Does diet or macronutrients intake drive the structure and function of gut microbiota?

Dynamic Changes in Rumen Microbial Diversity and Community Composition Within Rumen Fluid in Response to Various Storage Temperatures and Preservation Times

The aim of this study was to investigate the effects of storage temperature and preservation time on the microbial diversity and community composition of rumen fluid. Rumen fluid samples were collected from six Hu sheep fed on a high-forage diet and stored at -80 °C and -20 °C for intervals of 0, 7, 14, 30, 60, 120, and 240 days. DNA was extracted at each time point for 16S rRNA gene sequencing to evaluate the rumen microbial diversity and community composition. The results showed that storage temperature affected only the relative abundance of Proteobacteria, with no substantial impact on alpha-diversity or other microbial groups (p > 0.05), and no significant interaction effects were observed between storage temperature and preservation time (p > 0.05). Alpha-diversity indices such as Chao1, observed species, and PD whole tree showed dynamic changes after 7 days of storage, while the relative abundances of Verrucomicrobiota and Christensenellaceae R-7 group, as well as the energy metabolism metabolic pathway, exhibited significant alterations after 14 days of storage (p < 0.05). Notably, Patescibacteria, Rikenellaceae RC9 gut group, and Veillonellaceae UCG-001 abundances demonstrated significant changes after 240 days of storage (p < 0.05). Both principal coordinates analysis (PCoA) and non-metric multidimensional scaling (NMDS) showed distinct overlaps. This study suggests that storing rumen fluid at -80 °C and -20 °C does not influence rumen microbial diversity and community composition, whereas the storage time significantly impacts these factors, with most differences emerging after 14 days of preservation. Consequently, it is advised that the analysis of microbial diversity and community composition in rumen fluid samples be conducted within 14 days post-collection.

Dynamic Changes in Intestinal Microorganisms and Hematological Indices in Giraffes of Different Ages, and the Effect of Diarrhea on Intestinal Microbiota

This study employed high-throughput sequencing to explore bacterial diversity and hematological variations across different age groups of giraffes, as well as the impact of diarrhea on their intestinal microbiota. Additionally, the correlation between intestinal flora and hematological indices was examined for the first time. Firmicutes, Bacteroides, and Proteobacteria were the predominant bacterial groups in the giraffe's intestinal flora. The α-diversity analysis indicated significant variations in microbial diversity among giraffes of varying ages (p < 0.05). Furthermore, giraffes suffering from diarrhea exhibited significant alterations in the abundance of Proteobacteria and Actinobacteriota at the phylum level (p < 0.05). At the genus level, Rikenellaceae_RC9_gut_group, Monoglobus, and Prevotellaceae_UCG-004 had significant differences compared to healthy counterparts (p < 0.05). Hematological parameters such as lymphocyte count (Lym), red blood cell count (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), platelet count (PLT), and plateletcrit (PCT) varied significantly across different age groups (p < 0.05). A substantial correlation was observed between the intestinal microbiome composition and hematological parameters (p < 0.05). In conclusion, this study highlights significant differences in both the intestinal microbiome composition and hematological indices among giraffes of different ages. Diarrhea was found to significantly alter the abundance and composition of the intestinal microbial community. These insights provide a valuable theoretical foundation for the microbiological and hematological aspects of giraffe health management and breeding practices.

Lingguizhugan decoction alleviates obesity in rats on a high-fat diet through the regulation of lipid metabolism and intestinal microbiota

BACKGROUND

Individuals with obesity often experience elevated blood lipid levels, leading to a chronic low-grade inflammatory state, exacerbating liver oxidative stress, and increasing the risk of various metabolic diseases. Recent evidence suggests that intestinal microbiota and short-chain fatty acids (SCFAs) play crucial roles in the development and progression of obesity. While the mechanisms by which Lingguizhugan decoction (LGZGD) intervenes in obesity by improving lipid metabolism, enhancing insulin sensitivity, and reducing inflammatory responses are well-documented, its potential in intestinal microbiota and SCFAs remains unclear. This study aims to explore the impact of LGZGD on high-fat diet (HFD) induced obesity in rats and its regulatory effects on intestinal microbiota and SCFAs, providing new insights for obesity prevention and treatment.

METHODS

Fifty-one male SD rats were randomly divided into groups, with six in the normal control group (NC) receiving a ddH2O treatment and a standard diet. The remaining 45 rats were fed a high-fat diet (HFD) using D12451 feed. After 10 weeks, the rats on the HFD gained 20% more weight than the NC group, confirming the successful modeling of obesity. These rats were then randomly divided into the following groups: ddH2O high-fat diet model group (MC), 20 mg/kg/day Orlistat positive control group (Orlistat), 1.62 g/kg/day low-dose LGZGD group (LGZGL), and 3.24 g/kg/day high-dose LGZGD group (LGZGH) for 8 weeks. We evaluated changes in body weight, serum total cholesterol (TC), total triacylglycerol (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL) levels. Fat and liver tissues were collected for pathological analysis. Intestinal contents were aseptically collected for 16S rRNA gene sequencing and gas chromatography-mass spectrometry (GC-MS) to assess gut microbiota and SCFA levels.

RESULTS

LGZGD reduces body weight, TC, TG, LDL, and HDL levels, significantly reducing hepatic steatosis. Besides, it restored the richness and diversity of gut microbiota, which was reduced by HFD, altering the overall structure. Specifically, LGZGD significantly promoted the growth of Muribaculaceae and Dubosiella while inhibiting the growth of Christensenellaceae_R_7_group and UCG_005. It also restricts the production of caproic acid. Correlation analysis indicated positive correlations: Muribaculaceae with Butyric acid and Isovaleric acid; UCG_005 with TC, LDL, and HDL; and Christensenellaceae_R_7_group with TC and LDL.

CONCLUSION

LGZGD increased the abundance of beneficial gut microbiota in HFD-induced obese rats, improved gut microbiota dysbiosis, and inhibited the increase in caproic acid content. These results suggest that LGZGD can mitigate HFD-induced obesity, and its active components warrant further investigation.

The role of gut microbiota in a generalist, golden snub-nosed monkey, adaptation to geographical diet change

Changes in diet causing ecological stress pose a significant challenge to animal survival. In response, the gut microbiota, a crucial part of the host's digestive system, exhibits patterns of change reflective of alterations in the host's food component. The impact of temporal dietary shifts on gut microbiota has been elucidated through multidimensional modeling of both food component and macronutrient intake. However, the broad distribution of wild generalist and the intricate complexity of their food component hinder our capacity to ascertain the degree to which their gut microbiota assist in adapting to spatial dietary variations. We examined variation in patterns of the gut microbial community according to changes in diet and in a colobine monkey with a regional variable diet, the golden snub-nosed monkey (Rhinopithecus roxellana). Specifically, we analyse the interactions between variation in food component, macronutrient intake and the gut microbial community. We compared monkeys from four populations by quantifying food component and macronutrient intake, and by sequencing 16S rRNA and the microbial macro-genomes from the faecal samples of 44 individuals. We found significant differences in the diets and gut microbial compositions, in nutrient space and macronutrient intake among some populations. Variations in gut microbiota composition across distinct populations mirror the disparities in macronutrient intake, with a notable emphasis on carbohydrate. Geographical differences in the diet among of golden snub-nosed monkey populations will result in macronutrient intake variation, with corresponding differences in macronutrient intake driving regional differences in the compositions and abundances of gut microbiota. Importantly, the gut microbiota associated with core digestive functions does not vary, with the non-core gut microbiota fluctuating in response to variation in macronutrient intake. This characteristic may enable species heavily reliant on gut microbiota for digestion to adapt to diet changes. Our results further the understanding of the roles gut microbiota play in the formation of host dietary niches.

The role of host traits and geography in shaping the gut microbiome of insectivorous bats

The gut microbiome is a symbiotic microbial community associated with the host and plays multiple important roles in host physiology, nutrition, and health. A number of factors have been shown to influence the gut microbiome, among which diet is considered to be one of the most important; however, the relationship between diet composition and gut microbiota in wild mammals is still not well recognized. Herein, we characterized the gut microbiota of bats and examined the effects of diet, host taxa, body size, gender, elevation, and latitude on the gut microbiota. The cytochrome C oxidase subunit I (COI) gene and 16S rRNA gene amplicons were sequenced from the feces of eight insectivorous bat species in southern China, including Miniopterus fuliginosus, Aselliscus stoliczkanus, Myotis laniger, Rhinolophus episcopus, Rhinolophus osgoodi, Rhinolophus ferrumequinum, Rhinolophus affinis, and Rhinolophus pusillus. The results showed that the composition of gut microbiome and diet exhibited significant differences among bat species. Diet composition and gut microbiota were significantly correlated at the order, family, genus, and operational taxonomic unit levels, while certain insects had a marked effect on the gut microbiome at specific taxonomic levels. In addition, elevation, latitude, body weight of bats, and host species had significant effects on the gut microbiome, but phylosymbiosis between host phylogeny and gut microbiome was lacking. These findings clarify the relationship between gut microbiome and diet and contribute to improving our understanding of host ecology and the evolution of the gut microbiome in wild mammals.

IMPORTANCE

The gut microbiome is critical for the adaptation of wildlife to the dynamic environment. Bats are the second-largest group of mammals with short intestinal tract, yet their gut microbiome is still poorly studied. Herein, we explored the relationships between gut microbiome and food composition, host taxa, body size, gender, elevation, and latitude. We found a significant association between diet composition and gut microbiome in insectivorous bats, with certain insect species having major impacts on gut microbiome. Factors like species taxa, body weight, elevation, and latitude also affected the gut microbiome, but we failed to detect phylosymbiosis between the host phylogeny and the gut microbiome. Overall, our study presents novel insights into how multiple factors shape the bat's gut microbiome together and provides a study case on host-microbe interactions in wildlife.

Plant Secondary Compounds Promote White Adipose Tissue Browning via Modulation of the Gut Microbiota in Small Mammals

The browning of white adipose tissue (WAT) is a promising area of research for treating metabolic disorders and obesity in the future. However, studies on plant secondary compounds promoting WAT browning are limited. Herein, we explored the effects of swainsonine (SW) on gut microbiota and WAT browning in captive pikas. SW inhibited body mass gain, increased brown adipose tissue (BAT) mass, and induced WAT browning in pikas. The 16S rDNA sequencing revealed a significant reduction in the alpha diversity and altered community structure of the gut microbiota in captive pikas. However, the addition of SW to the diet significantly increased the alpha diversity of gut microbiota and the relative abundance of Akkermansia, Prevotella, and unclassified_f__Lachnospiraceae, along with the complexity of the microbial co-occurrence network structure, which decreased in the guts of captive pikas. Functional profiles showed that SW significantly decreased the relative abundances of energy metabolism, lipid metabolism, and glycan biosynthesis and metabolism, which were enriched in captive pikas. Furthermore, SW decreased deterministic processes of gut microbiota assembly in July and increased them in November. Finally, the genera Prevotella and unclassified_f__Prevotellaceae were positively correlated with BAT mass. Our results highlighted that plant secondary compounds promote WAT browning by modulating the gut microbiota in small mammals.

Prickly Ash Seeds improve immunity of Hu sheep by changing the diversity and structure of gut microbiota

Prickly Ash Seeds (PAS), as a traditional Chinese medicinal herb, have pharmacological effects such as anti-asthma, anti-thrombotic, and anti-bacterial, but their impact on gut microbiota is still unclear. This study used a full-length 16 s rRNA gene sequencing technique to determine the effect of adding PAS to the diet on the structure and distribution of gut microbiota in Hu sheep. All lambs were randomly divided into two groups, the CK group was fed with a basal ration, and the LZS group was given a basal diet with 3% of PAS added to the ration. The levels of inflammatory factors (IL-10, IL-1β, and TNF-α) in intestinal tissues were measured by enzyme-linked immunosorbent assay (ELISA) for Hu sheep in the CK and LZS group. The results indicate that PAS can increase the diversity and richness of gut microbiota, and can affect the community composition of gut microbiota. LEfSe analysis revealed that Verrucomicrobiota, Kiritimatiella, WCHB 41, and uncultured_rumen_bacterium were significantly enriched in the LZS group. KEGG pathway analysis found that LZS was significantly higher than the CK group in the Excretory system, Folding, sorting and degradation, and Immune system pathways (p < 0.05). The results of ELISA assay showed that the level of IL-10 was significantly higher in the LZS group than in the CK group (p < 0.05), and the levels of TNF-α and IL-1β were significantly higher in the CK group than in the LZS group (p < 0.05). LEfSe analysis revealed that the dominant flora in the large intestine segment changed from Bacteroidota and Gammaproteobacteria to Akkermansiaceae and Verrucomicrobiae after PAS addition to Hu sheep lambs; the dominant flora in the small intestine segment changed from Lactobacillales and Aeriscardovia to Kiritimatiellae and WCHB1 41. In conclusion, the addition of PAS to sheep diets can increase the number and types of beneficial bacteria in the intestinal tract, improve lamb immunity, and reduce intestinal inflammation. It provides new insights into healthy sheep production.

Species variations in the gut microbiota of captive snub-nosed monkeys

Introduction

Snub-nosed monkeys are species in danger of extinction due to habitat fragmentation and human activities. Captivity has been suggested as an Auxiliary Conservation Area (ASA) strategy. However, little is known about the adaptation of different species of snub-nosed monkeys to captive environments.

Methods

This study compared the gut microbiota between Rhinopithecus bieti, R. brelichi, and R. roxellana under identical captive conditions to provide insights for improving captive conservation strategies.

Results

The results showed that these three Rhinopithecus species shared 80.94% of their Operational Taxonomic Unit (OTU), indicating high similarity in gut microbiota composition. The predominant phyla were Firmicutes and Bacteroidetes for all three Rhinopithecus species, but differences were observed in diversity, characteristic bacterial communities, and predicted function. Significant enrichment of cellulolytic families, including Ruminococcaceae, Clostridiales vadinBB60 group, Christensenellaceae, and Erysipelotrichaceae, and pathways involved in propionate and butyrate metabolism in the gut of R. bieti suggested that it may have a superior dietary fiber utilization capacity. In contrast, Bacteroidetes, Ruminoccaceae, and Trichospiraceae were more abundant in R. brelichi and R. roxellana, and were associated with saccharide and glycan metabolic pathways. Moreover, R. brelichi and R. roxellana also had higher similarity in microbiota composition and predicted function.

Discussion

In conclusion, the results demonstrate that host species are associated with the composition and function of the gut microbiota in snub-nosed monkeys. Thus, host species should be considered when formulating nutritional strategies and disease surveillance in captive snub-nosed monkeys.