Low Possibility of Intra-Ovum Infection with Flavobacterium psychrophilum or Renibacterium salmoninarum in the Salmonid Coelomic Cavity

Abstract

In this study, rainbow trout Oncorhynchus mykiss and amago salmon O. masou were used to study intra-ovum infection with Flavobacterium psychrophilum and Renibacterium salmoninarum, respectively. To investigate the possibility of intra-ovum infection of eggs in the coelomic cavity, the contamination of coelomic fluid and egg contents from ripe females were examined. The ranges of viable counts of F. psychrophilum and R. salmoninarum in coelomic fluid were 10^1.0-4.2 and 10^1.6-9.9 CFU/mL, respectively. However, neither F. psychrophilum nor R. salmoninarum was isolated from the egg contents. It was concluded that there was little possibility of intra-ovum infection of salmonid eggs in the coelomic cavity.