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Tsuji M.,Mie Prefecture Fisheries Research Institute | Uji S.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Tsuchihashi Y.,Mie Prefecture Fisheries Research Institute | Okada K.,Mie Prefectural Owase Fish Farming Center | And 10 more authors.
Aquaculture Research | Year: 2016

The effects of the removal of the oily surface film on initial swim bladder inflation and survival in cultured seven-band grouper Hyporthodus septemfasciatus were investigated during the larval stage. Additionally, the relationship between swim bladder inflation failure and malformations in later stages was examined. To explore promotion conditions for inflation, duplicate experiments were conducted under three different water surface conditions: removal of the oily surface film (ROF group), covering the water surface with an oil film (COF group), and sealing the water surface with liquid paraffin (SLP group). Larval swim bladder inflation was first observed 14 days after hatching (DAH) in the ROF group; thereafter, swim bladder inflation rates increased to 11.1% and 38.7% until the end of the experiments. This indicates that initial swim bladder inflation occurs at the pre-flexion stage in larval development. Conversely, bladder inflation was rarely observed in the COF or SLP groups, indicating the promotional effect of surface film removal on larval swim bladder inflation and suggesting that gulping atmospheric air is necessary for initial inflation. Although larval water surface death occurred frequently in the ROF group, no significant difference existed in any group between the survival rates at 10 DAH and at the end of the experiment. The incidence rate of spinal curvature and deformation of the centra was significantly higher in individuals without initial swim bladder inflation, and these malformations mainly occurred in the caudal vertebra. Therefore, the removal of the oily surface film promotes initial swim bladder inflation and reduces larval malformations. © 2016 John Wiley & Sons Ltd.

Uji S.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Kurokawa T.,Tohoku National Fisheries Research Institute | Hashimoto H.,Nagoya University | Kasuya T.,Mie Prefectural Owase Fish Farming Center | Suzuki T.,Tohoku University
Development Growth and Differentiation | Year: 2011

Fugu (Takifugu rubripes) has contributed as an ideal model organism for understanding the structure and evolution of vertebrate genomes, but also has potential as a good model organism for developmental biology because of the availability of the genome information. However, there is no comprehensive report describing the developmental stages, which is fundamental data for developmental biology. Here we describe a series of stages of the embryonic development of fugu during the first 8days after fertilization, i.e. from fertilization to hatching. We define seven periods of embryogenesis - the zygote, cleavage, blastula, gastrula, segmentation, pharyngula, and hatching periods. Stages subdividing these periods are defined based on morphological characteristics. In addition, as a model experiment of gene expression analysis using this staging series, we performed in situ hybridization of aldh1a2, aldh1a3 and cyp26a1 that play regulatory roles in retinoic acid (RA) metabolism essential for embryogenesis. This report provides fundamental information on fugu embryogenesis, which is anticipated to facilitate the use of fugu as a model organism for developmental studies. © 2011 The Authors. Development, Growth & Differentiation © 2011 Japanese Society of Developmental Biologists.

Tsuji M.,Mie Prefecture Fisheries Research Institute | Abe H.,Mie Prefectural Tsu Public Health Center | Hanyuu K.,Mie Prefecture Fisheries Research Institute | Kuriyama I.,Forestry and Fisheries | And 9 more authors.
Fisheries Science | Year: 2014

The effects of rearing temperature (23-29 °C) during the larval and juvenile stage on survival, growth and skeletal malformations in the seven-band grouper Epinephelus septemfasciatus were investigated. The survival rate of juveniles 30-40 mm in total length emerging from eggs was higher at 25 and 26 °C (0.1-1.3 %) than at 23 °C or 27-29 °C (0.004-1.5 %). Growth (increase in total length) was accelerated at higher temperatures. The frequency of malformed individuals was lower at 25-27 °C (36.0-61.5 %) than at 23, 28 or 29 °C (65.3-76.9 %). Specific incidences of spinal curvature and centrum fusion or defects in juveniles were not related to rearing temperature. However, incidences of twisted or compressed vertebrae (6.5-64.0 %) were higher at higher temperatures, while the incidence of bifurcated neural spine was significantly higher at 23 °C (43.6-54.4 %) than at other temperatures (3.3-22.7 %). The incidence rate of spinal curvature (23.3 %) was significantly higher in juveniles with a deflated swim bladder, regardless of rearing temperature. The results of this study suggest that the optimum culture temperature for seven-band grouper is 25-26 °C, collectively considering the survival, growth and incidences of abnormalities. Our results also demonstrate the significance of identifying the conditions for swim bladder inflation to prevent spinal curvature in seven-band grouper. © 2013 The Japanese Society of Fisheries Science.

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