PSVI-13 - Changes in the taxonomic composition of the rumen of ruminants when introducing fat components into the diet

Fats are concentrated energy sources for cattle growth, but their inclusion in the diet has a huge impact on the taxonomic composition of the rumen. The aim of this study was to evaluate the effect of supplemental linseed oil administration (3% of dry matter (DM) diet) on microbiota and DM digestibility in the rumen. The studies carried out on Kazakh white-headed bull calves, aged 15 months, with chronic rumen fistula (diet - 70% grassland hay, 30% barley grain). Dietary dry matter digestibility (in-vitro in an artificial rumen system, for 24 hours) analyzed daily for 10 days, and microflora (fluid-bound) analyzed using high-throughput 16SrRNA gene sequencing (Illumina). Inclusion of LO showed a slight 3.5% increase in DM digestibility compared to C (52.0% versus 53.9%). The taxonomic composition of the rumen microbiocenosis in group C was mainly represented by the phylum Firmicutes (54.7%) and Bacteroidetes (39.3%), while other phylum numbers were less than 2%. When LO was injected, the dominance of phylum Bacteroidetes (64.2%), phylum Firmicutes (19.3%), and Verrucomicrobia (5.3%) was noted. The calculation of the Shannon index showed an increase in species diversity in the group that received LO. It was H'= 0.76, while in CH'= 0.42. The Simpson dominance index in group C was 0.44, in the group receiving LOD = 0.54. The obtained data show a positive effect. The linseed oil allow to increase the biodiversity of the rumen microbiome and the digestibility of DM feed, which can be used in fattening young cattle. This research performed with financial support from the project 0761-2019-0005.