Evaluation of effects of rumen fluid in combination with probiotic preparations and vanillin on the luminescence of a recombinant strain E. coli

¹ Orenburg state university, 460018, Orenburg, Russia
² Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, 9th Yanvarya St., 29, 460000, Orenburg, Russia

^* Corresponding author: kwan111@yandex.ru

Abstract

A way to assess the metabolic state of bacteria of rumen microflora cells is the registration of glow kinetics including recombinant strains, which is a reflection of stress states developing in the cell. The experiment evaluated the effect of rumen fluid in combination with probiotic strains and vanillin on the luminescence of a recombinant strain Escherichia coli MG1655 and digestibility of feed. The “in vitro” method with the rumen simulation technique (Rusitec) was used to determine the digestibility of the dry substance of feed. Using the initial sample, the glow level at the 30th minute was recorded at 3,149±145 RLU, which is 32% of the control level. In the presence of rumen fluid (at the concentration of 6.25%), there was observed an improved response by E.coli against Saccharomyces boulardii’s background (by 44%). The use of vanillin in rumen fluid increases the glow level of bacterial cells in the range of concentrations up to 50%, and in combination with probiotic strains, in the range of 25-50 %. In vitro conditions against the background of rumen fluid showed that vanillin in combination with probiotic strains Bifidobacterium longum and Bifidobacterium adolescentis / Lactobacillus acidophilus contributes to an increase in the digestibility of the dry substance of feed.