• Journal of Aquaculture
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• v.9 no.3
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• pp.247-254
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• 1996

Two experiments were conducted to evaluate dry pellet on growth of juvenile Korean rockfish (sebastes schlegeli) by comparing with moist pellet and raw fish-based moist pellet. In the first experiment, three replicate groups of 40 fish averaging 4.7 g were fed one of the following three experimental diets for 11 weeks : d교 pellet (DP) and moist pellet (MP) diets containing $56\%$ white fish meal (WFM) + $3\%$ soybean meal (SM) + $5\%$ corn gluten meal (CGM) as protein sources, or raw fish-based moist pellet (RMP, $50\%$ frozen horse mackerel+$50\%$ commercial fish feed). No significant differences were found among fish fed different pellet types of diets in daily weight gain and whole body composition (P>0.05). In the second experiment, two replicate groups of 140 fish averaging 10.9 g were fed one of the following three experimental diets for 8 weeks : DP and MP diets containing $38\%$ WFM+$15\%$ SM+$10\%$ CGM as protein sources, or RMP. Daily weight gain and feed efficiency from fish fed RMP were significantly (P>0.05) higher than those from fish fed DP diet. These different growth responses between two experiments may be due to dietary protein sources and nutrient content. findings showed that DP can be used as a practical diet for juvenile Korean rockfish.

• Journal of Aquaculture
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• v.10 no.2
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• pp.163-169
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• 1997

An experiment was conducted to determine the effects of feeding extruded-floating (EP), slow-sinking (SP), fast-sinking (FP) or moist (MP) prepared with two different levels of fish meal, respectively, on the growth, feed efficiency and body composition in Korean rockfish (Sebastes schlegeli). Triplicate groups of the 50 fish averaging 75g were fed each of the following diets : high fish meal (72% in diet)-EP, low fish meal SP, low fish meal-FP and low fish meal-MP for 15 weeks. Dietary fish meal levels or pellet types did not influence weight gain, feed efficiency and bo요 composition of the fish (P>0.05). Findings showed that each of EP, SP or FP can by used as a practical type of diet for Koran rockfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.679-685
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• 2012

A study was carried out to observe the effects of feed types on the growth, feed preference, and enteric feed transition rate of juvenile starry flounder, Platichthys stellatus for 45 days. Fifty fish (avg. 135 g) were stocked each in replication, and fed a commercial extruded pellet diet (EP, 45% protein) and a moist pellet diet (MP, 65% raw mackerel+35% feed powder in wet basis), respectively. The MP presented the higher performance than that of the EP on the feed efficiency ($68.3{\pm}0.9%$ for EP and $92.3{\pm}4.3%$ for MP) and the specific growth rate ($1.07{\pm}0.07$ for the EP and $1.20{\pm}0.05%$ for the MP). In contrast, the EP showed the higher feed preference in terms of the daily feed intake ($1.57{\pm}0.08%$ for the EP and $1.30{\pm}0.01$ for the MP) and the ad libitum feeding rate after a fast of 72 hours (1.73% for the EP and 1.35% for the MP). The feed transition rate through intestinal canals decreased exponentially in both the EP and the MP, showing the faster transition rate with the EP. In the result, starry flounder appeared to have the better feed preference to the EP, but have the higher feed efficiency and growth performance to the MP.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.4
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• pp.556-561
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• 2009

This study was conducted to evaluate the laboratory formulated extruded pellet (EP) for olive flounder Paralichthys olivaceus in the East Sea. Three replicate groups of 3,200 fish per each tank (initial weight of $28.1{\pm}0.2g$) were fed one of the two EPs (EP and CEP) and Moist pellet (MP) for 16 months in a commercial farm (Pohang, Korea). Survival was not significantly affected by experimental diets (P>0.05). Weight gain and specific growth rate of fish fed the EP were not significantly different from those of fish fed the MP, but that of fish fed CEP was significantly lower than that of fish fed EP and MP (P<0.05). Feed efficiency and protein efficiency ratio of fish fed the EP was significantly higher than those of fish fed MP (P<0.05), but not significantly different from those of fish fed CEP (P>0.05). The Contents of moisture, crude protein and crude lipid in the dorsal muscle were not significantly different among all groups (P>0.05). These results clearly indicated that the laboratory formulated extruded pellet used in this study can be developed to replace the moist pellet without affecting any growth performance of olive flounder in the commercial farm feeding trail.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.5
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• pp.720-726
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• 2006

In an attempt to develop an artificial diet for growing olive flounder (Paralichthys olivaceus), weight gain, feed utilization and nutrient retention were investigated in fish fed moist (MP), semi-moist (SMP) and extruded pellets (EP). Excretion of nitrogen and phosphorus was also estimated based on their whole body gain and intake. EP and MP composed of raw fish and SMP made of formulated powder feed with water were prepared to have the same energy contents on a dry matter basis. A total of 240 fish with an average initial weight of 120 g were randomly distributed to each (20 fish/tank) of 12 circular plastic tanks (4 tanks/treatment) and fed experimental diets for 8 weeks. Fish groups fed EP (209 g) or SMP (209 g) recorded higher final weight than those fed MP (176 g), while dry feed consumption was highest in SMP groups (106 g), followed by MP (71 g) and EP groups (62 g). As a consequence, fish groups fed EP showed much lower feed conversion ratio than the other two groups. Protein efficiency ratio was also significantly higher in fish groups fed EP (2.55) than in those fed MP (1.44) and SMP (1.31). Fish groups fed EP, which showed the highest nitrogen retention of 43.9%, resulted in the lowest excretion of nitrogen of 35.5 g per kg gain. Also, the lowest phosphorus excretion of 6.0 g per kg gain was found in the EP groups with the highest P retention (37.0%) among treatments. Although the EP groups had the lowest dietary energy intake, they retained the highest energy in the whole body among treatments. The present results showed that EP could be more advantageous than MP or SMP in terms of growth, feed utilization and excretion of nitrogen and phosphorus for olive flounder.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.609-615
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• 2012

A histo-pathogical examination was carried out to evaluate the effect of commercial extruded pellet (EP) and a raw fish moist pellet (MP) diet on the health of juvenile rockfish cultured in marine net-cage for 7 months. Fish were distributed randomly to each net cage as a group of 76,000 fish (initial mean body weight 5.9 g). After 2 months, the hypertrophy or swelling of liver parenchymal cells was identified in most individuals and lasted until 7 months. Livers in EP fed group frequently showed hypertrophic parenchyma and fatty change with occasional atrophic cells. However, after 4 months, lymphocytic infiltration in splenic parenchyma was seen in a number of individuals. In addition, the gastric glandular epithelium was atrophied and in the lumen of renal tubules protozoan parasites were frequently identified but there was no correlation with the type of feed. Moreover, juvenile rockfish on EP diet showed gross and microscopic hypertrophy of the liver which would be due to oversupply of feed. Severe hepatic cellular hypertrophy or swelling could lead to the damage of microcirculation. Especially fatty change and atrophic change of liver could be the result from the damage, which could be responsible for immunological problem. Lymphocytic infiltration of spleen on the MP diet suggests that juvenile rockfish could be frequently exposed to infectious antigens.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.4
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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.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.6
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• pp.1315-1323
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• 2013

The purpose of this research is to evaluate the effects of a commercial mixed extruded pellet(EP) and raw fish moist pellet(MP) diet on diseases prevalence and serological constituents and HSI of korean rockfish, Sebastes schlegeli grown in two commercial-scale aquaculture farms from June to December in 2009. The growth of MP-fed rockfish was slightly faster than EP-fed rockfish during experimental period, but did not show significant differences. The levels of TCHO, TG, Glucose and TP in the MP-fed rockfish group were higher than those of EP-fed group, whereas there was no significant difference in other biochemical factors of blood between two groups. In addition, bacteria and virus were not detected in both MP- and EP-fed rockfish groups, and the infection rates of gill fluke between two groups did not show clear difference. In conclusion, there was no comparable difference in growth and the health extents of one year rockfish by administration of the commercial mixed extruded pellet(EP) and raw fish moist pellet(MP) diets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.785-790
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• 2011

This study investigated the nutritive quality of olive flounder Paralichthys olivaceus fed either moist pellet (MP) or moist pellet mixed with mushroom extract (MPME) for 6 months. There was no significant difference in crude protein or extractive nitrogen in the muscle of flounder fed MP versus MPME (P > 0.05). The total amino acid content in the muscle of flounder fed MP was $15.22{\pm}5.24$ g/100 g, compared to $19.90{\pm}2.90$ g/100 g for flounder fed MPME. Essential amino acid content was $7.04{\pm}2.21$ g/100 g in the muscle of flounder fed MP versus $8.94{\pm}2.50$ g/100 g for MPME. Total amino acid content was higher in the muscle of olive flounder fed MPME, while essential amino acid content was higher in flounder fed MP. The ratio of non-essential amino acids to essential amino acids was $0.86{\pm}0.07$ for flounder fed MP and $0.81{\pm}0.08$ for flounder fed MPME. There was no significant difference in free amino acid content and fatty acid composition. The breaking strength of muscle of olive flounder fed MP was higher ($1.44{\pm}0.51\;kg/cm^2$) than in flounder fed MPME ($1.29{\pm}0.30\;kg/cm^2$). There was no evidence that dietary additives, such as mushroom extract, increase growth rate or nutritive quality of olive flounder.

• Journal of fish pathology
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• v.22 no.3
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• pp.283-291
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• 2009

This study was conducted to evaluate the effects of a commercial extruded pellet (EP) and raw fish moist pellet (MP) diet on disease prevalence and serum chemistry of olive flounder Paralichthys olivaceus grown in two commercial-scale aquaculture farms from July to December in 2008. The contents of serum GOT, GPT and glucose in fish fed EP diet (EP group) were higher than those of fish fed the MP diet (MP group). There were no distinct differences in survival rates and mean detection rates of fish pathogens among fish group fed the experimental diets. However, the mean detection rate of fish pathogens in MP group was higher than that of EP group from July to October which are high water temperature season. The dominant pathogens isolated in EP group were Dactylogyrus sp., E. tarda and red sea bream iridovirus (RSIV). On the other hand, Trichodina sp., Streptococcus spp., viral nervous necrosis virus (VNNV) were dominant in MP group.