Improved culture media for piscine hemoflagellates, Cryptobia and Trypanosoma (Kinetoplastida).
Increasing the Hepes buffer in minimum essential medium from 25 mM to 100 mM yielded a significantly larger number of Cryptobia salmositica. Cryptobia salmositica (pathogenic and nonpathogenic strains), Cryptobia bullocki, and Trypanosoma danilewskyi did not multiply either in heat-inactivated trout plasma (< or =25%) or in less than 10% fresh trout plasma. Both strains of C. salmositica multiplied better in 10% fresh trout plasma than in 25% heat-inactivated fetal bovine serum. In contrast, C. bullocki and T. danilewskyi multiplied better in 25% fetal bovine serum; 10% fetal bovine serum did not significantly reduce multiplication of C. bullocki. The nonpathogenic vaccine strain of C. salmositica cultured in 10% fresh trout plasma still protected rainbow trout from high parasitemia when challenged with the pathogen.