MICROBIOMES OF HUMAN, LIVESTOCK ANIMAL GASTROINTESTINAL TRACT, FOOD PRODUCTS AND COMPOUND FEEDS: CONNECTIONS AND IMPACTS. PART 2

Abstract

Research on the human gut microbiome began long ago and currently uses the latest modern methods and creates new insights and understanding. The human gut microbiome contains billions of microbial cells per 1 g of intestinal contents. These microbes include members of all superkingdoms: prokaryotes (kingdoms Bacteria and Archaea), eukaryotes (Fungi), and viruses. The taxonomic composition includes hundreds of bacterial species, dozens of archaeal and fungal species, and dozens of viral families. They are constantly in close connection and interaction with each other and with host cells and tissues. Methanogenic archaea have been shown to potentially impact the development of certain diseases, and fungi and bacteria are beneficial symbionts that have a significant impact on host health. Viruses are mostly bacteriophages that modulate bacterial populations. The impact on human health occurs through complex molecular mechanisms: microbes secrete biologically active metabolites that modulate cellular and tissue biochemical activity and, hence, the functioning of the immune system and other organs, including the CNS. In turn, the human body responds using its nervous and immune systems and local intestinal tissues that produce certain substances that modify the activity of microorganisms. This results in formation of a gut-brain axis consisting of afferent (to the brain) and efferent (from the brain) pathways. A correlation between the composition of the microbiota and the development of some intestinal and non-intestinal diseases, including neurodegenerative and behavioral disorders, has been shown. The human gut microbiota varies throughout a person's life, and differs significantly by age (from infancy to the elderly) in terms of the taxonomic proportions. At the same time, food products contain hundreds of species of microbes, i. e. various bacteria and fungi (yeast and mycelial). This food microbiota can have an impact on the gut microbiota, especially in children (infants, preschool) and elderly. However, this issue has not been investigated and should be studied in the future.