EFFECTS OF TEMPERATURE AND WHITE SUCKER (CATOSTOMUS-COMMERSONI) SERUMSUPPLEMENT ON THE IN-VITRO, MULTIPLICATION OF CRYPTOBIA-CATOSTOMI IN CELL-FREE CULTURE-MEDIUM

Cryptobia catostomi, a non-pathogenic haemoflagellate of white suckers (Catostomus commersoni) multiplied rapidly in modified TDL-15 medium supplemented with 10% fetal bovine serum and 1% heat-inactivated white sucker serum (WSS) at 10 degrees C and 18 degrees C. The numbers of C . catostomi counted were significantly higher in cultures incubated at 10 degrees C than in those incubated at 18 degrees C beginning at 3 w eeks post-incubation. The culture forms (from the eighth subculture at 9 months after isolation) were morphologically similar to blood forms and were infective to laboratory-raised white suckers. The parasite s urvived for about 4 weeks in the medium without WSS at 18 degrees C. T he present study indicates that WSS supplement supports the in vitro m ultiplication of C. catostomi and that its multiplication is temperatu re-dependent.