단백질 함량은 실험개시시와 15일째 유의한 차이를 보이지 않았다. 틸라피아의 지질 함량은 차이를 보이지 않았으나, 회분 함량은 차이를 나타냈다.

• 한국수산과학회지
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• 제32권2호
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• pp.180-185
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• 1999

본 연구에서는 양식장에서 많이 이용되고 있는 회전원판 반응기를 모의 순환 여과식 양어장에 적용하여 인공 양식수 처리 실험을 행하면서 어류의 최적 사육환경을 유지할 수 있는 운전인자를 도출하고자 하였다. 회전원판 반응기는 수리학적 체류시간이 감소하는 부하변동에대해 $5\~6$일 정도의 시간이 흐른 후 정상상태에 도달하였으며 수리학적 체류시간의 증가에 따라 모의 사육조의 암모니아 농도, 회전원판반응기의 암모니아성 질소 제거율 및 제거속도는 증가하였다. 14.6분의 수리학적 체류시간에서 암모니아성 질소의 제거율은 $82.5\%$로 실험조건 중 가장 낮았으나 사육조의 암모니아성 질소농도는 $1.28g/m^3$으로 가장 낮게 나타났다. 모의 사육조의 용존산소는 수리학적 체류시간의 변화와 무관하게 $5.0\~5.3g/m^3$의 범위로 유지되었으며 회전원판 반응기의 원판이 회전할 때 자체적으로 산소가 공급되어 암모니아 둥의 산화와 관련하여 별도의 용존산소 공급은 필요 없는 것으로 나타났다. 알칼리도 소모속도는 수리학적 체류시간의 증가에 따라 선형적으로 증가하였으며 알칼리도 소모속도와 암모니아제거속도의 비는 평균 7.73으로 암모니아성 질소 1 g의 질산화에 7.73g의 알칼리도가 소모되는 것으로 나타났다 회전원판반응기는 원판에 부착된 일부의 타가영양체 미생물에 의해 용존 유기물이 소모되어 COD가 감소되었으며 COD의 제거속도는 수리학적 체류시간의 감소에 따라 선형적으로 증가하여 14.6분의 수리학적 체류시간에서 $5.59\;g/m^3$의 가장 낮은 농도를 보였다.

• 한국동물생명공학회지
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• 제35권3호
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• pp.279-288
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• 2020

Changes of gonadal morphology and mRNA expression patterns of vitellogenin were investigated in Siberian sturgeon Acipenser baerii (Chondrostei) during its early gonadal maturation period. Early differentiations and morphological transitions of both ovaries and testes appeared to occur actively until the age of 3 years, however from then on, the maturation patterns to full maturity were largely gender-dependent, in which males showed a faster progression of maturation than did females while females experienced a steady-state progress with a lagged interval before entering the final maturation. Expression of vitellogenin mRNAs are closely correlated with transitional patterns of gonadal appearances. In both females and males, hepatic mRNA levels of vitellogenin exponentially increased in the earliest interval (up to 1-year-old). However, in subsequent periods, vitellogenin expression in females continued to increase with age, whereas in males, the expression stabilized at a younger age. Nevertheless, at the age older than or equal to 7-year-old, fully matured individuals showed a quite low level of vitellogenin expression in both females and males. Collectively, results from this study could be useful as a fundamental guideline to address the gonad maturation of this sturgeon species, which is helpful for making practical decisions about farming practices and management for caviar production on local sturgeon farms.

• 한국수산과학회지
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• 제30권2호
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• pp.211-215
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• 1997

감성돔, Acanthopagrus schlegeli 정자의 단기보존을 위한 기초자료를 얻기 위하여, 순환여과사육 시스템에서 사육한 전장 $25.9{\pm}1.7cm$, 체중 $292.8{\pm}53.7g$의 성숙한 어미로부터 정액을 채집하여 정자의 액상보존 효과를 조사하였다. 희석액별 단기 액상보존 실험에서 혈청을 사용하였을 때 보존 10일후 정자의 SAI와 생존율은 각각 0.3, $55.6\%$로 가장 좋았으며, 보존 7일후의 감성돔 알에 대한 수정률도 $47.7\%$로 혈청이 가장 좋았다. 정자를 pH $7\~8$의 희석액에서 보존하였을 때 가장 높은 SAI를 보였으며, 정자의 생존율과 SAI를 높이기 위한 항생제로는 neomycine(800ppm)이 효과적인 것으로 나타났다.