The effect of temperature on Aeromonas hydrophila infection in goldfish, Carassius auratus

The effect of temperature on Aeromonas hydrophila infection in goldfish, Carassius auratus, was studied using A. hydrophila strain A-3500. After comparison of four different infection methods. subcutaneous injection was selected. Different test temperatures were also tested and higher mortality was observed at 17 and 25degreesC during a 15-day period. SDS-PAGE analysis of outer membrane proteins prepared from A. hydrophila cultured at 10, 17, 25 and 32degreesC in formulated salt water showed different protein profiles. For example, a 40-kDa band was found only at 17 and 25degreesC. Phagocytic rates of A. hydrophila by goldfish macrophages at 10, 17. 25 and 32degreesC were 20.46 +/- 2.07. 16.15 +/- 1.39, 15.94 +/- 1.85 and 22.22 +/- 2.49%, respectively. The results indicated that temperature affects both the cell membrane structure of A. hydrophila and phagocytic activity of goldfish macrophages. resulting in varying fish mortality when infected at different temperatures.