• Korean Journal of Organic Agriculture
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• v.8 no.1
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• pp.79-88
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• 1999

In order top investigate the growth of water dropwort grown by sandculture irrigated with recirculated tilapia aquaculture water, these experiments were carried out. Fish(tilapia) production and biofiltration provided by sand cultured water dropwort(Oenanthe stolonifera DC.) were linked in a closed system of recirculation water. Water dropwort was irrigated with water drawn from the tilapia tank and drainage from sand beds was returned to the fish tank. The temperature, pH and EC of tilapia culture water were stable. The growth of water dropwort grown by sandculture with aquaculture water was normal. Microbial activity of the biofilterbed irrigated by tilapia rearing water was higher than that of biofilterbed irrigated by tapwater. The feasibility of an integrated, recirculatory system for concurrent production of water dropwort and fish with no additional fertilization application was demonstrated.

• Journal of fish pathology
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• v.22 no.2
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• pp.147-153
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• 2009

To study the biological activity of interleukin-$1\beta$(IL-$1\beta$), a proinflammatory cytokine, in nile tilapia, Oreochromis niliticus, the recombinant tilapia IL-$1\beta$ was produced in E. coli cells based on pQE vector. Ni-NTA (nitriloacetic acid) metal affinity chromatography was used to purify recombinant protein. The eluted fractions exhibited a single band of protein with a molecular weight of about 25kDa, which is in close agreement with 25.4 kDa predicted by the cDNA sequence. The biological activity of the purified recombinant tilapia IL-$1\beta$ was tested through its effects on IL-$1\beta$ gene expression, which are known as IL-$1\beta$ inducible genes in mammals and fishes. IL-$1\beta$ gene expression induced by poly I:C, a synthetic double stranded RNA, was also assessed in tilapia head kidney cells. IL-$1\beta$ gene expression was analysed using QPCR (quantitative polymerase chain reaction). The ratio of the indicated gene expression was expressed as the relative mRNA level to $\beta$-actin mRNA level, which is constitutively expressed in macrophages. Consequently, head kidney cells incubated for three hours with rIL-$1\beta$(10, 2, 1 $\mu{g}$/ml) showed a dose dependent increase in IL-$1\beta$ mRNA levels and 1 $\mu{g}$/ml of poly I:C was also able to induce IL-$1\beta$ gene expression in head kidney in tilapia.

• Journal of fish pathology
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• v.5 no.1
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• pp.19-27
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• 1992

A formalized bacterin(FKC) of Edwardsiella tarda, conjugated with/without Freund's complete adjuvant(FCA), Freund's incomplete adjuvant(FIA) and potassium aluminium sulfate(PAS), was administered by intraperitoneal injection to tilapia respectively. The tilapia were reared under indoor recirculating filter system. There were agglutinin titer increment in the tilapia which were administered not only FKC bacterin but also adjuvanted vaccines. But the producing time of the highest level of antibody in the immunized tilapia was different among vaccine preparation, i. e. FKC+FCA group and PAS+FKC group are between the 2nd and the 4th week, and FKC alone group is the 2nd week. In the challenge experiment with $2.5{\times}10^7\;CFU/ml$ or $2.5{\times}10^8\;CFU/ml$ of E. tarda T1123 to the tilapia immunized with vaccines, RPS above sixty was recorded both challenge dose in the tilapia which were 3 weeks after immunization with FKC+FCA, PAS+FKC and FKC alone, and the former dose 8 weeks after immunization with FCA+FKC and PAS+FKC. There were some resistance enhancement against E. tarda in the tilapia which were injected with adjuvant alone than that of control. As the results, the FCA or PAS adjuvanted vaccine is effective to sustain the defensible period against edwardsiellosis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.431-437
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• 1996

The efforts of removing the specific fresh water fishy odor were studied by inducing tilapia, Oreochromis niloticus, to sea water in the use of the flavoring chemicals such as pyrrolidine and piperidine as experimental flavors. The amines added to the grinded muscle of tilapia were recovered by $88\%$ for pyrrolidine and $90\%$ for piperidine. When live tilapia were retained in a tank containing 100 ppm solution of the flavor for 30 min and then begun to start the acclimation into sea water with daily increase of $5\%_{\circ}$ salinity within 7days, no amines in the skin and the muscle of tilapia were detected after 4 days of acclimation to sea water. For the purge effects of amino in the skin and the muscle of tilapia, the concentration of pyrrolidine and piperidine lost $73.4\%,\;83.7\%$ in the muscle and $93.6\%,\;90.6\%$ in the skin of tilapia after purging in fresh water for 72 hrs, while $66.2\%,\;73.6\%$ of amines were removed in the muscle and $90.1\%,\;87.7\%$ in the skin of tilapia acclimated to sea water after purging in on sea water for 72hr. Loss rates of pyrrolidine and piperidine were found to be $0.0231h-^{1}\;and\;0.0333\;h^{-1}$ from the muscle and $0.0652h-^{1}\;0.0413\;h^{-1}$from the skin of tilapia in the fresh water, while $0.0131h-^{1}\;and\;0.0354\;h^{-1}$ from the muscle, $0.0674h-^{1}\;and\;0.0549\;h^{-1}$ from the skin of tilapia in the sea water after 24hrs of exposure, respectively.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.195-202
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• 2015

The effects of waterborne arsenic (As) exposure on bioaccumulation and antioxidant defenses were examined in the liver and gills of tilapia, Oreochromis niloticus, under thermal stress. Tilapia were exposed to different As concentrations (0, 200, and $400{\mu}g\;L^{-1}$) at three water temperatures (20, 25, and $30^{\circ}C$) for 20 days. After As exposure, higher levels of As accumulation were observed in the gills compared with the liver in elevated water temperatures. In terms of the antioxidant response, glutathione (GSH) levels and the activities of glutathione reductase (GR), glutathione peroxidase (GPx), and glutathione S-transferase (GST) significantly decreased in the liver and gills of tilapia exposed to As for 20 days, regardless of the As concentration (200 and $400{\mu}g\;L^{-1}$) or water temperature. These enzyme activities exhibited greater fluctuations in the liver and gills of tilapia after As exposure in water warmer than $20^{\circ}C$. The present findings suggest that the simultaneous stress of temperature change and As exposure can accelerate As accumulation and alter the antioxidant enzymes activities of tilapia.

• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.101-108
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• 2023

Recently, in relation to climate change, many studies have been conducted to predict the potential habitat area and distribution range of tilapia and the suitability of habitat for each species. Most tilapia are tropical fish that cannot survive at water temperatures below 10 to 12℃, although some tilapia can survive at 6 to 8℃. This study predicted habitable areas and the possibility of spreading of habitat ranges of tilapia (Oreochromis niloticus and Oreochromis aureus) known to inhabit domestic streams. Due to climate change, it was found that habitats in the Geum River, Mangyeong River, Dongjin River, Seomjin River, Taehwa River, Hyeongsan River, and the flowing in East Sea were possible by 2050. In addition, it was confirmed that tilapia could inhabit the preferred lentic ecosystem such as Tamjin Lake, Naju Lake, Juam Lake, Sangsa Lake, Jinyang Lake, Junam Reservoir, and Hoedong Reservoir. In particular, in the case of tilapia, which lives in tributaries of the Geumho River, Dalseo Stream, and the Nakdong River, its range of habitat is expected to expand to the middle and lower of the Nakdong River system. Therefore, it is judged that it is necessary to prepare physical and institutional management measures to prevent the spread of the local population where tilapia currently inhabits and to prevent introduction to new habitats.

• Journal of Bio-Environment Control
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• v.8 no.3
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• pp.209-215
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• 1999

In order to develop facility for complex farming with aquaculture and vegetable nutrient culture and to investigate growth of tilapia and water quality in the channel type aquaculture system, these experiments were carried out. When tilapia(Tilapia nilotica) was reared in the channel type aquaculture system, Quality of culture water and growth of tilapia were normal. And the growth of tilapia in the channel type and round type aquaculture system was much the same. Channel type aquaculture facilities was applicable to the dual culture system for aquaculture and vegetable culture. Channel type integrated system was composed of aquaculture and sandculture bed, and it was thought that suitable size of the system was about 1.4m(width) $\times$ 1m(height) $\times$ 20m(length).

• Journal of Aquaculture
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• v.12 no.4
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• pp.283-292
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• 1999

Physiological responses (cortisol, glucose, GPT, GOT, hematocrit, sodium, chloride, potassium, total protein and osmolality), growth and survival rates of grey mullet and Nile tilapia were tested by the gradual salinity changes for 70 days. Three different sizes of grey mullet, small (MS, $13.3\pm1.8cm$), middle(MM, $28.9\pm3.6cm$) and large (ML, $36.0\pm2.0cm$), and three different sizes of tilapia, small (TS,$16.5\pm1.7cm$), middle (TM, $20.6\pm1.8cm$) and large (TL, $27.2\pm2.7cm$)were used. Salinity of reareing water was increased $\5textperthousand$ in every 5 days until it reached at $0\textperthousand$. The cortisol concentrations in all size groups of grey mullet were increased at both full strength seawater (SW) and fresh water (FW) at the end. The cortisol concentrations of TM and TL groups were higher in SW than FW (0 and 70 days). The GOT values of grey mullet were lower than those of Nile tilapia. The sodium concentrations of grey mullet in SW were ranged 160~184 mEq/$\ell$, while those of Nile tilapia were the highest in the SW. No mortality was observed in MM and ML groups but survival rate of MS group was 76$\textperthousand$. Overall survival rate of Nile tilapia was lower than grey mullet. Survival rate of TS, TM and TL groups were $79\textperthousand$, $29\textperthousand$ and $55\textperthousand$, respectively.

• Ocean and Polar Research
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• v.38 no.1
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• pp.81-88
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• 2016

In many fish species, including Nile tilapia (Oreochromis niloticus), gonadal development occurs at the expense of stored energy and nutrients. Therefore, reproductive systems are inhibited by limited food supply. It has been well established that reproductive function is highly sensitive to both metabolic status and energy balance. Nothing is known about the possible mediated connection between energy balance and reproduction. Kisspeptin, a neuropeptide product of the Kiss gene has emerged as an essential gatekeeper of reproduction and may be possibly be linked to energy balance and reproduction in non-mammalians. Thus, in this study, the effect of fasting (10 days) on the expression of kisspeptin and the gonadotropin-releasing hormone (GnRH) gene were assessed in Nile tilapia (male and female) using qRT-PCR. In addition, plasma levels of estradiol-$17{\beta}$ ($E_2$) and 11-ketotestosterone (11-KT) in adult tilapia were measured by ELISA. In male tilapia, fasting reduced Kiss2 and GnRH I mRNA expression in the brain and 11-KT level in comparison with the fed tilapia (p < 0.05). In females, however, there were no significant differences in GnRH I mRNA expression and $E_2$ between fish subjected to fasting and those fed (p > 0.05). These data indicate the impact of nutritional states on kisspeptin as a potential regulatory mechanism for the control of reproduction in male Nile tilapia.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.185-190
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• 1993

Tilapia cultured in fresh water were acclimated in sea water with daily increase of $5%_{\circ}$ of salinity and it was completely terminated at the 7th day (0 week). Each three tilapia acclimated were examined weekly based from 0 week to elucidate changes of chloride cells in gill, mineral contents and physical properties in muscle and biochemical characteristics in myofibrils. Chloride cells existed in gills were gradually developed in number and size by acclimation to sea water and became to almost constant state at the third week. Shearing value, compressing strength and content of minerals such as Mg, Na and K in muscle were showed remarkable increase by acclimation to sea water in comparison to those of muscle from tilapia reared in fresh water. Myofibrillar $Mg^{2+}-,\;Ca^{2+}-$ and $K^+(EDTA)-ATPase$ activities of tilapia acclimated in sea water also increased showing significant statistic difference (p<0.01) from those of tilapia reared in fresh water However. thermostability of myofibrils was dropped by acclimation to sea water. The increase of shearing value and compressing strength in the muscle of tilapia by acclimation to sea water would be attributed to the increase of myofibrillar ATPase activities which act to accelerate the decomposition rate of ATP. Therefore, it is suggested that this phenomenon associated with muscle contraction could be brought an improvement of texture of tilapia acclimated in sea water.