Effect of Flavobacterium columnare inoculation, antibiotic treatments and resident bacteria on rainbow trout Oncorhynchus mykiss eyed egg survival and external membrane structure

Abstract

This study was conducted to evaluate the potential pathogenicity of the bacterium Flavobacterium columnare on rainbow trout Oncorhynchus mykiss eyed eggs. Survival to hatching was unaffected by the inclusion in the incubation water of either 300 colony-forming units (CFU) ml(-1) or 3000 CFU ml(-1) of F. columnare at either 10 or 12 degrees C in either McConaughy or Shasta strain eyed eggs. Bacterial numbers, obtained via scanning electron microscopy or culture, and external membrane morphology were also not significantly different among eggs receiving different concentrations of F. columnare. Initial F. columnare burdens were significantly and positively correlated to the presence of biofilm on the egg external membrane, and biofilm was in turn significantly correlated with increased membrane degradation. The use of either streptomycin or tetracyclin antibiotics significantly reduced bacterial numbers on McConaughy strain eggs, and more eggs survived to hatch in those dishes treated with antibiotics.

Fish hatching strategies: a review

“…Oppen-Berntsen et al (1990) noted numerous failed hatching attempts among S. salar that were linked to perforations in the zona pellucida caused by low-grade fungal infections, while problems with hatching noted among Gadus morhua and H. hippoglossus were linked to damage caused to this membrane by microbial infections. Barnes et al (2009) described degradation of external membrane as an effect of Flavobacterium columnare infection in O. mykiss eggs. Hatching rates in bacterially infected eggs were found to be improved both by water UV treatment and aeration (Komar et al 2004) as well as by antibiotic treatment (Barnes et al 2009).…”

“…Barnes et al (2009) described degradation of external membrane as an effect of Flavobacterium columnare infection in O. mykiss eggs. Hatching rates in bacterially infected eggs were found to be improved both by water UV treatment and aeration (Komar et al 2004) as well as by antibiotic treatment (Barnes et al 2009). …”

Characterization of Bacteria Isolated from Landlocked Fall Chinook Salmon Eggs from Lake Oahe, South Dakota

“…However, the experimental inoculation of Rainbow Trout O. mykiss eggs with F. columnare did not result in increased egg mortality (Barnes et al 2009). Hence, it is likely that bacteria other than F. columnare may be involved in prehatching mortality of salmonid eggs.…”

Penicillin-G: Efficacy against <i>Flavobacterium psychrophilum</i> and evaluation of lethal dose limits for rainbow trout

“…Barnes et al [34] used streptomycin or tetracycline on rainbow trout eggs infected with F. columnare, improving hatching success and reducing bacterial abundance. However to our knowledge, no tests have evaluated antibiotic use on eggs for control of F. psychrophilum or evaluated potential limits for penicillin concentrations.…”