Preliminary Observations of Mortality Reduction in Stressed, Flavobacterium columnare–Challenged Golden Shiners after Treatment with a Dairy-Yeast Prebiotic

Abstract

We conducted preliminary studies to evaluate the effects of including dairy-yeast prebiotics in the diets of golden shiners Notemigonus crysoleucas with access to natural foods on their resistance to challenge with Flavobacterium columnare. In trial 1, fish were fed either a control diet or a 2% dairy-yeast prebiotic diet for 10 weeks in outdoor pools before challenge. In trial 2, fish fed the experimental diets were either subjected to confinement stress or left unmolested before challenge. Mortality (mean ± SE) was not significantly different in the control diet (23.4 ± 3.4%), the prebiotic diet (10.0 ± 3.3%), and the prebiotic diet with stress (16.7 ± 3.4%) treatments. However, mortality was significantly greater in the control diet with stress treatment (50.0 ± 3.3%) than in the other treatments. This preliminary investigation suggests that prebiotic supplementation in golden shiner feeds before a stressful event would significantly reduce the mortality from F. columnare.