• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.302-306
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• 2000

Gonad and blood samples were taken from cultured greenling (Hexagrammos otakii), and changes of steroid hormone levels in serum were examined in relation to the gonadosomatic index (GSI). GSI of female and male were not changed significantly between March and August and then began to increase from September showing the highest value in January. Hepatosomatic index (HSI) of female was the highest in December,'then decreased gradually until May. $Estradiol-l7{\beta} (E_2)$ level in blood of female reached to the highest level in December, then decreased rapidly in January. The level was maintained low until August and started to increase In September. Testosterone (T) level in blood of female was similar to trend of $E_2$ in female. $17{\alpha}2{\beta}-dihydroxy-4-pregnen-3-one (17{\alpha}20{\brta}-OHP)$ level in blood of female reached to the maximum in January, and then decreased rapidly from Febuary and maintained low until July. T level in blood of male reached to the highest value in December, and it started to decrease from January and maintained low until July, after then increased again, while $17{\alpha}20{\beta}-OHP$ level of male was similar to trend of female's.

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.122-126
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• 2002

A feeding trial was conducted to determine compensatory growth of juvenile olive flounder in the spring. Five treatments of fish with 3 replicates were prepared: the control group fish (C) fed twice daily for 8 weeks, the Sl, S2, S3 and S4 fish fed for 7, 6, 5 and 4 weeks after 1, 2, 3 and 4 weeks of starvation, respectively. Survival of olive flounder was not significantly different among treatments. Weight gain of flounder in S2 was significantly (P<0.05) higher than that of fish in S3 or S4, but not significantly different from that of fish in C or Sl. The poorest weight gain was observed in fish of S4 treatment. Specific growth rate (SGR) for flounder in S2 was significantly (P<0.05) higher than that for fish in C or S4, but not significantly different from that of fish in Sl or S3. Feed intake (g/fish) was proportional to duration of days of feeding except for flounder in S2, but not significantly different among C, Sl or S2. Feed efficiency ratio (FER) and protein efficiency ratio (PER) for flounder in S2 were significantly (P<0.05) higher than for fish in C, but not significantly different from those for fish in Sl, S3 or S4. Hepatosomatic index (HSI) and condition factor (CF) for flounder in Sl, S3 and S4 were not significantly different from those for fish in C, but significantly (P<0.05) lower than S2 except for CF in Sl at the end of the experiment. Proximate composition of the whole body of flounder was not significantly different among treatments. In considering results of the experiment, juvenile olive flounder achieved compensatory growth when properly fed after starved up to 2 weeks in the spring. Compensatory growth of fish was supported by improvement in SGR, FER and PER in fish starved.

• Journal of Aquaculture
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• v.21 no.4
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• pp.239-243
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• 2008

A $3{\times}2$ factorial experiment was conducted to investigate the proper dietary protein and lipid levels for the growth of sub-adult flounder Paralichthys olivaceus reared during the summer season. Six experimental diets were formulated to contain three levels of protein (45%, 50% and 55%) and two levels of lipid (9% and 14%). Duplicate groups of fish (initial body weight of 298 g) were hand-fed to apparent satiation during the summer season ($21.8{\pm}1.7^{\circ}C$) for 60 days. Survival of each group was over 83% and there was not significant difference among all groups. Weight gain of fish fed the 45% protein diet with 14% lipid was not significantly different from that of fish fed the 50% and 55% protein diets with 9% and 14% lipids, but weight gain of fish fed the 45% protein diet with 9% lipid was significantly lower than that of fish fed the 55% protein diets with 14% lipid. Feed efficiency tended to increase with increasing dietary lipid level at each protein levels, although no significant differences were observed at 50% and 55% protein levels. Protein efficiency ratio, daily feed intake, condition factor and hepatosomatic index were not significantly affected by dietary protein and lipid levels. Crude lipid content of the liver tended to increase with increasing dietary lipid level at the same protein levels, but the opposite appearance was found for moisture content. The contents of moisture, crude protein and crude lipid of the dorsal muscle were not significantly affected by dietary protein and lipid levels. Based on data obtained form this study, inclusion of dietary protein at level of 45% appears sufficient to support optimal growth, and an increase of dietary lipid level from 9% to 14% has beneficial effects on feed utilization of sub-adult flounder during the summer season.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.207-214
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• 2015

The effects of high carbohydrate diet on growth, serum physiological response, and hepatic heat shock protein 70 expression in Wuchang bream were determined at $25^{\circ}C$ and $30^{\circ}C$. At each temperature, the fish fed the control diet (31% CHO) had significantly higher weight gain, specific growth rate, protein efficiency ratio and hepatic glucose-6-phosphatase activities, lower feed conversion ratio and hepatosomatic index (HSI), whole crude lipid, serum glucose, hepatic glucokinase (GK) activity than those fed the high-carbohydrate diet (47% CHO) (p<0.05). The fish reared at $25^{\circ}C$ had significantly higher whole body crude protein and ash, serum cholesterol and triglyceride, hepatic G-6-Pase activity, lower glycogen content and relative levels of hepatic growth hormone (GH) gene expression than those reared at $30^{\circ}C$ (p<0.05). Significant interaction between temperature and diet was found for HSI, condition factor, hepatic GK activity and the relative levels of hepatic GH gene expression (p<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.257-261
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• 2009

Two feeding trials were conducted to investigate the effects of several dietary additives on growth and feed utilization of juvenile flounder. In the first experiment, three replicate groups of juveniles (average weight 1.5 g) were fed diets with or without wasabi extract and chitosan for 7 weeks. Survival rate, weight gain, protein efficiency ratio, hepatosomatic index and condition factor were not affected by the different dietary additives (P>0.05). Feed efficiency of fish fed the wasabi extract diet was significantly higher than that of fish fed the control diet (P<0.05). Daily feed intake of fish fed the wasabi extract diet was significantly lower than that of fish fed the other diets (P<0.05). In the second experiment, three replicate groups of juveniles (average weight 1.4 g) were fed diets with or without Pophyra powder for 7 weeks. Survival rate and weight gain were not significantly affected by dietary Pophyra powder (P>0.05). Feed efficiency and protein efficiency ratio of fish fed the Pophyra diet were significantly lower than those of fish fed the control diet (P<0.05). The results of these experiments suggest that feed efficiency of juvenile flounder may be improved by dietary supplementation with wasabi extract.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.6
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• pp.1285-1293
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• 2013

This study was conducted to investigate the effects of dietary inclusion of various additives Solid sulfur, fucoidan, and glucan on growth performance and immune responses in Juvenile olive flounder paralichthys olivaceus. Six experimental diets supplemented with : no additives (CON); 0.5 and 1.0% solid sulfur (S); 0.2 and 0.4% fucoidan (F); 0.1% glucan (G) of these additives diet on a dry-matter basis. Fish averaging $8.2{\pm}0.17g$ were fed one of six experimental diets in triplicate groups for 6 weeks. By the end of the feeding trial, weight gain, feed efficiency, specific growth rate, protein efficiency ratio, hepatosomatic index and condition factor of fish fed diet CON were significantly lower then those of fish fed the all additives diets (P < 0.05). In challenge test, fish were infected by intraperitonel injection of 0.1 ml bacterial suspension with Edwardsiella tarda per fish after the feeding trial. As a result fish fed All additive diet showed a lower cumulative mortality then did fish fed CON diet throughout the challenge test. In conclusion, these results indicated that solid sulfur, fucoidan and glucan enhanced the growth, feed efficiency and non-specific immune activity of juvenile flounder and protect the fish against microbial infections.

• Journal of Aquaculture
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• v.5 no.2
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• pp.109-115
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• 1992

Effects of intraperitonial injections of human chorionic gonadotropin (HCG) on ovulation and spawning of the loach, Misgurnus mizolepts, were investigated. Matured females spawned successfully by a single dose of 6 IU (HCG) per gram body weight. Spawning usually occured 13 to 25 hours after hormone injection. Most of the eggs were fertilized and hatched normally. Fertilization rate, hatching percentage and Pseudo-gonadosomatic index were not correlated with increasing HCG doses. For the study of multiple spawning of this species, fatness, hepatosomatic and gonadosomatic indices of artificially spawned females were checked for 42 days after first spawning. According to this result, females could spawn again 40 days after first spawning.

• Journal of Aquaculture
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• v.21 no.2
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• pp.107-110
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• 2008

This study was conducted to evaluate extruded pellet for the growth of grower Korean rockfish Sebastes schlegeli. Two replicate groups of 150 fish per each tank(initial mean weight 112 g) were fed one of four experimental extruded pellets for 8 months. Survival was 100% in all groups. Final mean weight, feed efficiency and protein efficiency ratio, feed intake and hepatosomatic index were not significantly different among all groups. Proximate compositions of the whole body and liver were not significantly different among all groups. It can be concluded that the dietary formulation used in four extruded pellets could be applied in the practical extruded pellet for grower Korean rockfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.546-551
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• 2013

This study examined the effects of the dietary inclusion of Porphyra and sea tangle Laminaria japonica on the growth, feed utilization, body composition, and plasma chemistry of juvenile Korean rockfish Sebastes schlegeli. Eight hundred and forty juvenile fish averaging 5.0 g were allocated 40 fish per tank to 21 180-L flow-through tanks. Seven experimental diets were prepared: control (Con) without additive, 0.5 and 1% Porphyra extract (PE), 3% Porphyra powder (PP), 0.5 and 1% sea tangle extract (STE) and 3% sea tangle powder (STP), referred to as PE-0.5, PE-1, PP-3, STE-0.5, STE-1, and STP-3, respectively. Each additive was included in the experimental diet at the expense of the same amount of wheat flour. Each experimental diet was fed to triplicate groups of fish. The experimental diets had no effect on the survival, weight gain or specific growth rate of the fish, feed consumption, feed efficiency ratio, protein efficiency ratio, protein retention, hepatosomatic index, condition factor, moisture or crude protein content of the entire body excluding the liver or moisture, crude protein or crude lipid content of the liver. None of the plasma parameters were affected by the experimental diets. Based on these results, the dietary inclusion of Porphyra and sea tangle did not affect the growth, feed utilization, body composition or plasma chemistry of juvenile Korean rockfish.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.383-390
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• 2014

A 15-wk feeding trial was conducted to examine the supplemental effects of Barodon on growth performance, gastrointestinal histology, feed digestibility and innate immunity in olive founder. A basal commercial diet was used as a control and two other diets were prepared by spraying 0.1% or 0.2% of Barodon. Triplicate groups of fish (BW, 145 g) were fed one of the test diets to apparent satiation twice daily. At the end of the feeding trial, fish growth performance was not significantly affected by dietary treatments; however, feed utilization was significantly improved (linear and quadratic, p<0.05) by Barodon supplementation. Significantly higher (p<0.05) survival rates were obtained in fish fed Barodon containing diets. Hepatosomatic index increased significantly in Barodon treated groups. Also, the use of Barodon resulted in significant increase (linear and quadratic, p<0.05) of intestine length and number of goblet cells. Significantly higher (Quadratic, p<0.05) apparent digestibility coefficient of DM was obtained by supplementation of Barodon. Lysozyme and myeloperoxidase activities increased quadratically and linearly, respectively, in Barodon treated fish. Also, significantly higher (linear and quadratic, p<0.05) superoxide dismutase activity was found in Barodon fed fish. The findings in this study show that inclusion of Barodon in diets for olive flounder improves feed utilization and digestibility, and positively affects digestive tract histology and innate immunity.