Influence of organic diets and probiotics on an experimental Flavobacterium psychrophilum infection in rainbow trout fry

Summary

Extended abstract published from the conference Flavobacterium 2012.
The aim of the Danish project OPTIFISH is to optimize growth and survival for organic cultured rainbow trout. OPTIFISH investigates how organic vs. non-organic diet types as well as diets with or without probiotics affect the intestine, the intestinal microbiota and survival rates of rainbow trout following exposure to pathogens. The project consists of several work packages, among them the backbone of the project, namely the feed experiments with fry as well as sampling from the different diet groups. The samples will be used for studies of the bacterial microbiota in the fish by e.g. traditional bacteriology and molecular methods (16S rRNA PCR combined with next generation sequencing) as well as for the immunological investigation of the intestine by gene expression studies by quantitative RT-PCR. Fish health will be investigated by experimental exposure of fry to pathogens, e.g. F.psychrophilum.
In the current experiment four diet types were tested on fry, a conventional type (Inicio®, BioMar A/S) with and without probiotics, as well as an organic type with and without probiotic. Bactocell® (Lallemand) was used as the probiotic.