• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.2
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• pp.128-138
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• 2011

In this study, energy budget was estimated to produce an efficient artificial seed. And it needs to enhance fisheries productivity of sandfish, A. japonicus. In order to estimate energy budget of the sandfish, A. japonicus juvenile fed on nonriched Artemia nauplii (NA) and the enriched Artemia nauplii (EA), of sandfish were reared at constant condition of seawater temperature of natural temperature (NT) and heated temperature (HT). During the reared period, energy used by the reared juveniles were calculated from estimates of data on ingestion, growth, oxygen consumption, nitrogen excretion and energy content. Energy budget of NT-NA, NT-EA, HT-NA and HT-EA were represented as 100C=66.49G+21.28M+0.78F+1.44U, 100C=67.54G+21.40M+9.39F+1.67U, 100C=66.86G+22.66M+8.01F+2.47U and 100C=67.06G+22.96M+7.70F+2.28U. The assimilation efficiency estimated NT-NA, NT-EA, HT-NA and HTEA were represented as 87.78%, 88.94%, 89.52% and 90.02%. Gross growth efficiency estimated NT-NA, NT-EA, HT-NA and HT-EA were represented as 66.49%, 67.54%, 66.86% and 67.06%. Net growth efficiency estimated NT-NA, NT-EA, HT-NA and HT-EA were represented as 75.75%, 75.94%, 74.68% and 74.49%. In this results, two ways could be considered to produce an efficient artificial seed of sandfish. To hasten the growth of sandfish juvenile, heated seawater (HT) and enriched Artemia nauplii (EA) should be inputted to reared condition. And to increase the energy efficiency, natural seawater (NT) and enriched Artemia nauplii (EA) should be inputted to reared condition.

• Journal of Aquaculture
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• v.21 no.3
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• pp.133-138
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• 2008

We evaluated the effects of dietary supplementation of scoria on growth performances and apparent protein digestibility in juvenile parrot fish Oplegnathus fasciatus and olive flounder Paralichthys olivaceus. In experiment, parrot fish at initial average weight of $7.6{\pm}0.01g(mean{\pm}SD)$ were divided into 9 groups(three groups per dietary treatment) and fed one of three isonitrogenous diets which contained 0%, 1% and 2% of scoria, respectively. Experiment was conducted with juvenile olive flounder to demonstrate the improved apparent digestibility of protein found in the experiment. Five experimental diets were formulated to contain different levels of scoria: Diet 1(control), 0% scoria; diet 2, 1% scoria; diet 3, 2% scoria; diet 4, 3% scoria; and diet 5, 4% scoria. After 9 weeks of feeding trial(Exp), no significant differences were observed on growth performances between Scoria 2% and the control group. However, the growth was significantly lower in scoria 1% compared to that of the control group. Hematological parameters were not affected by the supplementation of scoria. Interestingly, apparent protein digestibility was improved by dietary supplementation of scoria both in parrot fish and olive flounder. The findings suggest that dietary supplementation of 2-3% scoria is optimum levels in order to improve the protein digestibility in the diets for juvenile parrot fish and olive flounder.

• Journal of Aquaculture
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• v.22 no.1
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• pp.112-117
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• 2009

This study were conducted to investigate the effects of several additives in experimental diets on the growth, feed utilization and body composition of juvenile and grower rockfish. Three replicates of juveniles (3.6 g/fish) and two replicates growers (166 g/fish) were fed the experimental diets containing herb medicines mixture, Artemisia asiatica and Epimedium koreanum for 8 weeks. Dietary supplementation with herb medicines mixture had no beneficial effects on growth and feed utilization of juvenile fish. Weight gain, daily feed intake, condition factor and hepatosomatic index of grower fish fed the diet were not affected by dietary additive (P>0.05). Peed efficiency and protein efficiency ratio of grower fish fed the diet containing herb medicines mixture were significantly higher than those of fish fed the control diet (P<0.05), but not significantly different from fish fed the diet containing A. asiatica and E. koreanum (P>0.05). Proximate analysis of whole body, muscle, viscera and liver in the juvenile and grower were not affected by dietary additives (P>0.05). The results of this study suggest that feed efficiency and protein efficiency ratio of grower rockfish may improved by herb medicines mixture supplementation in the diet.

• Journal of Aquaculture
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• v.9 no.3
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• pp.215-222
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• 1996

An experiment was conducted to assess the effects of dietary 3,5,3'-triiodo-L-thyronine ($T_3$) at 0, 10, 20, 50, 100 ppm on growth and survival rate in juvenile black seabream held at $27.9{\pm}1.1^{\circ}C$ for 50 days. Fish were fed the $T_{3}$ experimental diet for 4() days by hand to satiation in $2{\~}4$ times per day. After 50 days period, food intake rate (${\%}$), feed efficiency (${\%}$), survival rate (${\%}$), growth of weight and length (specific growth rates), and condition factor were measured. Food intake rate was inversely related to the dietary $T_{3}$ level. But feed efficiency was not changed by $T_{3}$ level. $T_{3}$ slightly improved survival rate of larvae. Survival rate of larvae from 100 ppm was significantly higher than that of fish from control. Dietary $T_{3}$ influenced growth in length and weight. Growth of black seabream fed a diet containing 10 ppm of $T_{3}$ was significantly higher than that of fish fed control. However 100 ppm of $T_{3}$ induced the inhibition for length and weight growth. The condition factor was inversely related to the dietary $T_{3}$ content.

• Journal of Aquaculture
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• v.13 no.3
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• pp.239-244
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• 2000

To test survival growth of juvenile abalone, five different diet were constituted. Diet 1, the control, was constituted with white fish meal (15%), soybean meal (25%) and wheat flour (25%); diets 2,3 and 4 were constituted to replace each one of these ingradietns by supplementing Sargossum powder (upto 10 %) and the fifth one by Undularia powder. Survival of these abalones differed significantly. Diet 4 supported the fastest growth. There was no significant difference in the composition of these abalones hence Sargassum can be used as a substitute.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.406-412
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• 2014

To evaluate the influence of burrowing substrate on the rearing performance and ambicoloration of cultured flounder, Paralichthys olivaceus, we compared the daily food intake (DFI), feed efficiency (FE), survival, growth, proportion of pigmented skin on the blind side, and proportion of ambicolored fish. We reared juvenile flounders [total length (TL) $4.46{\pm}0.06cm$, body weight (BW) $0.77{\pm}0.03g$] in dark-green fiberglass-reinforced plastic (FRP) aquariums without (control) or with gravel substrate at a density of 200 fishes/ton for 120 days. While there was no difference in survival rate or growth, the DFI was lower and FE higher in the group raised with substrate than in the control. The proportions of pigmented area on the blind side and ambicolored fish were significantly higher in the control tank. Therefore, the supplement of substrate on the aquarium bottom positively affects the feeding efficiency, and inhibits abnormal pigmentation on the blind side in flounder farming at high density.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.745-749
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• 2017

We investigated the effects of different dietary lipid levels (7% or 14%) and feeding frequency (1-4 meals per day) on the growth performance and body composition of juvenile fancy carp Cyprinus carpio var. koi. Three replicate groups of fish (initial mean weight, 11.7 g) were fed to visual satiety with sinking dry pellet diets for 8 weeks. Neither feeding frequency nor lipid level affected fish survival. Weight gain was affected by feeding frequency but not dietary lipid level. Weight gain significantly increased with increased feeding frequency. Feed efficiency and protein efficiency ratio were affected by feeding frequency, but not dietary lipid level. Daily feed intake was affected by feeding frequency and dietary lipid level. Whole body moisture, crude lipid and ash contents were affected by feeding frequency, but not dietary lipid level. Based on these results, we conclude that the appropriate feeding frequency for the optimum growth of fancy carp fingerlings is four meals per day using sinking dry pellet.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.716-720
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• 2023

This study was designed to analyze the effects of reducing water turnover in olive flounder Paralichthys olivaceus farms, focusing on olive flounder growth, decreasing electricity costs, and developing measures to ensure business stability. Daily water turnover was set at 18 in the control group and six in the experimental group. Juvenile fish were reared for 12 months. No significant differences in mean weight were observed between groups until five months. After five months, the mean weight of the control group grew significantly faster than that of the experimental group. Maintaining water turnovers leverl at six turnovers for the first five months after stocking juvenile fish and then increasing water turnover resulted in a 34.4% reduction in electricity costs compared to the control group. This approach presents a potential method to enhance the profitability of olive flounder farms and ensure stable productivity and profitability without sacrificing olive flounder growth.

• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.75-84
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• 2014

To determine a suitable dietary protein/lipid (CP/CL) ratio in the early juvenile stages of hybrid porgy ($F_1$), female red sea bream (RSB) ${\times}$ male black sea bream, five diets with various CP/CL ratios-60/7, 55/12, 51/17, 46/23, and 41/28-were prepared and provided to juveniles in triplicate. At the smaller juvenile stage, $F_1$, weighing 0.32 g, a significantly higher specific growth rate (SGR) and feed efficiency (FE) were seen with 60/7 and 55/12 diets. However, in RSB weighing 0.26 g, SGR and FE were higher with the 60/7 diet than the other diets at $21^{\circ}C$. At the larger juvenile stage, $F_1$, weighing 3.7 g, there was no significant difference in SGR or FE among the diets, but RSB weighing 4.0 g fed 60/7, 55/12, and 51/17 diets had higher SGR and FE than 46/23 and 41/28 diets at $24^{\circ}C$. Moreover, survival and apparent nutrient retention of $F_1$ at both stages were significantly higher than those in RSB. These results indicate that both $F_1$ and RSB weighing ca. 0.3 g require a higher dietary CP/CL than those weighing ca. 4 g. Additionally, $F_1$ in both trials showed the suitability of a lower dietary CP/CL than RSB, indicating that mass production of $F_1$ juveniles will be more economical than RSB.

• Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.171-179
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• 2024

A study was conducted to evaluate dietary valine (Val) requirement for Pacific white shrimp (Penaeus vannamei). Five isonitrogenous (353 g/kg) and isocaloric (4.08 kcal/g) semi-purified diets containing graded levels of Val (2.7, 5.1, 8.7, 12.1 or 16.0 g/kg) were formulated. Quadruplicate groups of 12 shrimp (average body weight: 0.46 ± 0.00 g) were fed one of the experimental diets (2%-5% of total body weight) for 8 weeks. Maximum weight gain was observed in 8.7 g/kg Val group. However, the growth performance was reduced when Val concentration in diets were higher than 12.1 g/kg. Feed conversion ratio was significantly increased with 2.7 and 16.0 g/kg Val inclusion. Shrimp fed the diets containing 2.7 g/kg Val showed significantly lower protein efficiency ratio, whole-body crude protein and Val concentrations. Dietary inclusion of Val significantly improved the relative expression of insulin-like growth factor binding protein and immune-related genes (prophenoloxidase, lysozyme and crustin) in the hepatopancreas and 8.7 g/kg Val group showed highest expression among all the groups. The dietary requirement of Val for maximum growth of juvenile P. vannamei, estimated using polynomial regression analysis on growth, was 9.54 g/kg of Val (27.2 g/kg based on protein level) and maximum growth occurred at 9.27 g/kg of Val (26.2 g/kg based on protein level) based on broken-line regression analysis.