In vitro passages impact on virulence of Saprolegnia parasitica to Atlantic salmon, Salmo salar L. parr.
Bottom Line: The effect of serial in vitro subculturing on three pathogenic strains of Saprolegnia parasitica was investigated.Two of the strains declined in virulence after 15 successive in vitro subcultures, whereas one did not.It reveals that some strains degenerate more rapidly than others when subjected to successive in vitro subculturing on glucose-yeast extract.
Affiliation: Norwegian Veterinary Institute, Oslo, Norway.Show MeSH
Related in: MedlinePlus
Mentions: While passage resulted in significant reduction in virulence for strain 5337, examination for sexual reproductive structures (oogonia and antheridia) of isolates by day 14 post-challenge did not show production of oogonia or antheridia. The samples from this time point were incubated for an extra 2 weeks in the laboratory, and still no sexual reproductive structures were observed for any of the cultures. For strains 2736 and 5708, oogonia were observed at very low rates (Fig. 9), but these findings did not associate with virulence/mortality figures.