The impact of probiotic supplementation with effective microorganisms on water and gut microbiome of the Common carp

Abstract

The efficacy of probiotic products in aquaculture covers multiple aspects that act directly on fish, such as improving resistance to fungal, bacterial, and viral infections, reproduction, feed efficiency, and overall growth performance, or indirectly through improved water quality. In our experiment, the application of two commercial water and two commercial food EM supplements was tested for their effect on water and the intestinal microbiome of common carp (Cyprinus carpio), as well as on carp growth performance. Probiotic supplementation did not result in a clear pattern of changes in overall microbial diversity or in the modification of the abundance of single genera. However, its effect was clearly manifested by an increase in the final weight of the fish. The most consistent alteration was the significant increase in Lactococcus abundance in the intestinal microbiome community compared to the control observed in both experimental setups. We conclude that the positive effect of Lactococcus on growth performance can be achieved by feed supplementation, which allows the increased abundance of Lactococcus in the fish intestine, which has a positive impact on glucose absorption and metabolism already demonstrated in the literature.