Jin-Hyeok Lee

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 .

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.

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.

Interactive effect of dietary vitamin E and inorganic mercury on growth performance and bioaccumulation of mercury in juvenile olive flounder, Paralichthys olivaceus treated with mercuric chloride

A 6-week feeding trial was carried out to evaluate the effects of dietary vitamin E (dl-α-tocopheryl acetate, TA) on growth and mercury (Hg) accumulation in juvenile olive flounder (Paralichthys olivaceus) treated with mercuric chloride (HgCl2). Vitamin E and HgCl2 were added to the semi-purified basal diet. Six semi-purified diets in a 2 × 3 factorial design were formulated to contain 2 levels of Hg (0 or 20 mg HgCl2/kg diet) and 3 levels of vitamin E (0, 100, or 200 mg TA/kg diet). Experimental fish (n = 360, 9.99 ± 0.15 g) were randomly allocated into 30-L tanks at a density of 20 fish per tank with 3 replicates in each treatment and were fed twice a day. At the end of the feeding trial, dietary Hg depressed the growth performances in terms of weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) in fish, while fish fed the diets supplemented with vitamin E showed significant growth improvement in both presence and absence of HgCl2 in the diets (P < 0.05). Survival rate was not affected in fish fed the experimental diets. Whole body compositions of fish such as lipid and moisture contents were influenced by dietary vitamin E supplementation. Total Hg contents of muscle, liver and kidney tissues were significantly reduced in fish fed diets supplemented with vitamin E (P < 0.05), while the two-way ANOVA showed that increasing Hg concentration has resulted in a reduction in vitamin E. Whole body fatty acids of fish like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents were decreased by dietary Hg. However, supplementation of dietary vitamin E improved the α-linolenic acid (ALA) and EPA contents in fish. Our results suggest that dietary supplementation of vitamin E has potential effects on growth improvement and ameliorating inorganic Hg bioaccumulation in juvenile olive flounder.

Optimum Feeding Rate and Frequency in Juvenile Korean Rockfish Sebastes schlegeli Fed a Commercial Diet

우리나라 주요 어류양식 어종인 조피볼락(Sebastes schlegeli) 은 2010년 생산량이 20,918톤(국내 어류양식 총 생산량의 20%)으로 국내 어류양식에서 두 번째로 생산량이 많은 어종 이다(FAO, 2012). 다른 어종과 마찬가지로 조피볼락의 생산성 및 양식경영비에서 가장 중요하게 영향을 미치는 것은 사료이 며, 총 양식경영비의 50-60%에 이른다(Cho et al., 2006). 현재 까지 조피볼락 양식의 효율적인 관리와 생산성 향상을 위해서 많은 연구들이 수행되었다. 배합사료 개발을 위해 영양소 요구 량과 사료 원료 이용성에 관한 연구들이 수행 되었고(Lee et al., 1993; Kim and Bae, 1999), 배합사료에 의한 생사료 대체 가능 성과 같은(Lee and Jeon, 1996), 환경 친화적인 고효율 배합사 료 개발을 위하여 많은 연구들이 수행되고 있다. 하지만 조피볼 락을 비롯한 양식 어류의 성장은 사료 이외에 망갈이, 선별, 수 온 등의 외부 환경요인에 의해서 많은 영향을 받는다(Choi et al., 2009). 따라서, 양식어종에 대한 적합한 사료가 개발되더라 도 외부환경에 따른 사료공급방법이 제대로 이루어지지 않으 면 성장 및 사료효율이 달라지고, 수질오염 발생 등 많은 부작용 이 일어날 수 있기 때문에(Kim et al., 2005), 효율적인 사료공급

Dietary Fermented Soybean Meal as a Replacement for Fish Meal in Juvenile Olive Flounder Paralichthys olivaceus

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.

Effects of Dietary Inclusion of Various Additives on Growth Performance and Immune Responses in Juvenile Olive Flounder(Paralichthys olivaceus)

Abstract 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).