TThe present study investigated the effect of experimental infection with Ichthyophthirius multifiliis on physiological,
immunological and metabolic parameters in rainbow trout (Oncorhynchus mykiss) and chub (Leuciscus cephalus).
Both species developed an immune response against I. multifiliis that was detected in the peripheral blood
(i.e. increase in immunoglobulin concentrations in rainbow trout, increase in lymphocyte and thrombocyte
concentrations in chub), but not in the skin mucus. Anaemia was observed in both species of fish. In rainbow
trout there was also depletion of liver glycogen, disturbance in osmoregulation (decrease in serum osmolality
and Na+ and Cl concentrations) and possibly also impaired wound healing capacity (i.e. decrease in skin
mucus alkaline phosphatase and b-glucuronidase activity). Therefore, rainbow trout develop more severe
changes following this infection compared with chub.