• Fisheries and Aquatic Sciences
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• v.13 no.1
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• pp.63-70
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• 2010

Two feeding experiments were conducted to investigate the effects of dietary genetically modified (GM) soya and com on growth performance, feed utilization and body composition of juvenile olive flounder, Paralichthys olivaceus and rockfish, Sebastes schlegelii. For each fish species, four isonitrogenous (50% crude protein) and isocaloric (4.1 kcal/g) diets (designated as nGM soya, GM soya, nGM com and GM com) were formulated to contain 20% non-GM (nGM) and GM soya and com. Thirty olive flounder (initial body weight, 15.4${\pm}$0.4 g) and fifty rockfish (initial body weight, 3.1${\pm}$0.02 g) were distributed in each 400 L tank (200 L water) in a flow through system. Each experimental diet was fed to triplicate groups of fish to visual satiation, twice a day (9:00 hand 17:00 h) for 6 weeks. Growth performance was measured every three weeks. No effects of GM feedstuffs on survival were observed. Dietary inclusion of GM feedstuffs did not affect growth performance and feed utilization of fishes, except for rockfish fed GM com. Rockfish fed the GM com diet showed higher weight gain, daily feed intake and daily protein intake than did fish fed the nGM com diet, but no significant differences were observed in final body weight between the dietary treatments. Condition factor, hepatosomatic index, visceral somatic index and body composition were not altered by the inclusion of GM feedstuffs. These results indicate that dietary inclusion of GM soya and com could have no effects on growth performance and feed utilization of juvenile flounder and rockfish. Lower weight gain and feed intake in flounder and rockfish fed the diets containing 20% soya were likely due to anti-nutritional factors, rather than transgenic factors in the feedstuffs. Dietary inclusion of GM soya and com at the level tested did not alter the body composition of fishes. Further studies to investigate the effects of GM feedstuffs on health conditions and the development of fishes, as well as those of residue of transgenic fragments in ambient environments and in animals are necessary for safe use of the ingredients in aquaculture.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.180-186
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• 2022

This study was conducted to investigate the effects of different salinity on growth, survival and hematological parameters of juvenile chum salmon (Oncorhynchus keta). The fish were tested at salinity 0, 10, 20 and 30‰ for 30 days with three replicated groups. After the 30 days, the survival rate was 87.5% or more for 0, 10, 20‰ and significantly decreased to 75% at 30‰. Weight gain, specific growth rate, feed efficiency, daily feed intake, daily protein intake and protein efficiency ratio were the highest at 10‰. In the plasma components, the alanine aminotransferase (ALT) was significantly decreased at 10, 20 and 30‰ in compared with 0‰, whereas sodium (Na⁺) and chloride (Cl^-) was significant increased and there was no significant change in the total protein (TP) and potassium (K⁺). In conclusion, the optimal salt concentration for the growth of juvenile chum salmon (11~33 g) was confirmed to be 10‰, but the association with the change in blood composition should be further studied.

• Journal of Aquaculture
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• v.15 no.4
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• pp.253-260
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• 2002

To find the optimal rearing conditions for Saxidomus purpuratus juvenile, filtering activity was estimated as functions of algal concentration and temperature by measuring the rates of clearance (CR) and ingestion (IR), when S. purpuratus was feeding. The clams were fed on unialgal diet of Isochrysis galbana at 6 algal concentrations (4.6$\times$$10^4$~2.6$\times$$10^6$ cells/ml) and at 6 temperatures (5, 10, 15, 20, 25, and 30^{\circ}C ). Algal concentration significantly affected the CR and the IR at all temperatures. At lower algal concentrations, CR increased, but decreased beyond a particular concentration. The maximum CR ($CR_{max}$) at 5, 10, 15, 20, 25, and 30^{\circ}C were 0.30, 1.73, 5.95, 15.17, 21.12, and 0.33 $l/g/h$, respectively. Below the level of 5.6$\times$10$^{5}$ cells/ml, IR increased as algal concentration increased, but was saturated at higher concentrations. To maintain high growth rate of S. purpuratus, I. galbana should be supplied with more than 5.6$\times$10$^{5}$ cells/ml. The maximum IR ($IR_{max}$) at 5, 10, 15, 20, 25 and30^{\circ}C were $2.2$\times$10^8, $1.5\times$10^9, 3.4$\times$10^9, 4.9$\times$10^9, 5.3$\times$10^9, and 1.0$\times$10^8$ cells/g/h, respectively. As for temperature, both $CR_max$ and $IR_max$ increased remarkably with raising temperature from 5 to 25^{\circ}C, but rapidly decreased at 30^{\circ}C. Between 15 and 25^{\circ}C $CR_{max} and IR_{max}$ were higher and most stable, At this temperature range, the $Q_{10}/s for CR_{max} and IR_{max}$ were 3.5 and 1.6, respectively. Therefore the optimal thermal range for the juvenile is 15~$25^{\circ}C$. The annual variation in IR$_{max}$ predicted by natural seawater temperature shows that inactive period (with lower $IR_max$) lasts for 5 months (from December to April). To ensure higher growth of juvenile during this inactive period at hatcheries, rearing temperature should be elevated to $15^{\circ}C$.>.

• The Korean Journal of Malacology
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• v.31 no.4
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• pp.263-266
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• 2015

This study was performed to determine the effect of water temperature condition on survival rate and growth of juvenile geoduck (Panopea japonica). Panopea japonica juveniles were bred for 6 weeks at 12, 15, 18, 21, 24 and $27^{\circ}C$ on incubator. Juveniles median lethal times (LT50) were 29 hours in $27^{\circ}C$, 14.5 day in $24^{\circ}C$, 37.4 day in $21^{\circ}C$. Survival rate of water temperature 12, 15 and $18^{\circ}C$ showed a high survival rate in 95.0%, 95.0% and 93.3% at 6 weeks. As a result of culturing for 6 weeks at 12, 15, 18, 21 and $24^{\circ}C$, a daily growth of shell length and total weight was 0.10 mm, 0.12 mm, 0.13 mm, 0.16 mm and 0.14 mm, and 2.21 mg, 2.65 mg, 2.84 mg, 3.13 mg and 2.93 mg. Juvenile shell length and total weight have significantly increased at $15-21^{\circ}C$. However, mortality rate has significantly increased at more than $21^{\circ}C$. As a result, appropriate water temperature for juveniles culturing considered $15-18^{\circ}C$.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.11-19
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• 2001

This review discusses the effects and roles of insect hormones and insect growth regulators (IGRs) on vitellogenesis in adult insects. Insect vitellogenesis is regulated by hormones such as juvenile hormone (JH), ecdysteroids, and neurosecretory hormones (ovaryecdysteroidogenic hormone : OEH) released by neurosecretory cells, diet, and other elements(male specific protein of sperm fluid). In the fat bodies, the vitellogenins are synthesized by the stimulation of JH released by corpus allatum (CA) and ecdysteroids produced by follicle cells with the ovary in most insects. Furthermore, vitellogenins are released into the hemolymph, transported to the ovarioles by carrier protein, and incorporated into oocytes for the developing ovary. Of IGRs, juvenile hormone and its mimics such as methoprene and pyriproxifen appear to have pharmacological effects such as membrane lysis, destruction of salivary grand and midgut epithlial cells, fat body cells, and ovarian tissue, and also anti-juvenile hormone such as precocenes I and II appear to have specific cytotoxicity such as inhibition of corpus allatum and oocytes development. These results suggest that IGRs may be useful as agents for integrated pest management.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.746-752
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• 2013

An 8-week feeding experiment was conducted to evaluate three types of squid Sepia esculenta liver powder (SLP) as a dietary protein source for replacement of fish meal (FM) in the juvenile black rockfish, Sebastes schlegeli. For replacement of FM, six experimental diets were formulated with 5 or 10% of either of three types (A, B, C) of SLP: SLP-$A_5$, SLP-$A_{10}$, SLP-$B_5$, SLP-$B_{10}$, SLP-$C_5$, and SLP-$C_{10}$. One of the control diets contained 100% FM as the protein source, and the other was a commercial diet (Com). Fish with an average body weight of $6.50{\pm}0.03g$ ($mean{\pm}SD$) were allocated randomly in triplicate groups of 50 to aquaria and fed the experimental diets until satiation. The weight gain (WG) and specific growth rate (SGR) of fish fed the FM, SLP-$A_5$, SLP-$A_{10}$, and SLP-$B_5$ diets were higher than those of fish fed the Com, SLP-$B_{10}$, SLP-$C_5$ and SLP-$C_{10}$ diets. No significant differences were observed in WG and SGR among the diet groups, with the exception of the SLP-$C_{10}$ diet group. The feed efficiency (FE) and protein efficiency ratio (PER) of fish fed the SLP-$A_5$, SLP-$A_{10}$, and SLP-$B_5$ diets did not differ from those fed the control diet. However, fish fed SLP-$B_{10}$ and SLP-$C_{10}$ had lower FE and PER than the fish fed the FM, commercial, SLP-$A_5$, SLP-$A_{10}$, and SLP-$B_5$ diets. Both the SLP-A and SLP-B diets, but not the SLP-C diets, replaced up to 10% and 5% of FM for juvenile black rockfish, respectively. The results of this experiment provide information that will assist in formulating an inexpensive and practical diet containing SLP for juvenile black rockfish.

• The Korean Journal of Malacology
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• v.25 no.2
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• pp.121-126
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• 2009

This study was performed to determine the effect of temperature condition on growth of juvenile abalone Haliotis discus hannai with the different feeds. Two types of feed (dry sea tangle and experimental diet) at water temperatures of 20 and $23^{\circ}C$, and 23 and $26^{\circ}C$ were applied to experimental abalone twice. Forty-five juvenile abalone averaging 10.1 g in the first feeding trial and 11.5 g in the second feeding trial were randomly stocked into 6 of 50 L plastic rectangular containers each. Fishmeal, soybean meal and shrimp head meal was used as the primary protein source in the experimental diet. And dextrin and wheat flour, and soybean oil were used as the primary carbohydrate and lipid sources in the experimental diet, respectively. The dry sea tangle and experimental diet were fed to abalone once a day at the ratio of 1.5-2.0% total biomass of abalone with a little leftover in each experimental condition. Weight gain of abalone was significantly affected by feed type, but not by water temperature in the first feeding trial. Regardless of water temperature, weight gain of abalone fed the experimental diet was significantly higher than that of abalone fed the dry sea tangle. However, weight gain of abalone was significantly affected by water temperature, but not by feed type in the second feeding trial. Weight gain was highest in abalone fed the experimental diet at $23^{\circ}C$, followed by abalone fed the dry sea tangle at $23^{\circ}C$, abalone fed the experimental diet and dry sea tangle at $26^{\circ}C$, which was lowest. Moisture and crude protein content of the edible portion of abalone was significantly affected by feed type, but not by water temperature in the second feeding trial. However, ash content of the edible portion of abalone was significantly affected by water temperature, but not by feed type. In considering these results, it can be concluded that the well formulated feed was superior to the dry sea tangle for growth of juvenile abalone, and water temperature conditions of 20 and $23^{\circ}C$ seemed to be better than $26^{\circ}C$ to improve weight gain of abalone.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.391-398
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• 1997

Present study describes a method on the application of efficient tissue culture systems for the micro-propagation of juvenile and mature sawtooth oak(Quercus acutissima). Nodal segments with axillary buds were used as initial explant sources. WPM(Woody Plant Medium) was the best in growth and proliferation of shoot among the media tested. Although the single effect of zeatin revealed on two dorminant shoot elongation with normal growth until the elevation of levels up to 3.0mg/l, BAP($N^6$-benzyl amino purine) usually showed better response than zeatin on shoot multiplication and/or elongation. In addition, the incorporation of BAP and zeatin onto the culture media represents more effectiveness in shoot proliferation and its growth. Optimum concentrations of BAP and zeatin were 0.5 and 0.05~1.0mg/l, respectively. Ninety percent of the proliferated shoots was rooted on half-strength GD (Gresshoff and Doy, 1972) medium containing 0.5mg/l IBA(indole butyric acid) in 4 weeks after culture. More than 70% of the rooted plantlets survived after 5 months of transplanting into artificial soil mix containing equal amount of peatmoss and perlite. Among 27 plus tree clones which were grafted twice onto the juvenile rootstocks, only 4 clones revealed the possibility for shoot multiplication through tissue culture system. The capacity for the micropropagation using mature explant sources was highly depended on clonal differences compared with those of octet age. More than 90% of rooting ratio was obtained from the best responding clone. Among the 7 rooting media tested, GD medium was the best far rooting. The most effective rooting was obtained on half-strength GD medium containing 0.2 to 2.0mg/l IBA. More than 60% of rooted plantlets survived after 5 months of transplanting into the artificial soil mix.

• Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.300-307
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• 2010

This study examined the effects of the dietary inclusion of various concentrations of red ginseng byproduct (RB) and a mixture containing red ginseng byproduct, garlic extract, yeast and filler (CR) on the growth, body composition, serum chemistry, and lysozyme activity of juvenile olive flounder (Paralichthys olivaceus). Juvenile fish (n= 630) weighing 5.0 g were randomly distributed into 21 180 L flow-through tanks (30 fish/tank). Seven experimental diets were prepared in triplicate: a control diet without additive, and diets containing 0.5, 1 and 2% concentrations of RB (RB-0.5, RB-1, RB-2) and CR (CR-0.5, CR-1, CR-2) at the expense of wheat flour. After an 8-week feeding trial, serum chemistry and lysozyme activity of fish were measured. Mean weight gain was significantly higher in fish fed the control diet than in fish fed the RB and CR diets. The dietary inclusion of RB and CR reduced feed utilization. Mean serum glucose and triglyceride (TG) levels were higher in fish fed the control diet than in fish fed the other diets. Mean glutamate pyruvate transaminase (GPT) levels of fish fed the control and RB-2 diets were higher than those of fish fed the RB-0.5, RB-1, CR-1, and CR-2 diets. Mean lysozyme activity levels of fish fed the RB-0.5 and RB-1 diets were higher than those of fish fed the control and CR diets. The results of this study indicate that red ginseng byproduct may be utilized as an immunostimulant rather than as a growth promoter for juvenile olive flounder. Dietary inclusion of 0.5% red ginseng byproduct effectively improved serum glucose, GPT, TG, and lysozyme activity of the fish in this study.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.73-73
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• 2003

This study was carried out to evaluate the utilization of fermented skipjack tuna viscera (FSTV) in the diet for juvenile abalone Haliotis discus hannai. Lactobacillus bulgaricus was used for fermentation of skipjack tuna viscera. Eight isonitrogenous (about 30% crude protein) diets were formulated to include different levels (0%, 10%, 20% and 30%) of FSTV as a replacer of either dietary fish meal or soybean meal. Three replicate groups of abalone were fed the experimental diets containing different levels of FSTV for 7 weeks. The inclusion of FSTV up to 30% in fish meal-based diet had no significant effect on survival, body weight, shell growth, and proximate composition of abalone (P>0.05). Weight gain of abalone fed the diet substituting 10% FSTV for soybean meal was not significantly different to that of abalone fed the control diet, however this value decreased in abalone fed the 20% and 30% FSTV (P<0.05).The contents of crude protein and lipid of soft body in abalone fed soybean meal-based diets were significantly affected by dietary FSTV level (P<0.05). The results of this study indicate that FSTV can be used as a partial substitute protein source for fish meal or soybean meal in the formulated diet for juvenile abalone.