Alteration of the gut microbiome of the common carp (Cyprinus carpio L., 1758) mediated by probiotics and yeast prebiotic

The current study aimed to examine the relative impact of dietary supplementation on the intestinal microbiota of common carp, Cyprinus carpio L., 1758. Different types of dietary supplements, including the probiotic Pediococcus acidilactici, the yeast probiotic Saccharomyces cerevisiae, and a yeast-based multi-strain prebiotic, were tested at a concentration of 0.1% (1.0 g/1 kg). A total of 96 carps with an average body weight of 932±163 g were distributed in 12 fish tanks (1000 L), with 8 fish/tank. Fish received the experimental diet for 40 days. At the end of the trial, fish feces were withdrawn and the total bacterial community in the gut of common carp was analyzed using Illumina's NGS targeting the 16S rRNA gene. The Krona phyla richness pie chart showed that 11 bacterial phyla were recorded in fish fed the yeast prebiotic, with the top 3 phyla being Fusobacteria, Firmicutes, and Proteobacteria. Similarly, 10 phyla were found in fecal samples from carp fed P. acidilactici, with the top 3 phyla being Proteobacteria, Firmicutes, and Fusobacteria. Also, carp fed S. cerevisiae recorded nine phyla, the top three phyla being Fusobacteria, Firmicutes, and Proteobacteria. However, carp fed the basal diet only showed 14 phyla, with the most abundant phyla being Fusobacteriota, Bacteroidota, and Proteobacteria. This study concluded that the examined feed supplements can cause alteration in the composition of the gut microbiome of the carps reared in a recirculating system.