• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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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.

• Food Science and Preservation
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• v.18 no.5
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• pp.729-738
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• 2011

This study was conducted to investigate the effect of extruded pellets (EP) containing different levels of protein (51%-55%) and lipid (9%-15%) on flesh quality of flounder (Paralichthys olivaceus) comparing with raw fish-based moist pellet (MP). Two replicate groups of 40 fish per each tank (initial mean weight 106 g) were fed one of three experimental EP (EP1, EP2 and EP3) containing different protein and lipid levels, a commercial EP (EP4) and MP for 16 weeks. Moisture content of fish fed MP was significantly higher than that of fish fed all EP. Significantly higher contents of 16:1n-7, 20:4n-6, 20:5n-3 and lower 18:2n-6 were observed in fish fed EP4 and MP compared with fish fed EP1, EP2, EP3. The 22:6n-3 content was not significantly different among all groups. Taurine content of fish fed MP was significantly higher than that of fish fed all EP. Asparagine content of fish fed EP1 was significantly higher than that of fish fed EP2, EP, EP4 and MP. Significant difference were observed in lysine and serine contents of fish fed experimental diets. In nucleotides and their related compounds, ATP and AMP content was not affected by diets. Significant difference were observed in IMP contents of fish fed experimental diets. Textural properties, no significant difference was observed among the fish groups fed different diets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.451-456
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• 2010

This study was conducted to evaluate the quality characteristics (proximate composition, fatty acids, amino acids, sensory and textural properties) of whole body and dorsal muscle of olive flounders fed extruded pellets (EP) compared to raw fish-based moist pellets (MP). The olive flounders in this study were reared from 300 g to 1000 g for 7 months by feeding either EP or MP. The fatty acids and total amino acids of the whole body and dorsal muscle of the fish were similar among both groups. The major fatty acids in whole body and dorsal muscle werepalmitic acid and oleic acid. Finally, no significant differences were observed between groups for sensory and textural properties of the muscle. These results suggest that EP could be developed to replace MP without adverse effects on olive flounder quality.

• Journal of Aquaculture
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• v.18 no.1
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• pp.26-30
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• 2005

A 10-week feeding trial was conducted to determine the optimum feeding rate of two extruded pellets (EP1 and EP2) and raw fish-based moist pellet (MP) for juvenile flounder. Two replicate groups of the fish (average weight of 27 g) were fed EP and MP three times daily at different feeding rate (satiation and $85\%$ satiation). Weight gain of fish was not affected by diet, but affected by feeding rate. Weight gain with satiation feeding group showed :t tendency to higher compared to that of fish with $85\%$ satiation feeding at the same diet. Feed efficiency of fish was affected by diet, but not feeding rate. Feed efficiency of fish fed the EP1 and EP2 was higher than that of fish fed the MP at the same feeding rate. Daily feed intake was affected by diet and feeding rate. Daily feed intake of fish fed with satiation was higher than that of fish with $85\%$ satiation at same diet, and this variable of fish fed the MP was higher than that of fish fed the EP 1 and EP2. Protein efficiency ratio of fish fed the MP was significantly lower than that of fish fed the EP1 and EP2 regardless of feeding rate. Lipid content of whole body was affected by diet, and that of fish fed the EP2 and MP at satiation feeding was the highest. It can be concluded that satiation feeding will be good and EP is better than MP for growth of juvenile flounder grown from 27 g to 51 g.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.777-784
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• 2013

This study compared the effects of diets consisting of experimental extruded pellets (EP), commercial soft extruded pellets (SEP), and raw-fish-based moist pellets (MP) on the growth, flesh quality, and histology of the Korean rockfish Sebastes schlegeli. Three replicated groups of 60 fish each (initial mean weight 152 g) were fed one of two experimental EPs (EP1 and EP2), two commercial SEPs (SEP1 and SEP2), or MP for 11 weeks. The survival, weight gain, and final mean weight of the fish did not differ significantly among the groups. The highest feed efficiency was in fish fed MP (P<0.05), and the protein efficiency ratio of fish fed MP was significantly higher than that of fish fed EP1, EP2, or SEP1, but not significantly different from that of fish fed EP2. The daily feed intake of the fish fed the EPs and SEPs was significantly higher than that of the fish fed MP (P<0.05). The condition factor, Hepatosomatic Index, and Viscerasomatic Index of the fish did not differ significantly among the groups. No notable differences in the textural properties of the dorsal muscle, plasma biochemical parameters, or histological features of the fish were observed in fish fed any diet. This suggests that extruded pellets can be used to feed growing Korean rockfish without compromising growth, flesh quality, or histopathological change in comparison to raw fish-based moist pellets.

• The Journal of Fisheries Business Administration
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• v.40 no.3
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• pp.189-205
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• 2009

This study is aimed to analyze the economic feasibility comparison of the extruded pellets and moist pellets on the Oliver flounder culture farms in Jeju Island. In order to do this, we selected 2 farms (M and S farms) in Jeju Island as a sample. In the study, various analyses including productivity analysis, cost structure analysis, profitability and economic feasibility analysis by feed type were conducted for two sample farms of Oliver flounder culture. The results of economic analysis by feed type on the Oliver flounder culture can be summarized as follows; First, there were not significant differences in productivity by feed type. Second, results of the profitability analysis on farm M by feed type showed the profitability was estimated to be 15.52% and 9.83% in EP and MP, respectively. In addition, the profitability of farm S was estimated to be 28.37% and 33.72% in EP and MP, respectively. Third, results of the economic analysis on farm M by feed type indicated that an internal rate of return(IRR) was 8% and 7% and a benefit-cost ratio was shown to be 1.64 and 1.11 in EP and MP, respectively. Furthermore, the economic analysis of farm M by feed type showed that an IRR was 19% and 24% and a benefit-cost ratio was calculated to be 1.4 and 1.51 in EP and MP, respectively. In summary, it is especially emphasized that economic valuation is not related to feed types (EP and MP). Finally, in order to improve the economic feasibility, it should be more focused on the efficient business management of the Oliver flounder aquaculture.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.394-399
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• 2011

The effect of intermittent feeding on growth, feed utilization and body composition of subadult olive flounder fed extruded pellet (EP) in suboptimal temperature ($13.5{\pm}2.10^{\circ}C$) was determined. Two hundred twenty five subadult fish averaging 272 g were randomly distributed into fifteen of 300 L circular flow-through tanks (fifteen fish per tank). Five treatments with different days of feeding a week were prepared in triplicate: fish were hand-fed with EP to apparent satiation once a day, seven days a week (7DF), which was used as the control group or consecutive six, five, four and three days a week, for 12 weeks, referred to as 6DF, 5DF, 4DF and 3DF treatments, respectively. Weight gains and specific growth rates of fish in 6DF treatment were higher than those of fish in 7DF, 4DF and 3DF treatments, but not different from those of fish in 5DF treatment. Daily feed intake of fish in 6DF and 7DF treatments was higher than that of fish in 5DF, 4DF and 3DF treatments. Feed efficiency and protein efficiency ratio of fish were not different among treatments. There was no difference in the chemical composition of fish between treatments. Results of this study demonstrated that feeding five days per week could be recommended for subadult olive flounder fed extruded pellet in suboptimal temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.731-737
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• 2017

Substitution effect of fish meal and Saccharina japonica with soybean and rice bran in extruded pellet (EP) on juvenile abalone was determined. Two thousand five hundred and twenty juvenile abalone were distributed into 36 plastic containers. Four EP were prepared and extruder-pelletized. Twenty percent fish meal, 12% soybean meal and 14% Saccharina japonicawere included in the Control diet. Fifty percent of fish meal, combined 50% of fish meal and Saccharina japonica, and 100% of fish meal and Saccharina japonica were substituted with the same amount of soybean meal, and combined soybean meals and rice brans, referred to as FS50, FS50+SS50 and FS100+SS100 diets, respectively. Four domestic and 3 imported commercial diets for abalone and salted Saccharina japonica were prepared. The diets were fed to abalone once a day for 16 weeks. The highest survival was obtained in abalone fed FS50+SS50 diet. Weight gain and SGR of abalone fed FS50+SS50 diet was higher than those of abalone fed the FS50 and FS100+SS100 diets. Proximates of abalone was affected by dietary nutrient composition. In conclusion, 50% fish meal and combined 50% fish meal and Saccharina japonica could be replaced with the same amount of soybean meal and combined soybean meal and rice bran in EP of abalone.

• Journal of Aquaculture
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• v.20 no.1
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• pp.51-55
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• 2007

This study was conducted to evaluate the muscle quality of the olive flounder fed on extruded pellet (EP) diets compared with a raw fish moist pellet (MP) diet for olive flounder, Paralichthys olivaceus in a commercial scale for a year. The sensory and physical qualities and palatable compounds were compared for evaluation of muscle quality in fish. Four diets were formulated for this experiment: two experimental EP diets (EP 1 and 2), one commercial EP diet (CEP) and MP diet. Crude lipid of fish fed EP1 and EP2 was significantly higher (P<0.05) than that of fish fed CEP, but not significantly different from that of fish fed MP (P>0.05). In the palatable compounds, the free amino acids composition were much alike in that of all the diets. Proline, glycine and alanine from fish fed diet EPs were the most abundant compound among amino acid compositions. There was little difference in the free amino acid compositions of all flounder from localities and the growing conditions between wild and cultured fishes. Taurine of fish fed EP1 was dominantly high over that of fish fed EP2, CEP and MP. In all nucleotides and their related compounds, ATP and IMP from fish fed EP diets were higher (P<0.05) than those of fish fed MP. In the sensory score, overall-acceptability of fish fed EP2 were significantly higher (P<0.05) than that of fish fed EP1, CEP and MP. Hardness of physical properties from fish fed EP2 was significantly higher (P<0.05) than those of fish fed CEP (P<0.01). These results strongly suggest that diets EP could be developed to replace MP diet for the grow-out stage of olive flounder without adverse effect on growth performance.

• 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.