PSVIII-13 Evaluation of the effect of chlortetracycline on ruminal microbiome of ruminant against a background of plant extract

Abstract

Abstract The limited use of antibiotics stimulates the search for alternatives or ways to reduce antibiotic resistance in order to prevent diseases and increase the productivity of ruminants. The aim of this study was to evaluate the effect of Quercus cortex (QC) extract (0.5 ml/kg body weight) together with chlortetracycline (Ch) (20%, 10 g/head/day) on cattle ruminal microbiome against the background of control (C), extract of QC and Ch. They were added separately as a substrate to the diets of bulls with rumen fistula (dairy breed, 12-months, diet - 80% hay, 20% grain feed, within 20 days). Microflora was analyzed using highly efficient sequencing of 16S rRNA gene (Illumina). QC was prepared by purification, grinding (1–2 mm), extraction in a water bath (30 min, 70 ° C). The taxonomic composition of ruminal microbiocenosis in control animals was represented by Bacteria and Fungi domains — 82.1 and 17.9%; QC - 99.8 and 0.2% was not classified; Ch - 10.4 and 89.6%; QC + Ch - 95.2 and 4.8%. Feeding with QC + Ch led to a decrease in phylums Bacteroidetes (P ≤ 0.05), Firmicutes (P ≤ 0.05), Proteobacteria compared to C. An increase in bacteria of Bacteroidia class (by 42.9% (P ≤ 0.05)) due to the species Prevotella and a decrease in the class of Gammaproteobacteria (by 6.9%) were registered. The species composition was characterized by a decrease in bacteria of Lactobacillus, Faecalibacterium, Escherichia, Fibrobacter genera. Ch group characterized by a decrease Fungi Ascomycota (P ≤ 0.05) and an increase in Chytridiomycota (P ≤ 0.05) and were not identified in QC and QC + Ch. Thus, this study highlights the potential use of plant extracts as an additional feed supplement, which can reduce the negative effects of chlortetracycline on the development of gram-positive bacteria and Fungi. This research was performed with financial support from the RSF (16-16-10048).