• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.263-269
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• 2017

The mineral contents, and free amino acid, and fatty acid composition of rack and bag or suspended cultured oysters Crassostrea gigas were compared. The moisture content did not change much from 82.8% to 86.3% in the different culture methods. The glycogen level was low 4.7% during rack and bag culture but high 7.2% during suspended culture. The sodium level was the highest during suspended culture, while copper and zinc level were highest during rack and bag culture. The taurine level was 1,385-1,375 mg/100 g in oyster cultured using the rack and bag method, but that in the market sample was lowest at 1,015.8 mg/100 g. Hydroxyproline, glutamic acid, proline, glycine, and alanine were detected at high levels in the experimental oysters. The polyunsaturated fatty acid content was similar among samples. The docosahexaenoic acid level was 14% with rack and bag culture and 12% with suspended culture, whereas the eicosapentaenoic acid level was 15% with rack and bag culture and 20% with suspended culture. The atherogenic index (AI), thrombogenicity index (TI), and hypocholesterolemic/ hypercholesterolemic (h/H) ratio were important factors in the nutritional evaluation. The AI and TI values were 0.5-0.2, and the h/H ratio were 2.0 and 2.4 with the rack and bag and suspended culture, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.500-505
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• 2017

The nucleotides and their related compounds, including ATP (adenosine triphosphate), ADP (adenosine diphosphate), AMP (adenosine monophosphate), IMP (inosine monophosphate), HxR (inosine) and Hx (hypoxanthine), were nearly identical in oysters Crassostrea gigas from the two culture methods. The K-value was lower than the threshold value such as 11.2-12.1. Although oysters have low amount of IMP, it was detected in this experiment. DPPH radical scavenging activity did not vary significantly with sample amounts (100, 300, and $500{\mu}g/mL$). DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical scavenging activity was 76.0-80.7% compare with the ascorbic acid standard. Superoxide anion scavenging activity reached 49.3% in the rack-and-bag culture sample at $500{\mu}g/mL$. However, the reducing power and $Fe^{2+}$ chelating activity were very low compared with their respective standard. The oyster culture methods did not affect oyster quality in terms of antioxidant activities.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.45-54
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• 2012

We investigated environmental characteristics of the tidal flat oyster aquafarms to clarifyeffects of the tidal flat environmental factors on growth and mortality of the tidal flat oyster Crassostrea gigas by the Net Bag Rack Culture System in two districts in Western Korea. In this study, we have carried out the basic environmental investigation on growth of the single tidal flat, water quality and sediments, etc. in Taean and Seosan districts, Choongcheongnam-do, where the single tidal flat oyster aquaculture have been performed by the net bag rack culture system. In June 2011 when the final survey carried out at the two districts in western Korea, the mortality in Seosan district was higher than that in Tae-an district. Judging from the results of growth and mortality of the single tidal flat oysters investigated at two sites of Jinsan-ri in Taean and Chang-ri in Seosan districts, two results of Taean district showed higher growth and lower mortality than those of Seosan district. It is assumed that the proper acceptable density possible for growth of the tidal flat seeds and the secure of economics, in case of plastic cultivate net with the size of $50{\times}80cm$, are about 200 individuals. In this study, It was clarified that selection of the suitable sites, the input into the net bag of high quality oyster seeds and selective dispersion in the optimal density of the single tidal flat oyster have an effect on growth and mortality of the tidal flat oyster.