In Vivo Bioavailability of Selenium in Selenium-Enriched Streptococcus thermophilus and Enterococcus faecium in CD IGS Rats

Gabriela Krausova,Martina Huttl,Iva Mrvikova,Antonin Kana,Barbora Stankova,Ivana Hyrslova,Marek Vecka,Vera Kantorova,Hana Malinska

doi:10.3390/antiox10030463

Abstract

The selenium (Se) enrichment of yeasts and lactic acid bacteria (LAB) has recently emerged as a novel concept; the individual health effects of these beneficial microorganisms are combined by supplying the essential micronutrient Se in a more bioavailable and less toxic form. This study investigated the bioavailability of Se in the strains Enterococcus faecium CCDM 922A (EF) and Streptococcus thermophilus CCDM 144 (ST) and their respective Se-enriched forms, SeEF and SeST, in a CD (SD-Sprague Dawley) IGS rat model. Se-enriched LAB administration resulted in higher Se concentrations in the liver and kidneys of rats, where selenocystine was the prevalent Se species. The administration of both Se-enriched strains improved the antioxidant status of the animals. The effect of the diet was more pronounced in the heart tissue, where a lower glutathione reductase content was observed, irrespective of the Se fortification in LAB. Interestingly, rats fed diets with EF and SeEF had higher glutathione reductase activity. Reduced concentrations of serum malondialdehyde were noted following Se supplementation. Diets containing Se-enriched strains showed no macroscopic effects on the liver, kidneys, heart, and brain and had no apparent influence on the basic parameters of the lipid metabolism. Both the strains tested herein showed potential for further applications as promising sources of organically bound Se and Se nanoparticles.

Highlights

The selenium content in group fed a standard maintenance diet (group A) was determined by the addition of sodium selenite during the production of Altromin 1324
Selenized forms of the strains Streptococcus thermophilus CCDM 144 and Enterococcus faecium CCDM 922A were proven to represent a source of organically bound Se, SeCys2 being the most abundant Se species, followed by SeMet
The production of extracellular Se NPs of different sizes was confirmed by Transmission Electron Microscope (TEM) EDX in both the strains

Summary

Introduction

Natural antioxidants have attracted interest from researchers because of the diseases caused by free radicals and reactive oxygen species (ROS), including heart disease, atherosclerosis, neurological disorders, and type II diabetes. Organization (WHO) expects cardiovascular disease to be the leading cause of mortalities by 2030, affecting approximately 23.3 million people [1]. Enrichment of the diet with antioxidants is a basic prerequisite for maintaining good health. In addition to synthetic antioxidants, natural antioxidants, including probiotic microorganisms and their metabolic products, are available. Probiotic bacteria are defined as living microorganisms that, when consumed in sufficient quantities, confer health benefits to the host, such as the Antioxidants 2021, 10, 463.

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