詳細

青木　隆一郎 （アオキ　リュウイチロウ）

  • 水産研究所　助教
Last Updated :2024/05/19

コミュニケーション情報 byコメンテータガイド

  • コメント

    ハタ類を中心に、海産魚類の増養殖に関する実用的な研究を行っています。

  • 報道関連出演・掲載一覧

    ＜報道関連出演・掲載一覧＞ ●2023/7/29 　宮崎日日新聞 　宮崎市の魅力について

研究者情報

学位

  • 博士（農学）（2020年03月 近畿大学）

ホームページURL

科研費研究者番号

  • 70908318

ORCID ID

J-Global ID

研究キーワード

  • 交雑育種   種苗生産   水産増殖学   

現在の研究分野（キーワード）

    ハタ類を中心に、海産魚類の増養殖に関する実用的な研究を行っています。

経歴

  • 2021年04月 - 現在  近畿大学水産研究所奄美実験場
  • 2020年04月 - 2021年03月  近畿大学 水産養殖種苗センター奄美事業場
  • 2014年04月 - 2017年03月  東洋冷蔵株式会社営業第二部総合職

学歴

  • 2017年04月 - 2020年03月   近畿大学   農学研究科   水産学専攻
  • 2012年04月 - 2014年03月   近畿大学   農学研究科   水産学専攻
  • 2008年04月 - 2012年03月   近畿大学   農学部   水産学科

研究活動情報

論文

  • Ryuichiro Aoki; Shukei Masuma; Youhei Washio; Hisashi Chuda; Keitaro Kato
    Fisheries Science 2024年05月
  • Mai Sakakibara; Ryuichiro Aoki; Shukei Masuma; Osamu Nakamura; Sho Shirakashi; Shigeyuki Tsutsui
    Developmental & Comparative Immunology 105113 - 105113 2023年12月 [査読有り]
  • Shukei Masuma; Ryuichiro Aoki
    Aquaculture International 2023年11月 [査読有り]
  • Akito Taniguchi; Yuki Kuroyanagi; Ryuichiro Aoki; Mitsuru Eguchi
    Microbes and environments 38 3 2023年 [査読有り]
     
    A direct relationship exists between diverse corals and fish farming in Keten Bay, Amami-Oshima, Japan. The release of coral mucus has a significant impact on the microbial activity of surrounding seawater. To obtain a more detailed understanding of biogeochemical cycles in this environment, the effects of coral mucus on the community structure and function of bacteria in surrounding seawater need to be elucidated. We herein used a bromodeoxyuridine approach to investigate the structures and functions of bacterial communities growing close to mucus derived from two different Acropora corals, AC1 and AC2. The alpha diversities of actively growing bacteria (AGB) were lower in mucus-containing seawater than in control seawater and their community structures significantly differed, suggesting that the growth of specific bacteria was modulated by coral mucus. Rhodobacteraceae and Cryomorphaceae species were the most dominant AGB in response to the mucus of Acropora AC1 and AC2, respectively. In contrast, the growth of Actinomarinaceae, Alteromonadaceae, Flavobacteriaceae, and SAR86 clade bacteria was inhibited by coral mucus. The results of a Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) ana-lysis suggested that the predicted functions of AGB in mucus-containing seawater differed from those in seawater. These functions were related to the biosynthesis and degradation of the constituents of coral mucus, such as polysaccharides, sugar acids, and aromatic compounds. The present study demonstrated that complex bacterial community structures and functions may be shaped by coral mucus, suggesting that corals foster diverse bacterial communities that enhance the ecological resilience of this fish farming area.
  • Akito Taniguchi; Ryuichiro Aoki; Isamu Inoue; Mitsuru Eguchi
    PLOS ONE 17 10 e0275211 - e0275211 2022年10月 [査読有り]
     
    We investigated the succession process of intestinal bacteria during seed production in full-cycle aquaculture of Pacific bluefin tuna (Thunnus orientalis). During the seed production, eggs, healthy fish, rearing water, and feeds from three experimental rounds in 2012 and 2013 were collected before transferring to offshore net cages and subjected to a fragment analysis of the bacterial community structure. We identified a clear succession of intestinal bacteria in bluefin tuna during seed production. While community structures of intestinal bacteria in the early stage of larvae were relatively similar to those of rearing water and feed, the bacterial community structures seen 17 days after hatching were different. Moreover, although intestinal bacteria in the late stage of larvae were less diverse than those in the early stage of larvae, the specific bacteria were predominant, suggesting that the developed intestinal environment of the host puts selection pressure on the bacteria in the late stage. The specific bacteria in the late stage of larvae, which likely composed ‘core microbiota’, were also found on the egg surface. The present study highlights that proper management of the seed production process, including the preparation of rearing water, feeds, and fish eggs, is important for the aquaculture of healthy fish.
  • Shukei Masuma; Yuki Kusunoki; Ryuichiro Aoki
    Aquaculture Research 53 4 1268 - 1275 2021年11月 [査読有り]
     
    Longtooth grouper (LG), Epinephelus bruneus, which is a protogynous hermaphrodite fish, is a highly valued grouper in Japan. Recently, LG farming and larviculture have started in subtropical waters but the reproductive information is scarce. We conducted two experiments to estimate the breeding season for LG held in a sea cage at Amami Island, Japan. Seasonal changes of plasma sex steroid (E2 and 11-KT) levels were measured in Experiment 1. Blood samples were collected from April to July and September 2018 and February 2019. E2 levels of the females increased from February (0.43 ± 0.10 ng/ml) and were significantly higher between April (0.97 ± 0.14 ng/ml) and May (0.66 ± 0.07 ng/ml) compared with those of June, July, and September. Eleven-KT levels of males were also higher between February and June. Spermiation responses indicating maturity of testis were examined throughout the year in Experiment 2. Spermiation was also observed between February and June. These results suggested that the breeding season of LG in subtropical regions was between April and May, with a residual period in June, which was earlier than those of temperate sites of Mainland Japan.
  • Ryuichiro Aoki; Hisashi Chuda; Youhei Washio; Shukei Masuma; Keitaro Kato
    Fisheries Science 86 1 57 - 64 2019年11月 [査読有り]
     
    The aquaculture of greater amberjack Seriola dumerili is of considerable research interest worldwide. The larviculture methods employed to culture this species, however, are still under development, and the majority of farms still rely on wild-caught juveniles. One of the problems associated with the hatchery production of this species is the optimal selection of broodstock to ensure a stable supply of high-quality eggs. Specifically, no reliable low-stress sex-discrimination technique is currently available for selecting broodstock of this species. This study investigated the efficacy of a hormone-based sex-discrimination method in full-cycle cultured S. dumerili, ranging in age from 412 to 1150 days after hatching (DAH). Plasma concentrations of the female hormone 17β-estradiol (E2) and the male hormone 11-ketotestosterone (11-KT) were measured in both spawning and non-spawning seasons, and the optimal threshold levels for sex discrimination were estimated using a receiver operating characteristic curve. Sex discrimination using E2 produced several false positives in younger fish, and had an overall accuracy of 78.7%. However, sex discrimination using 11-KT had an accuracy of 96.7%, even in 412 DAH fish. This study demonstrated that sex discrimination using 11-KT is a reliable method for optimizing the sex ratio of S. dumerili broodstock, even before the broodstock mature.
  • Akito Taniguchi; Ryuichiro Aoki; Mitsuru Eguchi
    Aquaculture Research 47 2 370 - 378 2014年06月 [査読有り]
     
    A major concern in larvae production is a mass mortality caused by fish diseases. In larvae production, pumped-up natural seawater filtered through a sand filter system is used for fish rearing, and microalgae and rotifer cultures. Here, we investigated the community structures of eukaryotic microbes, as well as total bacteria and vibrios, in various processed ‘waters’ used in a larvae production site. We observed that ultraviolet irradiation of seawater was effective to reduce not only total bacteria and vibrios but also eukaryotic microbes. Moreover, the community structures of total bacteria and vibrios in rearing waters for fish larvae were different from those in rotifer cultures fed with Chlorella, but rather similar to those in natural seawater and microalgae cultures. These results suggest that the bacterial community in rearing waters may originate mainly from natural seawater and then be selected by microalgae in rearing water. Overall, this study provides useful information for avoiding the risk of fish disease outbreaks in a larvae production site.

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