• 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.

• 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 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.

• 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.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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.100-106
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• 2003

This study was conducted to investigate the supplementary effects of vitamin C and E to moist pellet on growth and body composition in juvenile olive flounder (Paralichthys olivaceus). Four groups of diet made : moist pellet (MP) diet group was used as the control group where the ratio of raw feed and commercial compound meal is 5:5 $(CP\;30\%,\;CL\;17\%),$ vitamin C added group (VC), vitamin I added group (VE) and vitamin C and I added group (VCE). The supplementary amount of vitamin C and E corresponded to 1000 mg/kg (dry wt.) and 220mg/kg (dry wt.), respectively. Vitamin C was destroyed $50\%$ and vitamin E was destroyed $20\%$ for manufacturing process. After 8 weeks feeding trial, weight gain was $121.9\%$ in MP group, while it ranged from 180.5 to $184.9\%$ in the VC, VE and VCE group. Feed efficiency was $71.\6%$ in MP group, whereas it ranged from 78.7 to $80.6\%$ in the VC, VE and VCE group, weight gain and feed efficiency of fish fed vitamin supplemented diets were significantly higher than control group and no significant difference among the vitamin added groups was observed (p>0.05). There were no significant differences in moisture, crude protein, crude lipid, crude ash, condition factor (CF), hepatosomatic index (HSI), and visceraweight index (VWI) of body composition. Hemoglobin (Hb) was $3.79\%$ in MP group, whereas $4.99\%$ in VC group, $4.55\%$ in VE group and $5.07\%$ in VCE group; Hb was significantly higher in the vitamin added groups than the control group (p<0.05). Vitamin C retention in liver was 18.1, 20.7, 46.6, 54.0 mg/kg in MP, VE, VC and VCE groups, respectively. Vitamin E retention in liver was 25.9, 53.8, 88.2, 124.5 mg/kg in MP, VC, VE and VCE groups, respectively. These results indicate that supplementation of vitamin C and E to moist pellet diet significantly improved growth and feed efficiency of olive flounder, and the mixed addition of vitamin C (1,000 mg/kg dry wt.) and vitamin E (220 mg/kg dry wt.) did not lead to the synergy effect.

• Journal of Fisheries and Marine Sciences Education
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• v.22 no.4
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• pp.529-536
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• 2010

This study was conducted to effect of extruded pellets (EPs) and moist pellet (MP) diet on growth and fish health parameters in farm cultured olive flounder Paralichthys olivaceus. Two replicate groups of 2,600 fish per each tank (initial weight of $30.1{\pm}0.2$ g) were fed one of the three EPs (EP1, EP2 and CEP) and one MP for 13 months. In field feeding experiment conducted in commercial flounder farm, survival, growth (30-600 g) and condition factor of fish fed experimental EP1 and EP2 were comparable to those of fish fed MP, but considerably higher feed efficiency and protein efficiency ratio were observed in fish fed experimental EPs. Viable cell counts from diet and water from MP diet were considerably higher than those from EP diet, and lysozyme activity from EP diet was higher than that from MP diet. GOT and GPT of fish fed the EP diet were considerably lower than those from MP group, but total protein and glucose concentration of fish fed the EP groups were not significantly different from that of fish fed the MP. Therefore, these results strongly suggest that EP diets could be developed to replace MP diet without adverse effects on growth performance and to enhance the immunity and protective ability of olive flounder against fish disease such as Vibro, Edwardsiella and Strptococcus.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.18-21
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• 1999

A feeding experiment was conducted to determine the effects of feeding frequency on growth and body composition in juvenile olive flounder (Paralichthys olivaceus). Triplicate groups of the 40 fish averaging 1.6 g were fed the 2 different commercial diets (D-1 and D-2) and moist pellet (MP) contained frozen horse mackerel and commercial binder meal at different feeding frequencies of 4 times daily, 3 times daily, 2 times daily, once a day or once in 2 days. Growth and feed intake of fish were affected by diets and feeding frequencies (P<0.05). Feed intake ($\%$ of body wt.) in the all diet groups was significantly decreased according to feeding frequency decreased (P<0.05). Weight gain of fish fed the each diet were increased according to feeding frequency increased, although no significant differences were observed between 3 times and 4 times daily (P>0,05). If the same feeding frequency, feed intake and growth of fish fed the moist pellet were lower (P<0.05) than those of commercial diets (D-1 or D-2), probably due to the relatively high moisture content or unbalanced nutrients. Whole body lipid content of fish fed the each diet at once in 2 days was the lowest among feeding frequencies. These results indicate that 3 times daily feeding regimen may be more effective than that of 4 times daily and moist pellet in this study will not be used as a practical type of diet for juvenile olive flounder weighing between 1,6 g and 4 g.

• Journal of Aquaculture
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• v.8 no.4
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• pp.261-269
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• 1995

A practical control diet was prepared and compared with raw fish ($80\%$ frozen horse mackerel + $20\%$ commercial binder meal) and moist pellet ($50\%$ frozen horse mackerel + $50\%$commercial binder meal) diets to develop a practical diet formulation for Korean rockfish (Sebastes schlegeli). Korean rockfish averaging 68.5g were fed with the three experimental diets for 11 months. Final average body weight was approximately 330g and showed no significant difference between fish groups (P>0.05). Feed efficiency of fish from control diet was significantly lower than those of fish from raw fish and moist pellet diets (P<0.05). Protein and lipid retention efficiency of fish ranged $26.9-28.8\%$ and $86.5-110.2\%$, respectively, without any significant difference between the different diets. At the end of the experiment, chemical composition for the various parts of fish body and flesh quality of the raw fish were examined. The data showed that there was no significant difference between fish from the different diet groups for moisture, protein and lipid contents of whole body, liver, and dorsal muscle. Also, thirty three panelists did not find any difference in color, smell, texture, and taste of the raw fish flesh. These results suggest that Korean rockfish can be cultured with a laboratory practical feed without any negative effects on growth, nutrient utilization, chemical composition of fish, and quality of raw fish. Therefore, the next step in developing practical feed is to modify the control diet for improving fish performance and reducing feed cost.