魚病研究
Online ISSN : 1881-7335
Print ISSN : 0388-788X
ISSN-L : 0388-788X
58 巻, 3 号
選択された号の論文の4件中1~4を表示しています
論文
  • Noritaka Hirazawa, Kento Kitagawa, Yoshiro Hirata
    原稿種別: Research Article
    2023 年 58 巻 3 号 p. 83-90
    発行日: 2023/09/15
    公開日: 2023/10/06
    ジャーナル 認証あり

    In this study, we assessed the influence of different water temperatures on the swimming ability of the oncomiracidium of Neobenedenia girellae. ​In addition, we investigated the temporal change in their infectivity to Seriola dumerili after hatching at 25°C. ​Most oncomiracidia in the cell culture flask filled with seawater deciliated and predominantly crept on the bottom by the end of 6 h experiment. ​Approximately 9% of the oncomiracidia in seawater-containing wells of a 12-well cell culture plate were non-swimming and became trapped in the air-water surface interface. ​However, these effects were mitigated when a polyethylene sheet was placed on the seawater surface in the wells. ​When conducting the experiment using this method, the oncomiracidia remained active and were still swimming at 60, 72, and 108 h after hatching at 30°C, 25°C, and 20°C, respectively. ​The retention time of the oncomiracidia's swimming ability decreased as the water temperature increased. ​The oncomiracidial infectivity was reduced after 24–25.5 h or more after hatching. ​At 5 days after the exposure to S. dumerili, the number of attached N. girellae was significantly lower, and their body length was significantly shorter when using oncomiracidia that were 36–37.5 h after hatching compared to freshly hatched ones.

  • Erina Fujiwara-Nagata, Yuki Naitou-Shibahara, Yoshitaka Kataoka, Hiroa ...
    原稿種別: Research Article
    2023 年 58 巻 3 号 p. 91-98
    発行日: 2023/09/15
    公開日: 2023/10/06
    ジャーナル 認証あり

    Flavobacterium psychrophilum can infect rainbow trout Oncorhynchus mykiss and ayu Plecoglossus altivelis, detrimentally affecting global aquaculture. ​This study aimed to understand the infectivity and host specificity of two F. psychrophilum strains, SG950607 and PH0424, which were isolated from the kidneys of rainbow trout and ayu, respectively. ​Rainbow trout (fry) and ayu (adult and fry) were infected via two methods: bath immersion and intraperitoneal injection. ​We investigated the ability of each F. psychrophilum strain to survive in the serum of non-original host fish species. ​Rainbow trout died upon being infected by PH0424. ​In addition, the complement of the rainbow trout did not show a bactericidal effect against PH0424. ​On the other hand, ayu infected with SG950607 survived, and their complement eliminated this strain. ​The difference in mortality rates is likely associated with the susceptibility of each strain to the complement activity possessed by the host fish.

短報
feedback
Top