THE EFFECT OF DEXTRANAL ON THE GUT BACTERIOBIOME OF CALVES

Abstract

Background. The search for more efficient pro- and prebiotics to improve calves’ health, including decreasing the incidence of intestinal infections and increasing biomass production, has been very actual. The effect of prebiotics, however, is poorly, especially as related to gut microbiome biodiversity. 
 The aim of this work was to study the influence of dextranal on the growth of calves and their gut(rectum) bacteriobiome.
 Materials and Methods. Bacteriobiome composition and structure was assessed in the control group (K, conventional diet) and dextranal-receiving group (D) in 18-20 days aged calves by 16S metabarcoding (V3-V4, Illumina MiSeq).
 Results. Overall, we found 377 operational taxonomic units (OTU) from 168 genera, 91 families, 55 orders, 30 classes and 11 phyla, with more than the half of the total number of identifies OTUs belonging to the Firmicutes phylum, followed by Bacteroidetes and Actinobacteria. The relative abundance of the phylum-specific nucleotide sequences followed the same order of dominance. Dextranal addition resulted in the increased (11.9 kg/calf, or 15%) of the living body mass of the two-months old calves in group D as compared with group K: consequently, the dextranal-related difference in the calves’ gut bacteriobiome composition and structure can be viewed as beneficial. It primarily concerns the decreased abundance of the opportunistic pathogen Escherichia/Shigella (Gammaproteobacteria) in group D. Overall 73 OTUs, including six dominant ones, were found to be differentially abundant in the groups. However, changes in the relative abundance of some OTUs were difficult to interpret, most likely due to the low strain/species resolution by 16S rRNA gene fragments’ sequences. As for the α- biodiversity, there were no differences between the groups, but the overall trend directed to the increasing α- biodiversity of the calves’ gut bacteriobiome after dextranal treatment.
 Conclusion. This study reports the first attempt to inventory the gut bacteriobiome of the cattle in the region, and the obtained results provide the basis for a more detailed and taxonomically targeted further research.