Nagasaki Prefectural Institute of Fisheries

Hirara, Japan

Nagasaki Prefectural Institute of Fisheries

Hirara, Japan
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Tanaka H.,Seikai National Fisheries Research Institute | Ohshimo S.,Seikai National Fisheries Research Institute | Takagi N.,Nagasaki Prefectural Institute of Fisheries | Ichimaru T.,Nagasaki Prefectural Institute of Fisheries
Fisheries Research | Year: 2010

We investigated the geographical origin and migration of anchovy Engraulis japonicus in Tachibana Bay, western Japan, using carbon and nitrogen stable isotope ratios (δ 13C and δ 15N, respectively). Stable isotope ratios of anchovy varied among seasonal samples for both δ 13C and δ 15N. In particular, the δ 13C values were clearly segregated; winter samples showed higher values (δ 13C > -17.5‰) than spring samples (δ 13C < -18.2‰). Moreover, these differences corresponded to the geographical variations in previously reported stable isotope ratios for anchovy; higher values in winter corresponded to the values of inshore habitat and lower values in spring corresponded to those of the offshore habitat. Therefore the spring population is considered to have originated from the offshore region and recently migrated to the sampling regions, while the winter population would have experienced the inshore region over an extended period. Our results support the general concept of the migration of anchovy populations deduced by the fishermen of Tachibana Bay. © 2009 Elsevier B.V. All rights reserved.

Nishizawa T.,Chonnam National University | Takami I.,Nagasaki Prefectural Institute of Fisheries | Yoshimizu M.,Hokkaido University | Oh M.-J.,Chonnam National University
Aquaculture | Year: 2011

It was recently reported that Poly(I:C) immunization of fish confers protection against viral infection. In this process, fish are immunized with a live pathogenic virus followed by administration of Poly(I:C), which induces a transient, non-specific antiviral state. As a result, fish survive the initial immunization with live virus, which would otherwise be lethal. In the present study, we tried to determine the exact dosage of red-spotted grouper nervous necrosis virus (RGNNV), the causative agent of viral nervous necrosis, required for Poly(I:C) immunization of sevenband grouper Epinephelus septemfasciatus. In Poly(I:C) immunization with more than 90% relative percentage survival (RPS) against RGNNV challenge with 104.3 TCID50/fish, approximately 104.0 TCID50/fish or greater of RGNNV was administered by intramuscular (IM) injection, whereas 105.3 TCID50/fish or greater of RGNNV was required for immersion methods. It was concluded that the degree of RGNNV infection must be similar to a fatal dose in order for the fish to become immune to RGNNV. Interestingly, antibody against RGNNV was not detected in the sera of fish immunized by immersion. Thus, Poly(I:C) immunization by immersion may have some interesting effects on the epidermal immune response in fish. © 2010 Elsevier B.V.

Matsuoka K.,Nagasaki University | Mizuno A.,Nagasaki University | Iwataki M.,Nagasaki University | Takano Y.,Nagasaki University | And 3 more authors.
Harmful Algae | Year: 2010

An unarmored dinoflagellate Cochlodinium polykrikoides has formed red tides responsible for fish mass mortalities especially in coastal areas of western Japan and southern Korea almost every summer to autumn. In laboratory culture, the optimum temperature for growth of the species is ca. 27°C. Since the species cannot survive in water of temperatures of less than 10°C, it was considered to over-winter in some certain regions as a motile form or resting cyst, and expand its distribution after the temperature increases to a level tolerable for growth. To determine the over-wintering regions and migration pattern of C. polykrikoides, occurrences of the motile cells were surveyed in the coastal and offshore areas of western Kyushu, Japan and south coast of the Korean Peninsula from April 2006 to August 2008. Cells of C. polykrikoides were found at 14 sites during the investigated period. Motile cells occurred throughout the year in Usuka Bay, Hirado of West Japan. From offshore regions of the Goto Islands and off Shin-Nagasaki Fishing Port, motile cells of C. polykrikoides were first detected from late May, and continuously occurred until February in Nama Bay of the Kami-Goto Islands. This first appearance was before red tides of C. polykrikoides reported at coastal areas in western Kyushu. In Korea, this species was first observed in May and disappeared after October in 2007. These occurrence patterns imply that Usuka Bay in Hirado is one of the over-wintering regions in western Kyushu, and also this species is possibly transported into the northern part of the East China Sea by the Tsushima Warm Current every year. © 2010 Elsevier B.V.

Takami I.,Nagasaki Prefectural Institute of Fisheries | Kwon S.R.,Hokkaido University | Nishizawa T.,Hokkaido University | Nishizawa T.,Chonnam National University | Yoshimizu M.,Hokkaido University
Diseases of Aquatic Organisms | Year: 2010

In immunization of fish with polyinosinic-polycytidylic acid (poly[I:C], a synthetic double-stranded RNA), injection of Poly(I:C) followed by challenge with a live virus induces a transient, non-specific antiviral state by interferon activity. When exposed to a virus while in this antiviral state, the fish acquire a specific and protective immunity against the corresponding viral disease and survive. In the present study, the effiacy of Poly(I:C) immunization was investigated in japanese flounder Paralichthys olivaceus using viral hemorrhagic septicemia virus (VHSV) as a model; the minimum dose of Poly(I:C) required for inducing protection and the duration of the antiviral state were determined, and a potentially curative effect of Poly(I:C) administration was assessed. The antiviral state was induced by administration of Poly(I:C) doses ranging from 12.5 to 200 μg fish-1. Minimum dose to induce the antiviral state (relative percentage survival, RPS:90%) was 12.5 μg fish -1. No curative effect of Poly(I:C) was observed in fish pre-infected with VHSV. Fish injected with 200 μg Poly(I:C) fish-1 were highly protected (RPS:100%) from an artificial challenge with VHSV, and specific antibodies against VHSV were detected. The corresponding high level of antiviral state against VHSV was attained 1 d post Poly(I:C) injection, lasted for 6 d and susequently decreased. Moreover, the surviving fish were highly protected from re-challenge with VHSV (RPS:100%). Thus, it was considered that an immunity against viral hemorrhagic septicemia was induced in the Japanese flounder by injecting live VHSV following Poly(I:C) administration. © Inter-Research 2010.

Giri A.,Tokyo University of Marine Science and Technology | Osako K.,Tokyo University of Marine Science and Technology | Okamoto A.,Nagasaki Prefectural Institute of Fisheries | Okazaki E.,Nagasaki Prefectural Institute of Fisheries | Ohshima T.,Tokyo University of Marine Science and Technology
Food Research International | Year: 2011

To evaluate the antioxidative properties of a newly developed fermented paste (squid miso) prepared from squid mantle flesh with Aspergillus oryzae-inoculated koji, we used in vitro models, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, nitric oxide (NO) and carbon-centered radical-scavenging activity (RSA), reducing power ability (RPA), and linoleic acid oxidation. The antioxidant activity of volatile compounds, which were extracted from squid miso by dichloromethane, was confirmed based on the results obtained by the oxidation models consisting of carotene linoleate and hexanal. The RSA of the miso against several radicals, including DPPH, hydroxyl, nitric oxide and carbon-centered radicals measured by ESR spectrometry increased gradually through the fermentation period. On the other hand, the RPA increased rapidly in early stages of fermentation. Proteins were hydrolyzed to peptides and amino acids during fermentation. Certain peptides of low molecular mass significantly contributed to RSA. 4-Ethylguaiacol in the RSA active fraction, which was obtained by column chromatography, was the most potent antioxidative in the volatile extract. Analysis of phenolics in ethyl acetate fraction clearly suggested that 4-ethylguaiacol in the squid miso is possibly a bioconversion product of ferulic acid derived from koji. However, the aqueous extracts containing antioxidative peptides contributed more remarkably to radical scavenging than heterocyclic volatiles and phenolics. © 2010.

Ogawa K.,University of Tokyo | Tanaka S.,Mie Prefecture Fisheries Research Institute | Sugihara Y.,Nagasaki Prefectural Institute of Fisheries | Takami I.,Nagasaki Prefectural Institute of Fisheries
Parasitology International | Year: 2010

A new sanguinicolid blood fluke, Cardicola orientalis n. sp., is described from the afferent branchial artery and heart of Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel) cultured in Mie and Nagasaki Prefectures, Japan. The new species is most similar to C. ambrosioi Braicovich, Etchegoin, Timi et Sardella, 2006 from the Brazilian flathead, Percophis brasiliensis Quoy & Gaimard, but can be differentiated by the position of the female genital pore (in midline or slightly sinistral in C. orientalis vs. sinistral in C. ambrosioi) and much longer distance between male and female genital pore (101 μm vs. 27 μm). In wet mount preparations of infected fish, eggs were accumulated in great numbers in the gill lamellae and afferent filament arteries. Importance of this blood fluke infection of cultured Pacific bluefin tuna in Japan is discussed. © 2009 Elsevier Ireland Ltd. All rights reserved.

Sugihara Y.,Nagasaki Prefectural Institute of Fisheries | Yamada T.,Nagasaki Prefectural Institute of Fisheries | Tamaki A.,Nagasaki University | Yamanishi R.,Osaka Museum of Natural History | Kanai K.,Nagasaki University
Parasitology International | Year: 2014

We found aporocotylid larval stages (sporocysts and cercariae) from five individuals of terebellid polychaete Terebella sp., which were collected from seabed substrate and ropes and floats attached to tuna cages in a tuna farm on the coast of Tsushima Island, Nagasaki, Japan. Nucleotide sequences of the regions of internal transcribed spacer 2 ribosomal DNA and 28S ribosomal DNA from these larval stages were 100% identical to those of Cardicola opisthorchis registered in GenBank. C. opisthorchis is a pathogen causing blood fluke infection of Pacific bluefin tuna Thunnus orientalis, which is considered to have a significant impact on the Japanese Pacific bluefin tuna aquaculture industry. This is the first description of the intermediate host of C. opisthorchis. This indicates that the life cycle of C. opisthorchis is completed within tuna farms in this area. © 2013 Elsevier Ireland Ltd.

Ogawa K.,University of Tokyo | Ishimaru K.,Kinki University | Shirakashi S.,Kinki University | Takami I.,Nagasaki Prefectural Institute of Fisheries | Grabner D.,University of Tokyo
Parasitology International | Year: 2011

A new aporocotylid blood fluke is described, based on specimens from the ventricle of the Pacific bluefin tuna, Thunnus orientalis (Temminck et Schlegel), cultured in Wakayama and Nagasaki Prefectures, Japan. The new species is morphologically similar to the members of the genus Cardicola Short, 1953, but shows distinct differences in the body form, location of the testis and the orientation of the ootype. The body of the new species is long and slender, whereas other Cardicola species are small and generally lanceolate. The testis is mostly located posterior to the caeca and anterior to the ovary, occupying 31-45% of body length, in contrast to the known Cardicola species, whose testis is typically intercaecal. The ootype is oriented anteriorly, while in most congeners, it is directed posteriorly or horizontally. Phylogenetic analyses of this aporocotylid, together with Cardicola orientalis Ogawa, Tanaka, Sugihara et Takami, 2010 from the same host, were conducted based on DNA sequences of the ITS2 rDNA and the 28S region of ribosomal RNA. The analyses revealed that the new blood fluke belongs to the genus Cardicola despite the marked morphological differences. Thus, this aporocotylid is named Cardicola opisthorchis n. sp. and the generic diagnosis is emended in this paper. In addition, 100% identity among the ITS2 sequences from the present species, Cardicola sp. from T. orientalis in Mexico and Cardicola sp. from the northern bluefin tuna, Thunnus thynnus (Linnaeus) in Spain suggests that C. opisthorchis n. sp. has a broad geographical distribution and that it infects both the Pacific and northern bluefin tuna. © 2011 Elsevier Ireland Ltd.

Kuwahara K.,Nagasaki Prefectural Institute of Fisheries | Konno K.,Hokkaido University
Food Chemistry | Year: 2010

The effect of sodium citrate (Na-citrate) on myosin and actin denaturation in myofibrils was investigated. Na-citrate significantly suppressed the thermal inactivation of Ca 2+-ATPase of carp myosin in a concentration-dependent manner. The effect was greater than that of sorbitol. A similar effect was observed with myofibrils in which myosin is stabilized by F-actin binding. Na-citrate dissolved myofibrils at lower concentration than NaCl. Nevertheless, Na-citrate at 1 M failed to denature F-actin in myofibrils, while 1 M NaCl denatured F-actin almost completely. Na-citrate suppressed the NaCl-induced F-actin denaturation. Sorbitol did not show such protective effect on F-actin denaturation. Moreover, Na-citrate suppressed the freeze denaturation of myofibrils at lower concentration than sorbitol. Thus, Na-citrate was proved to be superior to sorbitol. It was suggested that Na-citrate alone could substitute sorbitol as cryoprotectant in surimi and NaCl as dissolving reagent of myofibril in thermal gel production. © 2010.

Giri A.,Tokyo University of Marine Science and Technology | Osako K.,Tokyo University of Marine Science and Technology | Okamoto A.,Nagasaki Prefectural Institute of Fisheries | Ohshima T.,Tokyo University of Marine Science and Technology
Food Research International | Year: 2010

Aroma active compounds in commercial fermented fish meat paste product (fish miso), fermented soy paste (soy miso), fish sauce and soy sauces were characterized by using a dynamic headspace method for volatile isolation and GC olfactometry for odor perception. A total of 123 volatile compounds consisting mainly of aldehydes, alcohols, esters, ketones, furans, sulfur and nitrogen-containing compounds, aromatics and acids were consistently identified. A major 16 odor-active compounds were distinguished to contribute as key aroma compounds for the miso and sauce products. Olfactometric and sensory findings clearly differentiated miso products with caramelic, fruity aroma notes, whereas fish sauce products were characterized by ammoniacal, fishy, nutty and cheesy odor note. Soy sauce products, however, were dominated by nutty and cheese aroma. Use of koji for fish miso production was found effective to enhance sweet aroma to the product with a reduction of nutty, meaty and rancid nuance. Principal component analysis employed for statistical interpretations clearly elucidated the relationship among different types of fermented products. © 2010 Elsevier Ltd. All rights reserved.

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