Poster Presentations

Session Title: The Animal Microbiome
Presentation Date: Monday, August 18, 2008
Poster Board Number: 0379

DETERMINATION OF SUPEROXIDE DISMUTASE OF THE INTESTINAL MICROFLORA IN FRESHWATER FISHES ENDEMIC TO LAKE BIWA

M. Wakayama, S. Yano, H. Noda, T. Tachiki
Ritsumeikan University, Department of Biotechnology, Kusatsu, Japan

Aims: To isolate and characterize the intestinal bacteria in the freshwater fishes, Nigorobuna (Carassius auratus grandoculis Termminck et Schlegel), Gengorobuna (Car. Cuvieri Termminsk et Schlegel), and Wataka (Ischikauia steenackeri (Sauvage)), endemic to Lake Biwa and to estimate the activity of superoxide disumutase (SOD) of the isolates.
Methods and results: Aerobic bacteria including facultative anaerobes were isolated from the intestines of Nigorobuna, Gengorobuna, and Wataka among 12 freshwater fishes endemic to Lake Biwa with MRS and Luria-Bertani medium. They were identified to the genus and species using 16SrDNA analysis and Rapid 20E for identification of Enterobacteria. Aeromonas was found in three fish species as predominant bacterium, but Enterobacter in Wataka, Enterococcus in Nigorobuna and Gengorobuna, Citrobacter in Wataka, and Staphylococcus in Wataka were identified. This result indicates that the three fishes have the different community of intestinal bacteria from each other. As a result, the bacteria isolated and identified in this study were facultative anaerobes and SOD production was found in 10 strains from all genera.
Conclusion: Ten facultative anaerobes were isolated and identified from three freshwater fish species endemic to Lake Biwa and SOD activity was determined in all genera. Some bacteria such as Enterococcus malodoratus exhibited higher SOD activity in aerobic condition than in anaerobic condition.