Changes in serum parameters of Saprolegnia-infected brown trout, Salmo trutta L.

Abstract. Fungal infection of both wild and hatchery-reared sexually mature brown trout, Salmo trutta L., was caused by Saprolegnia diclina Humphrey Type 1. The major ions in the serum of infected fish were all significantly reduced in concentration and it is suggested that the primary cause of death was osmoregulatory breakdown resulting in a lethal haemodilution. Severe hypoproteinaemia and a significant reduction in the albumin/globulin ratio were reflected in the electro-phoretogram of the serum proteins from infected fish.