Fish Pathology
Online ISSN : 1881-7335
Print ISSN : 0388-788X
ISSN-L : 0388-788X
Volume 53 , Issue 4
Showing 1-5 articles out of 5 articles from the selected issue
Research Article
  • Mikio Tanaka, Keitaro Dairiki, Mayuri Nakajima, Goshi Kato, Takashi Sa ...
    Type: Research Article
    2018 Volume 53 Issue 4 Pages 117-123
    Published: December 15, 2018
    Released: January 23, 2019
    JOURNALS RESTRICTED ACCESS

    It was reported that progeny from the parents of goldfish Carassius auratus which had survived in herpesviral hematopoietic necrosis (HVHN) increased resistance against the disease, and consequently a resistant strain of Azumanishiki variety has been established in Saitama Fisheries Research Institute. ​In this study, we started breeding between the resistant Azumanishiki variety and a susceptible Kurodemekin variety and investigated the heredity of the resistant trait in the offspring in order to establish a new resistant strain of Kurodemekin. ​F1 bred between resistant Azumanishiki and Kurodemekin showed resistance in the challenge test with the causative virus (cyprinid herpesvirus 2), but F1 had no pop-eyed character. ​Crosses between F1 survivors in virus challenge produced F2, and about 25% of F2 showed pop eyes. ​We finally obtained the resistant pop-eyed Kurodemekin of F3 crossed between pop-eyed F2 survivors in virus challenge. ​Backcrosses between F1 survivors and Kurodemekin were also tested for the resistance in virus challenge. ​The mortality rates of F1, F2, F3 and the backcrosses in virus challenge suggested that the resistant trait against HVHN in the goldfish linage exhibited a Mendelian dominant inheritance pattern.

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Short Communications
  • Keigo Kobayshi, Germaine Lau Gek Khin, Sho Shirakashi, Yusuke Mukai, Y ...
    Type: Short Communication
    2018 Volume 53 Issue 4 Pages 124-127
    Published: December 15, 2018
    Released: January 23, 2019
    JOURNALS RESTRICTED ACCESS

    We developed a PCR-RFLP method to distinguish Benedenia seriolae and Neobenedenia girellae, both infecting amberjacks Seriola spp. more precisely than a morphological method. ​PCR products of 28S rRNA and COX1 were digested by Cla I and EcoR I, respectively. ​For all individuals of B. seriolae, the digestions split each of the PCR products into two fragments. ​On the other hand, although the products of most of the N. girellae samples were digested by neither the enzymes, only PCR products of 28S rRNA gene of three of the individuals were split into three fragments, suggesting they were the hybrid between the two species.

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  • Anna Papadopoulou, Tom Wiklund
    Type: Short Communication
    2018 Volume 53 Issue 4 Pages 128-131
    Published: December 15, 2018
    Released: January 23, 2019
    JOURNALS RESTRICTED ACCESS

    The fish pathogen Flavobacterium psychrophilum has been shown to occur in two colony phenotypes, rough and smooth. ​The aim of this study was to examine the effect of environmental and nutritional factors on the biofilm formation of both phenotypes under in vitro static conditions. ​The present study revealed that smooth cells displayed higher abilities of biofilm formation compared to rough cells in nutrient-rich media (TYES broth and fish feed) under static conditions, while biofilms formed by cells of both phenotypes were mainly Ca2+ dependent than Mg2+. ​Neither of the colony phenotypes was able to form biofilms in the low-nutrient medium (lake water) within 5 days.

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  • Takashi Iwaki, Tsukasa Waki, Jumpei Arakawa, Kazuo Ogawa
    Type: Short Communication
    2018 Volume 53 Issue 4 Pages 132-135
    Published: December 15, 2018
    Released: January 23, 2019
    JOURNALS RESTRICTED ACCESS

    Great cormorants Phalacrocorax carbo were found dead in a goldfish farm in Aichi Prefecture. They were infected with trematodes in the oral cavity. Based on morphological observation and genetic analysis, the trematodes were identified as Clinostomum complanatum. This is the first case reporting C. complanatum infection of great cormorants in Japan. Heavy metacercarial infection of goldfish was found in the same fish farm. The metacercariae were shown to be the same species as the adult worms from the bird by molecular analysis. These results suggest that great cormorant is involved in the life cycle of this trematode in farmed goldfish.

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