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Tanaka R.,National Fisheries University | Naiki K.,Iwate Fisheries Technology Center | Tsuji K.,Local Independent Administrative Agency Hokkaido Research Organization | Nomata H.,Local Independent Administrative Agency Hokkaido Research Organization | And 3 more authors.
Journal of Food Processing and Preservation | Year: 2013

Skinless fillets were prepared from Pacific saury Cololabis saira of varying degrees of freshness and then stored at -20 and -40C for 12 months to investigate the effects of lipid oxidation on quality deterioration. Peroxide value and 4-hydroxy-2-hexenal levels increased with storage temperature (-40<-20C) and corresponded with freshness. Peroxide value and 4-hydroxy-2-hexenal levels increased remarkably in frozen-thawed Pacific saury skinless fillets in comparison with raw Pacific saury; vitamin E was reduced for only 3 months. Lipid oxidation was inhibited when antioxitant-treated skinless fillets were stored at -20C for 12 months, immersed in 0.8% vitamin E or packed with an oxygen absorber. The 4-hydroxy-2-hexenal content was strongly correlated with propanal, a decomposition product of lipid oxidation that yields a fishy odor. © 2012 Wiley Periodicals, Inc.


Sadzuka Y.,Iwate Medical University | Sugiyama I.,Iwate Medical University | Miyashita M.,Iwate Medical University | Ueda T.,Iwate Fisheries Technology Center | And 4 more authors.
Biological and Pharmaceutical Bulletin | Year: 2012

Obesity is a major health problem showing increased incidence in developed and developing countries. We examined the effect of Euphausia pacifica (E. pacifica) (Pacific Krill) on high-fat diet (HFD)-induced obesity in C57BL/6 mice. No significant differences were observed in average food intake between the HFD and HFD with E. pacifica group, or the low-fat diet (LFD) and LFD with E. pacifica group for 18 weeks. The increased ratio of body weight in the HFD containing E. pacifica group was significantly reduced, being 10% lower than that with HFD group in the 18th week (HFD, 298.6±18.8% vs. HFD with E. pacifica, 267.8±16.2%; p<0.05), while the ratio for the LFD containing E. pacifica group was reduced by 4% compared with LFD group (LFD, 244.2±11.6% vs. LFD with E. pacifica, 234.1±18.0%). There were no effects of E. pacifica on total cholesterol levels in serum and liver, whereas the supplement of E. pacifica tended to decrease triglyceride levels in the HFD groups. The leptin level in serum was significantly decreased in the HFD group (p<0.01) by E. pacifica. The adipocyte area (1926±1275 μm 2) in the HFD containing E. pacifica group was significantly reduced by 20% (p<0.001) compared with the HFD group. These results suggested that E. pacifica supplementation in the diet is beneficial for the prevention of HFD-induced obesity. © 2012 The Pharmaceutical Society of Japan.


Kobayashi T.,Iwate Fisheries Technology Center | Kobayashi T.,Iwate Inland Fisheries Technology Center | Nakano N.,Iwate Fisheries Technology Center | Muto T.,Tohoku University | Endo Y.,Tohoku University
Acta Protozoologica | Year: 2011

Suctorians of the genus Ephelota are stalked ciliates and ectocommensals of marine invertebrates and plants. Ephelota gigantea has long been known as a major nuisance to the cultured seaweed industries in the coastal area of northeastern Japan. However, little is known about its life history, so in situ growth experiments were performed in the vicinity of wakame (Undaria pinnatifida) long-line culture in Iwate Prefecture, and the development of swarmers was investigated in the laboratory. The stalk elongated first, followed by enlargement of body length and body width, with body width increasing linearly with time. Over 5-6 days, E. gigantea increased 4-5-fold by external budding. Such an experiment was carried out for the first time for E. gigantea and possibly for any Ephelota species. The information obtained is important not only in understanding the life history of this species but also for understanding the interactions with host organisms.


Kobayashi T.,Iwate Fisheries Technology Center | Kijima A.,Tohoku University
Journal of Shellfish Research | Year: 2010

To demonstrate inbreeding depression in various traits of Pacific abalone Haliotis discus hannai, 12 inbreeding full-sib families (brother-sister mating) and 13 outbreeding full-sib families were produced by factorial mating using the parents from two full-sib families. All 25 full-sib families were reared for 158 days after settlement, and 8 of the inbred and outbred full-sib families were reared until 3 y 4 mo of age. Inbreeding depression traits between inbred and outbred crosses were compared. No significant differences in fertilization rate, hatchability, and veliger survival rate were observed between the inbreeding and outbreeding crosses. Deformity rate in veliger larvae from the inbred crosses was significantly higher than that among the outbred crosses (t-test, P < 0.01). Significantly lower survival rates were observed in the inbreeding crosses at 109 days after settlement (t-test, P < 0.01) and between 1 y 4 mo-old and 3 y 4 mo-old crosses (t-test, P < 0.05). Mean increases in shell length were not different between the inbred and outbred crosses. Gonad indexes in both crosses were investigated in 3 y 4 mo-old families. The gonad index among inbreeding crosses was significantly lower than that of the outbreeding crosses (analysis of covariance: df = 1, SS = 13.141, F = 25.834, P < 0.01). Significant inbreeding depression in larval deformity rate, juvenile and adult survival rates, and gonad index of Pacific abalone was detected. Although only 2 full-sib families were used as parental broodstock, this is the first long-term rearing examination, from fertilization to adult, of inbreeding depression in Pacific abalone.


Mizusawa K.,Kitasato University | Kobayashi Y.,Kitasato University | Kobayashi Y.,Hiroshima University | Yamanome T.,Iwate Fisheries Technology Center | And 2 more authors.
General and Comparative Endocrinology | Year: 2013

In teleosts, as their names suggest, the main target cells of melanocyte-stimulating hormone (MSH) and melanin-concentrating hormone (MCH) are the chromatophores in the skin, where these peptide hormones play opposing roles in regulating pigment migration. These effects are obvious especially when their activities are examined in vitro. On the contrary, while MCH also exhibits activity in vivo, MSH does not always stimulate pigment dispersion in vivo because of predominant sympathetic nervous system. A series of our investigations indicates that this is also the case in barfin flounder, Verasper moseri. Interestingly, we observed that mch expression and the tissue contents of MCH can be easily influenced by changes in environmental color conditions, while gene expression and tissue contents related to MSH scarcely respond to color changes. Transcripts of MSH and MCH receptor genes have been identified in a variety of tissues of this fish species, suggesting that these are multifunctional peptide hormones. Nevertheless, chromatophores in the skin still offer important clues in the efforts to elucidate the functions of melanotropic peptides. Herein, we review the most recent advancements of our studies on MSH and MCH and their receptors in the barfin flounder and discuss the interrelations between these peptides, focusing on their roles in influencing pigment migration in the skin. © 2012 Elsevier Inc.


Watanabe K.,Hokkaido National Fisheries Research Institute | Sasaki K.,Tohoku National Fisheries Research Institute | Saito T.,Hokkaido National Fisheries Research Institute | Ogawa G.,Iwate Fisheries Technology Center
Fisheries Science | Year: 2015

The Great East Japan Earthquake may have resulted in increased mortality of artificially propagated chum salmon fry (2010 year class) from Iwate Prefecture (CSI), both in the hatchery and after release. Individuals from the 2010 year class will return in 2014–2015. To evaluate the potential for future issues associated with the effects of the earthquake, we simulated CSI population dynamics using a model that incorporated stratified earthquake-influenced survival rates λl (l = 0.00−1.00 at intervals of 0.25) under various scenarios. Under laissez-faire scenarios (median exploitation rate EMed) under low post-release survival rate SLow and all λl, the median number of hatchery-released fry Ht′ did not reach the target H* in 2014 and 2015. The probability Pj,t of not meeting the targets was 0.56−1.00 (2014) and 0.79−1.00 (2015). Meanwhile, with simulation of a low exploitation rate, SLow, and a higher λl (0.50), the Pj,t in 2014 and 2015 was 0.00−0.17 and 0.21−0.72, respectively. Under SMed and SHigh, Ht′ reached H* at λl (>0.50) regardless of El, and the cumulative catch varied primarily with Sl. Our results suggest that simulations can provide a method of predicting potential issues and can offer insight into strategies to minimize future problems. © 2015, Japanese Society of Fisheries Science.


Nanba N.,Kitasato University | Fujiwara T.,Iwate Fisheries Technology Center | Kuwano K.,Nagasaki University | Ishikawa Y.,Iwate Fisheries Technology Center | And 2 more authors.
Journal of Applied Phycology | Year: 2011

Undaria pinnatifida sporophytes, originating from the same strain, were cultured at the commercial cultivation site exposed to wave action and the uncultivated site protected from water action of Okirai Bay, Northeast Japan, from January to April 2007; simultaneously, water flow velocity, water temperature, salinity, NO3 + NO2, and chlorophyll a were monitored to investigate the effect of water environment on their growth and morphology. Water temperature and salinity fluctuated within the optimal range for their growth whereas water flow velocity at the cultivation site was greatly fast compared with that at the uncultivated site. Successive chlorophyll a increases synchronized with NO3 + NO2 decreases were observed only at the uncultivated site for over a month; indicating developments of phytoplankton blooms and their nutrient consumption under the low-flow condition. Meanwhile, blade growth rate of cultured sporophytes was higher at the cultivation site than at the uncultivated site. Their thallus size expressed by six morphological characters (blade length, stipe length, blade wet weight, stipe wet weight, blade width, and undivided blade width) at the cultivation site became large in comparison with that at the uncultivated site. Their three morphological correlations (correlations between blade length and thallus length; blade wet weight and thallus wet weight; and undivided blade width and blade width) differed between the sites. They produced a thick and flat blade at the cultivation site but formed a thin and wrinkled blade at the uncultivated site. These results show the significant impact of water flow velocity on their growth and morphology. © 2010 Springer Science+Business Media B.V.


Yamada H.,Iwate Biotechnology Research Center | Ueda T.,Iwate Fisheries Technology Center | Yano A.,Iwate Biotechnology Research Center
PLoS ONE | Year: 2011

Background: Pacific Krill (Euphausia pacifica) are small, red crustaceans, similar to shrimp, that flourish in the North Pacific and are eaten in Japan. Methods and Findings: We investigated the effect of a water-soluble extract of Pacific Krill on adipocytes and discovered that this extract suppressed triglyceride accumulation in adipocytes. Furthermore, the water-soluble extract of Pacific Krill suppressed the expression of two master regulators of adipocyte differentiation, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα). C/EBPβ promotes PPARγ and C/EBPα expression, but the water-soluble extract of Pacific Krill did not inhibit the expression of C/EBPβ or C/EBPβ-mediated transcriptional activation. The Pacific Krill extract was more effective than a PPARγ antagonist in suppressing PPARγ and C/EBPα expression. Conclusions: These results indicated that the water-soluble extract of Pacific Krill was not simply a PPARγ antagonist, but that it prevented triglyceride accumulation in adipocytes by suppression of PPARγ and C/EBPα via a pathway that is independent of C/EBPβ. © 2011 Yamada et al.


Goto T.,Iwate Fisheries Technology Center | Shibata H.,Kitasato University
Marine Pollution Bulletin | Year: 2015

Abundance and composition of anthropogenic marine debris were assessed on the basis of six bottom trawl surveys conducted on the continental slope off Iwate Prefecture, Pacific coast of northern Japan, in 2003, 2004 and 2011, and the temporal changes due to the Tohoku earthquake and tsunami in March 2011 evaluated. In 2003 and 2004, 54-94 items km-2 of marine debris, dominated by sea-base sourced items mainly comprising fishing gear and related items from adjacent fishing grounds on the continental shelf, were quantified. In the post-earthquake period, the density increased drastically to 233-332 items km-2, due to an increase in land-base sourced items generated by the tsunami. However, a major increase in abundance after the disaster, compared to the total amount of tsunami debris swept into the sea, was not found. Additional sources of land-based debris from the adjacent continental shelf are suggested in the present waters. © 2015 Elsevier Ltd.


PubMed | Kitasato University and Iwate Fisheries Technology Center
Type: Journal Article | Journal: Marine pollution bulletin | Year: 2015

Abundance and composition of anthropogenic marine debris were assessed on the basis of six bottom trawl surveys conducted on the continental slope off Iwate Prefecture, Pacific coast of northern Japan, in 2003, 2004 and 2011, and the temporal changes due to the Tohoku earthquake and tsunami in March 2011 evaluated. In 2003 and 2004, 54-94 items km(-2) of marine debris, dominated by sea-base sourced items mainly comprising fishing gear and related items from adjacent fishing grounds on the continental shelf, were quantified. In the post-earthquake period, the density increased drastically to 233-332 items km(-2), due to an increase in land-base sourced items generated by the tsunami. However, a major increase in abundance after the disaster, compared to the total amount of tsunami debris swept into the sea, was not found. Additional sources of land-based debris from the adjacent continental shelf are suggested in the present waters.

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