• 한국수산과학회지
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• 제36권2호
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• pp.163-169
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• 2003

The floating bead filter was tested for treatment of aquacultural water in a pilot-scale recirculating aquaculture system. Performance of floating bead filter on the removal of total suspended solids (TSS) and the treatment of nitrogen sourer such as total ammonia nitrogen (TAN), nitrite nitrogen and nitrate nitrogen were evaluated. The system was stocked with Nile tilapia at an initial rearing densities of $5\%\;and\;7\%$ over 30 days. The average TSS removal rates were $43.0\;g/m^2{\cdot}day\;and\;39.5\;g/m^2{\cdot}day$ for rearing density of $5\%\;and\;7\%$, respectively. As rearing density increased from $5\%\;to\;7\%$. the TAN removal efficiency decreased from $22.0\%\;to\;17.7\%$. At the rearing densities of $5\%\;and\;7\%$, the average TAN removal rates and removal efficiencies were $38.8\;g/m^2{\cdot}day,\;15.6\%\;and\;37.8\;g/m^2{\cdot}day.\;17.7\%,$ respectively. The average TAN removal rate was $37.8-38.8\;g/m^3{\cdot}day.$ The oxygen consumption by floating bead filter was higher than theoretical oxygen consumption rate by nitrification.

• 한국발생생물학회지:발생과생식
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• 제26권1호
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• pp.13-21
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• 2022

Neurokinin B (NKB) is a neuropeptide involved in the regulation of reproductive endocrine system of vertebrate animals, including fish. However, the pathway of NKB action in fish has not been clearly elucidated. In order to clarify the effect of NKB and NKF (neurokinin F) on gonadotropic hormone (GTH) gene expression in the pituitary, we studied the changes of LHβ and FSHβ gene expressions by using two different pituitary culture methods (whole pituitary culture or dispersed pituitary cell culture). Pituitaries were removed from mature female and male Nile tilapia. Changes of LHβ and FSHβ gene expressions were measured and compared after the treatment with NKB or NKF peptides at concentrations 0 to 1,000 nM. Expression of GTH genes in the whole pituitary cultures treated with NKB or NKF peptides did not show significant difference except in female at one concentration when treated with NKF. On the contrary, there were significant changes of GTH gene expressions in the dispersed pituitary cell cultures when treated with NKB and NKF peptides. These results suggest that dispersed pituitary cell culture is more relevant than whole pituitary culture in studying the function of pituitary, and that NKB and NKF could act directly on the pituitary to regulate the expression of GTH genes.

• 한국양식학회지
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• 제9권4호
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• pp.363-375
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• 1996

천연 astaxanthin 색소를 다량 함유한 phaffia 효모를 양식 어류에게 공급하였을 때, 이 색소가 어류의 성장과 소화, 흡수되는 정도를 조사하기 위하여 이스라엘 잉어($650{\pm}20$ g), 비단잉어($80{\pm}10$ g) 및 나일틸라피아($200{\pm}20$ g)의 사료에 phaffia 효모를 $10\%$ 첨가하여 10주간 공급한 다음 성장률, 체조성, 근육의 탄력도 및 근육 색과 체색 등의 변화를 측정하였다. Phaffia 효모 첨가 사료에 대한 효모 대조구로서 $10\%$의 맥주 효모 첨가 사료구를, 그리고 이들 두가지 반정제 효모 사료에 대한 성장 대조구로서 시판 상품 사료구를 설정하여 10주간 사육한 결과 이스라엘 잉어, 비단잉어 및 틸라피아의 성장에는 모든 사료 공급구에서 유의적인 차이가 없었다(P>0.05). 이들 실험어의 근육 내의 일반 성분은 실험 후에도 현저한 차이가 나타나지 않아(P>0.05), phaffia 효모나 맥주 효모 사료가 체성분 조성에는 영향이 없는 것으로 나타났다. 또한 횟감으로 이용되는 어종인 이스라엘 잉어와 틸라피아의 근육에 쫄깃한 정도를 나타내는 기계적 탄력도와 관능적 탄력도를 측정한 결과 모두 유의적인 차이는 나타나지 않았다(P>0.05). 실험어의 근육에 phaffia 효모에서 유래되는 붉은 색소의 침착은 이스라엘 잉어와 비단잉어 실험구에서는 근육내의 색소 분석과 관능적 측정 실험 모두에서 현저하게 높게 나타났지만(P<0.05), 틸라피아에서는 색소 분석과 관능적 측정 실험 모두에서 유의적인 차이가 나타나지 않았다(P>0.05).

• Fisheries and Aquatic Sciences
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• 제5권1호
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• pp.59-63
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• 2002

Swim up fry of the Nile tilapia, Oreochromis niloticus, were fed 0 or 60 mg l7-methyltestos­terone (MT) per kg feed for 30 days. Fish that had been fed 0 or 60 ppm MT for the first 30 days were subsequently fed a commercial diet for 56 weeks to evaluate growth, survival, sex ratio, body composition, gonadosomatic index and the total edible portion. Mean body weight of MT treated group and untreated group were 1.7 g and 1.1 g, respectively at the end of the treatment for 30 days $(P<0.05)$. The experiment was terminated after a total of 60 weeks, the mean body weight of the MT treated population was 1,016 g and that of the untreated population was 762g $(P<0.05)$. However, the final mean body weight of untreated males (l, 086g) was not significantly different from treated males (l,016 g), but the mean body weight of the female group was 512 g. Therefore, the reason for the lower mean body weight of the untreated group was entirely due to stunted females. The percentage fillet yield of MT treated fish$(34.6\%)$ was not significantly different from that of the untreated males $(34.4\%)$, but the untreated females were lower than those of both treated and untreated male groups $(32.4\%)$ (P<0.05). There were no significant differences in the percentage of the all edible portion (AP) between MT treated and untreated males, but females were lower than males. Females are smaller fish in size and the gonads are larger in proportion which were discarded along with the intestine this explains the observed difference. Total biomass of the two groups were 134.8kg and 104.5kg per $m^3$, respectively. The proportion of fish reaching a marketable size of over 800 g in body weight within 14 months were $78\%$ in the MT treated group and $41\%$ in the untreated group.

• Asian-Australasian Journal of Animal Sciences
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• 제25권1호
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• pp.37-43
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• 2012

We have investigated the effect of melatonin (MLT) on specific growth rate (SGR% $day^{-1}$), condition factor (k), gonado-somatic-index (GSI), histological structures of gonads, serum as well as gonadal protein and lipid in Nile tilapia Oreochromis niloticus. MLT treatment in the dose of 25 ${\mu}g/L$ for three weeks reduced SGR% $day^{-1}$ ($0.9{\pm}0.04$) as compared to control ($1.23{\pm}0.026$). The GSI value was significantly (p<0.05) reduced to $1.77{\pm}0.253$ from control where it was $2.56{\pm}0.25$. Serum protein level increased from $9.33{\pm}2.90$ mg/ml (control) to $11.67{\pm}1.45$ mg/ml after MLT treatment while there was depressed serum triglycerides ($86.16{\pm}1.078$ mg/dl) and cholesterol ($126.66{\pm}0.88$ mg/dl) as compared to control values where these were $123.0{\pm}1.23$ mg/dl and $132.0{\pm}1.65$ mg/dl respectively. Histological structure of ovary showed small eggs of early perinucleolus stage after MLT treatment while testicular structure of control and MLT treated fish was more or less similar. It is concluded that exogenous melatonin suppressed SGR% $day^{-1}$, GSI, ovarian cellular activity, protein and lipid biosynthesis, in tilapia suggesting that melatonin is useful in manipulating the gonadal maturity in fishes.

• 한국수산과학회지
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• 제47권1호
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• pp.23-30
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• 2014

The present study investigated the effects of dietary Edwardsiella tarda (E. tarda) specific bacteriophage (phage) and Bacillus subtilis (B. subtilis) mixture on innate immune responses and antibacterial activity of Nile tilapia, Oreochromis niloticus. In a dietary experiment, tilapia were fed the control diet (C), a phage-only supplemented diet (P), a B. subtilis only supplemented diet (B), or a B. subtilis and phage mixed diet (B+P). A respiratory burst and significant increase in lysozyme activity (P<0.05) were noted in the B+P group, as compared to other groups after 4 days of feeding. The B group showed a significant (P<0.05) increase in respiratory burst and lysozyme activity versus the C and P groups, whereas no significant increases (P<0.05) were observed in the P and C groups. $ACH_{50}$ was significantly up-regulated in the B+P group versus other groups after 8 days of feeding (P<0.05). In vivo antibacterial activity was significantly enhanced in the B+P fed group, as compared to other groups (P<0.05) after 7 days of E. tarda challenge. A significant (P<0.05) increase in antibacterial activity was seen in the B group, as compared to C or P groups after 14 days of feeding. These results suggest that a B. subtilis and phage mixture could be utilized as an alternative to antibiotics in the control of fish diseases caused by E. tarda.

• 한국양식학회지
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• 제11권1호
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• pp.83-90
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• 1998

사료에 한방 생약 제재인 어보산을 첨가하여 틸라피아의 성장을 향상시키고, 사료 계수의 개선을 통한 나일틸라피아의 양식 생산성을 향상시키기 위하여 수행한 실험 결과는 다음과 같다. 1. 사료내 어보산 첨가 농도에 따른 자어의 성장. 어보산 첨가구는 대조구에 비해 어체중 성장, 증체율, 일일 성장률 및 사료 계수가 향상되었다. 첨가구중에서는 0.25%, 0.5% 및 1.0% 첨가구가 2.0%에 비해 어체중 성장, 증체율, 일일 성장률이 높았고 사료 계수는 0.25% 첨가구가 가장 낮았다. 2. 사료내 어보산 0.3% 첨가에 따른 중간 육성어 및 성어의 성장. 어보산 첨가구는 대조구에 비해 어체중 성장, 증체율, 일일 성장률및 사료 계수가 유의하게 좋았다. 3. 어보산이 첨가된 사료를 공급한 실험구의 체조성 분석. 실험어의 등 근육과 간의 단백질, 수분, 지방 및 회분 함량은 대조구와 유의한 차이가 없었다.

• 한국수산과학회지
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• 제45권6호
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• pp.648-653
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• 2012

The present study examined the effects of dietary supplementation with nucleotide (inosine monophosphate product, IMP) on the growth performance, feed utilization, and non-specific immune responses of juvenile tilapia Oreochromis niloticus. Triplicate groups of tilapia (initial body weight, $7.4{\pm}0.04$ g) were fed experimental diets containing 0%, 0.05%, 0.1%, and 0.2% IMP. Fish were fed six times a day until apparent satiation for 13 weeks. At the end of the feeding trial, final body weight and food utilization of fish fed 0.1% IMP were significantly higher than those of fish fed the control diet. Results of hematological parameters were not affected by dietary IMP. However, blood protein level was significantly higher in the 0.05% treatment, as compared to that of the control and 0.2% IMP diets. Myeloperoxidase activity was higher in fish fed 0.1% IMP than in fish fed the control and 0.2% IMP diets. These results suggest that dietary supplementation with IMP can enhance the growth performance, feed utilization, and innate immune response of juvenile tilapia. The optimal IMP supplementation level appears to be 0.1% in practical feed formulations for tilapia.

• Journal of Animal Science and Technology
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• 제56권1호
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• pp.3.1-3.7
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• 2014

We examined the effects of Prunella vulgaris Labiatae (P. vulgaris L.) on specific and non-specific immune responses of Nile tilapia, Oreochromis niloticus. The optimal concentration without toxicity of P. vulgaris was determined to $30-40{\mu}g/ml$ in vitro and $120{\mu}g$/100 g of fish in vivo. P. vulgaris significantly elicited an antibody titer compared to FCA or ${\beta}$-glucan. ${\beta}$-glucan plus P. vulgaris group synergistically enhanced antibody production. No significant difference in antibody production was observed between P. vulgaris and P. vulgaris plus ${\beta}$-glucan group. A respiratory burst activity of head kidney (HK) leucocytes of tilapia administered with 300 or $500{\mu}g$ P. vulgaris was significantly (p < 0.05) enhanced compared with the PBS-injected control group and FCA-treated group. Maximum increase in the NBT reduction value was observed in $500{\mu}g$ P. vulgaris group but no significant difference was found between 300 and $500{\mu}g$ P. vulgaris group. The level of serum lysozyme activity was significantly (p < 0.05) higher in the 300 and $500{\mu}g$ P. vulgaris than $100{\mu}g$ P. vulgaris and FCA group. The phagocytic activities of HK leucocytes from tilapia administered with 300 and $500{\mu}g$ P. vulgaris were significantly (p < 0.05) higher than $100{\mu}g$ P. vulgaris and the control group. P. vulgaris was revealed with a good immunoadjuvant evoking the specific and non-specific immune responses of tilapia.

• 한국어병학회지
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• 제24권2호
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• pp.85-93
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• 2011

Edwardsiella tarda (E. tarda)는 담수 및 해수어에 광범위하게 감염을 일으키는 그람 음성 박테리아이다. 본 연구에서는 서해안 넙치 양식장에서 분리한 E. tarda에 대해 특이 용균을 보이는 파아지를 분리하여 파아지의 활성에 미치는 환경적 요인인 pH와 배양 온도의 영향 등을 조사하였다. 또한 어류모델로서는 담수어종인 Nile tilapia (Oreochromis niloticus)를 이용하였으며 E. tarda와 파아지와의 상호작용을 알아보았다. pH 안정성 실험에서는 담수보다 해수에서 높은 활성을 보였으며 온도 안정성 실험 결과 $50^{\circ}C$까지 일정한 활성을 보였다. Tilapia 감염 실험에서는 파아지와 E. tarda를 접종하였다. 그 결과 실험군은 대조군에 비해 24시간째까지 E. tarda수가 일정하게 감소하는 것을 확인하였으며 파아지는 처음 접종 양보다 약간 증폭됨을 알 수 있었다. 본 연구의 결과는 E. tarda에 의해 발생되는 질병을 특이 파아지를 이용하여 제어할 수 있음을 암시해준다.