Assessment of feed complex effect on rumen microbiota of cows under polymicrobial feed contamination

Abstract

The research goal was to evaluate the effect of the feed complex “AntiKlos” (lauric acid + Bacillus spp.) on the rumen microbiota of lactating cows under conditions of polymicrobial feed contamination. The scientific and economic experiment was conducted on a dairy farm in the Omsk Region in two groups of 5 Red Steppe Holsteinized cows for 30 days. The control group received the standard basic diet without any additives. The trial group received the “AntiKlos” complex (OOO Biotrof, St. Petersburg) at a dose of 50 g per head per day in addition to the basic diet. Rumen fluid was collected by rumen centesis from all 10 cows before and after the experiment. Quantitative PCR (qPCR) was used to determine the total bacterial mass and the abundance of the following microorganisms: Methanosphaera stadtmanae, Escherichia coli, Proteus spp., Blautia spp., Eubacterium rectale, Prevotella spp., Bifidobacterium spp., Lactobacillus spp., Enterococcus spp., Acinetobacter spp., and others (a total of 33 taxa were analyzed). The use of the feed complex was associated with a trend of reducing E. coli 2.35 times (from 4.00 × 10⁵ ± 5.1 × 10⁴ to 1.70 × 10⁵ ± 2.7 × 10⁴ GE g), Enterococcus spp. - 1.9 times (from 1.90 × 10⁶ ± 8.0 × 10⁵ to 1.00 × 10⁶ ± 3.0 × 10⁵ GE g), and methanogenic archaea Methanosphaera stadtmanae (from 3.80 × 10⁷ ± 1.5 × 10⁷ to 3.30 × 10⁷ ± 1.30 × 10⁷ GE g), while in the control group these indices increased. The total bacterial mass in the trial group had an increasing trend (from 4.60 × 10¹² ± 1.31 × 10¹² to 5.60 × 10¹² ± 1.4 × 10¹² GE g) while in the control group it tended to decrease (from 2.18 × 10¹² ± 4.5 × 10¹¹ to 1.70 × 10¹² ± 4.8 × 10¹¹ GE g). In the trial group, complete disappearance of Proteus (vulgaris/mirabilis) and preservation of the abundance of Prevotella spp. were also found indicating a sanitizing effect of the additive without a negative impact on key fermentative processes of the rumen.