Bong-Joo Lee

Effects of Dietary Supplementation of Spirulina and Quercetin on Growth, Innate Immune Responses, Disease Resistance Against Edwardsiella tarda, and Dietary Antioxidant Capacity in the Juvenile Olive Flounder Paralichthys olivaceus

A 10-week feeding trial was conducted to examine the effects of dietary spirulina and quercetin on growth, innate immunity, disease resistance and dietary antioxidant capacity in the juvenile olive flounder. Triplicate groups of fish (initial body weight, 2.9 ± 0.01 g) were fed one of isonitrogenous (48% crude protein) and isocaloric (17.4 MJ/kg DM) experimental diets containing 0% spirulina (as a control), 3.4% spirulina, or 6.8% spirulina with or without supplementation of 0.5% quercetin (designated as CON, SP3.4, SP6.8, and SP6.8 + Q, respectively) at a rate of 3% body mass twice daily. Higher dietary antioxidant capacity was found with spirulina supplementation, and the highest value (P < 0.05) was obtained with SP6.8 + Q diet. At the end of the feeding trial, no significant effects were observed on growth performance, body composition and disease resistance against Edwardsiella tarda. Lysozyme activity was significantly increased by spirulina supplementation (P < 0.05), and the highest value was observed in the group fed SP6.8 + Q diet. Also, significantly higher respiratory burst activity (P < 0.05) was found in SP3.4 group. According to the results of this study, dietary supplementation of 3.4% spirulina may enhance innate immunity of olive flounder.

Dietary Hizikia fusiformis glycoprotein-induced IGF-I and IGFBP-3 associated to somatic growth, polyunsaturated fatty acid metabolism, and immunity in juvenile olive flounder Paralichthys olivaceus.

This study was aimed to examine the effect of dietary glycoprotein extracted from the sea mustard Hizikia fusiformis (Phaeophyceae: Sargassaceae) as a dietary supplement on growth performance in association with somatotropin level, proximate compositions, and immunity in juvenile olive flounder Paralichthys olivaceus. Water-ethanol extracted glycoprotein from H. fusiformis was supplemented to three fishmeal-based diets at the concentration of 0, 5, and 10gkg(-1) diet (designated as H0, H5, and H10, respectively). After a 12week-long feeding trial, growth performance and biochemical responses were analyzed including proximate composition, and whole body amino acids and fatty acids. We also measured plasma insulin like growth factor (IGF), IGF-binding protein (IGFBP) and interleukin (IL). The fish fed H5 showed the greatest weight gain among the dietary treatments. In parallel with the growth, the fish fed the diets containing H. fusiformis glycoprotein showed an increased plasma IGF-I activity and increased expression of 43-kDa IGFBP-3 compared to that in the control, whereas an opposite trend was observed for 34-kDa IGFBP-1. Although no differences were found in the level of whole body linoleic acid (C18:2n-6) and linolenic acid (C18:3n-3) among treatments, increases in arachidonic acid (ARA, C20:4n-6), eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) were observed in fish fed H5 compared to control. IL-2 and -6 levels increased significantly in fish fed H10 compared to those in the control indicating increased immunity. These results suggest that supplementation of H. fusiformis glycoprotein in fish diet may be beneficial for fish growth and immunity in juvenile olive flounder.

Comparison of Extruded and Moist Pellets for Growth Performance, Water Quality and Histology of Olive Flounder Paralichthys olivaceus in Jeju Fish Farm

Abstract 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 .

Effect of Food Particle Size, Stocking Density and Feeding Frequency on the Growth Performance of Juvenile Korean Rockfish Sebastes schlegelii

We performed four sets of feeding trials to establish optimum feed size (Exp-I), stocking density (Exp-II) and feeding frequency (Exp-III and IV) for Korean rockfish. In Exp-I, three different particle sizes of a commercial diet (small, 2.0-2.1 mm; medium, 2.4-3.2 mm; and large, 4.0-5.3 mm) were fed to four replicate groups of fish (), each of which was fed to apparent satiation for six weeks. In Exp-II, fish () were reared at four stocking densities (1.5, 3.0, 4.5 and 6.0 ) and fed a commercial diet to apparent satiation for four weeks. In Exp-III, fish () were fed a commercial diet once, twice, thrice, or a day at a feeding ratio of 3.25% of body mass. Another group of fish was fed the same commercial diet a day to apparent satiation; this treatment was designated FS (five times satiation/day). In Exp-IV, fish () were fed a commercial diet once, twice, thrice or a day to apparent satiation. Another group of fish was fed to apparent satiation once every 48 hours. In Exp-I, fish fed the large particle (4.0-5.3 mm) diet had a significantly higher feed conversion ratio and lower protein efficiency ratio than fish fed the small particle diet. In Exp-II, groups of fish reared at densities of 4.5 and 6.0 had significantly higher feed intake and growth performance than fish reared at 1.5 and 3.0 . In Exp-III, fish fed to apparent satiation had significantly higher growth performances than fish fed once or a day. A significantly higher feed conversion ratio and a lower protein efficiency ratio were obtained in the FS group. In Exp-IV, growth performance and feed utilization efficiency were not significantly affected by experimental variation in feeding frequency. Fish fed to apparent satiation once every 48 hours had better feed utilization than those in other treatments and growth performances of those were comparable. Therefore, the optimum feed particle size, stocking density and feeding frequency for Korean rockfish under conditions we used were 2.0-3.2 mm, 4.5-6.0 , and once a day or once every 48 hour, respectively.

Optimum Feeding Rate for Sub-adult Olive Flounder (384 g) Paralichthys olivaceus Fed Practical Extruded Pellets at Optimum Water Temperatures (20-24.5℃)

세계 양식선진국은 환경친화적 배합사료를 사용하여 지속가 능한 양식업을 육성하고 양식시스템을 자동화하는 등 경쟁력을 강화하고 있다. 배합사료의 사용은 자동공급기를 통해 사료를 공급할 수 있을 뿐 아니라 체계적인 사육관리를 통해 양식방법 을 효율화 시킬 수 있다. 우리나라도 안전한 양식수산물 공급, 수산자원 남획 및 어장환경오염 방지 등 지속가능한 양식업 육 성을 위하여 배합사료 사용 확대가 필요한 시점이다(Kim et al., 2014). 최근 제주, 여수, 신안, 거제, 울진 및 영덕을 배합사료 시 범지역으로 선정하여 다양한 해산어류를 생사료를 사용하지 않 고 배합사료를 사용하여 양식하고 있다. 하지만 각 양식어종에 대한 배합사료 공급프로그램이 개발되지 않아 실제 양식현장 에서는 대부분 만복공급을 실시하고 있는 실정이다. 배합사료 의 만복공급은 사료의 허실로 인한 수질오염 및 생산단가 상승 을 초래하며, 소화 및 대사 장애 등의 문제점이 발생할 수 있다 적수온(20-24.5°C)에서 사육한 미성어기(384 g) 넙치 (Paralichthys olivaceus)의 배합사료 적정 공급률 김성삼·김강웅·김경덕·이봉주·한현섭·김재원·배승철·이경준*

Optimum Feeding Rate in Growing Olive Flounder Paralichthys olivaceus Fed Practical Expanded Pellet at Optimum Water Temperature (19-21℃)

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.

Optimum Feeding Rate for Growing Olive Flounder (317 g) Paralichthys olivaceus Fed Practical Extruded Pellets at Optimum Water Temperature (21-24℃)

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

Effects of a Commercial Extruded Pellet on Growth Performance and Water Quality in Growing Olive Flounder Paralichthys olivaceus

This study was conducted to evaluate the effect of commercial extruded pellet (EP) diet on the growth and water quality compared with a raw fish moist pellet (MP) diet for flounder on field feeding experiments. Three replicate groups of 130 fish per each tank (initial weight of 380 g) were fed one of the EP and Moist pellet (MP) for 7 months. In field feeding experiment, no significant difference was observed in final mean weight of fish fed the experimental EP (1,233 g) and MP (1,237 g), and any noticeable problem caused by feeding the experimental EP was not found during the whole period of feeding trial. Feed efficiency of fish fed the experimental EP was higher than that of MP, and there was no significant difference in survival between the fish fed experimental EP and MP. The concentrations of SS, COD, TN and TP of seawater in tanks of MP groups were 1-5 times higher than those of EP groups. Therefore, these results strongly suggest that diet EP could be developed to replace MP diet for the marketable size of production for flounder without adverse effects on growth performance and water quality.

Optimum Feeding Rate for Sub-adult Olive Flounder (370 g) Paralichthys olivaceus Fed Practical Extruded Pellets at Low Water Temperature (12-14℃)

양식환경에서 사료섭취율은 어류의 성장에 영향을 미치는 가 장 큰 요인 중 하나이며(Li et al., 2004), 사료를 섭취한 후 소화, 대사, 흡수 및 배설의 복합적인 생리과정을 거쳐 어류는 성장하 게 된다(Brett et al., 1970). 어류는 변온동물로 수온에 따라 체 내 소화효소 활성이 달라지며(Pelleiter et al., 1995), 수온이 낮 아지면 소화효소 및 대사 활성이 떨어져 사료섭취량이 떨어지 고(Fauconneau et al., 1983), 이와 반대로 적정수온으로 상승하 게 되면 소화효소 및 대사활성의 증가하면서 먹이섭취 활성도 증가하게 된다(NRC, 2011). 적정수온 이상의 고수온으로 올라 가면 다시 먹이섭취 활성은 떨어지게 된다. 넙치의 경우 자연환 경에서 서식수온은 10-27°C 범위이며, 양식환경에서 적정사육 수온은 8-25°C 이지만 4-28°C에서도 사육이 가능하며, 최적 사 육수온은 21-24°C로서 수온 10°C 이하와 27°C 이상에서는 먹 이섭취 활성이 현저하게 떨어진다(NFRDI, 2006). 따라서 수온 에 따른 적정 사료 공급률을 설정하여 사료가 과잉 혹은 부족하 지 않게 급여하는 것은 사료효율 및 어류 성장에 영향을 미치므 저수온(12-14°C)에서 사육한 미성어기(370 g) 넙치(Paralichthys olivaceus)의 배합사료 적정 공급률 김성삼·김강웅·김경덕·이봉주·한현섭·이경준*

Optimal Feeding Frequency for Juvenile Korean Rockfish Sebastes schlegeli Fed Commercial Diet at Two Different Water Temperatures

We conducted two feeding trials to investigate the optimal feeding frequency of juvenile Korean rockfish Sebastes schlegeli fed a commercial diet of expanded pellets containing 47.2% crude protein, 9.2% crude lipid, and 14.5% ash at two different water temperatures. In the first experiment, triplicate groups of 20 fish with an average weight of 2 g were fed an equal amount of diet (5.97% based on body weight) at one of six feeding frequencies (2, 3, 4, 5, 7, or 9 meals/day) for four weeks at . After four weeks, we measured weight gain (WG), specific growth rate (SGR), feeding efficiency (FE), and protein efficiency ratio (PER). Fish fed diet five meals/day grew significantly better than those fed nine meals/day. The second experiment used identical experimental conditions and feeding regions, except the food ration was slightly less (5.92% based on body weight) and the water temperature was increased to . After four weeks, we again measured WG, SGR, FE and PER. Fish fed seven meals/day grew significantly faster than those fed 2, 3, 4, or 9 meals/day. Whole-body protein levels in fish fed three meals/day was higher than those fed four meals/day in water, but whole-body lipids in the fish fed four meals/day was higher than those fed two meals/day in water. A second-order polynomial analysis based on WG suggested the optimal feeding frequency for juvenile Korean rockfish was five meals/day at and six meals/day at , indicating that fish reared in higher water temperature require higher feeding frequencies.