Obesity is a problem of modern health care that causes the occurrence of many concomitant diseases: arterial hypertension, diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular diseases. New strategies for the treatment and prevention of obesity are being developed that are based on using probiotics for modulation of the gut microbiota. Our study aimed to evaluate the bacterial composition of the gut of obese patients before and after two weeks of lactic acid bacteria (Lactobacillus acidophilus, Lactiplantibacillus plantarum, Limosilactobacillus fermentum, and Lactobacillus delbrueckii) intake. The results obtained showed an increase in the number of members of the phylum Actinobacteriota in the group taking nutritional supplements, while the number of phylum Bacteroidota decreased in comparison with the control group. There has also been an increase in potentially beneficial groups: Bifidobacterium, Blautia, Eubacterium, Anaerostipes, Lactococcus, Lachnospiraceae ND3007, Streptococcus, Escherichia-Shigella, and Lachnoclostridium. Along with this, a decrease in the genera was demonstrated: Faecalibacterium, Pseudobutyrivibrio, Subdoligranulum, Faecalibacterium, Clostridium sensu stricto 1 and 2, Catenibacterium, Megasphaera, Phascolarctobacterium, and the Oscillospiraceae NK4A214 group, which contribute to the development of various metabolic disorders. Modulation of the gut microbiota by lactic acid bacteria may be one of the ways to treat obesity.

High-throughput sequencing has made it possible to extensively study the human gut microbiota. The links between the human gut microbiome and ethnicity, religion, and race remain rather poorly understood. In this review, data on the relationship between gut microbiota composition and the nationality of people and their religion were generalized. The unique gut microbiome of a healthy European (including Slavic nationality) is characterized by the dominance of the phyla Firmicutes, Bacteroidota, Actinobacteria, Proteobacteria, Fusobacteria, and Verrucomicrobia. Among the African population, the typical members of the microbiota are Bacteroides and Prevotella. The gut microbiome of Asians is very diverse and rich in members of the genera Prevotella, Bacteroides Lactobacillus, Faecalibacterium, Ruminococcus, Subdoligranulum, Coprococcus, Collinsella, Megasphaera, Bifidobacterium, and Phascolarctobacterium. Among Buddhists and Muslims, the Prevotella enterotype is characteristic of the gut microbiome, while other representatives of religions, including Christians, have the Bacteroides enterotype. Most likely, the gut microbiota of people of different nationalities and religions are influenced by food preferences. The review also considers the influences of pathologies such as obesity, Crohn’s disease, cancer, diabetes, etc., on the bacterial composition of the guts of people of different nationalities.

Probiotics are living microorganisms that provide numerous health benefits for their host. Probiotics have various effects on the body; for example, they change gut microbiota, improve the integrity of the epithelial barrier and have anti-inflammatory effects. The use of probiotic supplements that are based on lactic acid bacteria and bifidobacteria is one of the approaches that are used to balance gut microflora. In our study, we evaluated the effects of supplements, which were based on members of the Lactobacillaceae family and bifidobacteria, on the gut microbiome of healthy mice using the 16S rRNA sequencing method. The data that were obtained demonstrated that when mice received the probiotic supplements, statistically significant changes occurred in the composition of the microbiome at the phylum level, which were characterized by an increase in the number of Actinobacteriota, Bacteroidota, Verrucomicrobia and Proteobacteria, all of which have potentially positive effects on health. At the generic level, a decrease in the abundance of members of the Nocardioides, Helicobacter and Mucispirillum genus, which are involved in inflammatory processes, was observed for the group of mice that was fed with lactic acid bacteria. For the group of mice that was fed with bifidobacteria, a decrease was seen in the number of members of the Tyzzerella and Akkermansia genus. The results of our study contribute to the understanding of changes in the gut microbiota of healthy mice under the influence of probiotics. It was shown that probiotics that are based on members of the Lactobacillaceae family have a more positive effect on the gut microbiome than probiotics that are based on bifidobacteria.

Aging is one of the most serious factors for central nervous dysfunctions, which lead to cognitive impairment. New highly effective drugs are required to slow the development of cognitive dysfunction. This research studied the effect of dimethyl fumarate (DMF), methylene blue (MB), and resveratrol (RSV) on the cognitive functions of 15-month-old mice and their relationship to the maintenance of mitochondrial quality control in the brain and the bacterial composition of the gut microbiome. We have shown that studied compounds enhance mitochondrial biogenesis, mitophagy, and antioxidant defense in the hippocampus of 15-month-old mice via Nrf2/ARE pathway activation, which reduces the degree of oxidative damage to mtDNA. It is manifested in the improvement of short-term and long-term memory. We have also shown that memory improvement correlates with levels of Roseburia, Oscillibacter, ChristensenellaceaeR-7, Negativibacillus, and Faecalibaculum genera of bacteria. At the same time, long-term treatment by MB induced a decrease in gut microbiome diversity, but the other markers of dysbiosis were not observed. Thus, Nrf2/ARE activators have an impact on mitochondrial quality control and are associated with a positive change in the composition of the gut microbiome, which together lead to an improvement in memory in aged mice.

Determining the taxonomic composition of microbial consortia of the piglet intestine is of great importance for pig production. However, knowledge on the variety of the intestinal microbiome in newborn piglets is limited. Piglet diarrhea is a serious gastrointestinal disease with a high morbidity and mortality that causes great economic damage to the pig industry. In this study, we investigated the microbiome of various sections of the piglet intestine and compared the microbiome composition of healthy and diarrheal piglets using high-throughput sequencing of the 16S rRNA gene. The results showed that bacteria of the Lactobacillus genus were the most common in the ileum, while Fusobacterium and Bacteroides dominated in the rectum. Comparing the microbiome composition of healthy and diarrheal piglets revealed a reduced number of Lactobacillus bacteria as a hallmark of diarrhea, as did an increased content of representatives of the Escherichia-Shigella genus and a reduced number of Bacteroides, which indicates the contribution of these bacteria to the development of diarrhea in piglets. The relative abundance of Enterococcus bacteria was higher in the diarrhea group. Although some bacteria of this genus are commensals, a small number of species may be associated with the development of diarrhea in piglets. Therefore, our results indicate that the gut microbiome may be an important factor in the development of diarrhea in piglets.

Mastitis is the most common disease for cattle, causing great economic losses for the global dairy industry. Recent studies indicate the multi-agent and microbiome diversity of this disease. To understand the nature of mastitis and investigate the role of the microbiome in the development of pathologies in the udder of bovines, we performed NGS sequencing of the 16S rRNA gene of cow’s milk with pathologies of the udder. The obtained data show a significant increase in the Cutibacterium, Blautia, Clostridium sensu stricto 2, Staphylococcus, Streptococcus and Microbacterium genera for groups of cows with udder pathologies. Increasing relative abundance of the Staphylococcus and Streptococcus genera was associated with subclinical mastitis. Our data show that a relative increase in abundance of the Staphylococcus and Microbacterium genera may be an early sign of infection. We have shown, for the first time, an increase in the Colidextribacter, Paeniclostridium and Turicibacter genera in groups of cows with mastitis. These results expand our understanding of the role of the microbiome in the development of bovine mastitis.