• 한국수산과학회지
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• 제52권1호
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• pp.43-48
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• 2019

This study was conducted to investigate the effect of extruded pellet (EP) size on the growth performance of olive flounder Paralichthys olivaceus at the juvenile (Exp-I; $62.2{\pm}0.05$), growing (Exp-II; $150{\pm}1$) and sub-adult (Exp-III; $299{\pm}1$) stages. In Exp-I (3, 4, 5 and 6 mm diets), Exp-II (4, 9, 11 and 13 mm diets) and Exp-III (9, 11, 13 and 16 mm diets), triplicate groups of fish were fed four EP diets of different pellet sizes. In Exp-I, larger pellet sizes were significantly better than the smallest pellet size (3 mm). In Exp-II, significantly improved feed and protein efficiency were observed with increasing pellet size. The feed conversion ratios of the fish fed the 4 and 9 mm diets were significantly lower than those of fish fed 11 and 13 mm diets. The dietary digestibility of protein and energy was higher in smaller EPs than in larger sizes. In Exp-III, the growth performance of fish was not affected by the pellet size. However, feed intake was significantly affected, increasing with increasing pellet size. Therefore, the optimum pellet sizes for olive flounder under the conditions in this study were 5 mm for 60-150 g fish and 9 mm for 150-500 g fish.

• 한국양식학회지
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• 제18권4호
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• pp.287-292
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• 2005

본 연구는 넙치 육성용으로 실험 부상배합사료와 시판사료 및 생사료의 효능을 비교하기 위해 평균 체중 43.5 g의 넙치를 8주 동안 사육하였다. 실험사료로 4종류의 부상배합사료(EPl-EP4), 시판사료 4종류(EP5-EP8)및 습사료(MP)를 준비하여 1일 3회 만복으로 공급하였다. 사육실험 결과, 생존율은 모든 실험구에서 $85\%$ 이상으로 양호하였으며, 증중률은 EP2-EP4 실험구에서 가장 높은 값을 보였으며, EP6 실험구에서 가장 낮았다. 사료효율과 단백질효율은 MP 실험구에서 가장 낮은 값을 보인 반면, 일일 사료섭취율과 일일 단백질섭취율은 MP 실험구에서 가장 높은 값을 보였다. 어체의 단백질 함량은 실험구간에 유의한 차이가 없었으나, 수분, 지질 및 회분 함량은 사료에 따라 유의한 차이를 보였다. 혈액의 총 단백질은 모든 실험구간에 유의한 차이가 없었으며 , 중성지방은 EP3 실험구에서 높은 값을 보이긴 하였지만, EP7 실험구를 제외한 모든 실험구간에 유의한 차이는 없었다. 이상의 결과들로 보아 평균체중 42 g${\~}$108 g인 넙치의 성장을 위해 EP2-EP4를 공급하여도 좋을 것으로 판단된다.

• Environmental Analysis Health and Toxicology
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• 제17권1호
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• pp.1-6
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• 2002

Effects on nonylphenol (NP) treatment on early development of fertilized eggs and survival of larvae in olive flounder, Paralichthys olivaceus were investigated. Fertilized eggs and hatched larvae were exposed to aqueous solutions of NP at nominal concentrations of 50, 100, 150 and 200 $\mu\textrm{g}$/L. In the control I and II (methanol-carrier control) groups, the hatchability of fertilized eggs were 90.7$\pm$7.02 and 90.0$\pm$5.29％ (P <0.05), respectively. However, treatments of NP concentrations at 50, 100, 150 and 200 ug/L were reduced to 78.7$\pm$4.16, 46.0$\pm$9.17, 48.0$\pm$3.46 and 33.3$\pm$11.02% (P<0.05), respectively. The time to hatching of fertilized eggs was delayed in high-dose NP treatment groups rather than control groups. Fertilized eggs of NP immersed group could not hatch normally, and also vertebra of the larvae observed as abnormal shape. Cumulative mortality of hatched larvae after 26hr NP treatment was 38.3, 78.3, 88.3 and 100% in NP 50, 100, 150 and 200 ug/L treatment groups, respectively. Whereas, control I and II were 11.7, 16.7% (P<0.05). Hatched larvae showed most death at the embryonic development stage with abnormalities. These results suggest that NP treatment in fertilized eggs and larvae was inhibited as normally development for fertilized egg and growing of larvae.

• 한국수산과학회지
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• 제42권6호
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• pp.604-608
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• 2009

This study was conducted to evaluate extruded pellet (EP) diet compared with a raw fish moist pellet (MP) diet for flounder, Paralichthys olivaceus on field feeding experiments in Jeju area. The experimental EP diet (juvenile, growing and adult) was prepared based on the former studies on nutrient requirements and feed ingredient of flounder. Fish were distributed randomly to each aquarium as a group of 102,300 fish (initial mean weight 97 g) in field experiment I and reared randomly to each aquarium as a group of 40,000 fish (initial mean weight 120 g) in field experiment II. In field feeding experiment I conducted in commercial flounder farm, survival, wt. gain (94-1,090 g), feed efficiency and condition factor of fish fed experimental EP were comparable to those of fish fed MP, but considerably higher protein efficiency ratio were observed in fish fed experimental EP. In field feeding experiment II, no significant difference was observed in final mean weight of fish fed the experimental EP (1,234 g) and MP (1,286 g), and any noticeable problem caused by feeding the experimental EP was not found during the whole period of feeding trial. Survival of fish fed the experimental EP was lower than that of MP, and there was no significant difference in feed efficiency between the fish fed experimental EP and MP. Therefore, these results strongly suggest that diet EP could be developed to replace MP diet for the marketable size (1.3 kg) of production for flounder without adverse effects on growth performance. In particular, abdominal dropsy and reduction of condition factor, which are frequently occurred in commercial EP feeding farms, were not observed in flounder fed experimental EP.

• 수산해양교육연구
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• 제25권3호
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• pp.553-563
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• 2013

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 (P<0.05). Linolenic acid(18:3) and n-6/n-3 ratio in dorsal muscle of fish fed EP were significantly higher than those of fish fed MP (P<0.05). No significant differences were observed in the results of the flavor, color, taste and texture of the muscle of the fish fed EP compared to those fed MP (P>0.05). 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.

• 한국발생생물학회지:발생과생식
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• 제17권3호
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• pp.241-246
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• 2013

To effects of sex maturation in olive flounder by regulating long photoperiod, gonadal development and GTH mRNA expression in the pituitary were investigated. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from September 2011 to March 2012. The results showed that natural photoperiodic group showed a higher gonadosomatic index (GSI) than long photoperiodic group during the spawning season (March 2012). The histological analysis of ovarian tissue showed that natural photoperiod group of ovaries contained vitellogenic oocytes, but long photoperiod group of ovaries mainly contained perinucleolus staged oocyte and oil-drop staged oocytes. The FSH mRNA of olive flounder, under natural photoperiod group, showed a significantly higher expression but no significant difference under long photoperiod group. The $LH{\beta}$ mRNA showed a significantly higher expression only under natural photoperiod group. These results may suggest that long photoperiodic information regulates secretion of pituitary FSH and LH and maintain early growing stage of gonadal development in this species.

• Fisheries and Aquatic Sciences
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• 제10권4호
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• pp.191-195
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• 2007

The aim of this study was to assess whether size-rank at the juvenile stage is associated with growth performance and sex ratio in olive flounder (Paralichthys olivaceus). Juveniles (mean body weight, $8.8{\pm}0.9\;g$) were selected from two age groups, with the high size-rank group (HSRG) fish in the upper 19.3-67.3% of 104 days post-hatching (dph) age group and the low size-rank group (LSRG) fish in the lower 9.0-55.7% of 116 dph age group. Triplicate groups of 100 fish were reared over 32 weeks. A heavier final body weight was observed in the HSRG ($360{\pm}12\;g$) compared to the LSRG ($315{\pm}9\;g$, P<0.05), whereas no differences in feed intake, feeding efficiency, and mortality were seen between the experimental groups. The percentage of females was significantly higher in the HSRG (51.7%) than in the LSRG (30.8%, P<0.05). In addition, a remarkable increase in growth was recorded in females, indicating that the relative frequency of females increased with a body weight increase. The results suggest that high size-rank juvenile olive flounder have better growth performance and a higher percentage of females, because females start growing faster than males before size grading occurs.

• Asian-Australasian Journal of Animal Sciences
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• 제21권6호
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• pp.868-872
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• 2008

This experiment was conducted to evaluate the long term effects of dehulled soybean meal (DHSM) as fish meal (FM) replacer in the diet for olive flounder, Paralichthys olivaceus, for 42 wk at a commercial fish farm. The four experimental diets were MP (moist pellet based on raw fish), $DHSM_0$ (fish meal based dry pellet), $DHSM_{30}$ (30% fish meal was replaced by DHSM) and COMD (commercial dry pellet). Fish were fed one of the four diets containing 50% crude protein and 16.7 kJ available energy/kg diet for 42 wk. Fish averaging $3.20{\pm}0.04g$ ($mean{\pm}SD$) were initially distributed to each tank as a group of 6,000 fish reared in a flow-through system. At the end of the experiment, average body weight of fish was $315{\pm}9.3g$ ($mean{\pm}SD$) ). Weight gain (WG) and feed efficiency (FE) of fish fed MP, DHSM0 and DHSM30 showed no significant difference among the diet treatments. However, WG and FE of fish fed MP were significantly higher than those of fish fed COMD (p<0.05). Specific growth rate (SGR), protein efficiency ratio (PER) and survival of fish fed all diets were not significantly different among the dietary treatments. Therefore, these results indicate that DHSM could replace up to 30% white fish meal with amino acid supplementation in olive flounder diets for long-term feeding practice at the commercial farm.

• 한국수산과학회지
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• 제36권1호
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• pp.65-67
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• 2003

Flounder (Paralichthys olivaceus) fish goes through metamorphosis in the larvae phase. In this phase, it secretes much thyroid hormone to control metamorphosis. Sharp change in the environment and nutrition deficiency may cause stress in the metamorphosis phase. It leads to interfering with the development of thyroid hormone and finally inhibits the normal growth of larvae. In this study, the correlation between the change in thyroid hormones and the albinism appearance was examined by growing them with low temperature ($13^{\circ}C$) stress over the premetamorphosis stages (stage $D\~F$) of flounder metamorphosis. Albinism rate was $15\%$ in the low temperature group and $25\%$ in the control goup. $T_{4}\;and\;T_{3}$ of the control group tended to increase from stage F as larvae grew. $T_{4}$ increased 2 times compared to the control group as 72 ng/g at stage H, the increasing phae of water temperature, in the low temperature group. $T_{3}$ increased 8 times compared to the control group as 2.9 ng/g at stage E, the decreasing phase of water temperature. Therefore, it is judged that the albinism appearance of flouner is caused from the sharp increase in $T_{3}$ by the inappropriate secretion of thyroid hormone.

• 수산해양교육연구
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• 제24권4호
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• pp.602-608
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• 2012

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.