• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.753-760
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• 2013

Two feeding trials were conducted to investigate the effects of feeding rate and frequency on growth performance and body composition of juvenile Korean rockfish Sebastes schlegeli reared at $15.0{\pm}0.3^{\circ}C$. In the first trial, three replicate fish groups averaging $2.07{\pm}0.03g$ were fed a commercial diet with one of seven different daily feeding rates: 1.00%, 2.00%, 2.50%, 2.75%, 3.00%, 3.25%, and satiation (3.34%) based on body weight (BW). After four weeks of feeding, fish fed the 3% diet showed significantly higher weight gain (WG) and feed efficiency (FE) than fish that received the other feeding rates. In the second trial, the optimum feeding frequency was evaluated with three replicate fish groups averaging $2.04{\pm}0.03g$. Fish were fed a commercial diet at 2.87% BW with six different daily feeding frequencies: 2, 3, 4, 5, 7, or 9 meals. After four weeks of feeding, WG, specific growth rate, FE, and protein efficiency rate in fish fed 3 meals $d^{-1}$ were significantly higher than those of fish fed 7 or 9 meals $d^{-1}$. In both feeding trials, proximate composition of the entire body changed depending on the feeding rate or frequency. A broken-line regression analysis based on weight gain suggested that the optimum daily feeding rate and frequency for juvenile Korean rockfish at $15^{\circ}C$ was 2.9% BW $d^{-1}$ and 2-3 meals $d^{-1}$, respectively.

• 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.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.229-234
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• 2002

Possibility of raising sunshine bass during the winter season in Korea was investigated. Also, the effect of feed on growth and body composition of sunshine bass was compared at the various salinity. Twenty sunshine bass $(Mean\;weight\;\pm S.D.\: :\;53.9 \pm 0.24 g)$ were stocked into the eighteen circular flow-through tanks. A 2 (feed) $\times$ 3 (salinity) factorial design with triplicate was used for this study. Feed was prepared into the 2 groups: the raw fish-based me>ist pellet (MP) containing $59.5\%$ crude protein and $9.4\%$ crude lipid, and commercial sinking red sea bream feed (CF) containing $49.9\%$ crude protein and $9.4\%$ crude lipid, respectively. And salinity was prepared into the 3 groups: freshwater $(0\%)$, brackishwater $(15\%)$, and seawater $(32\%)$. Fish were fed to satiation twice daily for 6 days a week. Fish were all survived at the end of the 8-week feeding trial. Weight gain (WG) and specific growth rate (SGR) of sunshine bass were significantly (P<0.05) affected by both feed and salinity. WG and SGR of sunshine bass fed the MP were significantly (P<0.05) higher than those of fish fed the CF in the same salinity. Amount of dry feed fed was significantly (P<0.05) affected by both feed and salinity. Feed consumption by sunshine bass fed on the MP was significantly (P<0,05) higher than by fish fed on the CF in the same salinity. Feed efficiency ratio (FER) was significantly (P<0,05) affected by salinity, but not by feed. Protein efficiency ratio (PER) was significantly (P<0.05) affected by both feed and salinity. Moisture and protein content of the whole-body of fish was not significantly (P>0.05) affected by either feed or salinity. However, lipid and ash content of the whole-body of fish was significantly (P<0.05) affected by salinity, but not by feed. In conclusion, the MP was superior to CF for growth of sunshine bass during the winter season in Korea and no mortality occurred. And sunshine bass seemed to grow better in freshwater $(0\%)$ and brac-kishwater $(15\%)$ than seawater $(32\%)$ under these experimental conditions, in terms of improvement in FER and PER in freshwater or brackishwater.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.552-558
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• 2013

This study was performed to determine effects of the supplementation of Kimchi lactic acid bacterial culture in extruded pellets (EP) on the growth, body composition, blood chemistry and immune response of olive flounder Paralichthys olivaceus. Four hundred eighty individuals averaging 16.1 g were randomly distributed into 12, 180 L flow-through tanks (forty fish per tank). Four concentrations of Kimchi lactic acid bacterial culture (KL) were prepared: Control (0%), 0.1%, 0.2% and 0.5%. Three concentrations (0.1%, 0.2% and 0.5%) of Kimchi lactic acid bacterial culture were each diluted to 10% of EP weight and then fully absorbed by EP for 10 minutes. Each diet was fed to triplicate groups of fish. Fish were hand-fed to apparent satiation twice a day for 8 weeks. At the end of the 8-week feeding trial, the plasma lysozyme and bacterial activities of fish were determined. In addition, the cumulative mortality of fish was monitored for 8 days after their artificial infection with Edwardsiella tarda. The weight gain, specific growth rate, feed efficiency ratio, protein efficiency ratio, protein retention, hepatosomatic index and condition factor of fish were not affected by dietary supplementation with KL. None of the proximate composition, plasma parameters, lysozyme or bactericidal activities of fish was affected by dietary supplementation with KL. However, the cumulative mortalities of fish fed EP containing 0.1% and 0.5% Kimchi lactic acid bacterial culture were relatively low compared to that of fish fed the control diet. In conclusion, dietary supplementation with KL did not effectively improve growth, feed utilization, body composition, plasma chemistry, lysozyme, bactericidal activities or immune response of olive flounder after E. tarda infection under these experimental conditions.

• Ocean and Polar Research
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• v.26 no.3
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• pp.415-423
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• 2004

An experiment was conducted to investigate the differences of total ammonia nitrogen (TAN) excretion rates and feces production rates among the offsprings from cultured Japanese strain (JJ, mean BW; $17.1{\pm}0.1g$), intraspecific hybrid strain between cultured Japanese and selected Korean strain (JK, mean BW: $17.1{\pm}0.1g$) and selected Korean strain(KK, mean BW: $21.5{\pm}0.1g$) of red sea bream in order to compare their dietary protein utilization efficiency. Fish were hand-fed with a commercial diet containing 46.7% crude protein for 2 weeks, three times daily 09:00, 13:00 and 17:00. After daily feeding, the TAN excretion rates reached peaks of 49.03, 58.75 and 36.26mg/kg fish/hr for the JJ, JK and KK strain, respectively, during the daytime. The value of the KK strain was significantly lower than that of the JJ and JX shuin (P<0.05), however daily TAN excretion rates of the JJ, JK and KK strain were not different (P>0.05). When fish were fed at satiation after 4 days of starvation, TAN excretion rates reached the maximum values 4 hours after the feeding fur the KK (31.23 mg/kg fish/hr) and 6 hours after the feeding fur the JJ (44.19 mg/tg fish/hr) and JK strain (41.70 mg/kg fish/hr). After 3 days of starvation, the daily endogenous TAU excretion rates (ETE) for the JJ, JK. and KK strain were 286.91, 215.66 and 179.29mg/kg fish/day, respectively. The value of the KK strain was lower than that of the JJ and JK strain (P<0.05). The total feces production rates of the JJ, JK and KK strain were not significantly different, however the proportions of feces production rates by time for the JJ, JK and KK strain were different (P<0.05). As overall results, efficiency of dietary protein utilization of JJ, JK and KK seems to be different and KK strain could offer a desirable option for aquaculture purpose.

• Journal of Aquaculture
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• v.19 no.2
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• pp.140-146
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• 2006

This study was conducted to investigate the effect of dietary oxidized oil and ${\alpha}$-tocopherol level on growth and body composition of juvenile flounder. To prepare oxidized diets, squid liver oil was oxidized by aeration at $25^{\circ}C$ for 30 days. The six diets were prepared to contain 6% fresh or oxidized squid liver oil as the lipid sources in combination with three levels of ${\alpha}$-tocopheryl acetate at 0, 80 and 800 mg/kg diet. Triplicate groups of fish ($3.9{\pm}0.1$) were fed to apparent satiation twice a day for 8 weeks. Survival was not significantly different among treatments. Weight gain, feed efficiency, daily feed intake, protein efficiency ratio and condition factor of fish fed the fresh oil diets were significantly higher than those of fish fed the oxidized oil diets (P<0.05). The increase of the vitamin E level in diets did not result in any significant improvement on growth performance of fish fed both oil diets. The vitamin E content of the liver and dorsal muscle increased with increasing dietary vitamin E level at both oil diet groups. A decreasing trend in vitamin E content of the tissues was observed in fish fed the oxidized oil diets at the same dietary vitamin E level. Significantly higher moisture content and lower crude lipid content were observed in the whole body of fish fed the oxidized oil diets than fish fed the fresh oil diets (P<0.05). Dietary lipid source affected the fatty acid content of the whole body; higher contents of saturated and monoenoic fatty acids, and lower n-3 HUFA contents such as 20:5n-3 and 22:6n-3 were observed in fish fed the oxidized oil diets than those of fish fed fresh oil diets. The results of this study suggest that the dietary oxidized oil may impair the growth performance, and an increase in ${\alpha}$-tocopheryl acetate supplementation have no beneficial effect on growth and feed efficiency of juvenile flounder.

• Journal of Aquaculture
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• v.10 no.3
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• pp.311-320
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• 1997

The experiment was conducted t determine the effects of water temperature and daily feeding rate on Koran rockfish growth. The first experiment was carried out to know the growth of the fish in the different water temperature. The second experiment was carried out to know the effects of feeding rate of the fish. In the first experiment, feed efficiency was unaffected by the different water temprature 12, 15 and $18^{\circ}C$, but feed intake and growth rate were affected by the water temperature. Feed intake and growth rate of the fish reared in $15^{\circ}C$ were higher than those of the other groups. In the second experiment, feed efficiency was unaffected by feeding rate except the starve group. Daily growth rate of the fish fed 1.0% diet/BW or more. HSI, VSI, condition factor, GOT, GPT, TG, GL and Ht of fed groups were unaffected by the feeding rate in the experiment. Absoption ratios of protein and lipid were not different with the different feeding rates in fed fish groups. These results indicate that the optimum daily feeding rate of yearling Korean rockfish is about 70-80% of satiation rate.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.369-374
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• 2012

A $3{\times}2$ factorial experiment was conducted to determine the effects of dietary protein and lipid levels on the growth and body composition of juvenile far eastern catfish. Six diets were formulated to contain three levels of protein (20%, 30% and 40%) and two levels of lipid (9% and 17%). Triplicate groups of fish (initial body weight of 7.6 g) were hand-fed to apparent satiation for 66 days. Final mean weight was improved with increasing dietary protein and lipid levels, and the highest final mean weight was observed in fish fed the 40/17 (% protein/% lipid) diet. No significant difference was observed in final mean weight for fish fed between 30/17 diet and 40/9 diet. Feed efficiency of fish fed the diets containing over 30% protein levels with 9% and 17% lipid levels were significantly higher than those of fish fed the 20% protein levels. Feed efficiency of fish fed the 30/17 diet was not significantly different from that of fish fed the 40/9 diet or 40/17 diet. Feed efficiency and protein efficiency ratio of fish fed the 20% protein diets with 17% lipid level were significantly higher than those of fish fed 9% lipid diet. Daily feed intake of fish tended to decrease with increasing dietary protein and lipid levels. Moisture content of whole body in fish fed the 9% lipid diets was significantly higher than that of fish fed the 17% lipid diets at the same protein level, but the opposite trends were found for crude lipid content. Significant effects of dietary lipid were observed for most fatty acids, according to their relative values in the diets. The results of this study suggest that the protein requirement for maximum growth of juvenile far eastern catfish may be higher than 40%, and an increase of dietary lipid level from 9% to 17% can improve growth and feed utilization.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.490-498
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• 2011

Two consecutive feeding trials investigated the effects of feeding rate and pellet expansion by water-soaking on the growth performance, blood components and histology of olive flounder Paralichthys olivaceus. The first two experiments were carried out to determine the effects of pellet expansion and feeding rate. In the first experiment, growth performance, feed utilization and survival of fish were not significantly affected by pellet expansion for six weeks. There were no significant differences in hematocrit, hemoglobin, aspartate aminotransferase, alanine aminotransferase, glucose and total protein of fish fed the expanded pellet. However, whole-body lipid content of fish in the non-expanded group was significantly higher than that in the expanded group. Histological analysis of the anterior intestine revealed that fish in the expanded group had shorter and smaller mucous folds. These results indicate that pellet expansion had no beneficial effect in terms of growth performance, feed utilization and fish health. In the second experiment, weight gain and feed efficiency were significantly increased as feeding rate increased from 0 to 2.5% body weight per day (BW/d), but there were no significant differences in weight gain or feeding efficiency in fish fed the expanded pellet at ratios of 2.5% BW/d and satiation for three weeks. Plasma aspartate aminotransferase activity of fish fed the expanded pellet at a ratio of 2.5% was significantly lower than that of starved fish. Histological analysis of the anterior intestine revealed that fish in the 0% group had shorter mucous folds. Broken-line regression analysis suggested that the optimum juvenile olive flounder feeding rate was 3.5% BW/d during the low temperature season ($16-17^{\circ}C$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.232-236
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• 2011

A feeding trial was carried out to investigate the effect of different fish meal and wheat flour contents in extruded pellets on the growth and apparent nutrient digestibility of olive flounder Paralichthys olivaceus. Four extruded pellets (HB1, HB1T, HB2 and HB2T) were prepared using two kinds of high quality brown fish meal and low quality tuna fish meal. Two diets (HB1 and HB2) contained two different kinds of brown fish meal, respectively; in HB1T and HB2T, we substituted 50 % of the brown fish meal with 10 % wheat flour. Three replicate groups of fish (initial body weight of 82 g) were fed the experimental pellets to visual satiation for 15 weeks. The highest weight gain was observed in fish fed HB1, and weight gain of fish fed HB2 was significantly higher than that of fish fed HB2T (P<0.05). Feeding efficiency for fish fed HB1 was significantly higher than that of fish fed HB1T and HB2T (P<0.05), but was not significantly different from fish fed HB2. Apparent dry matter digestibility in HB1 and HB2 was significantly higher than in HB1T and HB2T (P<0.05). The highest crude protein digestibility was observed in HB1, and protein digestibility in HB1T and HB2 was higher than in HB2T (P<0.05). The results of this study suggest that fish meal quality considerably affects growth and nutrient digestibility of olive flounder fed extruded pellets, and the use of HB1 is recommended over HB1T, HB2 and HB2T for efficient olive flounder production.