• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.577-581
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• 2014

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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.582-587
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• 2014

We investigated the effects of feeding rate on the growth, blood components, and histology of sub-adult olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : $384.2{\pm}5.91g$) was determined under the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.3%, 0.5%, and 0.7% body weight (BW) per day, and to satiation. The feeding trial was conducted using a flow-through system with ten 1.2-metric ton aquaria receiving filtered seawater at $20-24.5^{\circ}C$ for 3 weeks. After the feeding trial, the weight gain (WG) and specific growth rate (SGR) were significantly higher in fish fed at 0.7% BW/day and those fed to satiation (0.9% BW/day) than in fish fed at other feeding rates or in the unfed fish. These parameters were negative and significantly lower in the unfed fish than in those fed the experimental diet at all feeding rates. There were no significant differences in WG and SGR among fish fed at 0.3 and 0.5% BW/day and among those fed at 0.7% BW/day and to satiation. The histological changes in the hepatopancreas, kidney, and anterior intestine of fish fed at 0, 0.5, and 0.9 % BW/day did not differ much. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 384 g was 0.74% BW per day at the optimum water temperatures.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.234-240
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• 2014

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 $240{\pm}10.9$ 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 $19-21^{\circ}C$ 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.769-776
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• 2013

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 $FSM_{0}$, $FSM_{10}$, $FSM_{20}$ $FSM_{30}$, 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.761-768
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• 2013

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 $17.5^{\circ}C$. 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 $20^{\circ}C$. 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 $17.5^{\circ}C$ water, but whole-body lipids in the fish fed four meals/day was higher than those fed two meals/day in $20^{\circ}C$ water. A second-order polynomial analysis based on WG suggested the optimal feeding frequency for juvenile Korean rockfish was five meals/day at $17.5^{\circ}C$ and six meals/day at $20^{\circ}C$, indicating that fish reared in higher water temperature require higher feeding frequencies.

• Journal of Life Science
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• v.28 no.1
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• pp.90-98
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• 2018

Eggshell (ES) is a by-product of table eggs with high content of calcium carbonate which can be used as a calcium source in feed. In this study, we have first illuminated the potential application of ES as a novel carrier for probiotics. The carriers used in the study include a SBM (Soybean meal), ESL (Eggshell powder with large particles), ESF (Eggshell powder with fine particles), and the complex carriers (SBM+ESL, SBM+ESF). The structure of carriers absorbed by L. plantarum was confirmed by SEM image. Among these carriers, the complex carrier SBM+ESF showed the highest viability of L. plantarum with pH 7~8 during four weeks storage at room temperature. The SBM+ESF was further tested as a carrier for various probiotic strains at $4^{\circ}C$ or $30^{\circ}C$. All the probiotic strains showed high viability at $4^{\circ}C$ storage. However, a significant reduction of Lactobacillus cells was observed at $30^{\circ}C$ storage. B. lichenifomis maintained high viability whereas B. subtilis, B. amyloliquefaciens, and S. cerevisiae showed the reduction of $2{\log}_{10}$ (CFU/g). These results suggest that if the ESF as a calcium source in feed was mixed with SBM, it can be used as an effective complex carrier for improving the viability of some probiotics including B. licheniformis.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.1
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• pp.34-39
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• 2007

Penaeidins are members of a special family of antimicrobial peptides existing in several species of shrimp and play a crucial role in the immunological defense of shrimp. In this study, we isolated and characterized one EST clone (penaeidin) from cDNA library of fleshy prawn Fenneropenaeus chinensis hemocytes. Amino acids sequence comparison and phylogenetic analysis with other known penaeidins revealed that our clone was completely identical to F. chinensis Penaeidin 3-2 (Accession no. ABC33920), which composed of 71 amino acids with a putative signal peptide (1-19) and a cysteine-rich domain (C-terminal part). The expression and distribution of Penaeidin 3-2 transcripts in shrimp were detected in hemocytes, hepatopancreas, and muscles, and that Penaeidin 3-2 was constitutively expressed mainly in hemocytes. The artificial infection of white spot syndrome virus to F. chinensis resulted in Penaeidin 3-2 mRNA up-regulation in hemocytes, suggesting that the possible role of Penaeidin 3-2 in host defense system of F. chinensis.

• Journal of agricultural medicine and community health
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• v.4 no.1
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• pp.71-80
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• 1979

Paragonimiasis is a common trematodiasis of medical importance and one of public health problems in many areas of sob thern part of Korea. During the last sixty years, several on the prevalence among the Korean population have been carried out by various investigators, although the general distribution and prevalences of paragonimiasis are now yet clearly determind. This study was undertaken to evaluate the status of human paragonimiasis in Kang Hwa Gun, Kyung gi Province, Korea by the use of intradermal screening test whih Veronal buffered saline antigen. A total number of 208 residents (male 119, female 89) of all age group in Kilgeong-Ri, Yangdo Myun, Kang Hwa Gun were examined by the intradermal test with paragonimus antigen. The infestation rate of crayfish with Paragonimus metacerearia was also examine in Konneung and Jeoungha village, Kilgeong-Ri from March 1973 to October 1978 by the interval of two to five years. 1. In the resnlt of 208 residents, Kilgeong-Ri, the positive rate showed in 29.3% in as a whole(36.1% in male, 20.2% in female). The highest positive rate showed in 10 to 19 age group(41.5%). 2. Among the residents in Kilgeong-Ri, Paragonimus eggs were detected in 11 residents by the sputum and the stool examinations without the intradermal test result. 3. The infestation rate of crayfish with Paragonimus inetacercaria was 90.6%(116 out of 128 crayfishes) in Konneung village, and 61.5%(24 out of 39) crayfishes) in Jeongha village, Kilgeng-Ri. 4. The fluctation of the infestation tate and density of crayfish with Paragonimus metacercaria was decreased by the interval of two to five years in Konneung and Jeongha village in Kilgeong-Ri.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.611-618
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• 2016

A $3{\times}2$ 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 cal/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 $18^{\circ}C$) 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 $13^{\circ}C$, whereas, that of fish fed at 0.25 and 0.4% BW/d were significantly or slightly lower at 18 than $13^{\circ}C$. Feed efficiency and protein efficiency ratio of fish fed to satiation were not significantly different between 13 and $18^{\circ}C$, but those of fish fed at 0.25 and 0.4% BW/d were significantly higher at 13 than $18^{\circ}C$. 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 $18^{\circ}C$, respectively. In the restricted feeding regime, compromised growth of fish were worsen in higher water temperature ($18^{\circ}C$ vs. $13^{\circ}C$). 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.

• Development and Reproduction
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• v.16 no.2
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• pp.87-93
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• 2012

Reproductive biology (maturation and spawning) of the female tongue sole Cynoglssus semilaevis were examined in 154 specimens caught from the west coast of Korea (between February and November 2010). Monthly changes of gonadosomatic index (GSI) and condition factor (CF) were peaked in September. Hepatosomatic index (HSI) showed a negative correlation with those of the GSI. Ovaries were classified into six stages based on the development of advanced oocyte and histological characteristics: virgin/immature, early developing, developing, late developing, ripe/spawning and spent/regressing stage. The relationship between fecundity (F) and total length (TL) of the fish was expressed as $F=251.43TL^{0.1264}$, and body weight (BW) was expressed as F=1130.4BW-880848. Biological minimum size of female was 46.87 cm (TL).