Limited studies discussed the impact of probiotics and prebiotics on fish microbiome. This research aimed to examine the effects of different feed additives on the intestinal microbiota of the common carp (Cyprinus carpio ).
Three different types of feed additives including live lactic acid bacterium Pediococcus acidilactici , Saccharomyces cerevisiae and YANG prebiotic were tested at the concentration of 1 g/kg. Fish with average body weight of 932±163 g were fed with supplemented diet of each type for 41 days in a recirculation system containing 12 units (size=1000 liter each unit, 8 fish per unit). Water temperature, pH, TDS, dissolved oxygen, NO-2, NO-3, and NH+4 concentrations were maintained to be at the optimum levels in all fish tanks . At the end of the experiment, fish feces samples were collected and the bacterial communities structure found in the intestines of c ommon carp were analyzed through a metagenomic approach using 16S rRNA sequencing.
The results of the metagenomic analysis of carp fed with a diet supplemented with YANG showed 11 different groups of bacterial phyla detected with the top three phyla, Fusobacteria , Firmicutes, and Proteobacteria. In contrast, fecal samples from carp fed with P. acidilactici recorded 10 phyla, the top three phyla were Proteobacteria, Fusobacteria, and Firmicutes . Fish fed with S. cerevisiae recorded 9 phyla, the top three phyla were Fusobacteria, Proteobacteria, and Firmicutes . However, samples fro m carp fed with the control diet recorded 14 phyla, t he top three phyla were Fusobacteriota, Proteobacteria, and Bacteroidota.