Effects of chronic chemical exposure on immune system responses to pathogen infection in common carp

2015 Fiscal Year Final Research Report

• Project/Area Number: 26740030
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental impact assessment
• Research Institution: Ehime University
• Principal Investigator: Nakayama Kei 愛媛大学, 沿岸環境科学研究センター, 講師 (80380286)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 免疫毒性 / 細菌感染症 / 抗炎症薬 / Aeromonas / 慢性毒性 / 環境毒性学

Outline of Final Research Achievements

In order to assess chemically-induced immunosuppressive effects in fish, we have developed a test method for evaluation of the chemical effects on a natural host-pathogen interaction. In a preliminary test, when common carp (Cyprinus carpio) were exposed to 1.0 × 10∧6 colony forming unit (CFU)/mL Aeromonas salmonicida, 90% mortality was observed after 9 days post-infection (dpi). To validate the test method, carp were exposed to 1 mg/L dexamethasone (Dex), an immunosuppressive agent. One week after the exposure test started, fish from each group were bath infected at 2.9 × 10∧4 CFU/mL A. salmonicida. After 7 dpi, fish in the Dex-exposed and A. salmonicida infected group started to die, and 100% mortality was observed in the group after 35 dpi. On the other hand, bacterial infection-associated mortality was not observed in A. salmonicida infected fish without Dex exposure. Thus, the test method developed in this study is thought to be useful to evaluate immunotoxicity in fish.

Free Research Field

環境毒性学