TWENTY-FOURTH ANNUAL EASTERN FISH HEALTH WORKSHOP Royal Pavilion Resort, Atlantic Beach, NC MARCH 9-11, 1999 Temperature Dependence And Bile Requirement Of Spironucleus vortens, An Intestinal Parasite Of The Freshwater Angelfish Somboon Sangmaneedet and Stephen A. Smith Department of Biomedical Sciences and Pathobiology, Virginiac/Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA The Intestinal parasite, Spironucleus vortens, was studies in an artificial medium at different temperature levels or in medium supplemented with different bile concentrations at 25oC. Parasites multiplied quickly at 28oC and 31oC and reached maximum numbers on day 5 of cultivation, whereafter they did not survive. At 25oC, parasites survived longer than those at 28oC and 31oC with no difference in multiplication rate during the exponential phase. The longest survival period was seen at 22oC, although the growth rate of the parasite was not as high as those at 25, 28 and 31oC. At higher temperatures of 34 and 37oC, no parasites were observed alive after the second day of cultivation. All cultures supplemented with bile, from 0.05 to 1.6 mg per ml, yielded parasite numbers lower than cultures with no bile. In addition, parasite growth was significantly suppressed in medium supplemented with higher concentrations (3.2 and 6.4 mg per ml) of bile. These results indicate that the optimal condition for in vitro cultivation of S. vortens is 25oC without supplementation with bile. Return to 24th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page