• Journal of Aquaculture
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• v.21 no.4
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• pp.299-303
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• 2008

A 6 and 8-week feeding trial was conducted to determine optimal feeding rate for parrot fish Oplegnathus fasciatus during the low temperature season. To estimate the optimal feeding rate calculated by weight growth rate, one year (mean body weight: 62.7 g) and the two year old parrot fish (mean body weight: 344.7 g) were stocked under low water temperature conditions. The optimal feeding rates in low water temperature condition of $15^{\circ}C$ were calculated as 1.61% of body weight (90% of satiation level) for the one year of 62 g, and calculated as 0.28% of body weight (80% of satiation level) for the two years old fish.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.67-67
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• 2003

Dorsal aorta cannulated rainbow trout averaging 505 $\pm$ 6.5g (Mean $\pm$ SD) were divided into 7 groups (5 fish per group). Twenty four hour post feeding, cannulated fish were intubated with one of seven L-amino acid diets containing graded levels of Valine (Val. : 0.45, 0.95, 1.20, 1.45, 1.70, 1.95 or 2.45%) at 1% of body weight. Blood samples were taken at 0, 5 and 24hr after feeding the experimental diets. Post-prandial (5h after feeding) plasma-free Valine concentrations (PPval.) increased linearly from fish fed diets containing Valine between 0.45 and 1.45%, but the concentration remained constant from fish fed diets containing valine between 1.45 and 2.45%. Post-absorptive (24h after feeding) plasma free valine concentrations (PAval) increased linearly from fish fed diets containing valine between 0.45 and 1.45%, but the concentration remained constant from fish fed diets containing valine between 1.45 and 1.95%. Using the broken-line model analysis, the dietary valine requirement by PPval and PAval could be 1.44 and 1.50% in rainbow trout, respectively. These results supported that the estimated dietary valine requirement by PP(val.) and PA(val.) could be in close agreement with the values obtained from the previous conventional feeding method. Thus, the use of PFAA concentrations for determining essential amino acid requirements could be possible in rainbow trout with dorsal aorta cannulation.

• Nutritional Sciences
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• v.6 no.2
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• pp.78-84
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• 2003

The objective of this study was to examine the effects of seven dietary oils on the serum lipid patterns of rats. Seventy weanling Wistar Kyoto rats were divided into seven groups of ten rats each. Walnut oil (rich in PUFA), wheat germ oil (rich in PUFA), corn oil (rich in PUFA), canola oil (rich in monounsaturated fatty acids), fish oil (rich in PUFA), primrose oil (rich in PUFA), and palm oil (rich in saturated fatty acids) were employed for 21 days. Serum total cholesterol concentrations for rats fed palm oil, walnut oil, and wheat germ oil were significantly higher than were concentrations for rats receiving corn oil. fish oil, and primrose oil. The mean serum LDL cholesterol values for rats fed fish oil, primrose oil, and corn oil were significantly lower than those for rats fed walnut oil, wheat germ oil, canola oil, and palm oil. HDL cholesterol concentrations were the highest when wheat germ oil was fed and the lowest when fish oil was fed. The feeding of wheat germ oil and palm oil to rats resulted in considerably higher serum triglyceride levels than did all other treatments. The feeding of wheat germ oil to rats resulted in considerably higher serum phospholipid levels. Serum phospholipid concentrations were significantly lower in rats fed the canola oil, fish oil, ,and primrose oil diets, when compared to concentrations achieved with the feeding of walnut oil, wheat germ oil, corn oil, and palm oil. Palm oil, which has a high ratio of saturated to polyunsaturated fatty acids, resulted in the highest serum total cholesterol and highest LDL cholesterol levels, while fish oil, primrose oil, and corn oil produced the lowest total cholesterol and LDL cholesterol. Wheat germ oil produced the highest values for HDL cholesterol, triglycerides, and phospholipids. In general, feeding oils rich in polyunsaturated fatty acids produced more favorable responses than feeding oils containing large amounts of monounsaturated or saturated fatty acids.

• The Journal of Information Systems
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• v.32 no.4
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• pp.137-147
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• 2023

Purpose The domestic aquaculture industry in South Korea utilizes both formulated feeds and live feeds for the cultivation of fish. While nutrient-rich live feeds, particularly using fry, have been preferred since the past, formulated feeds are gaining attention due to issues related to overfishing and environmental concerns. Formulated feeds are advantageous for storage and supply but require a sustained feeding regimen due to the comparatively slower growth rate compared to live feeds. As the aging population in rural areas leads to a shortage of labor, automated feeding systems are increasingly being adopted in aquaculture facilities. To enhance the efficiency of such systems, it is crucial to quantitatively analyze the behavioral changes in fish based on the presence or absence of feed. Design/methodology/approach In the study, RGB cameras and infrared cameras were used to analyze fish activity according to feeding, and an outline extraction algorithm was applied to analyze the differences resulting from this. Findings Unlike RGB cameras, infrared cameras are more suitable for analyzing underwater fish activity as they convert objects' thermal energy into images. It was observed that Canny, Sobel, and Prewitt filters showed the most distinct identification of fish activity.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.357-362
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• 2006

The feeding habits of John Dory (Zeus faber) were studied by examining the stomach contents of 317 specimens collected from January 2004 to December 2005 in the coastal waters off Gori, Korea. The standard length (SL) of the specimens ranged from 12 to 42 cm. Z. faber is a piscivore and consumes mainly teleost fish such as Psenopsis anomala, Trichiurus lepturus and Conger myriaster. Its diet also includes shrimp and cephalopods. Smaller individuals (<25 cm SL) consume shrimp and small fish such as Glossanodon semifasciatus. The proportion of these prey items decreases with increasing fish size, and this decrease is paralleled by increased consumption of lager fish such as Psenopsis anomala and Trichiurus lepturus. The prey size increases with Z. faber size.

• 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 Marine Life Science
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• v.7 no.1
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• pp.1-9
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• 2022

This investigation aimed to assess the appetite response changes of olive flounder to starving and re-feeding conditions. Three different feeding groups (2 weeks feeding, fed; 2 weeks starving, starved; and 1 week starving and 1 week feeding, re-fed) were established to examine the changes in appetite-related genes for each group. The weight gain of the fish was highest for the fed group and lowest for the starving group. Based on the daily feed intake (DFI) and cumulative feed intake (CFI), overall food intake was found to increase in the re-fed group more than in the fed group from week 1 to week 2 of the experiment. Hypocretin neuropeptide precursor (HCRT) and galanin receptor 1 (GAL-R1) mRNA expression in the brain of olive flounder were decreased in the starved group. Corticotropin-releasing hormone (CRH) was decreased in all experimental groups, except for the fed group. However, overall leptin concentrations in the plasma did not change across groups. Considering the differences between this study and previous studies on starving and feeding, various factors (except the production and expression mechanisms of appetite-related factors in response to starving) are likely acting on the appetite responses of the fish. In this study, a 1-week re-feeding period induced substantial effects on appetite response when compared to a 2-week feeding period. These findings show that even if re-feeding is performed after starving, the unbalance caused by the re-feeding can affect various physiological changes in fish by feed intake efficiency.

• 한국해양학회지
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• v.21 no.2
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• pp.85-91
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• 1986

Diet and feeding patterns of 10 species of gonostomatid fish in the Rockall Trough and Porcupine Seabight, northeastern Atlantic, were investigated as a part of studies analyzing the meso-and upper bathypelagic micronektonic fish communities in these two areas. Copepods were the major food organisms, composing more than 72% in both areas, and ostracods the second most abundant prey organisms (〉13%). The results of stomach content analyses reveals that most of gonostomatids, including two important species, Cyclothone braueri and C. microdon, feed continuously regardless of light cycle and a little at a time. The gonostomatids appear to be planktivores that consume small-sized prey; relative size of most preys was about one-tenth of fish length. These feeding patterns could be an adaptive characteristic of fish living in great deep water where the food items are scarcely present. In general there are no considerable inter-and intraspecific differences, not to mention regional differences, in the feeding of the gonostomatids at both stations except the large specimen of Gonostoma elongatum fed fish. Thus several coexisting species of the gonostomatid fish utilize the same resources, showing competitive relationships.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.3
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• pp.667-675
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• 2014

Two types of diets, extruded pellet (EP) and raw-fish-based moist pellet (MP) were fed to compare growth, water quality and histology of olive flounder, Paralichthys olivaceus in Jeju fish farm. Two groups of 7000 fish per each tank (initial mean weight 51 g) were fed one of two diets for 7 months. At the end of the feeding trial, significant differences were found in weight gain and feed utilization. Dissolved oxygen (DO) level of the MP tank was decreased from 7.98 to 6.89 after feeding. There were no significant differences in hematocrit, hemoglobin, alanine aminotransferase and aspartate aminotransferase of fish fed the two diets. Whole body protein content of fish fed the EP was significantly higher than that of fish fed the MP. While the feeding rate by month indicated numerically decreased, fish fed the MP had higher feed intake than that of fish fed the EP. Histological examination of hepatopancreas, kidney, and anterior intestine of fish fed the EP did not show any negative effects compared to those of fish fed the MP. This study revealed that EP could substitute for MP in terms of growth performance, blood parameters, water quality and histology of olive flounder.