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Microorganisms Dec 2022Ruminants are foregut fermenters that have the remarkable ability of converting plant polymers that are indigestible to humans into assimilable comestibles like meat and... (Review)
Review
Ruminants are foregut fermenters that have the remarkable ability of converting plant polymers that are indigestible to humans into assimilable comestibles like meat and milk, which are cornerstones of human nutrition. Ruminants establish a symbiotic relationship with their microbiome, and the latter is the workhorse of carbohydrate fermentation. On the other hand, during carbohydrate fermentation, synthesis of propionate sequesters H, thus reducing its availability for the ultimate production of methane (CH4) by methanogenic archaea. Biochemically, methane is the simplest alkane and represents a downturn in energetic efficiency in ruminants; environmentally, it constitutes a potent greenhouse gas that negatively affects climate change. is a very versatile microbe capable of processing a wide range of proteins and polysaccharides, and one of its fermentation products is propionate, a trait that appears conspicuous in strain 23. Since propionate, but not acetate or butyrate, constitutes an H sink, propionate-producing microbes have the potential to reduce methane production. Accordingly, numerous studies suggest that members of the genus have the ability to divert the hydrogen flow in glycolysis away from methanogenesis and in favor of propionic acid production. Intended for a broad audience in microbiology, our review summarizes the biochemistry of carbohydrate fermentation and subsequently discusses the evidence supporting the essential role of in lignocellulose processing and its association with reduced methane emissions. We hope this article will serve as an introduction to novice researchers and as an update to others more conversant with the topic.
PubMed: 36677293
DOI: 10.3390/microorganisms11010001 -
Oncogene Feb 2023Appendectomy impacts the homeostasis of gut microbiome in patients. We aimed to study the role of appendectomy in colorectal cancer (CRC) risk through causing gut...
Appendectomy impacts the homeostasis of gut microbiome in patients. We aimed to study the role of appendectomy in colorectal cancer (CRC) risk through causing gut microbial dysbiosis. Population-based longitudinal study (cohort 1, n = 129,155) showed a 73.0% increase in CRC risk among appendectomy cases throughout 20 years follow-up (Adjusted sub-distribution hazard ratio (SHR) 1.73, 95% CI 1.49-2.01, P < 0.001). Shotgun metagenomic sequencing was performed on fecal samples from cohort 2 (n = 314). Gut microbial dysbiosis in appendectomy subjects was observed with significant enrichment of 7 CRC-promoting bacteria (Bacteroides vulgatus, Bacteroides fragilis, Veillonella dispar, Prevotella ruminicola, Prevotella fucsa, Prevotella dentalis, Prevotella denticola) and depletion of 5 beneficial commensals (Blautia sp YL58, Enterococcus hirae, Lachnospiraceae bacterium Choco86, Collinsella aerofaciens, Blautia sp SC05B48). Microbial network analysis showed increased correlation strengths among enriched bacteria and their enriched oncogenic pathways in appendectomy subjects compared to controls. Of which, B. fragilis was the centrality in the network of the enriched bacteria. We further confirmed that appendectomy promoted colorectal tumorigenesis in mice by causing gut microbial dysbiosis and impaired intestinal barrier function. Collectively, this study revealed appendectomy-induced microbial dysbiosis characterized by enriched CRC-promoting bacteria and depleted beneficial commensals, signifying that the gut microbiome may play a crucial role in CRC development induced by appendectomy.
Topics: Animals; Mice; Gastrointestinal Microbiome; Dysbiosis; Appendectomy; Longitudinal Studies; Colorectal Neoplasms
PubMed: 36539569
DOI: 10.1038/s41388-022-02569-3 -
Scientific Reports Aug 2017Nitrogen metabolism in gut systems remains poorly studied in spite of its importance for microbial growth and its implications for the metabolism of the host. Prevotella...
Nitrogen metabolism in gut systems remains poorly studied in spite of its importance for microbial growth and its implications for the metabolism of the host. Prevotella spp. are the most predominant bacteria detected in the rumen, but their presence has also been related to health and disease states in the human gut and oral cavity. To explore the metabolic networks for nitrogen assimilation in this bacterium, changes in gene expression profiles in response to variations in the available nitrogen source and to different concentrations of ammonium were analyzed by microarray and reverse transcription quantitative PCR, and linked with function by further proteomic analysis. The observed patterns of transcript abundances for genes involved in ammonium assimilation differed from the classical "enteric paradigm" for nitrogen utilization. Expression of genes encoding high substrate affinity nitrogen assimilation enzymes (GS-GOGAT system) was similar in growth-limiting and non-limiting nitrogen concentrations in P. ruminicola 23, whereas E. coli and Salmonella spp. responses to excess nitrogen involve only low substrate affinity enzymes. This versatile behavior might be a key feature for ecological success in habitats such as the rumen and human colon where nitrogen is rarely limiting for growth, and might be linked to previously reported Prevotella spp. population imbalances relative to other bacterial species in gut systems.
Topics: Ammonium Compounds; Escherichia coli; Gene Expression Profiling; Metabolic Networks and Pathways; Microarray Analysis; Nitrogen; Prevotella ruminicola; Proteome; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Salmonella
PubMed: 28798330
DOI: 10.1038/s41598-017-08463-3 -
Nutrients Jul 2022Precision dietary interventions (e.g., altering proportions of dietary protein fractions) has significant implications for the efficiency of nutrient use in ruminants,...
Precision dietary interventions (e.g., altering proportions of dietary protein fractions) has significant implications for the efficiency of nutrient use in ruminants, as well as lowering their environmental footprint, specifically nitrogen (N) emissions. Soluble protein (SP) is defined as the protein fraction that is rapidly degraded in the rumen (e.g., non-protein N and true protein), and our previous study found that regulating SP levels could improve N efficiency in Hu sheep. Thus, the present study was conducted to explore in vitro how protein fractions with different SP levels modulate the rumen microbial community and its association with N metabolism. Four dietary treatments with different SP proportions and similar crude protein (CP) content (~14%) were formulated (% of CP): 20 (S20), 30 (S30), 40 (S40) and 50 (S50). Results showed that NH3-N content increased with increasing SP levels at 4, 12 and 24 h; TVFA, acetate, propionate and valerate were higher in S30 and S40 (p < 0.05) and had quadratic effects (p < 0.05). Moreover, dry matter digestibility (DMD) and N digestibility (ND) were all decreased with S20 and S50 (p < 0.05). The S30 and S40 treatments increased the abundance of Bacteroidetes and Prevotella (Prevotella_ruminicola) but decreased the abundance of Firmicutes and Proteobacteria (p < 0.05). Bacterial pathways related to amino acid and fatty acid metabolism also were enriched with S30 and S40. The abundance of Entodinium was increased with S30 and S40 and had a positive correlation with Prevotella, and these two genera also played an important role in N metabolism and VFA synthesis of this study. In conclusion, bacterial and protozoal communities were altered by the level of SP (% of CP), with higher SP levels (~50% of CP) increasing the microbial diversity but being detrimental to rumen N metabolism.
Topics: Animal Feed; Animals; Bacteria; Diet; Dietary Proteins; Digestion; Fermentation; Nitrogen; Rumen; Sheep; Solubility
PubMed: 35889928
DOI: 10.3390/nu14142972 -
Frontiers in Physiology 2022The integrity of the intestinal epithelium is crucial for human health and is harmed in autism spectrum disorder (ASD). An aberrant gut microbial composition resulting...
INTRODUCTION
The integrity of the intestinal epithelium is crucial for human health and is harmed in autism spectrum disorder (ASD). An aberrant gut microbial composition resulting in gut-derived metabolic toxins was found to damage the intestinal epithelium, jeopardizing tissue integrity. These toxins further reach the brain the gut-brain axis, disrupting the normal function of the brain. A mechanistic understanding of metabolic disturbances in the brain and gut is essential to design effective therapeutics and early intervention to block disease progression. Herein, we present a novel computational framework integrating constraint based tissue specific metabolic (CBM) model and whole-body physiological pharmacokinetics (PBPK) modeling for ASD. Furthermore, the role of gut microbiota, diet, and oxidative stress is analyzed in ASD.
METHODS
A representative gut model capturing host-bacteria and bacteria-bacteria interaction was developed using CBM techniques and patient data. Simultaneously, a PBPK model of toxin metabolism was assembled, incorporating multi-scale metabolic information. Furthermore, dynamic flux balance analysis was performed to integrate CBM and PBPK. The effectiveness of a probiotic and dietary intervention to improve autism symptoms was tested on the integrated model.
RESULTS
The model accurately highlighted critical metabolic pathways of the gut and brain that are associated with ASD. These include central carbon, nucleotide, and vitamin metabolism in the host gut, and mitochondrial energy and amino acid metabolisms in the brain. The proposed dietary intervention revealed that a high-fiber diet is more effective than a western diet in reducing toxins produced inside the gut. The addition of probiotic bacteria , , , and to the diet restores gut microbiota balance, thereby lowering oxidative stress in the gut and brain.
CONCLUSION
The proposed computational framework is novel in its applicability, as demonstrated by the determination of the whole-body distribution of ROS toxins and metabolic association in ASD. In addition, it emphasized the potential for developing novel therapeutic strategies to alleviate autism symptoms. Notably, the presented integrated model validates the importance of combining PBPK modeling with COBRA -specific tissue details for understanding disease pathogenesis.
PubMed: 35330929
DOI: 10.3389/fphys.2022.760753 -
Journal of Animal Science Nov 2022The rumen is a vital organ containing vast amounts of microbes that play a key role in the digestion of nutrients and affect the production performance of ruminants....
The rumen is a vital organ containing vast amounts of microbes that play a key role in the digestion of nutrients and affect the production performance of ruminants. However, few studies have focused on the characterization of the ruminal microbiota composition and function in cows with long-term difference milk protein concentrations, and the relationship between milk protein concentration and ruminal microbiota remains elusive. In this study, we collected the data of milk protein concentrations of 1,025 Holstein cows for 10 mo on a commercial farm. Based on the milk protein concentrations, 30 cows were selected and divided into three groups (n = 10 per group): low milk protein group (LMP, milk protein concentration < 3.1%), medium milk protein group (MMP, 3.1% ≤ milk protein concentration < 3.4%), and high milk protein group (HMP, milk protein concentration ≥ 3.4%). The ruminal microbiome, metabolome, VFA concentrations and proportions, and amino acid profiles of the three groups were analyzed. The data showed that free amino acid (FAA) levels were lower in the rumen and higher in the plasma of HMP cows (P < 0.05). In addition, lower NH3 concentrations were observed in the rumen, plasma, and milk of the HMP cows (P < 0.05). Protease activity and isobutyric acid molar proportion in the rumen were lower in the HMP group (P < 0.05). Microbiome analysis showed that HMP cows had lower microbial diversity (represented as Shannon and Simpson indices) than LMP cows. At the genus level, lower relative abundances of Prevotella_1 and Ruminococcaceae_UCG_005 were observed in the HMP group (P < 0.05). At the operational taxonomic unit (OTU) level, a lower relative abundance of OTU3 (Prevotella ruminicola) was observed in the HMP group (P < 0.05). We found that the relative abundances of ruminal Prevotella_1 and OTU3 (Prevotella ruminicola) were negatively correlated with milk protein concentration (P < 0.05). These findings suggested that the cows with long-term high milk protein concentrations had lower microbial diversity and weaker protein degradation ability in the rumen. Furthermore, our observations identified a correlation between the milk protein concentration and ruminal microbiota.
Topics: Female; Cattle; Animals; Milk Proteins; Rumen; Lactation; Fatty Acids, Volatile; Fermentation; Diet; Microbiota; Prevotella; Metabolome; Amino Acids; Animal Feed
PubMed: 35938984
DOI: 10.1093/jas/skac253 -
Frontiers in Microbiology 2021Previous studies have focused on the rumen microbiome and enteric methane (CH) emissions in dairy cows, yet little is known about steers, especially steers of dairy...
Previous studies have focused on the rumen microbiome and enteric methane (CH) emissions in dairy cows, yet little is known about steers, especially steers of dairy breeds. In the present study, we comparatively examined the rumen microbiota, fermentation characteristics, and CH emissions from six non-cannulated Holstein (710.33 ± 43.02 kg) and six Jersey (559.67 ± 32.72 kg) steers. The steers were fed the same total mixed ration (TMR) for 30 days. After 25 days of adaptation to the diet, CH emissions were measured using GreenFeed for three consecutive days, and rumen fluid samples were collected on last day using stomach tubing before feeding (0 h) and 6 h after feeding. CH production (g/d/animal), CH yield (g/kg DMI), and CH intensity (g/kg BW) were higher in the Jersey steers than in the Holstein steers. The lowest pH value was recorded at 6 h after feeding. The Jersey steers had lower rumen pH and a higher concentration of ammonia-nitrogen (NH-N). The Jersey steers had a numerically higher molar proportion of acetate than the Holstein steers, but the opposite was true for that of propionate. Metataxonomic analysis of the rumen microbiota showed that the two breeds had similar species richness, Shannon, and inverse Simpson diversity indexes. Principal coordinates analysis showed that the overall rumen microbiota was different between the two breeds. Both breeds were dominated by , and its highest relative abundance was observed 6 h after feeding. The genera , , and the species , and were more abundant in Holstein steers while the genera , , and the species , and in the Jersey steers. The Jersey steers were dominated by while the Holstein steers by . The overall results suggest that sampling hour has little influence on the rumen microbiota; however, breeds of steers can affect the assemblage of the rumen microbiota and different mitigation strategies may be needed to effectively manipulate the rumen microbiota and mitigate enteric CH emissions from these steers.
PubMed: 33868186
DOI: 10.3389/fmicb.2021.601061 -
Frontiers in Microbiology 2022It was acknowledged long ago that microorganisms have played critical roles in animal evolution. Tibetan wild asses (TWA, ) are the only wild perissodactyls on the...
It was acknowledged long ago that microorganisms have played critical roles in animal evolution. Tibetan wild asses (TWA, ) are the only wild perissodactyls on the Qinghai-Tibet Plateau (QTP) and the first national protected animals; however, knowledge about the relationships between their gut microbiota and the host's adaptability remains poorly understood. Herein, 16S rRNA and meta-genomic sequencing approaches were employed to investigate the gut microbiota-host associations in TWA and were compared against those of the co-resident livestock of yak () and Tibetan sheep (). Results revealed that the gut microbiota of yak and Tibetan sheep underwent convergent evolution. By contrast, the intestinal microflora of TWA diverged in a direction enabling the host to subsist on sparse and low-quality forage. Meanwhile, high microbial diversity (Shannon and Chao1 indices), cellulolytic activity, and abundant indicator species such as Spirochaetes, Bacteroidetes, , and supported forage digestion and short-chain fatty acid production in the gut of TWA. Meanwhile, the enterotype identification analysis showed that TWA shifted their enterotype in response to low-quality forage for a better utilization of forage nitrogen and short-chain fatty acid production. Metagenomic analysis revealed that plant biomass degrading microbial consortia, genes, and enzymes like the cellulolytic strains (, and ), as well as carbohydrate metabolism genes (GH43, GH3, GH31, GH5, and GH10) and enzymes (β-glucosidase, xylanase, and β-xylosidase, etc.) had a significantly higher enrichment in TWA. Our results indicate that gut microbiota can improve the adaptability of TWA through plant biomass degradation and energy maintenance by the functions of gut microbiota in the face of nutritional deficiencies and also provide a strong rationale for understanding the roles of gut microbiota in the adaptation of QTP wildlife when facing harsh feeding environments.
PubMed: 35923394
DOI: 10.3389/fmicb.2022.949002 -
Journal of Molecular Microbiology and... 2015To reassemble Prevotella ruminicola genome from rumen metagenomic data of cattle and buffalo and compare with the published reference genome.
AIM
To reassemble Prevotella ruminicola genome from rumen metagenomic data of cattle and buffalo and compare with the published reference genome.
METHOD
Rumen microbial communities from Mehsani buffaloes (n = 8) and Kankrej cattle (n = 8), each adapted to different proportions of a dry or green roughage diet, were subjected to metagenomic sequencing by Ion Torrent PGM, and subsequent reads were analyzed by MG-RAST. Using reference-guided assembly of the sequences against the published P. ruminicola strain 23, draft genomes of 2.56 and 2.46 Mb were reconstructed from Mehsani buffalo and Kankrej cows, respectively. The genomes were annotated using the RAST Server and carbohydrate active enzyme (CAZyme) analysis.
RESULTS
Taxonomic analysis by MG-RAST revealed P. ruminicola to be the most abundant species present among the rumen microflora. Functional annotation of reconstructed genomes using the RAST Server depicted the maximum assignment of coding sequences involved in the subsystems amino acid and derivatives and carbohydrate metabolism. CAZyme profiling revealed the glycoside hydrolases (GH) family to be the most abundant. GH family subclassification revealed that the extracted genomes had more sequence hits for GH2, GH3, GH92 and GH97 as compared to the reference.
CONCLUSION
The results reflect the metabolic significance of rumen-adapted P. ruminicola in utilizing a coarse diet for animals based on acquisition of novel genetic elements.
Topics: Animals; Bacteria; Bacterial Proteins; Buffaloes; Cattle; Gastrointestinal Microbiome; Genome, Bacterial; Metagenomics; Open Reading Frames; Phylogeny; Prevotella ruminicola; Rumen
PubMed: 26304839
DOI: 10.1159/000437265 -
Frontiers in Microbiology 2021This study was conducted to examine the influences of replacing soybean meal (SBM) with fermented soybean meal (FSBM) in the diet of lactating Holstein cattle on rumen...
This study was conducted to examine the influences of replacing soybean meal (SBM) with fermented soybean meal (FSBM) in the diet of lactating Holstein cattle on rumen fermentation and ruminal bacterial microbiome. Twenty-four lactating Chinese Holstein dairy cattle were assigned to each of the two treatments in a completely randomized design: the SBM group [the basal total mixed ration (TMR) diet containing 5.77% SBM] and the FSBM group (the experimental TMR diet containing 5.55% FSBM). This trial lasted for 54 days (14 days for adjustment and 40 days for data and sample collection), and samples of rumen liquid were collected on 34 d and 54 d, respectively. The results showed that replacing SBM with FSBM significantly increased the molar percentages of propionate ( < 0.01) and valerate ( < 0.05), but reduced the total volatile fatty acid (TVFA) concentration ( < 0.05), butyrate molar proportion ( < 0.05), and the acetate to propionate ratio ( < 0.01). The copy numbers of total bacteria ( < 0.05), ( < 0.01), ( < 0.01), and spp. ( < 0.05) in the FSBM group were greater, while the density of ( < 0.05) was lower than those in the SBM treatment. Additionally, and were significantly enriched ( < 0.05) in the rumen fluid of FSBM-fed cows, despite the fact that there was no remarkable difference in the Alpha diversity indexes, structure and KEGG pathway abundances of the bacterial community across the two treatments. It could hence be concluded that the substitution of FSBM for SBM modulated rumen fermentation and rumen bacterial microbiota in lactating Holstein dairy cows. Further research is required to elucidate the relevant mechanisms of FSBM, and provide more insights into the application of FSBM in dairy cattle.
PubMed: 33584627
DOI: 10.3389/fmicb.2021.625857