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Mercury isotope ratios in fish tissues have been used to infer sources and biogeochemical processes of mercury in aquatic ecosystems. More experimental studies are however needed to understand the internal dynamics of mercury isotopes and to further assess the feasibility of using fish mercury isotope ratios as a monitoring tool. We exposed Olive flounder (Paralichthys olivaceus) to food pellets spiked with varying concentrations (400, 1600 ng/g) of methylmercury (MeHg) and inorganic mercury (IHg) for 10 weeks. Total mercury (THg), MeHg concentrations, and mercury isotope ratios (δ202Hg, Δ199Hg, Δ200Hg) were measured in the muscle, liver, kidney, and intestine of fish. Fish fed mercury unamended food pellets and MeHg amended food pellets showed absence of internal δ202Hg and Δ199Hg fractionation in all tissue type. For fish fed IHg food pellets, the δ202Hg and Δ199Hg values of intestine equilibrated to those of the IHg food pellets. Kidney, muscle, and liver exhibited varying degrees of isotopic mixing toward the IHg food pellets, consistent with the degree of IHg bioaccumulation. Liver showed additional positive δ202Hg shifts (∼0.63‰) from the binary mixing line between the unamended food pellets and IHg food pellets, which we attribute to redistribution or biliary excretion of liver IHg with a lower δ202Hg to other tissues. Significant δ202Hg fractionation in the liver and incomplete isotopic equilibration in the muscle indicate that these tissues may not be suitable for source monitoring at sites heavily polluted by IHg. Instead, fish intestine appears to be a more suitable proxy for identifying IHg sources. The results from our study are essential for determining the appropriate fish tissues for monitoring environmental sources of IHg and MeHg.

An 8-wk feeding trial was conducted to estimate the optimum dietary protein level and protein-to-energy (P/E) ratio in juvenile parrot fish, Oplegnathus fasciatus. Eight experimental diets were formulated with two energy levels and four protein levels for each energy level. Diets containing crude protein (CP) at 35, 40, 45, and 50% had either 12.5 or 14.6 kJ/g of energy. Fish averaging 7.1 ± 0.06 g (mean ± SD) were fed one of the experimental diets for 8 wk. At the end of the feeding trial, weight gain (WG) of fish fed 45 and 50% CP in the 12.5 kJ/g diet was significantly higher than fish fed the 35% CP diet (P

A 3×2 factorial experiment was conducted to investigate effects of water temperature and feeding rate on growth and body composition of olive flounder. Triplicate groups of fish (initial body weight of 118 g) fed a extruded pellet (55% protein and 4708 ㎈/g) to satiation and at restricted feeding rates of 0.25 and 0.4% body weight per day (BW/d) at the different water temperatures (13 and 18℃) for 9 weeks. Weight gain increased significantly with increase in feeding rates at each temperature. Weight gain of fish fed to satiation was significantly higher at 18 than 13℃, whereas, that of fish fed at 0.25 and 0.4% BW/d were significantly or slightly lower at 18 than 13℃. Feed efficiency and protein efficiency ratio of fish fed to satiation were not significantly different between 13 and 18℃, but those of fish fed at 0.25 and 0.4% BW/d were significantly higher at 13 than 18℃. The major finding of this study is that satiation feeding is efficient for optimal growth and feed efficiency of grower oliver flounder (116-164 g) in suboptimal water temperatures. The maintenance feeding ration which is zero growth performance, were 0.30 and 0.41% BW/day at 13 and 18℃, respectively. In the restricted feeding regime, compromised growth of fish were worsen in higher water temperature (18℃ vs. 13℃). It might be related to high metabolic rate of fish that spend more energy for maintenance metabolism. Based on these results, we suggest that a satiation feeding regime is recommended for a productive growth of grower olive flounder in the suboptimal temperature.

We conducted a 90-day feeding experiment to evaluate the growth and energy budget of the sea cucumber Apostichopus japonicus. Sea cucumbers with a mean initial wet body weight of 3.03±0.06 g were fed one of the following three diets: an eel fecal solid diet, rainbow trout fecal solid diet, or a commercial diet at a water temperature of 17±1°C and salinity of 32±1 psu. The results suggested that the diets affected the final body weight, specific growth rate (SGR), food ingestion, feces production ratio, and hence the growth and energy budget of the sea cucumbers. Sea cucumbers fed the eel and rainbow trout fecal solid diets showed poorer energy absorption, assimilation, and growth than those fed the commercial diet. The sea cucumbers fed the commercial diet had a significantly higher SGR and proportion of energy used for growth than those fed the other two diets. Sea cucumbers fed the rainbow trout fecal solid diet showed a comparatively higher ingestion rate and feces production ratio than those fed the commercial diet. The eel and rainbow trout fecal solid diets, therefore, were not suitable for sea cucumbers in intensive cultivation. Our findings will facilitate further development of more appropriate diets for culture of sea cucumber.

Mercury (Hg) is known as a highly toxic heavy metal, and its toxicity varies depending on its form due to different toxicokinetics between inorganic and organic Hg. Limited information on comparison of Hg toxicity concerning its chemical form by oral exposure is currently available in cultured fishes. Therefore, we conducted a comparative study to have a better understanding of distinct toxic effects between mercuric chloride (HgCl2) and methylmercury chloride (CH3HgCl) in Korean rockfish. The 12-weeks dietary exposure of HgCl2 and CH3HgCl with its graded levels (0.4–6.4 ppm) (2 × 5 factorial design) in the young-of-the-year rockfish (initial weight: 82 ± 0.3 g) resulted in neither interactive nor main effects on whole-organism responses, including growth, feed utilization, and survival. However, the distinct pattern of Hg accumulation between the two forms in dorsal muscle, brain, liver and kidney tissues was observed, showing that the rockfish fed the CH3HgCl-contained diets exhibited the dose-dependent accumulation throughout the sampling points (1, 2, 4, 8, and 12 weeks post feeding), whereas those fed the HgCl2-contained diets did not show such response. The CH3HgCl exposure induced higher oxidative stress and immunotoxicity, reflected by the elevated plasma superoxide dismutase and lysozyme activities, respectively. In addition, the CH3HgCl-induced alteration in plasma measurements, including the plasma aspartate transaminase activity and total protein level was found. Taken together, the dietary exposure of methylmercury chloride had more pronounced toxic effects than mercuric chloride in the young-of-year rockfish, needed to be taken into consideration for regulation of maximum allowed levels for Hg by its chemical form.

외국의 수산선진국은 배합사료를 기반으로 주요 양식어종을 생산하고 있으며, 각 양식어종에 대한 배합사료 공급량 및 공 급횟수에 대한 배합사료 공급프로그램이 개발되었다(NRC, 2011). 우리나라에서 가장 많이 양식되고 있는 넙치는 2014년 기준 전체 해산어 총 생산량 중 51%를 차지하는 중요한 양식어 종이다(Kim et al., 2014). 아직까지 넙치 양식은 잡어에 기반한 습사료를 이용하여 양식되고 있으며, 최근 제주지역에서 배합 사료 사용이 활성화 되어 점차 확대되고 있다(Oh et al., 2014). 하지만 아직까지 넙치에 대한 배합사료 공급률에 대한 정보는 부족한 실정이며, 특히 100 g 이상의 성장기, 미성어기 및 성어 기 넙치를 대상으로 한 연구는 미비한 실정이다. 어류양식에 있어 총 양식경영비의 50-60%가 사료비로 지출 되고 있으며(Cho et al., 2006), 배합사료의 공급량은 양식어류 의 성장 및 사료효율 등에 영향을 미치므로 매우 중요하게 관리 되어야 한다. 하지만 넙치에 대한 배합사료 공급률에 대한 자료 가 미비하여 실제 양식현장에서는 대부분 만복급여를 하고 있 는 실정이다. 배합사료의 만복공급은 사료의 허실로 인한 수질 오염 및 생산단가 상승을 초래하며, 소화 및 대사 장애 등의 문 제점이 발생할 수 있다(Kim et al., 2014; Lee et al., 2014). 따라 서 수온에 따른 적정 사료 공급률을 설정하여 사료가 과잉 혹은 고수온에서 사육한 성장기 및 미성어기 넙치(Paralichthys olivaceus)의 배합사료 적정 공급률 김성삼·김강웅·김경덕·이봉주·한현섭·이경준*

배합사료의 공급방법 및 적절한 사육환경의 조성은 양식어류 의 성장과 건강에 직접적인 영향을 미치는 요인이며(Brett and Groves, 1979), 개별 양어장의 운영방법에 따라 경제성에 큰 영 향을 미친다(Oh et al., 2013). 양어용 배합사료는 양식어종의 성장단계에 맞춰 다양한 크기로 성형되어 판매되고 있지만 각 성장단계별 크기의 구분이 광범위하여 양식어업인들이 적정 사 료크기를 선택하는데 다소 어려움이 있다. 양식어종별로 상품 크기가 다르고 성장속도의 차이가 있어 사료의 크기는 큰 차이 를 보인다. 넙치의 경우 시판 배합사료의 크기는 1 mm에서 18 mm까지 매우 다양하다. 넙치 배합사료 크기에 대한 연구로는 사육수온별(고수온, 적수온 및 저수온) 및 성장단계별(치어, 육 성어 및 미성어)로 수행되었으며 사료크기가 커질수록 성장률 과 사료효율 등이 증가되는 경향을 보였고, 적수온에 육성어기 넙치를 대상으로 동일한 사료량을 공급한 결과 사료크기가 큰 실험구가 유의적으로 높은 성장률을 보였다(Heo, 2011). 사료 크기는 결국 사료섭취량 및 소화와 밀접한 관계가 있고 결국 성 장에 영향을 미치므로 적정 사료크기의 선택은 매우 중요하다 (Jobling, 1987). 국내 주요 양식어종 중 하나인 조피볼락을 대 상으로 3가지(small, medium, large) 배합사료 크기를 설정하 여 사육실험을 실시한 결과 성장률에서 유의적인 차이를 보이 지 않았지만 사료 크기가 증가함에 따라 성장률이 감소하는 경 향을 보였고, 사료계수 및 단백질전환효율에서는 크기가 작은 사료 그룹이 크기가 큰 사료 그룹과 비교하여 유의적으로 높은 효율을 보였다(Oh et al., 2013). 이것은 조피볼락의 경우 적정 배합사료의 크기, 사육밀도 및 용존산소 농도가 넙치 (Paralichthys olivaceus)의 성장에 미치는 영향

This study compared the effects of feeding diets consisting of an experimental extruded pellet with tapioca starch (EEP), commercial extruded pellet (CEP), and raw-fish-based pellet (MP) on the growth, flesh quality, and apparent digestibility coefficient of the olive flounder Paralichthys olivaceus. Two replicated groups of 4,000 fish each (initial mean weight: 81.8±3.5 g) were fed one of the experimental diets for 5 months. After the feeding trial, the final mean weight, weight gain, specific growth rate, and feed efficiency of fish fed the EEP was significantly higher than those of fish fed the CEP and MP. Moisture content in the whole-body of fish fed MP was significantly higher than those of fish fed other diets. However, the highest crude protein in the whole-body was found in fish groups fed the EEP. Significantly higher contents of 24:1n-9, 20:5n-3, 22:6n-3 and lower 18:1n-7 was observed in fish fed the EEP compared with fish fed the MP. The amino acid contents in the whole-body showed significant differences in the composition depending on the feed, but the distribution of free amino acids showed similar patterns. Among amino acids, glutamic acid showed the highest content in all the experimental groups, and the threonine, cysteine, and lysine contents were significantly higher in the groups fed with EEP and CEP than in the group fed with MP. Digestibility of nutrients of the EEP was significantly higher than that of fish fed the CEP. This suggests that extruded pellets can be used to feed olive flounder without compromising growth and flesh quality in comparison to raw-fish-based moist pellets. Formulation of the EEP could be used as a practical feed for olive flounder.

This study was conducted to compare an experimental extruded pellet (EP) and raw fish-based moist pellet (MP) on growth performance, whole-body and dorsal muscle composition, and textural properties of dorsal muscle for olive flounder Paralichthys olivaceus. Four groups of 8,000 fish (initial mean weight 27.1±0.05 g) per concrete tank (10×10 m) were fed the experimental diets for 16 months. After the feeding trial, no significant differences were observed in final mean body weight, weight gain, specific growth rate, feed intake, survival, and condition factor between EP and MP groups. However, feed efficiency of fish fed the EP was significantly higher than that of fish fed the MP. Moisture content in the whole-body of fish fed the MP was significantly higher than that of fish fed the EP. Significantly higher contents of polyunsaturated fatty acid (PUFA) in whole-body and dorsal muscle were observed in fish fed the EP compared with fish fed the MP. Any notable differences in amino acid contents or textural properties of the dorsal muscle were not observed in fish fed either the EP or the MP. The results of this study indicated that the EP could be developed to replace MP for the market size of production in olive flounder without the adverse effects on growth performance. Formulation of the EP could be used as a practical feed for olive flounder.

Two consecutive feeding trials were conducted to evaluate the effects of extruded pellet (EP) and raw fish-based moist pellet (MP) in the juvenile (experiment I) and sub-adult (experiment II) stages of olive flounder, Paralichthys olivaceus. The fish were distributed randomly to three aquarium tanks...

A feeding trial was conducted to determine the optimum dietary protein requirement of young far eastern catfish Silurus asotus. Five isocaloric diets were formulated to contain graded levels of protein (35, 40, 45, 50, and 55%). Triplicate groups of fish (initial body weight of 44 g) were hand-fed to apparent satiation for 9-weeks. Weight gain and specific growth rate of fish fed 55% protein diet were significantly higher than those of fish fed 35 and 40% protein diets, but not significantly different from those of fish fed 45 and 50% protein diets. The feed efficiency of fish fed 50 and 55% protein diets was significantly higher than that of fish fed 35, 40 and 45% protein diets. The protein efficiency ratio of fish fed 40% protein diet was significantly higher than that of fish fed 45, 50 and 55% protein diets, but not significantly different from that of fish fed 35% protein diet. The dietary protein level significantly affected whole body lipid and moisture contents. The results of this study suggest that the 45% protein in the diet is optimal for maximum growth of young far eastern catfish weighing in the range of 44 to 227 g.

The aim of this study was to investigate the effect of diet extruder conditions, such as feed-loading rate and screw speed, on growth performance and biochemical responses in olive flounder Paralichthys olivaceus. Over 8 wks, we used four identical diets (triplicated per treatment) with differing ratios of feed-loading rate (kg/h):screw speed (rpm/min) in a laboratory-scaled twin-screw extruder of 50:640, 80:640, 120:640, and 80:400, designated as EP1, EP2, EP3, and EP4, respectively. Screw speed impacted the buoyancy of experimental diets. Diets produced at a screw speed of 640 rpm/min floated for > 24 hrs, whereas those produced at a speed of 400 rpm/min sank between 10 s and 5 min. Fish that were fed EP1 and EP4 diets grew significantly faster than those fed EP2 and EP3 diets. Fish fed EP1 diets ate and gained weight most efficiently among treatments, a result that is likely to be related to feed-loading rate, i.e., ingredients extruded at a low feed-loading rate may have more time to cook in the pre-conditioner of the extruder. A cooked diet may be easier to digest in fish. Fish fed EP4 diets also showed significant weight gain, as compared to those fed EP2 and EP3 diets. However, we found no differences among treatments in proximate compositions of dorsal muscle, liver, and viscera of fish. Our results suggest that extruder conditions, may influence feed quality, impacting feed efficiency and growth of fish.

We investigated the effects of feeding rate on the growth performance, blood components, and histology of grow-ing olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : 316.7±6.18 g) was de-termined under the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.4%, 0.6%, and 0.8% of body weight (BW) per day, and to satiation. Feeding trial was conducted using a flow-through system with 10 1.2-metric ton aquaria receiving filtered seawater at 21-24°C for 3 weeks. Weight gain (WG) and specific growth rate (SGR) were significantly higher in fish fed to satiation (1.0% BW/day) than in those in other treatments. These parameters were negative and significantly lower in the starved fish than in fish fed the experimental diet at all feeding rates. There were no significant differences in WG and SGR among fish fed at 0.4%, 0.6%, and 0.8% BW/day. Hematocrit and hemoglobin in fish fed to satiation were significantly lower than those in other treatments. Histological changes of fish fed at 0.6% BW/day indicated that this group was in the best condition; differences were not found in tissues of fish fed at 0%, 0.6% and 1.0% BW/day. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 317 g was 0.99% BW per day at the optimum water temperature.Key words: Olive flounder, Feeding rate, Optimum water temperature, Histology, Hepatopancreas

A feeding trial was conducted to investigate the effects of dietary carotenoid source and level on growth performance, feed utilization, skin pigmentation, antioxidant responses and fatty acid composition of juvenile olive flounder, Paralichthys olivaceus . Three carotenoid sources derived from Carophyll-pink (AX), paprika extract (PE) and either Haematococcus pluvialis extract (HE) or raw H. pluvialis (HR) were evaluated at 100 or 200 mg/kg carotenoid, respectively. These dietary treatments were designated AX100, AX200, PE100, PE200, HE100, HE200 or HR100. The CON diet without supplementation of carotenoid was considered as the control diet. Juvenile olive flounder (average body weight, 9.5 ± 0.2 g) were randomly distributed in a flow-through tank system. Each experimental diet was fed to three replicate groups of fish to visual satiation twice per day for 8 weeks. Survival, weight gain and daily feed intake were not different to control group. Fish fed the HE200 diet showed higher feed efficiency and protein efficiency ratios compared to those of fish fed the CON, AX100, PE100, PE200 and HE100 diets. Total carotenoid in the dorsal muscle, skin and whole body of fish fed the diets containing carotenoids was higher than that of fish fed the CON diet. L * and b * values of the fish skin were not altered by dietary carotenoid sources and levels. However, a * values of fish fed the diets containing carotenoids were significantly higher than that of fish fed the control diet. Liver and plasma SOD activities of the fish fed diets containing carotenoids were lower than those of the control group. Radical scavenging activities of dietary carotenoids were increased in the muscle, liver, and plasma by dietary carotenoid source, except for the liver and plasma of AX100 and AX200 diets. The present results suggest that dietary inclusion of paprika and H. pluvialis extract at a concentration of approximately 100 mg/kg carotenoid could increase total carotenoid, antioxidant activities and skin pigmentation of olive flounder as efficiently as commercial synthetic astaxanthin.

We investigated the effects of feeding rate on the growth performance, blood components, and histology of growing olive flounder Paralichthys olivaceus. We determined the optimum feeding rate (initial fish mean weight of g) at the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.5%, 0.75%, and 1.0% body weight (BW) per day, and to satiation. Feeding trial was conducted using a flow-through system with 10 1.2-metric ton aquaria receiving filtered seawater at for three weeks. Weight gain (WG) for fish fed to satiation was significantly higher than that of unfed fish and fish fed at 0.5% and 0.75% BW per day. The WG of fish fed at 1.0% BW per day was significantly higher than that of unfed fish and of fish fed at 0.5% BW per day. However, there were no significant differences in WG between fish fed at 0.5% BW per day and those fed at 0.75% BW per day, between fish fed at 0.75% BW per day and those fed at 1.0% BW per day, and between fish fed at 1.0% BW per day and those fed to satiation. The specific growth rates of fish fed at 1.0% BW per day and those fed to satiation were significantly higher than those of unfed fish and of fish fed at 0.5% BW per day. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 240 g was 1.09% BW per day at the optimum water temperature.

Two types of diets, extruded pellet (EP) and raw-fish-based moist pellet (MP) were fed to compare growth, water quality and histology of olive flounder, Paralichthys olivaceus in Jeju fish farm. Two groups of 7000 fish per each tank (initial mean weight 51 g) were fed one of two diets for 7 months. At the end of the feeding trial, significant differences were found in weight gain and feed utilization. Dissolved oxygen (DO) level of the MP tank was decreased from 7.98 to 6.89 after feeding. There were no significant differences in hematocrit, hemoglobin, alanine aminotransferase and aspartate aminotransferase of fish fed the two diets. Whole body protein content of fish fed the EP was significantly higher than that of fish fed the MP. While the feeding rate by month indicated numerically decreased, fish fed the MP had higher feed intake than that of fish fed the EP. Histological examination of hepatopancreas, kidney, and anterior intestine of fish fed the EP did not show any negative effects compared to those of fish fed the MP. This study revealed that EP could substitute for MP in terms of growth performance, blood parameters, water quality and histology of olive flounder.Key words : Olive flounder, Extruded pellet, Moist pellet, Dissolved oxygen, HistologyCorresponding author : 064-754-3423, kjlee@jejunu.ac.kr* 2014 .

This study was carried out to investigate the influences of dietary levels, ratios and sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the growth and fatty acid compositions of juvenile olive flounder Paralichthys olivaceus. Sixteen diets containing five levels of EPA (0.5%, 1.0%, 1.5%, 2.0%, and 4.0%), five levels of DHA (0.5%, 1.0%, 1.5%, 2.0% and 4.0%), three ratios of EPA/DHA (75/25, 50/50 and 25/75), two levels of squid liver oil (5% and 10%) and a control diet containing 5% soybean oil were hand-fed to triplicate groups of fish (average weight, 9.7 ± 0.3 g) for 8 weeks. Survival, specific growth rate, feed efficiency and protein efficiency ratio of fish were not affected by dietary EPA and DHA levels or ratios. Also, the dietary treatment had no significant effect on the lipid and protein contents of muscle and whole body of fish. A corresponding increase in the EPA and DHA contents of fish occurred with increasing EPA and DHA levels in their diets. Our results suggest that juvenile olive flounder require a dietary EPA level of approximately 0.32% in the presence of 0.74% DHA for sui table survival and growth, and that EPA and DHA levels in fish muscle can increase to as much as 32% and 53%, respectively, of the total fatty acid content.

This study was conducted to investigate the effects of different taurine levels on the conjugated bile acid composition and growth of juvenile rockfish. Five taurine level diets were made by the supplementation of taurine (0%, 0.5%, 1.0%, 1.5% and 2.0%) to a basal diet. Fish meal washed with 70% ethanol to exclude taurine was used for the sole protein source. Feeding experiments were accomplished at 15°C using juvenile fish (initial BW: 13.5 g). Fish were fed the experimental diets for 4 months. At the end of experiments, fish were weighed and stored at −80°C for analysis of free amino acids and conjugated bile acids contents. The growth performance and feed efficiency of Korean rockfish were improved by taurine supplementation in the experimental diets. The taurine contents of the whole body increased with the increase in the taurine supplementation. The primary conjugated bile acids in gall bladder were taurocholic acid (83.5–165.6 mg mL−1) and taurochenodeoxycholic acid (6.3–20.0 mg mL−1). Total bile acids increased with increases in dietary taurine. Taurocholic acid content was more than 95% of the total conjugated bile acids. This indicates that taurine is the sole amino acid to make conjugated bile acid in Korean rockfish. Dietary taurine levels improved the conjugated bile acid composition in juvenile Korean rockfish.

This study compared the effects of diets consisting of experimental extruded pellets (EP), commercial soft extruded pellets (SEP), and raw-fish-based moist pellets (MP) on the growth, flesh quality, and histology of the Korean rockfish Sebastes schlegeli. Three replicated groups of 60 fish each (ini...

This study evaluated fermented soybean meal (FSM) as a fish meal (FM) replacement and determined the appropriate amount of FSM in juvenile olive flounder diet. Twenty-four aquaria with a flowing-water system were stocked with fish averaging 20.9 g at a density of 25 fish/tank. Five experimental diets were prepared replacing FM with 0, 10, 20, 30, or 40% FSM based on FM protein (designated FSM 0, FM 10, FSM 20 FSM 30, and FSM 40 , respectively). Two additional diets were prepared that replaced 30 or 40% of the FM with FSM with added amino acids (methionine and lysine) (designated FSM 30+AA , and FSM 40+AA , respectively). Fish (triplicates) were fed one of the eight experimental diets (50% crude protein and 16.7 kJ available energy g -1 diet) for 8 weeks. Survival did not differ among the treatments during the feeding experiment. There were no significant differences in weight gain (WG) or specific growth rate (SGR) among the fish fed diets with up to 30% of the FM replaced. However, fish fed FSM 40 or FSM 40+AA had a reduced WG and SGR, as compared to FSM 0 (control) (P < 0.05). The feed efficiency and apparent digestibility showed a similar trend (P < 0.05). The proximate composition in the whole body of fish differed only between the control and FSM 40 for the crude protein level and between the control and FSM 30+AA for the crude lipid level. The whole-body amino acid composition did not differ among treatments. No significant differences were found between the diet groups with and without amino acid supplementation, indicating that amino acid supplementation had no effect. The major finding of this study is that fermented soybean meal may replace up to 30% of fish meal without amino acid supplementation for normal growth of juvenile olive flounder.

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±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.Key words : Olive flounder, Additive, Solid Sulfur, Fucoidan, GlucanCorresponding author : 054-230-3620, kangwoongkim@korea.kr* ( , RP-2013-AQ-160).

This study was carried out to investigate and compare the effects of various dietary lipid sources on growth performance, body composition, fatty acid profiles, and hepatic and plasma antioxidant enzyme activities of juvenile rockfish, Sebastes schlegeli. Three replicate groups of fish (initial mean weight, 1.7 ± 0.04 g) were fed four isonitrogenous and isolipidic diets containing either fish oil (FO), soybean oil (SO), linseed oil (LO), or a mixture of SO and LO (SO + LO) for 8 wk. There were no significant differences in survival, weight gain, feed efficiency, and protein efficiency ratios of fish fed the diets containing different lipid sources (P > 0.05). The fatty acids compositions of the liver and muscle tissues reflected the dietary fatty acid compositions. Liver and muscle of fish fed the SO diet had high concentration of linoleic acid, whereas those of fish fed the LO diet were rich in linolenic acid. Liver and muscle of fish fed the FO diet had significantly (P

This study was conducted to compare extruded pellets (EP) and soft extruded pellets (SEP) with a raw fish-based moist pellet (MP) diet on the growth and flesh quality of Korean rockfish Sebastes schlegeli. Three groups of 20,000 fish (initial mean weight 133 g) per net-cage (6×12×7 m) were fed commercial EP , SEP or MP for 16 months. The survival of fish fed SEP was higher than those of fish fed EP or MP. The highest growth performances were observed in the mean weight gain, total weight gain, and feed efficiency of fish fed MP , followed by those fed EP and SEP. Among the fish fed on extruded pellets, the total weight gain of fish fed SEP was higher than that of those fed EP, while fish fed EP grew faster than those fed SEP. No notable differences in body composition, sensory scores or textural properties of the dorsal muscle were observed in fish fed on EP , SEP or MP. Thus, it is suggested that extruded pellets, rather than raw fish-based moist pellets, could be fed to Korean rockfish without compromis ing flesh quality.

This study was conducted to evaluate the quality characteristics (proximate composition, fatty acids, amino acids and sensory properties) of whole body and dorsal muscle in olive flounder, which is switch size from juvenile to growing fed extruded pellets (EP) and raw fish-based moist pellet (MP) for 9 months. Sample was collected at 5 and 9 months to compare with those of EP and MP. Whole body crude protein of fish fed EP at 9 months was significantly higher than that of fish fed MP (P0.05). Based on the experimental results, we concluded that olive flounder cultured with EP is not inferior to those fed MP for quality characteristics of whole body and muscle.

This study investigated the utilization of beef tallow and dextrin as non-protein energy sources in the diet of juvenile far eastern catfish Silurus asotus. Three replicated groups of juveniles (initial mean weight of 3.6 g) were fed diets containing high levels of beef tallow or dextrin for six weeks. The final mean weight of fish fed on a 17% lipid diet with a high level of beef tallow was significantly higher than that of fish fed on a 9% lipid diet with a high level of dextrin (P=0.04). No significant differences were observed in the feed efficiency and protein efficiency ration of fish fed on the experimental diets. Crude lipid content and the C18:0, 1n-9 and C18:2n-6 contents of whole-body fish were significantly affected by diet (P＜0.05). The results of this study suggest that beef tallow is better than dextrin as a non-protein energy source for improving the growth of juvenile far eastern catfish, and that beef tallow could be economically used as an ingredient in practical feed.

A beam is a major load-carrying member in many engineering structures. Beams with properly designed cross sections and stiffeners are required to enhance the structural properties. Such a design may cause various coupling behaviors, and therefore, an accurate analysis is essential for the proper design of beams. In this research, we manufactured box-beams with stiffeners, which mimic the out-of-plane composite bending-shear coupling behavior reported in literature. A modal test is carried out to obtain the dynamic characteristics, such as natural frequencies and mode shapes, of the box-beam. The obtained results are compared with those of 3D FEM, which confirm that the out-of-plane bending-shear coupling behavior reported in literature is possible. The coupling behavior can be controlled by the proper design of the stiffeners.

Two consecutive studies were conducted to evaluate the dietary supplementation of citrus by-products (CB) fermented with probiotic bacteria on growth performance, feed utilization, innate immune responses and disease resistance of juvenile olive flounder. In Experiment I, five diets were formulated to contain 0% (control) or 3% four different CB fermented with Bacillus subtilis (BS), Enterococcus faecium (EF), Lactobacillus rhamnosus (LR) and L. plantarum (LP) (designated as CON, CBF-BS, CBF-EF, CBF-LR and CBF-LP, respectively). During 10 weeks of a feeding trial, growth performance and feed efficiency were not significantly different among all the fish groups. However, fish fed CBF containing diets had significantly higher survivals than the CON group. Disease resistance of fish against Edwardsiella tarda was increased by the fermentation of CB. In Experiment II, we chose the BS as a promising probiotic and formulated five diets to contain 0%, 2%, 4%, 6% and 8% CBF-BS. Growth performance was not significantly affected by the CBF-BS supplementation during 6 weeks of a feeding trial. Innate immunity of fish was significantly enhanced by CBF-BS supplementation. Myeloperoxidase and lysozyme activities were increased in a dose-dependent manner by dietary CBF-BS inclusions. In a consecutive challenge test against E. tarda, an increased disease resistance was found by CBF-BS supplementation. These studies indicate that the fermentation process of CB with probiotic has beneficial effects on innate immunity and thereby increases disease resistance of olive flounder against E. tarda. Bacillus subtilis can be used as a promising probiotic microbe for by-product fermentation in fish feeds.

This study evaluated the effects of adding sea mustard Undaria pinnatifida glycoprotein to the diet of juvenile olive flounder Paralichthys olivaceus on its growth, and levels of insulin-like growth factor I (IGF-I), IGF binding proteins (IGFBPs), and interleukins. Three experimental diets (U0, U0.5, and U1.0) were formulated that contained different amounts of an extract of U. pinnatifida (0, 0.5, and 1.0%, respectively). Experimental groups were established in triplicate (30 fish/group) and fed for 12 weeks. The experimental group fed 1.0% added U. pinnatifida glycoprotein had the greatest rate of weight gain, which differed significantly from the other experimental groups. SDS-PAGE of the plasma IGF-I and muscle protein showed that the experimental groups taking U. pinnatifida glycoprotein had significantly more IGF-I and a ca. 200 kDa protein, as compared to the control group. In addition, the amount of IGFBP-3 at ca. 43 kDa increased in the group given the U. pinnatifida extract, as compared to the control group. The interluekin-2, -4, -6, and -12 levels paralleled the level of growth factor in the groups given the U. pinnatifida extract. In conclusion, supplementing the diet of olive flounder with U. pinnatifida glycroprotein improved its growth and immunity.

This study evaluated the effects of the number of feeding days and feeding rate on the growth of growing-out flounder Paralichthys olivaceus. Three replicated groups of fish () were hand-fed a commercial feed under different feeding regimes for 9 weeks. Fish in group 6F-1S were fed to satiation twice daily for 6 consecutive days and starved for 1 day. Fish in groups 4F-1S and 3F-1S were fed to satiation twice daily for 4 and 3 days, respectively, and starved for 1 day. Fish in group 6F-90% were fed a diet of 90% of 6F-1S twice daily for 6 consecutive days and starved for 1 day. The weight gain, feed efficiency and daily feed intake of the fish groups in 4F-1S and 3F-1S were not significantly different from those of group 6F-1S. The weight gain and feed efficiency of fish in group 6F-90% were not significantly different from those of group 6F-1S. The results of this study suggest that the growth of growing-out flounder fed to satiation twice daily for 4 or 3 days after starving 1 day was similar to that of fish fed to satiation for 6 days, and that the proper feeding rate for growth could be lowered to 90% of satiation without growth suppression.