DAO 33:57-61 (1998)  -  doi:10.3354/dao033057

In vitro cultivation and temperature-dependent growth of two strains of Spironucleus barkhanus (Diplomonadida: Hexamitidae) from Atlantic salmon Salmo salar and grayling Thymallus thymallus

Erik Sterud*

Norwegian College of Veterinary Medicine, PO Box 8146 Dep., N-0033 Oslo, Norway

Spironucleus barkhanus from muscle abscesses of farmed Atlantic salmon Salmo salar L., and from the gall bladder of grayling Thymallus thymallus (L.) was cultivated axenically in a medium routinely used for cultivation of the human pathogen Giardia duodenalis. Trophozoites multiplied by binary division, but multinucleated cells (<10 nuclei) were frequently observed. Complete cell divisions were never observed in these cells. Both strains grew at all temperatures tested (5, 10, 15 and 20°C). However, continuous growth of the salmon strain at 20°C was not possible. Growth potential, calculated as minimum generation time, showed relatively small differences both between strains and among temperatures, but the results indicate that the grayling strain had both a slightly higher optimum temperature and a higher upper temperature limit than the salmon strain.


Farmed salmon · Giardia · Hexamita · Nuclei acid staining · Systemic infection


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