The unique gut microbiome of giant pandas involved in protein metabolism contributes to the host's dietary adaption to bamboo

Mammalian colonic contribution of amino acids to whole-body homeostasis

PURPOSE OF REVIEW

The colon is an effective bioreactor with auxotrophic microbiota that can serve by hydrolyzing dietary and endogenous protein, as well as by synthesizing essential amino acids through nitrogen salvage. Due to assumed negligible amino acid absorption, this colonic contribution was thought to be minimal, but this may not be true.

RECENT FINDINGS

Several studies that examined the colonic environment in health and disease, show the presence of proteases in the colonic lumen, which are of both host and microbial origin, along with indirect evidence of amino acid transporters in the colonic epithelium. There are also amino acid biosynthetic pathways in the microflora, and the contribution of colonic amino acid to host amino acid nutrition has been shown in wild animals. Yet, current direct and quantitative evidence on amino acid absorption in human colon is minimal.

SUMMARY

Although amino acid absorption in colon is not very well established, current studies show that substantial amounts of amino acid could possibly be contributed to the host by the colon. There is a need for assessing this contribution quantitatively using direct isotopic methods under different nutritional conditions, dietary intakes, and clinical conditions.

Multiomics of yaks reveals significant contribution of microbiome into host metabolism

An intensive feeding system might improve the production cycle of yaks. However, how intensive feeding system contributes to yak growth is unclear. Here, multi-omics, including rumen metagenomics, rumen and plasma metabolomics, were performed to classify the regulatory mechanisms of intensive feeding system on yaks. Increased growth performance were observed. Rumen metagenomics revealed that Clostridium, Methanobrevibacter, Piromyces and Anaeromyces increased in the intensively fed yaks, contributing to amino acid and carbohydrate metabolism. The grazing yaks had more cellulolytic microbes. These microbiomes were correlated with the pathways of "Alanine aspartate and glutamate metabolism" and "Pyruvate metabolism". Intensive feeding increased methane degradation functions, while grazing yaks had higher methyl metabolites associated with methane production. These rumen microbiomes and their metabolites resulted in changes in plasma metabolome, finally influencing yaks' growth. Thus, an intensive feeding system altered the rumen microbiome and metabolism as well as host metabolism, resulting in improvements of yak growth.

Nutrient Utilization and Gut Microbiota Composition in Giant Pandas of Different Age Groups

Proper feeding and nutrition are vital for maintaining the health of giant pandas (GPs), yet the impact of dietary changes and gut microbiota on their nutrient utilization remains unclear. To address these uncertainties, we investigated nutrient intake and apparent digestibility, as well as gut microbiota composition across different age groups of giant pandas: sub-adults (SGPs), adults (AGPs), and geriatrics (GGPs). Our findings revealed notable shifts in dietary patterns from SGPs to GGPs. As they aged, significantly more bamboo shoots and less bamboo were consumed. Consequently, GGPs showed significantly reduced crude fiber (CF) intake and digestibility, while crude protein (CP) did not alter significantly. In addition, 16S rRNA microbial sequencing results showed that unidentified_Enterobacteriaceae and Streptococcus were the dominant genera among all age groups. The relative abundance of the genus Enterococcus in GGPs was significantly higher than that in SGPs and AGPs (p < 0.05). Overall, our results indicated the importance of bamboo shoots as a major source of protein in GGPs' diet, which can effectively compensate for the certain nutritional loss caused by the reduction in bamboo intake. Age-related changes in bacterial abundance have an effect on specific nutrient apparent digestibility in the gut of GPs. The data presented in this study serve as a useful reference for nutritional management in different ages of GPs under healthy conditions.

Comprehensive analysis of key host gene-microbe networks in the cecum tissues of the obese rabbits induced by a high-fat diet

The Cecum is a key site for cellulose digestion in nutrient metabolism of intestine, but its mechanisms of microbial and gene interactions has not been fully elucidated during pathogenesis of obesity. Therefore, the cecum tissues of the New Zealand rabbits and their contents between the high-fat diet-induced group (Ob) and control group (Co) were collected and analyzed using multi-omics. The metagenomic analysis indicated that the relative abundances of Corallococcus_sp._CAG:1435 and Flavobacteriales bacterium species were significantly lower, while those of Akkermansia glycaniphila, Clostridium_sp._CAG:793, Mycoplasma_sp._CAG:776, Mycoplasma_sp._CAG:472, Clostridium_sp._CAG:609, Akkermansia_sp._KLE1605, Clostridium_sp._CAG:508, and Firmicutes_bacterium_CAG:460 species were significantly higher in the Ob as compared to those in Co. Transcriptomic sequencing results showed that the differentially upregulated genes were mainly enriched in pathways, including calcium signaling pathway, PI3K-Akt signaling pathway, and Wnt signaling pathway, while the differentially downregulated genes were mainly enriched in pathways of NF-kappaB signaling pathway and T cell receptor signaling pathway. The comparative analysis of metabolites showed that the glycine, serine, and threonine metabolism and cysteine and methionine metabolism were the important metabolic pathways between the two groups. The combined analysis showed that CAMK1, IGFBP6, and IGFBP4 genes were highly correlated with Clostridium_sp._CAG:793, and Akkermansia_glycaniphila species. Thus, the preliminary study elucidated the microbial and gene interactions in cecum of obese rabbit and provided a basis for further studies in intestinal intervention for human obesity.

What Can the Gut Microbiota of Animals Teach Us about the Relationship between Nutrition and Burden of Lifestyle Diseases?

The gut microbiota performs several crucial roles in a holobiont with its host, including immune regulation, nutrient absorption, synthesis, and defense against external pathogens, significantly influencing host physiology. Disruption of the gut microbiota has been linked to various chronic conditions, including cardiovascular, kidney, liver, respiratory, and intestinal diseases. Studying how animals adapt their gut microbiota across their life course at different life stages and under the dynamics of extreme environmental conditions can provide valuable insights from the natural world into how the microbiota modulates host biology, with a view to translating these into treatments or preventative measures for human diseases. By modulating the gut microbiota, opportunities to address many complications associated with chronic diseases appear. Such a biomimetic approach holds promise for exploring new strategies in healthcare and disease management.

Hybridization alters red deer gut microbiome and metabolites

The host genes play a crucial role in shaping the composition and structure of the gut microbiome. Red deer is listed as an endangered species by the International Union for the Conservation of Nature, and its pilose antlers have good medicinal value. Hybridization can lead to heterosis, resulting in increased pilose antler production and growth performance in hybrid deer. However, the role of the gut microbiome in hybrid deer remains largely unknown. In this study, alpha and beta diversity analysis showed that hybridization altered the composition and structure of the gut microbiome of the offspring, with the composition and structure of the hybrid offspring being more similar to those of the paternal parents. Interestingly, the LefSe differential analysis showed that there were some significantly enriched gut microbiome in the paternal parents (such as g_Prevotellaceae UCG-003, f_Bacteroidales RF16 group; Ambiguous_taxa, etc.) and the maternal parents (including g_Alistipes, g_Anaerosporobacter, etc.), which remained significantly enriched in the hybrid offspring. Additionally, the hybrid offspring exhibited a significant advantage over the parental strains, particularly in taxa that can produce short-chain fatty acids, such as g_Prevotellaceae UCG-003, g_Roseburia, g_Succinivibrio, and g_Lachnospiraceae UCG-006. Similar to bacterial transmission, metagenomic analysis showed that some signaling pathways related to pilose antler growth ("Wnt signaling pathway," "PI3K Akt signaling pathway," "MAPK signaling pathway") were also enriched in hybrid red deer after hybridization. Furthermore, metabolomic analysis revealed that compared with the paternal and maternal parents, the hybrid offspring exhibited significant enrichment in metabolites related to "Steroid hormone biosynthesis," "Tryptophan metabolism," "Valine, leucine and isoleucine metabolism," and "Vitamin B metabolism." Notably, the metagenomic analysis also showed that these metabolic pathways were significantly enriched in hybrid deer. Finally, a correlation analysis between the gut microbiome and metabolites revealed a significant positive correlation between the enriched taxa in hybrid deer, including the Bacteroidales RF16 group, Prevotellaceae, and Succinivibrio, and metabolites, such as 7α-hydroxytestosterone, L-kynurenine, indole, L-isoleucine, and riboflavin. The study contributes valuable data toward understanding the role of the gut microbiome from red deer in hybridization and provides reference data for further screening potential probiotics and performing microbial-assisted breeding that promotes the growth of red deer pilose antlers and bodies, development, and immunity.

The antioxidant activity and metabolomic analysis of the supernatant of Streptococcus alactolyticus strain FGM

Strain-specific probiotics can present antioxidant activity and reduce damage caused by oxidation. Streptococcus alactolyticus strain FGM (S. alactolyticus strain FGM) isolated from the chicken cecum shows potential probiotic properties which have been previously demonstrated. However, the antioxidant properties of S. alactolyticus strain FGM remain unknown. In this view, cell-free supernatant (CFS), intact cells (IC) and intracellular extracts (CFE) of strain FGM and 3 strains of Lactobacillus (LAB) were prepared, and their scavenging capacities against DPPH, hydroxyl radicals and linoleic acid peroxidation inhibitory were compared in this study. The effects of strain FGM cell-free supernatant (FCFS) on NO production, activity of SOD and GSH-Px in RAW264.7 cells and LPS-induced RAW264.7 cells were analyzed. The metabolites in the supernatant were quantitated by N300 Quantitative Metabolome. It was shown that the physicochemical characteristics of CFS to scavenge DPPH, hydroxyl radicals, and linoleic acid peroxidation inhibitory were significantly stronger than that of IC and CFE in the strain FGM (P < 0.05), respectively 87.12% ± 1.62, 45.03% ± 1.27, 15.63% ± 1.34. FCFS had a promotional effect on RAW264.7 cells, and significantly elevated SOD and GSH-Px activities in RAW264.7 cells. 25 μL FCFS significantly promoted the proliferation of RAW264.7 cells induced by LPS, increased the activities of SOD and GSH-PX, and decreased the release of NO. Furthermore, among the differential metabolites of FCFS quantified by N300, 12 metabolites were significantly up-regulated, including lactic acid, indole lactic acid, linoleic acid, pyruvic acid etc., many of which are known with antioxidant properties. In conclusion, FCFS had good antioxidant properties and activity, which can be attributed to metabolites produced from strain FGM fermentation. It was further confirmed that S. alactolyticus strain FGM and its postbiotic have potential probiotic properties and bright application prospects in livestock and poultry breeding.

The effect and mechanism of volatile oil emulsion from leaves of Clausena lansium (Lour.) Skeels on Staphylococcus aureus in vitro

This study aimed to develop a suitable dosage form of volatile oil from wampee leaves and to explore its antibacterial mechanism in vitro. The chemical composition of the volatile oil from wampee leaves was determined by gas chromatography-mass spectrometry (GC-MS). Different microemulsion ratios were tested and their stabilities were investigated to determine the optimal ratio. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the wampee leaves volatile oil emulsion (WVOE) against Salmonella typhimurium (S. typhimurium) and Staphylococcus aureus (S. aureus) were determined using double-dilution and plate-counting methods, respectively. Morphological changes in these two bacteria were observed using scanning electron microscopy. Death, ultrastructural morphology, and biofilm formation were also assessed for S. aureus. Finally, we established an S. aureus-infected Lewis lung carcinoma (LLC) cell model to evaluate the protective effects of the volatile oil emulsion and the associated mechanisms. The volatile oil extracted from wampee leaves contained 37 compounds, of which 96.49% were aromatic hydrocarbons, terpenoids, and their oxygen-containing derivatives. The emulsion was most stable at 1:1 in the oil phase and 1:9 in the water phase. WVOE had poor antibacterial activity against S. typhimurium, but the MIC and MBC against S. aureus were 312.5 and 2,500 μg/mL, respectively. S. aureus survival rates were 84.6%, 14.5%, and 12.8% in the 1/2, 1, and 4 × MIC groups, respectively, compared with 97.2% in the control group. S. typhimurium survival was not affected by WVOE treatment. WVOE administration induced cavity formation and abnormal binary fission, and significantly inhibited biofilm formation in S. aureus cells. The WVOE notably reduced the number of S. aureus and inhibited TLR4, NLRP3, NF-κB, IL-6, IL-18, and TNF-α gene expression in S. aureus-infected LLC cells. The WVOE had a significant inhibitory effect on S. aureus and altered its cell membrane permeability. Moreover, it alleviated inflammation by inhibiting the NF-κB-NLRP3 pathway in S. aureus-infected LLC cells.

A comprehensive analysis of antibiotic resistance genes in the giant panda gut

In this study, we have successfully constructed a comprehensive database of metagenome-assembled genomes (MAGs) pertaining to the gut microbiota of the giant panda. Through our analysis, we have identified significant reservoirs of antibiotic resistance genes (ARGs), namely Escherichia coli, Citrobacter portucalensis, and Klebsiella pneumoniae. Furthermore, we have elucidated the primary contributors to ARGs, including Streptococcus alactolyticus and Clostridium SGBP116, in both captive and wild pandas. Additionally, our findings have demonstrated a higher prevalence of ARGs in the metagenome, with notable expression of the RPOB2 gene in S. alactolyticus. Crucially, 1217 ARGs shared homology with human gut ARGs, underscoring the interaction relationship between pandas and human microbiomes. These findings are instrumental in understanding the antibiotic resistance landscape in the giant panda's gut, providing a framework for developing strategies to combat antibiotic resistance and safeguard the health of this endangered species.

Dietary β-hydroxybutyric acid improves the growth performance of young ruminants based on rumen microbiota and volatile fatty acid biosynthesis

Introduction

The ketone body β-hydroxybutyric acid (BHB) plays critical roles in cellular proliferation and metabolic fuel utilization; however, its effects on the rumen microbiota remain unknown.

Methods

Here, three doses of BHB (low, medium, and high) were supplemented to early-weaned goat kids.

Results

Compared with controls, the beneficial effects of BHB on growth and rumen development were observed in goats at 90 days of age (d). The low dose of dietary BHB increased the concentration of rumen acetate, propionate, and butyrate on d90. The sequencing results of the rumen microbiota revealed marked shifts in rumen microbial community structure after early-weaned goat kids consumed BHB for 2 months. The signature bacterial ASVs for each treatment were identified and were the main drivers contributing to microbial interactions in the rumen. The bacteria associated with rumen weight were also correlated with body weight. Some classified bacterial signatures, including Prevotella, Olsenella umbonate, and Roseburia faecis, were related to rumen volatile fatty acids and host development.

Conclusion

Overall, dietary BHB altered rumen microbiota and environments in young goats, which contributed to rumen development and growth.

Effects of Different Types of Dietary Fibers on Lipid Metabolism and Bile Acids in Weaned Piglets

The aim of this study was to investigate the effects of dietary fiber on the serum biochemistry, bile acid profile, and gut microbiota in piglets. Twenty-four pigs (initial body weight: 10.53 ± 1.23 kg) were randomly divided into three treatments with eight replicate pens of one pig per pen for 21 d. The dietary treatments consisted of the following: (1) a fiber-free diet (NS); (2) a fiber-free diet + 3% fructooligosaccharides (SI); (3) a fiber-free diet + 3% dietary fiber mixture (fructooligosaccharides, long-chain inulin, and microcrystalline cellulose at the ratio 1:1:1; MIX). The results showed that compared with the NS group, the 3% SI diet reduced the serum total cholesterol (TC) concentration of the piglets (p < 0.05). The metabolomics results showed that the 3% SI diet increased the level of taurohyocholic acid (THCA) and α-muricholic acid, and the 3% MIX diet increased the level of THCA and cholic acid (p < 0.05). The use of 3% SI or MIX decreased the glycodeoxycholic acid (GDCA) level in the bile of the piglets (p < 0.05). The correlation analysis shows that the GDCA was positively related to the TC. The 16S rRNA gene sequencing results showed that UCG-002 and Holdemanella were enriched in the SI group, while Bacteroides was enriched in the MIX group. The microbial function prediction indicated that SI supplementation tended to elevate the relative abundance of gut bacteria capable of expressing bile acid-metabolizing enzymes. To sum up, the regulatory effect of dietary fiber on lipid metabolism is related to bile acids in piglets. Compared with MIX, SI is more likely to regulate bile acids through the gut microbiota.

Screening and evaluation of skin potential probiotic from high-altitude Tibetans to repair ultraviolet radiation damage

Human skin microbes play critical roles in skin health and diseases. Microbes colonizing on the skin of Tibetans living in the high-altitude area for generations may have a stronger ability to resist the harsh environment, such as high ultraviolet radiation (UV). Isolation of a potential probiotic from Tibetans skin is beneficial for resistance of skin disease for humans in the world. In this study, the signature microbiota for Tibetan skin were characterized compared to low-altitude humans. Next, using culture-omics, 118 species were isolated. The culturability of high-altitude of Tibetan skin microbiome reached approximate 66.8%. Next, we found that one strain, Pantoea eucrina, had the greatest ability to repair UV damage to the skin as the lowest pathological score was observed in this group. Interestingly, another animal trial found this bacterium resisted UV rather than its metabolites. Using whole genome sequencing, this strain P. eucrina KBFS172 was confirmed, and its functions were annotated. It might involve in the metabolic pathway of carotenoid biosynthesis with anti-oxidative stress properties, which plays critical roles in UV-damage repair. In conclusion, we characterized the signature microbes of skin in high-altitude Tibetans, isolated a skin bacterium of Pantoea eucrina KBFS172 which could repair UV damage via involving the metabolic pathway of carotenoid biosynthesis. Our results provide a new potential skin probiotic for skin disease prevention or sunburn.

The role of gut archaea in the pig gut microbiome: a mini-review

The gastrointestinal microbiota of swine harbors an essential but often overlooked component: the gut archaea. These enigmatic microorganisms play pivotal roles in swine growth, health, and yield quality. Recent insights indicate that the diversity of gut archaea is influenced by various factors including breed, age, and diet. Such factors orchestrate the metabolic interactions within the porcine gastrointestinal environment. Through symbiotic relationships with bacteria, these archaea modulate the host's energy metabolism and digestive processes. Contemporary research elucidates a strong association between the abundance of these archaea and economically significant traits in swine. This review elucidates the multifaceted roles of gut archaea in swine and underscores the imperative for strategic interventions to modulate their population and functionality. By exploring the probiotic potential of gut archaea, we envisage novel avenues to enhance swine growth, health, and product excellence. By spotlighting this crucial, yet under-investigated, facet of the swine gut microbiome, we aim to galvanize further scientific exploration into harnessing their myriad benefits.

The effects of differential feeding on ileum development, digestive ability and health status of newborn calves

Pre-weaning is the most important period for the growth and development of calves. Intestinal morphology, microbial community and immunity are initially constructed at this stage, and even have a lifelong impact on calves. Early feeding patterns have a significant impact on gastrointestinal development and microbial communities. This study mainly analyzed the effects of three feeding methods on the gastrointestinal development of calves, and provided a theoretical basis for further improving the feeding mode of calves. it is very important to develop a suitable feeding mode. In this study, we selected nine newborn healthy Holstein bull calves were randomly selected and divided into three groups (n = 3), which were fed with starter + hay + milk (SH group), starter + milk (SF group), total mixed ration + milk (TMR group). After 80 days of feeding Feeding to 80 days of age after, the ileum contents and blood samples were collected, and the differences were compared and analyzed by metagenomic analysis and serum metabolomics analysis. Results show that compared with the other two groups, the intestinal epithelium of the SH group was more complete and the goblet cells developed better. The feeding method of SH group was more conducive to the development of calves, with higher daily gain and no pathological inflammatory reaction. The intestinal microbial community was more conducive to digestion and absorption, and the immunity was stronger. These findings are helpful for us to explore better calf feeding patterns. In the next step, we will set up more biological replicates to study the deep-seated reasons for the differences in the development of pre-weaning calves. At the same time, the new discoveries of neuro microbiology broaden our horizons and are the focus of our future attention.