• Fisheries and Aquatic Sciences
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• 제21권6호
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• pp.15.1-15.9
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• 2018

Background: Inflammation has been known to associate with many human diseases. The objective of this study was to evaluate an anti-inflammatory effect of ozonated krill (Euphausia superba) oil, which was prepared by the treatment of krill oil using ozone gas. The anti-inflammatory activity was evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Results: Ozonated krill oil significantly inhibited nitric oxide (NO) production and suppressed the mRNA and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 macrophages. Ozonated krill oil also reduced the mRNA expression of inflammatory cytokines such as interleukin (IL)-$1{\beta}$, IL-6, and tumor necrosis factor (TNF)-${\alpha}$ in LPS-stimulated RAW 264.7 macrophages. To elucidate the mechanism underlying the anti-inflammatory activity of ozonated krill oil, we evaluated the effects of ozonated krill oil on the activation of mitogen-activated protein kinases (MAPKs) pathway. Ozonated krill oil suppressed the LPS-stimulated phosphorylation of p38 MAPK and c-Jun N-terminal kinases (JNK). Conclusion: This study revealed that the ozonated krill oil exhibited an anti-inflammatory effect in LPS-stimulated RAW 264.7 macrophages. To the best of our knowledge, this is the first report that ozonated krill oil suppressed pro-inflammatory mediator and cytokine expression in LPS-stimulated RAW 264.7 macrophages by inhibiting the phosphorylation of p38 MAPK and JNK.

• Fisheries and Aquatic Sciences
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• 제17권2호
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• pp.189-195
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• 2014

Headspace volatile compounds of cold-stored and freeze-dried Krill Eupausia superba were analyzed to investigate their flavor qualities using a system combining a dynamic headspace isolator, an automatic thermal desorber, and a gas chromatograph-mass-selective detector. Levels of oxidation products of polyunsaturated fatty acids such as aldehydes, alcohols, and ketones, which are known to give seafood a nasty smell because of their low flavor threshold values, increased during cold storage of krill. Notably, levels of 2-methylpropanal, 3-methylbutanal, 2-methylbutanal and 2-butanone increased during its storage. They can be considered index compounds of off-odor according to freshness degradation during storage. By contrast, in freeze-dried krill powder, levels of aldehydes, ketones, and aromatic compounds decreased rapidly. Only alcohols, which did not greatly affect the food flavor, were isolated in large amounts. It was confirmed that levels of oxidized compounds of krill increased during cold storage, but decreased in freeze-dried krill.

• 한국수산과학회지
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• 제21권5호
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• pp.292-296
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• 1988

This review has dealt with the topics of biology of Antarctic krill, Euphausia superba. There are much of work on various aspects of the biological pattern of krill, in particular on reproduction, feeding and longevity. Nevertheless, the details of winter biology of krill still remained to be unclear. It is suggested that three kinds of energy Pathways, from inorganic or organic materials to krill, may occur in the Antarctic Ocean.

• 한국수산과학회지
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• 제21권5호
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• pp.303-310
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• 1988

This review has dealt with the topics of biology of Antarctic krill, Euphausia superba. There are much of work on various aspects of the biological pattern of krill, in particular on reproduction, feeding and longevity. Nevertheless, the details of winter biology of krill still remained to be unclear. It is suggested that three kinds of energy Pathways, from inorganic or organic materials to krill, may occur in the Antarctic Ocean.

• 한국식품과학회지
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• 제24권1호
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• pp.14-24
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• 1992

페기물로부터 얻어지는 보리새우(Penaeus japonicus) 껍질과 단백질이용의 전망성이 좋은 antarctic krill(Euphasis superba)을 시료로 하여, chitin의 산업적 이용을 위한 기초연구로서, 보다 효율적인 chitin의 추출조건을 설정하고, 새로운 방법으로 추출한 chitin들의 물리적, 화학적 성질들을 비교하였다. 본 연구에서 선정된 추출 방법으로 chitin을 추출한 결과 보리새우의 껍질을 출발물질로 한 정제 chitin은 순백색의 powder로 얻어졌으며, 정제 chitin의 질소함량 및 ash함량은 각각 6.64%와 0.4%로 나타났다. krill의 chitin의 경우에는 6.35%의 질소함량과 0.4%의 ash함량을 나타내었다. 고유점도를 측정하여 formic acid 용액계에서 구한 정제 chitin의 분자량은 krill의 경우 $1.56{\times}10^{5}$, 보리새우의 경우 $1.78{\times}10^{5}$, Sigma C 3641이 $0.18{\times}10^{5}$으로 나타났으며, N-acetylglucosamine의 중합도는 krill의 경우 약 750, 보리새우의 경우 약 850이었다. 본 연구의 추출방법으로 정제된 chitin은 비교적 아세틸화도가 큰 것으로 확인되었고, 추출후의 아미노산 잔존량 중에서 methionine이 많이 남아있는 것이 특징으로 나타났다.

• Fisheries and Aquatic Sciences
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• 제10권4호
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• pp.215-219
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• 2007

Long-tenn variation in krill (Euphausia superba) and salp (mainly Salpa thompsoni) stocks was compared to environmental changes in the Atlantic and Indian sectors of the Antarctic. Environmental conditions examined were air temperature, water temperature, salinity, and sea-ice extent from 1926 to 1938 and from 1982 to 2000. The long-term pattern of krill was opposite to that of salp: krill stock decreased while salp stock increased concurrently. Krill stock was about three-fold higher from 1926 to 1938 than from 1982 to 2000, but salp was about four -fold lower in 1926-1938 than in 1982-2000. A wanning trend was observed in the environmental data, and the long-term variation in krill and salp stocks was affected by this trend.

• Ocean and Polar Research
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• 제26권4호
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• pp.679-684
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• 2004

To determine if Antarctic krill employ body shrinkage as one of its overwintering mechanisms in the field, Euphauia superba and Euphausia crystallorophias were collected during fall and winter in and around Marguerite Bay through US Southern Ocean GLOBEC field programs during fall and winter 2001 and 2002. The relationships between the body length and weight of both krill species were exponentially correlated with no significant differences between the two species (p>0.05). The ratio between eye diameter and body length of individual krill was examined in an expectation that it could be used as an indicator of the body shrinkage as previously suggested by Shin and Nicol (2002). These ratios were significantly different between the two krill species. Especially, E . crystallorophias had bigger eyes than E. superba. In both krill species, eye diameters were highly correlated with body lengths (regression coefficients ${\geq}0.70$). For E. crystallorophias, no significant differences of the ratio of eye diameter/body length were detected between fall and winter. Even though the ratios for E. superba were seasonally varied, it was not clear whether body shrinkage was an actual and critical overwintering mechanism for the krill population found in this study area. These results suggest that some individuals of E. superba might experience the body shrinkage during a part of their liff, but this morphological index alone (eye diameter/body length) may be insufficient to unambiguously separate the shrunk krill from the non-shrunk ones in the field-collected animals.

• Ocean and Polar Research
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• 제23권4호
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• pp.425-431
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• 2001

From an ecological point of view, the western part of the Atlantic sector is one of the most productive areas in the Southern Ocean. Antarctic krill (Euphausia superba) and krill-dependent predators such as fish, seals, and birds are abundant there, and most krill fisheries have operated in this area since 1970s. The hottest issues for the proper management of krill resources nowadays are to determine total biomass in this area, and to identify environmental forces controlling stock fluctuation. This paper reviews and collates information on ongoing oceanographic activities in the Antarctic Peninsula region concerning these issues. To delineate the status and function of Antarctic krill population in Antarctic marine ecosystems, multinational researches along the Antarctic Peninsula area have been developing recently. Four member states of CCAMLR (Japan, Russia, UK, and USA) had conducted acoustic surveys in January-February 2000 (socalled CCAMLR-2000 survey), and krill standing stock at 120 kHz was estimated to be 44.29 million metric tonnes in the western Atlantic sector of the Southern Ocean. On the other hand, the Southern Ocean GLOBEC (SO-GLOBEC) Programme has prepared a serial winter survey to examine the factors that govern krill survivorship and distribution in relation to shelf circulation processes. Ship-based surveys using ice-breakers are being conducted by three nations (Germany, UK, and USA) around the Marguerite Bay during the austral fall and winter 2001 and 2002. In addition to these two large-scale surveys, some CCAMLR members have carried out joint oceanographic surveys near the South Shetland Islands to detect ecosystem changes since 1994. Especially from December 1999 to February 2000, in conjunction with CCAMLR-2000 survey, four nations (Japan, Korea, Peru, and USA) conducted acoustic surveys to produce time-series information on krill distribution and biomass near the South Shetland areas. Though the aims of each program and the approach to solve the scientific questions were different each other, the results from each program fill the gaps between programs. Further cooperation and exchange in these activities could be beneficial to each program.

• 한국수산과학회지
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• 제46권4호
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• pp.343-350
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• 2013

Instant krill gruel was produced using peeled Antarctic krill Euphausia superba as a high nutritional ingredient and the food quality was investigated. The food quality of krill gruel was examined by measuring proximate composition, cholesterol, calorie, Hunter color value, total amino acids, fatty acids, fluoride, viscoelastic properties, and by sensory evaluation. The krill gruel had a moisture content of 87% and a pH of 6.65. The krill gruel contained 51 kcal/100 g, and 0.1% fat and 3.5 mg/100 g cholesterol. Its fatty acid composition exhibited high levels of unsaturated fatty acids. The levels of oleic acid and linolenic acid were high, and n-3, n-6, and n-9 fatty acid contents ranged from 1% to 6%. The total amino acid content was 2132 mg/100 g, and the levels of glutamic acid, aspartic acid, leucine, alanine, and arginine were particularly high. Essential amino acids accounted for over 30% of the total amino acids. Fluoride level in the krill gruel was 3.07 mg/kg. The viscoelastic properties of the krill gruel were determined as 6.28 Pa at shear stress of 2.51 Pa. In the recovery test, the elastic restoring force after deformation was low.

• 동아시아식생활학회지
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• 제19권5호
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• pp.776-782
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• 2009

This study was conducted to develop functional soybean paste with krill (Euphausiacea) as compared to a conventional soybean paste (S1). Soybean containing 10%, 20% and 30% (w/w) krill (S2~S4, respectively) was prepared and quality characteristics (moisture, crude fat, crude protein, ash, reducing sugar, pH, titratable acidity, total acidity and buffering power) were assessed during fermentation for 150 days. As well, antioxidative activities of krill soybean paste were compared to those of control soybean paste based on total phenolic compound content and free radical scavenging activity, including the 1,1-diphenyl-2-picryl-hydrazil (DPPH) scavenging activity and the thiobarbituric acid value (TBA value). The moisture content of all samples decreased to 41.91~53.47% during fermentation, while the crude fat increased to 1.98~5.21% with increasing addition of krill. Additionally, crude protein increased slightly to 8.24~14.08% with increasing addition of krill after 120 days of fermentation. Ash content was 15.96~18.92%. The reducing sugar content of S2, S3 and S4 was higher than those of S1 with increasing length of fermentation. S2, S3, and S4 displayed progressive decreases in pH and progressive increases in titratable acidity compared to S1. The total acidity of all samples was increased, while the buffering power was decreased with increasing fermentation. Especially, the buffering power of S1 was lower than that of S2, S3 and S4. DPPH radical scavenging activity of lipophilic extracts from S2, S3 and S4 was slightly higher than those of S1. However, the radical scavenging activity of hydrophilic extracts from all samples had similar tendencies, regardless of the krill content or fermentation period. Total phenolics increased with increasing fermentation time and TBA value increased with increasing fermentation time and krill content.