The effect of the probiotic Pediococcus acidilactici on the gut microbiota ecology of rainbow trout (Oncorhynchus mykiss Walbaum) analysed using DGGE

Abstract

The microbiota of the gastrointestinal tract heavily influences the health, growth and survival of fish. Probiotics have proved effective in improving fish productivity in aquaculture. Research suggests that probiotics, supplemented in the feed, may elicit these benefits by altering the ecology of the gastrointestinal microbiota. The probiotic Pediococcus acidilactici has been successfully used for terrestrial animals and humans but its use in aquatic organisms has been less researched. In the present study, rainbow trout Oncorhynchus mykiss (Walbaum) were fed a diet that contained Ped. Acidilactici, or a control diet. Analysis of the posterior digesta bacteria, using a non-culture dependant technique, Denaturing Gradient Gel Electrophoresis (DGGE), showed that Ped. acidilactici had some effects on the ecology of the microbiota but this was not statistically significant compared to controls. This study suggests that Ped. acidilactici must be fed at a dose above the manufacturer’s recommended dose, of 106 CFU g-1 of feed, for more than four weeks for significant changes in the microbiota to occur.