Metabolism and functions of L-glutamate in the epithelial cells of the small and large intestines

Effect of monosodium glutamate supplementation in diet on fatty acid profiles, genes expression related to lipid metabolism and egg yolk cholesterol in late phase of production in laying hens

In an experiment with four treatments and five replicates, the effects of adding monosodium glutamate (MSG) to the diet in late phase of egg production was studied on performance, and lipid metabolism in laying hens. Dietary treatments included the control basal diet without MSG and the other treatments adding 0.4%, 0.8% and 1.2% MSG in the control diet respectively. The effect of supplementation of MSG on egg weight, egg production, feed conversion ratio and egg mass was insignificant (p < 0.05). Adding MSG to the diet significantly increased feed intake and blood polyunsaturated fatty acids concentration (p < 0.05). Intake of 0.8% and 1.2% MSG in the diet up regulated the mRNA expression of acetyl-coenzyme A carboxylase, fatty acid synthase and lipoprotein lipase in the abdominal and liver tissues in comparison to the control group. Blood very low-density lipoprotein-cholesterol, triglycerides and cholesterol concentration were increased in treatment fed with a diet containing 0.8% MSG compared to the control group (p < 0.05). The effect of MSG on total egg yolk cholesterol concentration was not significant. In conclusion, the results of the present experiment indicated that adding MSG increased feed intake and blood polyunsaturated fatty acid concentration.

Colorectal cancer microbiome programs DNA methylation of host cells by affecting methyl donor metabolism

BACKGROUND

Colorectal cancer (CRC) arises from complex interactions between host and environment, which include the gut and tissue microbiome. It is hypothesized that epigenetic regulation by gut microbiota is a fundamental interface by which commensal microbes dynamically influence intestinal biology. The aim of this study is to explore the interplay between gut and tissue microbiota and host DNA methylation in CRC.

METHODS

Metagenomic sequencing of fecal samples was performed on matched CRC patients (n = 18) and healthy controls (n = 18). Additionally, tissue microbiome was profiled with 16S rRNA gene sequencing on tumor (n = 24) and tumor-adjacent normal (n = 24) tissues of CRC patients, while host DNA methylation was assessed through whole-genome bisulfite sequencing (WGBS) in a subset of 13 individuals.

RESULTS

Our analysis revealed substantial alterations in the DNA methylome of CRC tissues compared to adjacent normal tissues. An extensive meta-analysis, incorporating publicly available and in-house data, identified significant shifts in microbial-derived methyl donor-related pathways between tumor and adjacent normal tissues. Of note, we observed a pronounced enrichment of microbial-associated CpGs within the promoter regions of genes in adjacent normal tissues, a phenomenon notably absent in tumor tissues. Furthermore, we established consistent and recurring associations between methylation patterns of tumor-related genes and specific bacterial taxa.

CONCLUSIONS

This study emphasizes the pivotal role of the gut microbiota and pathogenic bacteria in dynamically shaping DNA methylation patterns, impacting physiological homeostasis, and contributing to CRC tumorigenesis. These findings provide valuable insights into the intricate host-environment interactions in CRC development and offer potential avenues for therapeutic interventions in this disease.

Colonization of vancomycin-resistant Enterococcus faecium in human-derived colonic epithelium: unraveling the transcriptional dynamics of host-enterococcal interactions

Enterococcus faecium is an opportunistic pathogen able to colonize the intestines of hospitalized patients. This initial colonization is an important step in the downstream pathogenesis, which includes outgrowth of the intestinal microbiota and potential infection of the host. The impact of intestinal overgrowth on host-enterococcal interactions is not well understood. We therefore applied a RNAseq approach in order to unravel the transcriptional dynamics of E. faecium upon co-culturing with human derived colonic epithelium. Co-cultures of colonic epithelium with a hospital-associated vancomycin resistant (vanA-type) E. faecium (VRE) showed that VRE resided on top of the colonic epithelium when analyzed by microscopy. RNAseq revealed that exposure to the colonic epithelium resulted in upregulation of 238 VRE genes compared to the control condition, including genes implicated in pili expression, conjugation (plasmid_2), genes related to sugar uptake, and biofilm formation (chromosome). In total, 260 were downregulated, including the vanA operon located on plasmid_3. Pathway analysis revealed an overall switch in metabolism to amino acid scavenging and reduction. In summary, our study demonstrates that co-culturing of VRE with human colonic epithelium promotes an elaborate gene response in VRE, enhancing our insight in host-E. faecium interactions, which might facilitate the design of novel anti-infectivity strategies.

L-Glutamine Substantially Improves 5-Fluorouracil-Induced Intestinal Mucositis by Modulating Gut Microbiota and Maintaining the Integrity of the Gut Barrier in Mice

SCOPE

This study investigates the potential of glutamine to mitigate intestinal mucositis and dysbiosis caused by the chemotherapeutic agent 5-fluorouracil (5-FU).

METHODS AND RESULTS

Over twelve days, Institute of Cancer Research (ICR) mice are given low (0.5 mg kg-1) or high (2 mg kg-1) doses of L-Glutamine daily, with 5-FU (50 mg kg-1) administered between days six and nine. Mice receiving only 5-FU exhibited weight loss, diarrhea, abnormal cell growth, and colonic inflammation, correlated with decreased mucin proteins, increased endotoxins, reduced fecal short-chain fatty acids, and altered gut microbiota. Glutamine supplementation counteracted these effects by inhibiting the Toll-like receptor 4/nuclear factor kappa B (TLR4/NF-κB) pathway, modulating nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) oxidative stress proteins, and increasing mammalian target of rapamycin (mTOR) levels, thereby enhancing microbial diversity and protecting intestinal mucosa.

CONCLUSIONS

These findings underscore glutamine's potential in preventing 5-FU-induced mucositis by modulating gut microbiota and inflammation pathways.

A long journey to the colon: The role of the small intestine microbiota in intestinal disease

The small intestine represents a complex and understudied gut niche with significant implications for human health. Indeed, many infectious and non-infectious diseases center within the small intestine and present similar clinical manifestations to large intestinal disease, complicating non-invasive diagnosis and treatment. One major neglected aspect of small intestinal diseases is the feedback relationship with the resident collection of commensal organisms, the gut microbiota. Studies focused on microbiota-host interactions in the small intestine in the context of infectious and non-infectious diseases are required to identify potential therapeutic targets dissimilar from those used for large bowel diseases. While sparsely populated, the small intestine represents a stringent commensal bacterial microenvironment the host relies upon for nutrient acquisition and protection against invading pathogens (colonization resistance). Indeed, recent evidence suggests that disruptions to host-microbiota interactions in the small intestine impact enteric bacterial pathogenesis and susceptibility to non-infectious enteric diseases. In this review, we focus on the microbiota's impact on small intestine function and the pathogenesis of infectious and non-infectious diseases of the gastrointestinal (GI) tract. We also discuss gaps in knowledge on the role of commensal microorganisms in proximal GI tract function during health and disease.

Dietary L-Glu sensing by enteroendocrine cells adjusts food intake via modulating gut PYY/NPF secretion

Amino acid availability is monitored by animals to adapt to their nutritional environment. Beyond gustatory receptors and systemic amino acid sensors, enteroendocrine cells (EECs) are believed to directly percept dietary amino acids and secrete regulatory peptides. However, the cellular machinery underlying amino acid-sensing by EECs and how EEC-derived hormones modulate feeding behavior remain elusive. Here, by developing tools to specifically manipulate EECs, we find that Drosophila neuropeptide F (NPF) from mated female EECs inhibits feeding, similar to human PYY. Mechanistically, dietary L-Glutamate acts through the metabotropic glutamate receptor mGluR to decelerate calcium oscillations in EECs, thereby causing reduced NPF secretion via dense-core vesicles. Furthermore, two dopaminergic enteric neurons expressing NPFR perceive EEC-derived NPF and relay an anorexigenic signal to the brain. Thus, our findings provide mechanistic insights into how EECs assess food quality and identify a conserved mode of action that explains how gut NPF/PYY modulates food intake.

Exploring the role of sporadic BRAF and KRAS mutations during colorectal cancer pathogenesis: A spotlight on the contribution of the endosome-lysosome system

The highly heterogenous nature of colorectal cancer can significantly hinder its early and accurate diagnosis, eventually contributing to high mortality rates. The adenoma-carcinoma sequence and serrated polyp-carcinoma sequence are the two most common sequences in sporadic colorectal cancer. Genetic alterations in adenomatous polyposis coli (APC), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and tumour protein 53 (TP53) genes are critical in adenoma-carcinoma sequence, whereas v-Raf murine sarcoma viral oncogene homolog B (BRAF) and MutL Homolog1 (MLH1) are driving oncogenes in the serrated polyp-carcinoma sequence. Sporadic mutations in these genes contribute differently to colorectal cancer pathogenesis by introducing distinct alterations in several signalling pathways that rely on the endosome-lysosome system. Unsurprisingly, the endosome-lysosome system plays a pivotal role in the hallmarks of cancer and contributes to specialised colon function. Thus, the endosome-lysosome system might be distinctively influenced by different mutations and these alterations may contribute to the heterogenous nature of sporadic colorectal cancer. This review highlights potential connections between major sporadic colorectal cancer mutations and the diverse pathogenic mechanisms driven by the endosome-lysosome system in colorectal carcinogenesis.

Non-targeted metabolomics identifies biomarkers in milk with high and low milk fat percentage

Milk is widely recognized as an important food source with health benefits. Different consumer groups have different requirements for the content and proportion of milk fat; therefore, it is necessary to investigate the differential metabolites and their regulatory mechanisms in milk with high and low milk fat percentages (MFP). In this study, untargeted metabolomics was performed on milk samples from 13 cows with high milk fat percentage (HF) and 13 cows with low milk fat percentage (LF) using ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS). Forty-eight potential differentially labeled compounds were screened using the orthogonal partial least squares-discriminant analysis (OPLS-DA) combined with the weighted gene co-expression network analysis (WGCNA) method. Amino acid metabolism was the key metabolic pathway with significant enrichment of L-histidine, 5-oxoproline, L-aspartic acid, and L-glutamic acid. The negative correlation with MFP differentiated the HF and LF groups. To further determine the potential regulatory role of these amino acids on milk fat metabolism, the expression levels of marker genes in the milk fat synthesis pathway were explored. It was noticed that L-histidine reduced milk fat concentration primarily by inhibiting the triglycerides (TAG) synthesis pathway. L-aspartic acid and L-glutamic acid inhibited milk fat synthesis through the fatty acid de novo and TAG synthesis pathways. This study provides new insights into the mechanism underlying milk fat synthesis and milk quality improvement.

How did antibiotic growth promoters increase growth and feed efficiency in poultry?

It has been hypothesized that reducing the bioenergetic costs of gut inflammation as an explanation for the effect of antibiotic growth promoters (AGPs) on animal efficiency, framing some observations but not explaining the increase in growth rate or the prevention of infectious diseases. The host's ability to adapt to alterations in environmental conditions and to maintain health involves managing all physiological interactions that regulate homeostasis. Thus, metabolic pathways are vital in regulating physiological health as the energetic demands of the host guides most biological functions. Mitochondria are not only the metabolic heart of the cell because of their role in energy metabolism and oxidative phosphorylation, but also a central hub of signal transduction pathways that receive messages about the health and nutritional states of cells and tissues. In response, mitochondria direct cellular and tissue physiological alterations throughout the host. The endosymbiotic theory suggests that mitochondria evolved from prokaryotes, emphasizing the idea that these organelles can be affected by some antibiotics. Indeed, therapeutic levels of several antibiotics can be toxic to mitochondria, but subtherapeutic levels may improve mitochondrial function and defense mechanisms by inducing an adaptive response of the cell, resulting in mitokine production which coordinates an array of adaptive responses of the host to the stressor(s). This adaptive stress response is also observed in several bacteria species, suggesting that this protective mechanism has been preserved during evolution. Concordantly, gut microbiome modulation by subinhibitory concentration of AGPs could be the result of direct stimulation rather than inhibition of determined microbial species. In eukaryotes, these adaptive responses of the mitochondria to internal and external environmental conditions, can promote growth rate of the organism as an evolutionary strategy to overcome potential negative conditions. We hypothesize that direct and indirect subtherapeutic AGP regulation of mitochondria functional output can regulate homeostatic control mechanisms in a manner similar to those involved with disease tolerance.

Epigenetic mechanisms of particulate matter exposure: air pollution and hazards on human health

Environmental pollution nowadays has not only a direct correlation with human health changes but a direct social impact. Epidemiological studies have evidenced the increased damage to human health on a daily basis because of damage to the ecological niche. Rapid urban growth and industrialized societies importantly compromise air quality, which can be assessed by a notable accumulation of air pollutants in both the gas and the particle phases. Of them, particulate matter (PM) represents a highly complex mixture of organic and inorganic compounds of the most variable size, composition, and origin. PM being one of the most complex environmental pollutants, its accumulation also varies in a temporal and spatial manner, which challenges current analytical techniques used to investigate PM interactions. Nevertheless, the characterization of the chemical composition of PM is a reliable indicator of the composition of the atmosphere, the quality of breathed air in urbanized societies, industrial zones and consequently gives support for pertinent measures to avoid serious health damage. Epigenomic damage is one of the most promising biological mechanisms of air pollution-derived carcinogenesis. Therefore, this review aims to highlight the implication of PM exposure in diverse molecular mechanisms driving human diseases by altered epigenetic regulation. The presented findings in the context of pan-organic cancer, fibrosis, neurodegeneration and metabolic diseases may provide valuable insights into the toxicity effects of PM components at the epigenomic level and may serve as biomarkers of early detection for novel targeted therapies.

Safety and Suitability of Infant Formula Manufactured from Extensively Hydrolyzed Whey Protein Compared to Intact Protein: A Combined Analysis of Two Randomized Controlled Studies

Our aim was to assess the nutritional safety and suitability of an infant formula manufactured from extensively hydrolyzed protein in comparison to infant formula manufactured from intact protein (both with low and standard protein content). We performed a combined analysis of raw data from two randomized infant feeding studies. An analysis of covariance (ANCOVA) model was used to determine the non-inferiority of daily weight gain (primary outcome; margin -3 g/day), with the intervention group as a fixed factor and geographic region, sex, and baseline weight as covariates (main model). The data of 346 infants exposed to the formula were included in the analysis. The sample size of the per-protocol analysis with 184 infants was too small to achieve sufficient statistical power. The lower limit of the 97.5% confidence interval (-0.807) of the mean group difference in daily weight gain (i.e., 2.22 g/day) was above the -3 g/day margin (full analysis set). Further anthropometric parameters did not differ between the infant formula groups throughout the study. Growth was comparable to breastfed infants. We conclude that the infant formula manufactured from extensively hydrolyzed protein meets infant requirements for adequate growth and does not raise any safety concerns.

Targeting mitochondria with antioxidant nutrients for the prevention and treatment of postweaning diarrhea in piglets

Post-weaning diarrhea (PWD) in piglets poses a significant challenge and presents a grave threat to the global swine industry, resulting in considerable financial losses and compromising the welfare of animals. PWD is commonly associated with gut homeostatic imbalance, including oxidative stress, excessive inflammation, and microbiota dysbiosis. Antibiotic use has historically been a common initiative to combat PWD, but concerns about the development of antibiotic resistance have led to increased interest in alternative strategies. Mitochondria are key players in maintaining cellular homeostasis, and their dysfunction is intricately linked to the onset and progression of PWD. Accumulating evidence suggests that targeting mitochondrial function using antioxidant nutrients, such as vitamins, minerals and polyphenolic compounds, may represent a promising approach for preventing and treating PWD. Moreover, nutrients based on antioxidant strategies have been shown to improve mitochondrial function, restore intestinal redox balance, and reduce oxidative damage, which is a key driver of PWD. The present review begins with an overview of the potential interplay between mitochondria and gut homeostasis in the pathogenesis of PWD in piglets. Subsequently, alternative strategies to prevent and treat PWD using antioxidant nutrients to target mitochondria are described and discussed. Ultimately, we delve into potential limitations and suggest future research directions in this field for further advancement. Overall, targeting mitochondria using antioxidant nutrients may be a promising approach to combat PWD and provides a potential nutrition intervention strategy for regulating gut homeostasis of weaned piglets.

Amino acid-stimulated insulin secretion: a path forward in type 2 diabetes

Qualitative and quantitatively appropriate insulin secretion is essential for optimal control of blood glucose. Beta-cells of the pancreas produce and secrete insulin in response to glucose and non-glucose stimuli including amino acids. In this manuscript, we review the literature on amino acid-stimulated insulin secretion in oral and intravenous in vivo studies, in addition to the in vitro literature, and describe areas of consensus and gaps in understanding. We find promising evidence that the synergism of amino acid-stimulated insulin secretion could be exploited to develop novel therapeutics, but that a systematic approach to investigating these lines of evidence is lacking. We highlight evidence that supports the relative preservation of amino acid-stimulated insulin secretion compared to glucose-stimulated insulin secretion in type 2 diabetes, and make the case for the therapeutic potential of amino acids. Finally, we make recommendations for research and describe the potential clinical utility of nutrient-based treatments for type 2 diabetes including remission services.

High fat diet reveals sex-specific fecal and liver metabolic alterations in C57BL/6J obese mice

Obesity is a major health concern that poses significant risks for many other diseases, including diabetes, cardiovascular disease, and cancer. Prevalence of these diseases varies by biological sex. This study utilizes a mouse (C57BL/6J) model of obesity to analyze liver and fecal metabolic profiles at various time points of dietary exposure: 5, 9, and 12 months in control or high fat diet (HFD)-exposed mice. Our study discovered that the female HFD group has a more discernable perturbation and set of significant changes in metabolic profiles than the male HFD group. In the female mice, HFD fecal metabolites including pyruvate, aspartate, and glutamate were lower than control diet-exposed mice after both 9th and 12th month exposure time points, while lactate and alanine were significantly downregulated only at the 12th month. Perturbations of liver metabolic profiles were observed in both male and female HFD groups, compared to controls at the 12th month. Overall, the female HFD group showed higher lactate and glutathione levels compared to controls, while the male HFD group showed higher levels of glutamine and taurine compared to controls. These metabolite-based findings in both fecal and liver samples for a diet-induced effect of obesity may help guide future pioneering discoveries relating to the analysis and prevention of obesity in people, especially for females.

Characterization of Metabolite Landscape Distinguishes Medicinal Fungus Cordyceps sinensis and other Cordyceps by UHPLC-Q Exactive HF-X Untargeted Metabolomics

Cordyceps represent a valuable class of medicinal fungi with potential utilization. The overexploitation and resource scarcity of Cordyceps sinensis (CS) have led to the emergence of Cordyceps such as Cordyceps militaris (CM) and Cordyceps cicadae (CC) as substitutes. The medicinal value of CS is often considered superior to other Cordyceps, potentially owing to differences in active ingredients. This study aimed to evaluate the differences in the composition and abundance of the primary and secondary metabolites of CS and its substitutes by untargeted metabolomics. A total of 4671 metabolites from 18 superclasses were detected. CS and its substitutes were rich in amino acids, lipids, organic acids, and their derivatives. We statistically analyzed the metabolites and found a total of 285 differential metabolites (3'-Adenylic acid, O-Adipoylcarnitine, L-Dopachrome, etc.) between CS and CC, CS and CM, and CM and CC, which are potential biomarkers. L-glutamate and glycerophospholipids were differential metabolites. A KEGG enrichment analysis indicated that the tyrosine metabolic pathway and tryptophan metabolism pathway are the most differentially expressed pathways among the three Cordyceps. In contrast, CS was enriched in a higher abundance of most lipid metabolites when compared to CM and CC, which may be an indispensable foundation for the pharmacological functions of CS. In conclusion, systematic, untargeted metabolomics analyses for CS and other Cordyceps have delivered a precious resource for insights into metabolite landscapes and predicted potential components of disease therapeutics.

The Eph/ephrin system symphony of gut inflammation

The extent of gut inflammation depends largely on the gut barrier's integrity and enteric neuroimmune interactions. However, the factors and molecular mechanisms that regulate inflammation-related changes in the enteric nervous system (ENS) remain largely unexplored. Eph/ephrin signaling is critical for inflammatory response, neuronal activation, and synaptic plasticity in the brain, but its presence and function in the ENS have been largely unknown to date. This review discusses the critical role of Eph/ephrin in regulating gut homeostasis, inflammation, neuroimmune interactions, and pain pathways. Targeting the Eph/ephrin system offers innovative treatments for gut inflammation disorders, offering hope for enhanced patient prognosis, pain management, and overall quality of life.

Mitochondrial remodeling and energy metabolism adaptations in colonic crypts during spontaneous epithelial repair after colitis induction in mice

Mucosal healing has emerged as a therapeutic goal to achieve lasting clinical remission in ulcerative colitis. Intestinal repair in response to inflammation presumably requires higher energy supplies for the restoration of intestinal barrier and physiological functions. However, epithelial energy metabolism during intestinal mucosal healing has been little studied, whereas inflammation-induced alterations have been reported in the main energy production site, the mitochondria. The aim of the present work was to assess the involvement of mitochondrial activity and the events influencing their function during spontaneous epithelial repair after colitis induction in mouse colonic crypts. The results obtained show adaptations of colonocyte metabolism during colitis to ensure maximal ATP production for supporting energetic demand by both oxidative phosphorylation and glycolysis in a context of decreased mitochondrial biogenesis and through mitochondrial function restoration during colon epithelial repair. In parallel, colitis-induced mitochondrial ROS production in colonic epithelial cells was rapidly associated with transient expression of GSH-related enzymes. Mitochondrial respiration in colonic crypts was markedly increased during both inflammatory and recovery phases despite decreased expression of several mitochondrial respiratory chain complex subunits after colitis induction. Rapid induction of mitochondrial fusion was associated with mitochondrial function restoration. Finally, in contrast with the kinetics expression of genes involved in mitochondrial oxidative metabolism and in glycolysis, the expression of glutaminase was markedly reduced in the colonic crypts both during colitis and repair phases. Overall, our data suggest that the epithelial repair after colitis induction is characterized by a rapid and transient increased capacity for mitochondrial ATP production in a context of apparent restoration of mitochondrial biogenesis and metabolic reorientation of energy production. The potential implication of energy production adaptations within colonic crypts to sustain mucosal healing in a context of altered fuel supply is discussed.

Effects of glutamine, glutamate, and aspartate on intestinal barrier integrity and amino acid pool of the small intestine in piglets with normal or low energy diet

Aspartate (asp), glutamate (glu), and glutamine (gln) are the major energy fuels for the small intestine, and it had been indicated in our previous study that the mix of these three amino acid supplementations could maintain intestinal energy homeostasis. This study aimed to further investigate whether the treatment of gln, glu, and asp in low energy diet affects the intestinal barrier integrity and amino acid pool in weaning piglets. A total of 198 weaned piglets were assigned to 3 treatments: control (basal diet + 1.59% L-Ala); T1 (basal diet + 1% L-Gln + 0.5% L-Glu + 0.1% L-Asp); and T2 (low energy diet + 1% L-Gln + 0.5% L-Glu + 0.1% L-Asp). The blood, jejunum, and ileum were obtained on day 5 or on day 21 post-weaning, respectively. Our results showed that T1 and T2 treatments increased the abundances of occludin, claudin-1, and claudin-3 in the small intestine while decreasing the serum diamine oxidase (DAO) and D-lactate levels in weaning piglets. Meanwhile, T1 and T2 treatments significantly increased the positive rate of proliferating cell nuclear antigen (PCNA) of the small intestine, promoting intestinal cell proliferation. We also found that supplementation with glu, gln, and asp improved the serum amino acid pool and promoted ileal amino acid transporter gene expression of slc3a2, slc6a14, and slc7a11 in weaned piglets. Additionally, on day 21 post-weaning, T1 and T2 treatments stimulated the phosphorylation of the mTOR-S6K1-4EBP1 signaling pathway in the small intestine, which may implicate the enhanced protein synthesis rate. In summary, dietary supplementation of gln, glu, and asp was beneficial to the intestinal barrier function and amino acid pool regulation, while the benefits of gln, glu, and asp treatment might be diminished by the low-energy diet. The results demonstrated that the supplementation of gln, glu, and asp under low energy levels was preferentially supplied as the energy fuel to restore the gut barrier function in piglets on day 5 post-weaning. With the increase in age and intestinal maturation (on day 21 post-weaning), gln, glu, and asp supplementation could also show an effect on the regulation of the amino acid pool and protein synthesis.

Evaluating Brewers' Spent Grain Protein Isolate Postprandial Amino Acid Uptake Kinetics: A Randomized, Cross-Over, Double-Blind Controlled Study

Valorization and utilization of brewers' spent grain (BSG) are of great interest in terms of reducing food waste and promoting more sustainable food systems. In this study, we aimed to evaluate the nutritional value of upcycled barley/rice proteins (BRP) extracted from BSG and compare this with pea proteins (PP). A randomized, cross-over, double-blind controlled trial was conducted with twelve participants (age: 24 ± 2.8 years, BMI: 23.3 ± 3.0 kg/m²). During three separate visits with a one-week washout period between visits, participants received 20 g BRP, PP, or the benchmark protein whey (WP). Blood-free amino acids (AA) were measured to determine postprandial AA uptake kinetics. The estimated total AA (TAA) uptake of BRP was 69% when compared to WP and 87% when compared to PP. The time to reach the maximum values was similar between the three protein sources. When comparing individual essential AA responses between BRP and PP, we observed higher responses in methionine and tryptophane and lower responses in lysine, histidine, and isoleucine for BRP compared to PP. This study demonstrates that BRP exhibits comparable postprandial TAA uptake profiles to PP. The findings highlight the complementarity of BRP and PP, which may offer the potential for blending approaches to optimize protein quality for overall health.

Metabolomics and transcriptomics analyses provide new insights into the nutritional quality during the endosperm development of different ploidy rice

Autotetraploid rice is developed from diploid rice by doubling the chromosomes, leading to higher nutritional quality. Nevertheless, there is little information about the abundances of different metabolites and their changes during endosperm development in autotetraploid rice. In this research, two different kinds of rice, autotetraploid rice (AJNT-4x) and diploid rice (AJNT-2x), were subjected to experiments at various time points during endosperm development. A total of 422 differential metabolites, were identified by applying a widely used metabolomics technique based on LC-MS/MS. KEGG classification and enrichment analysis showed the differences in metabolites were primarily related to biosynthesis of secondary metabolites, microbial metabolism in diverse environments, biosynthesis of cofactors, and so on. Twenty common differential metabolites were found at three developmental stages of 10, 15 and 20 DAFs, which were considered the key metabolites. To identify the regulatory genes of metabolites, the experimental material was subjected to transcriptome sequencing. The DEGs were mainly enriched in starch and sucrose metabolism at 10 DAF, and in ribosome and biosynthesis of amino acids at 15 DAF, and in biosynthesis of secondary metabolites at 20 DAF. The numbers of enriched pathways and the DEGs gradually increased with endosperm development of rice. The related metabolic pathways of rice nutritional quality are cysteine and methionine metabolism, tryptophan metabolism, lysine biosynthesis and histidine metabolism, and so on. The expression level of the genes regulating lysine content was higher in AJNT-4x than in AJNT-2x. By applying CRISPR/Cas9 gene-editing technology, we identified two novel genes, OsLC4 and OsLC3, negatively regulated lysine content. These findings offer novel insight into dynamic metabolites and genes expression variations during endosperm development of different ploidy rice, which will aid in the creation of rice varieties with better grain nutritional quality.

Bacillus coagulans (Weizmannia coagulans) XY2 attenuates Cu-induced oxidative stress via DAF-16/FoxO and SKN-1/Nrf2 pathways and gut microbiota regulation

Copper (Cu) pollution has become a serious environmental problem especially in recent decades. In this study, the mechanisms of Bacillus coagulans (Weizmannia coagulans) XY2 against Cu-induced oxidative stress were explored through a dual model. In mice, Cu disturbed microbial community structure, revealing an increased level of Enterorhabdus abundance and decreased levels of Intestinimonas, Faecalibaculu, Ruminococcaceae and Coriobacteriaceae_UCG-002 abundance. Meanwhile, B. coagulans (W. coagulans) XY2 intervention reversed this trend along with alleviated Cu-induced metabolic disturbances by increasing levels of hypotaurine and L-glutamate and declining levels of phosphatidylcholine and phosphatidylethanolamine. In Caenorhabditis elegans, nuclear translocation of DAF-16 and SKN-1 was inhibited by Cu, which in turn suppressed antioxidant-related enzymes activities. XY2 mitigated biotoxicity associated with oxidative damage caused by Cu exposure via regulating DAF-16/FoxO and SKN-1/Nrf2 pathways and intestinal flora to eliminate excess ROS. Our study provides a theoretical basis formulating future strategy of probiotics against heavy metal contamination.

Review: A systematic review of the effects of functional amino acids on small intestine barrier function and immunity in piglets

The need to reduce the use of antibiotics and zinc oxide at the pharmacological level, while preserving the performance of postweaning piglets, involves finding adequate nutritional strategies which, coupled with other preventive strategies, act to improve the sustainability of the piglet-rearing system. Amino acids (AAs) are the building blocks of proteins; however, they also have many other functions within the body. AA supplementation, above the suggested nutritional requirement for piglets, has been investigated in the diets of postweaning piglets to limit the detrimental consequences occurring during this stressful period. A systematic review was carried out to summarise the effects of AAs on gut barrier function and immunity, two of the parameters contributing to gut health. An initial manual literature search was completed using an organised search strategy on PubMed, utilising the search term " AND ". These searches yielded 302 articles (published before October 2021); 59 were selected. Based on the method for extracting data (synthesis of evidence), this review showed that L-Arginine, L-Glutamine and L-Glutamate are important functional AAs playing major roles in gut morphology and immune functions. Additional benefits of AA supplementation, refereed to a supplementation above the suggested nutritional requirement for piglets, could also be observed; however, data are needed to provide consistent evidence. Taken together, this review showed that supplementation with AAs during the weaning phase supported a plethora of the physiological functions of piglets. In addition, the data reported confirmed that each amino acid targets different parameters related to gut health, suggesting the existence of potential synergies among them.

House ammonia exposure causes alterations in microbiota, transcriptome, and metabolome of rabbits

Introduction

Pollutant gas emissions in the current production system of the livestock industry have negative influences on environment as well as the health of farm staffs and animals. Although ammonia (NH3) is considered as the primary and harmful gas pollutant in the rabbit farm, less investigation has performed to determine the toxic effects of house ammonia exposure on rabbit in the commercial confined barn.

Methods

In this study, we performed multi-omics analysis on rabbits exposed to high and low concentration of house ammonia under similar environmental conditions to unravel the alterations in nasal and colonic microbiota, pulmonary and colonic gene expression, and muscular metabolic profile.

Results and discussion

The results showed that house ammonia exposure notably affected microbial structure, composition, and functional capacity in both nasal and colon, which may impact on local immune responses and inflammatory processes. Transcriptome analysis indicated that genes related to cell death (MCL1, TMBIM6, HSPB1, and CD74) and immune response (CDC42, LAMTOR5, VAMP8, and CTSB) were differentially expressed in the lung, and colonic genes associated with redox state (CAT, SELENBP1, GLUD1, and ALDH1A1) were significantly up-regulated. Several key differentially abundant metabolites such as L-glutamic acid, L-glutamine, L-ornithine, oxoglutaric acid, and isocitric acid were identified in muscle metabolome, which could denote house ammonia exposure perturbed amino acids, nucleotides, and energy metabolism. In addition, the widespread and strong inter-system interplay were uncovered in the integrative correlation network, and central features were confirmed by in vitro experiments. Our findings disclose the comprehensive evidence for the deleterious effects of house ammonia exposure on rabbit and provide valuable information for understanding the underlying impairment mechanisms.

Dietary glutamate enhances intestinal immunity by modulating microbiota and Th17/Treg balance-related immune signaling in piglets after lipopolysaccharide challenge

The purpose of this study was to explore the effects of glutamate on piglet growth performance and intestinal immunity function, and to further elucidate its mechanism. In a 2 × 2 factorial design involving immunological challenge (lipopolysaccharide (LPS) or saline) and diet (with or without glutamate), twenty-four piglets were randomly assigned to four groups, each with 6 replicates. Piglets were fed with a basal or glutamate diet for 21 d before being injected intraperitoneally with LPS or saline. Piglet's intestinal samples were collected 4 h after injection. Results showed that glutamate increased daily feed intake, average daily gain, villus length, villus area, and villus length to crypt depth ratio (V/C), and decreased the crypt depth (P < 0.05). Furthermore, glutamate increased the mRNA expression of forkhead box P3 (FOXP3), a signal transducer and activator of transcription 5 (STAT5) and transforming growth factor beta, while decreasing the mRNA expression of RAR-related orphan receptor c and STAT3. Glutamate increased interleukin-10 (IL-10) mRNA expression while decreasing the mRNA expression of IL-1β, IL-6, IL-8, IL-17, IL-21, and tumor necrosis factor-α. At the phylum level, glutamate increased the Actinobacteriota abundance and Firmicutes-to-Bacteroidetes ratio while decreasing Firmicutes abundance. At the genus level, glutamate improved the abundance of beneficial bacteria (e.g., Lactobacillus, Prevotellaceae-NK3B31-group, and UCG-005). Furthermore, glutamate increased the concentrations of short-chain fatty acids (SCFAs). Correlation analysis revealed that the intestinal microbiota is closely related to Th17/Treg balance-related index and SCFAs. Collectively, glutamate can improve piglet growth performance and intestinal immunity by modulating gut microbiota and Th17/Treg balance-related signaling pathways.

Identification and Quantification of Proliferating Cells in Skeletal Muscle of Glutamine Supplemented Low- and Normal-Birth-Weight Piglets

One way to improve the growth of low-birth-weight (LBW) piglets can be stimulation of the cellular development of muscle by optimized amino acid supply. In the current study, it was investigated how glutamine (Gln) supplementation affects muscle tissue of LBW and normal-birth-weight (NBW) piglets. Longissimus and semitendinosus muscles of 96 male piglets, which were supplemented with 1 g Gln/kg body weight or alanine, were collected at slaughter on day 5 or 26 post natum (dpn), one hour after injection with Bromodeoxyuridine (BrdU, 12 mg/kg). Immunohistochemistry was applied to detect proliferating, BrdU-positive cells in muscle cross-sections. Serial stainings with cell type specific antibodies enabled detection and subsequent quantification of proliferating satellite cells and identification of further proliferating cell types, e.g., preadipocytes and immune cells. The results indicated that satellite cells and macrophages comprise the largest fractions of proliferating cells in skeletal muscle of piglets early after birth. The Gln supplementation somewhat stimulated satellite cells. We observed differences between the two muscles, but no influence of the piglets' birth weight was observed. Thus, Gln supplements may not be considered as effective treatment in piglets with low birth weight for improvement of muscle growth.

Metabolomic Analyses to Identify Candidate Biomarkers of Cystinosis

Cystinosis is a rare, devastating hereditary disease secondary to recessive CTNS gene mutations. The most commonly used diagnostic method is confirmation of an elevated leukocyte cystine level; however, this method is expensive and difficult to perform. This study aimed to identify candidate biomarkers for the diagnosis and follow-up of cystinosis based on multiomics studies. The study included three groups: newly-diagnosed cystinosis patients (patient group, n = 14); cystinosis patients under treatment (treatment group, n = 19); and healthy controls (control group, n = 30). Plasma metabolomics analysis identified 10 metabolites as candidate biomarkers that differed between the patient and control groups [L-serine, taurine, lyxose, 4-trimethylammoniobutanoic acid, orotic acid, glutathione, PE(O-18:1(9Z)/0:0), 2-hydroxyphenyl acetic acid, acetyl-N-formil-5-metoxikinuramine, 3-indoxyl sulphate]. As compared to the healthy control group, in the treatment group, hypotaurine, phosphatidylethanolamine, N-acetyl-d-mannosamine, 3-indolacetic acid, p-cresol, phenylethylamine, 5-aminovaleric acid, glycine, creatinine, and saccharic acid levels were significantly higher, and the metabolites quinic acid, capric acid, lenticin, xanthotoxin, glucose-6-phosphate, taurine, uric acid, glyceric acid, alpha-D-glucosamine phosphate, and serine levels were significantly lower. Urinary metabolomic analysis clearly differentiated the patient group from the control group by means of higher allo-inositol, talose, glucose, 2-hydroxybutiric acid, cystine, pyruvic acid, valine, and phenylalanine levels, and lower metabolite (N-acetyl-L-glutamic acid, 3-aminopropionitrile, ribitol, hydroquinone, glucuronic acid, 3-phosphoglycerate, xanthine, creatinine, and 5-aminovaleric acid) levels in the patient group. Urine metabolites were also found to be significantly different in the treatment group than in the control group. Thus, this study identified candidate biomarkers that could be used for the diagnosis and follow-up of cystinosis.

Large intestinal dynamics differ between fowl and swine: Anatomical modifications, microbial collaboration, and digestive advantages from fibrolytic enzymes

The large intestinal systems of fowl and swine recover nutrients from ileal indigesta by a strategically different manner. Indigesta with fowl enter a short colon where retro-peristalsis using urine from the urodeum carries small particulates and solutes into both ceca while coarse materials collect in the cloaca. Fowl repetitively add fine and soluble materials into both ceca to continue fermentation until complexity of the remainder exceeds microbial action, then contents apart from faeces are entirely evacuated. Indigesta with swine initially enter a short cecum followed by a lengthy progression through to the rectal ampulla. Wall out-pocketings of circular muscle or haustrae occur throughout the length of the pig's cecum and helicoidal colon. Each pocket carries contents acquired earlier in the cecum. Motility collects fines and solutes into haustrae during their progression through the colon whereas coarse particulates assemble in the core. Haustrae contents continually ferment during movement to the distal colon with resulting volatile fatty acids (VFA) and electrolytes being absorbed. Mucin loosely covers the lumen surface in caeca as well as helicoidal colon that may capture microbes from active intestinal contents as well as release others to sustain fermentation. The microbial community continually modifies to accommodate fibre complexity as encountered. Resistant starches (RS) and simple oligosaccharides rapidly ferment to yield VFA while encouraging butyric acid in the cecum and anterior colon, whereas non-starch polysaccharides (NSP) complexity requires extended durations through the remaining colon that enhance acetic acid. Residual fibre eventually results in undue complexity for fermentation and consolidates at termination of the colon. These compact pellets are placed on core contents to form faeces having a nodular surface. Acetic, propionic, and butyric acids represent the bulk of VFA and are derived from non-digestible carbohydrates. Fibrolytic enzymes, when supplemented to feed, may increase the proportion of oligosaccharides and simpler NSP to further the rate as well as extent of fermentation. Active absorption of VFA by mucosal enterocytes employs its ionized form together with Na⁺, whereas direct membrane passage occurs when non-dissociated. Most absorbed VFA favour use by the host with a portion of butyric acid together with by-products from protein digestion being retained to reform mucin and sustain mucosal integrity.

Aspartate Alleviates Colonic Epithelial Damage by Regulating Intestinal Stem Cell Proliferation and Differentiation via Mitochondrial Dynamics

SCOPE

Proliferation and differentiation of intestinal stem cells (ISCs) are crucial for functional restoration after injury, which can be regulated by nutritional molecules. Aspartate is implicated in maintaining intestinal barrier after injury, but underlying mechanisms remain elusive. Here, this study seeks to investigate if aspartate alleviates colonic epithelial damage by regulating ISC function, and to elucidate its mechanisms.

METHODS AND RESULTS

Eight-week-old male C57BL/6 mice supplement with or without 1% L-aspartate are subjected to drinking water or 2.5% DSS to induce colitis. In this study, aspartate administration alleviates the severity of colitis, as indicated by reduced body weight loss, colon shortening, and inhibited pro-inflammatory cytokine expression in DSS-challenged mice. Additionally, aspartate promotes colonic epithelial cell proliferation and differentiation after DSS-induced damage in mice. Pretreatment with aspartate not only enhances ISC proliferation but also induces ISC differentiation toward enterocytes and goblet cells, which prevent TNF-α-induced colonoid damage. Mechanistically, aspartate ameliorates DSS/TNF-α-induced perturbation of mitochondrial metabolism and maintains mitochondrial dynamics in colonic epithelium and colonoids. Moreover, aspartate-mediated ISC proliferation and differentiation are primarily dependent on mitochondrial fusion rather than fission.

CONCLUSIONS

The findings indicate that aspartate promotes ISC proliferation and differentiation to alleviate colonic epithelial damage by regulation of mitochondrial metabolism and dynamics.

Development of Intestinal Injury and Restoration of Weaned Piglets under Chronic Immune Stress

This study aimed to investigate the effects of lipopolysaccharide (LPS)-induced chronic immune stress on intestinal morphology and function, immune system, oxidative status, and mitochondrial function in piglets. Fifty healthy Duroc × Landrace × Yorkshire piglets (21 ± 2 days old, barrow, 6.98 ± 0.14 kg body weight) were selected and randomly allotted to five groups, which were slaughtered at 0 (0 group), 1, 5, 9, and 15 d of LPS injection. The results showed that compared with the piglets without LPS injection, LPS injection significantly impaired the intestinal morphology and permeability at 1, 5, and 9 d, as manifested by the increased serum lactic acid and decreased ratio of villus height to crypt depth (p < 0.05). Moreover, intestinal inflammation and oxidative and mitochondrial injury were caused at 1 d, as manifested by upregulated IL-6 mRNA expression, increased malondialdehyde content, and impaired mitochondrial morphology (p < 0.05). However, these parameters were restored to levels identical to 0 group at 9~15 d, accompanied by significantly increased antioxidant capacity, enhanced protein expression of CD3+ and CD68+, and upregulated mRNA abundance of genes related to mitochondrial biogenesis and functions (p < 0.05). Collectively, these results suggest that the intestinal injury of piglets caused by chronic immune stress could be self-repaired.

Free Amino Acid-Enriched Diets Containing Rapidly but Not Slowly Digested Carbohydrate Promote Amino Acid Absorption from Intestine and Net Fluxes across Skeletal Muscle of Pigs

BACKGROUND

The approach to matching appropriate carbohydrates alongside free amino acids to achieve optimal muscle growth remains unclear.

OBJECTIVES

We investigated whether the consumption of a diet containing rapidly digested carbohydrate and free amino acids can enhance intestinal absorption and muscular uptake of amino acids in pigs.

METHOD

Twelve barrows (28 kg; 11 wk old) with catheters installed in the portal vein, mesenteric vein, femoral artery, and femoral vein were randomly assigned to consume 1 of 2 free amino acid-enriched diets (3.34%) containing rapidly [waxy corn starch (WCS)] or slowly [pea starch (PS)] digested carbohydrate for 27 d. Blood was collected to determine the fluxes of plasma glucose and amino acids across the portal vein and the hindlimb muscle. Dietary in vitro carbohydrate digestive rates were also determined. Data were analyzed using repeated-measures (time × group) ANOVA.

RESULTS

Carbohydrate in vitro cumulative digestibility at 30 and 240 min was 69.00% and 95.25% for WCS and 23.25% and 81.15% for PS, respectively. The animal experiment presented WCS increased individual amino acids (lysine, 0.67 compared with 0.53 mmol/min; threonine, 0.40 compared with 0.29 mmol/min; isoleucine, 0.33 compared with 0.22 mmol/min; glutamate, 0.51 compared with 0.35 mmol/min; and proline, 0.51 compared with 0.27 mmol/min), essential amino acid (EAA; 3.26 compared with 2.65 mmol/min), and branched-chain amino acid (BCAA; 0.86 compared with 0.65 mmol/min) fluxes across the portal vein during 8 h postprandial, as well as individual amino acids (isoleucine, 0.08 compared with 0.02 mmol/min; leucine, 0.06 compared with 0.02 mmol/min; and glutamine, 0.44 compared with 0.25 mmol/min), EAA (0.50 compared with 0.21 mmol/min), and BCAA (0.17 compared with 0.06 mmol/min) net fluxes across the hindlimb muscle during 8 h postprandial compared with PS (P < 0.05).

CONCLUSIONS

A diet containing rapidly digested carbohydrate and free amino acids can promote intestinal absorption and net fluxes across hindlimb muscle of amino acids in pigs.

Harnessing conserved signaling and metabolic pathways to enhance the maturation of functional engineered tissues

The development of induced-pluripotent stem cell (iPSC)-derived cell types offers promise for basic science, drug testing, disease modeling, personalized medicine, and translatable cell therapies across many tissue types. However, in practice many iPSC-derived cells have presented as immature in physiological function, and despite efforts to recapitulate adult maturity, most have yet to meet the necessary benchmarks for the intended tissues. Here, we summarize the available state of knowledge surrounding the physiological mechanisms underlying cell maturation in several key tissues. Common signaling consolidators, as well as potential synergies between critical signaling pathways are explored. Finally, current practices in physiologically relevant tissue engineering and experimental design are critically examined, with the goal of integrating greater decision paradigms and frameworks towards achieving efficient maturation strategies, which in turn may produce higher-valued iPSC-derived tissues.

L-leucine supplementation reduces growth performance accompanied by changed profiles of plasma amino acids and expression of jejunal amino acid transporters in breast-fed intra-uterine growth-retarded piglets

Previously, we provided an evidence that L-leucine supplementation facilitates growth performance in suckling piglets with normal birth weight. However, it remains hitherto obscure weather breast-fed piglets displaying intrauterine growth restriction (IUGR) show a similar effect in response to L-leucine provision. In this study, seven-day-old sow-reared IUGR piglets were orally administrated with L-leucine (0, 0.7 1.4, 2.1 g/kg BW) twice daily for two weeks. Increasing leucine levels hampered the growth performance of suckling IUGR piglets. The average daily gain of IUGR piglets was significantly reduced in 1.4 g/kg BW and 2.1 g/kg BW L-leucine supplementation groups (P < 0.05). Except for ornithine and glutamine, the plasma concentrations of other amino acids were abated as L-leucine levels increased (P < 0.05). Leucine supplementation led to reduction in the levels of urea, blood ammonia, blood glucose, triglyceride, and total cholesterol, as well as an elevation in the level of low density lipoprotein cholesterol in suckling IUGR piglets (P < 0.05). In addition, 1.4g/kg BW of L-leucine enhanced the mRNA expression of ATB 0,+ , whereas decreased the mRNA abundances of CAT1, y+LAT1, ASCT2 and b 0,+ AT in the jejunum (P < 0.05). Concomitantly, the jejunum of IUGR piglets in L-leucine group contains more ATB0,+ and less SNAT2 protein than in the control (P < 0.05). Collectively, L-leucine supplementation impairs growth performance in breast-fed IUGR piglets, which may be associated with depressed nutritional conditions and alterations in the uptake of amino acids and the expression of amino acid transporters in the small intestine.

A Novel Probiotic Bacillus subtilis Strain Confers Cytoprotection to Host Pig Intestinal Epithelial Cells during Enterotoxic Escherichia coli Infection

Enteric infections caused by enterotoxic Escherichia coli (ETEC) negatively impact the growth performance of piglets during weaning, resulting in significant economic losses for the producers. With the ban on antibiotic usage in livestock production, probiotics have gained a lot of attention as a potential alternative. However, strain specificity and limited knowledge on the host-specific targets limit their efficacy in preventing ETEC-related postweaning enteric infections. We recently isolated and characterized a novel probiotic Bacillus subtilis bacterium (CP9) that demonstrated antimicrobial activity. Here, we report anti-ETEC properties of CP9 and its impact on metabolic activity of swine intestinal epithelial (IPEC-J2) cells. Our results showed that pre- or coincubation with CP9 protected IPEC-J2 cells from ETEC-induced cytotoxicity. CP9 significantly attenuated ETEC-induced inflammatory response by reducing ETEC-induced nitric oxide production and relative mRNA expression of the Toll-like receptors (TLRs; TLR2, TLR4, and TLR9), proinflammatory tumor necrosis factor alpha, interleukins (ILs; IL-6 and IL-8), augmenting anti-inflammatory granulocyte-macrophage colony-stimulating factor and host defense peptide mucin 1 (MUC1) mRNA levels. We also show that CP9 significantly (P < 0.05) reduced caspase-3 activity, reinstated cell proliferation and increased relative expression of tight junction genes, claudin-1, occludin, and zona occludens-1 in ETEC-infected cells. Finally, metabolomic analysis revealed that CP9 exposure induced metabolic modulation in IPEC J2 cells with the greatest impact seen in alanine, aspartate, and glutamate metabolism; pyrimidine metabolism; nicotinate and nicotinamide metabolism; glutathione metabolism; the citrate cycle (TCA cycle); and arginine and proline metabolism. Our study shows that CP9 incubation attenuated ETEC-induced cytotoxicity in IPEC-J2 cells and offers insight into potential application of this probiotic for ETEC infection control. IMPORTANCE ETEC remains one of the leading causes of postweaning diarrhea and mortality in swine production. Due to the rising concerns with the antibiotic use in livestock, alternative interventions need to be developed. In this study, we analyzed the cytoprotective effect of a novel probiotic strain in combating ETEC infection in swine intestinal cells, along with assessing its mechanism of action. To our knowledge, this is also the first study to analyze the metabolic impact of a probiotic on intestinal cells. Results from this study should provide effective cues in developing a probiotic intervention for ameliorating ETEC infection and improving overall gut health in swine production.

Supplementation of mixed doses of glutamate and glutamine can improve the growth and gut health of piglets during the first 2 weeks post-weaning

The aim of this study was to test the effect of mixing doses of glutamate (Glu) and glutamine (Gln) on the growth, health and gut health of post-weaning piglets. One hundred twenty weaned piglets (24 ± 2 days of age) were assigned to 6 dietary groups: (1) standard diet (CO); (2) CO plus Glu (6 kg/Ton): 100Glu; (3) CO plus 75Glu + 25Gln; (4) CO plus 50Glu + 50Gln; (5) CO plus 25Glu + 75Gln and (6) CO plus 100Gln. At days 8 and 21, blood was collected for haematological and reactive oxygen metabolite analysis, intestinal mucosa for morphological and gene expression analysis, and caecal content for microbial analysis. Data were fitted using a Generalised Linear Model (GLM). Piglet growth increased linearly with an increase in Gln from d7 to d14. The Glu:Gln ratio had a quadratic effect on faecal consistency and days of diarrhoea, neutrophil% and lymphocyte%, and a positive linear effect on monocyte% in the blood at d8. The amino acids (AAs) reduced the intraepithelial lymphocytes in the jejunum, and 100Gln improved intestinal barrier integrity at d8. The caecal microbiota did not differ. Overall, this study suggested a favourable effect of mixing Glu and Gln (25 + 75-50 + 50) as a dietary supplementation in post-weaning piglets to benefit the immune and barrier function of the gut, resulting in an increase in faecal consistency and improvement of growth during the first 2 weeks post-weaning.

Evidence-based pathogenesis and treatment of ulcerative colitis: A causal role for colonic epithelial hydrogen peroxide

In this comprehensive evidence-based analysis of ulcerative colitis (UC), a causal role is identified for colonic epithelial hydrogen peroxide (H₂O₂) in both the pathogenesis and relapse of this debilitating inflammatory bowel disease. Studies have shown that H₂O₂ production is significantly increased in the non-inflamed colonic epithelium of individuals with UC. H₂O₂ is a powerful neutrophilic chemotactic agent that can diffuse through colonic epithelial cell membranes creating an interstitial chemotactic molecular “trail” that attracts adjacent intravascular neutrophils into the colonic epithelium leading to mucosal inflammation and UC. A novel therapy aimed at removing the inappropriate H₂O₂ mediated chemotactic signal has been highly effective in achieving complete histologic resolution of colitis in patients experiencing refractory disease with at least one (biopsy-proven) histologic remission lasting 14 years to date. The evidence implies that therapeutic intervention to prevent the re-establishment of a pathologic H₂O₂ mediated chemotactic signaling gradient will indefinitely preclude neutrophilic migration into the colonic epithelium constituting a functional cure for this disease. Cumulative data indicate that individuals with UC have normal immune systems and current treatment guidelines calling for the suppression of the immune response based on the belief that UC is caused by an underlying immune dysfunction are not supported by the evidence and may cause serious adverse effects. It is the aim of this paper to present experimental and clinical evidence that identifies H₂O₂ produced by the colonic epithelium as the causal agent in the pathogenesis of UC. A detailed explanation of a novel therapeutic intervention to normalize colonic H₂O₂, its rationale, components, and formulation is also provided.

Differential gene expression in iPSC-derived human intestinal epithelial cell layers following exposure to two concentrations of butyrate, propionate and acetate

Intestinal epithelial cells and the intestinal microbiota are in a mutualistic relationship that is dependent on communication. This communication is multifaceted, but one aspect is communication through compounds produced by the microbiota such as the short-chain fatty acids (SCFAs) butyrate, propionate and acetate. Studying the effects of SCFAs and especially butyrate in intestinal epithelial cell lines like Caco-2 cells has been proven problematic. In contrast to the in vivo intestinal epithelium, Caco-2 cells do not use butyrate as an energy source, leading to a build-up of butyrate. Therefore, we used human induced pluripotent stem cell derived intestinal epithelial cells, grown as a cell layer, to study the effects of butyrate, propionate and acetate on whole genome gene expression in the cells. For this, cells were exposed to concentrations of 1 and 10 mM of the individual short-chain fatty acids for 24 h. Unique gene expression profiles were observed for each of the SCFAs in a concentration-dependent manner. Evaluation on both an individual gene level and pathway level showed that butyrate induced the biggest effects followed by propionate and then acetate. Several known effects of SCFAs on intestinal cells were confirmed, such as effects on metabolism and immune responses. The changes in metabolic pathways in the intestinal epithelial cell layers in this study demonstrate that there is a switch in energy homeostasis, this is likely associated with the use of SCFAs as an energy source by the induced pluripotent stem cell derived intestinal epithelial cells similar to in vivo intestinal tissues where butyrate is an important energy source.

Mitochondrial function in intestinal epithelium homeostasis and modulation in diet-induced obesity

Background

Systemic low-grade inflammation observed in diet-induced obesity has been associated with dysbiosis and disturbance of intestinal homeostasis. This latter relies on an efficient epithelial barrier and coordinated intestinal epithelial cell (IEC) renewal that are supported by their mitochondrial function. However, IEC mitochondrial function might be impaired by high fat diet (HFD) consumption, notably through gut-derived metabolite production and fatty acids, that may act as metabolic perturbators of IEC.

Scope of review

This review presents the current general knowledge on mitochondria, before focusing on IEC mitochondrial function and its role in the control of intestinal homeostasis, and featuring the known effects of nutrients and metabolites, originating from the diet or gut bacterial metabolism, on IEC mitochondrial function. It then summarizes the impact of HFD on mitochondrial function in IEC of both small intestine and colon and discusses the possible link between mitochondrial dysfunction and altered intestinal homeostasis in diet-induced obesity.

Major conclusions

HFD consumption provokes a metabolic shift toward fatty acid β-oxidation in the small intestine epithelial cells and impairs colonocyte mitochondrial function, possibly through downstream consequences of excessive fatty acid β-oxidation and/or the presence of deleterious metabolites produced by the gut microbiota. Decreased levels of ATP and concomitant O₂ leaks into the intestinal lumen could explain the alterations of intestinal epithelium dynamics, barrier disruption and dysbiosis that contribute to the loss of epithelial homeostasis in diet-induced obesity. However, the effect of HFD on IEC mitochondrial function in the small intestine remains unknown and the precise mechanisms by which HFD induces mitochondrial dysfunction in the colon have not been elucidated so far.

Lactoferrin Supplementation during Gestation and Lactation Is Efficient for Boosting Rat Pup Development

Lactoferrin (LF) is an iron-binding protein found at relatively high concentrations in human milk. LF, which is little degraded in the infant intestinal lumen, is known to stimulate the proliferation and differentiation of the small intestine epithelial cells. The present study was designed to evaluate in the rat model the effects of bovine LF (bLF) given to the mothers during gestation and lactation on the growth of the offspring. Female Wistar rats were randomly separated into two groups of animals that received from mating and during gestation and lactation a standard diet including or not including bLF (10 g/kg of diet). The pups' growth was determined up to postnatal day 17 (PND17), and parameters related to lean and fat mass, intestinal differentiation, intestinal barrier function, bone mineral density, osteoblast activity, and brain development were measured. In addition, metabolites in pup plasma were determined at PND17. bLF was detected in the plasma and milk of the supplemented mothers as well as in the pup plasma. Although the body weight of the pups in the two groups did not differ at birth, the pups recovered from the supplemented mothers displayed an increase body weight from PND12 up to PND17. At PND17 in the bLF group, increased small intestine epithelial cell differentiation was detected, and colon barrier function was reinforced in association with increased expression of genes coding for the tight-junction proteins. Regarding bone physiology, improved bone mineral density was measured in the pups. Lastly, the plasma metabolite analysis revealed mainly higher amino acid concentrations in the LF pups as compared to the control group. Our results support that bLF ingestion by the mother during gestation and lactation can promote pup early life development. The potential interest of supplementing the mothers with bLF in the case of risk of compromised early life development of the offspring in the context of animal and human nutrition is discussed.

Fate of undigested proteins in the pig large intestine: What impact on the colon epithelium?

Apart from its obvious agronomic interest in feeding billions of people worldwide, the porcine species represents an irreplaceable experimental model for intestinal physiologists and nutritionists. In this review, we give an overview on the fate of proteins that are not fully digested in the pig small intestine, and thus are transferred into the large intestine. In the large intestine, dietary and endogenous proteins are converted to peptides and amino acids (AA) by the action of bacterial proteases and peptidases. AA, which cannot, except in the neonatal period, be absorbed to any significant level by the colonocytes, are used by the intestinal microbes for protein synthesis and for the production of numerous metabolites. Of note, the production of the AA-derived metabolites greatly depends on the amount of undigested polysaccharides in the pig's diet. The effects of these AA-derived bacterial metabolites on the pig colonic epithelium have not yet been largely studied. However, the available data, performed on colonic mucosa, isolated colonic crypts and colonocytes, indicate that some of them, like ammonia, butyrate, acetate, hydrogen sulfide (H₂S), and p-cresol are active either directly or indirectly on energy metabolism in colonic epithelial cells. Further studies in that area will certainly gain from the utilization of the pig colonic organoid model, which allows for disposal of functional epithelial unities. Such studies will contribute to a better understanding of the potential causal links between diet-induced changes in the luminal concentrations of these AA-derived bacterial metabolites and effects on the colon epithelial barrier function and water/electrolyte absorption.

Dietary supplementation with monosodium glutamate enhances milk production by lactating sows and the growth of suckling piglets

This study was conducted to test the hypothesis that increasing dietary content of glutamate through addition of monosodium glutamate (MSG) enhances milk production by lactating sows and the growth of their offspring. Thirty multiparous sows (Landrace × Large White) were assigned randomly into one of three dietary groups: control (a corn- and soybean meal-based diet), the basal diet + 1% MSG, and the basal diet + 2% MSG. Diets were made isonitrogenous by the addition of appropriate amounts of L-alanine. Lactating sows had free access to drinking water and were fed twice daily their respective diets. The number of live-born piglets was standardized to 9 per sow at day 0 of lactation (the day of farrowing). On days 3, 15, and 29 of lactation, body weight and milk consumption of piglets were measured, and blood samples obtained from sows and piglets at 2 h and 1 h after feeding, respectively. Feed intake of sows did not differ (P > 0.05) among the three groups of sows. Concentrations of aspartate, glutamine, citrulline, arginine, tryptophan, proline, branched-chain amino acids, and glutamate were greater (P < 0.05) in the plasma of MSG-supplemented sows and their piglets than for controls. When compared with the control, dietary supplementation with 1-2% MSG increased (P < 0.05): concentrations of many free amino acids (including glutamate plus glutamine) and all protein-bound amino acids in milk; the milk intake of piglets by 14-25%; and daily weight gains of piglets by 23-44%. These results indicate that dietary supplementation with 1-2% MSG to lactating sows enhances milk production to support the growth of sow-reared piglets.

Oxidation of amino acids, glucose, and fatty acids as metabolic fuels in enterocytes of developing pigs

Enterocytes of young pigs are known to use glutamine, glutamate, and glucose as major metabolic fuels. However, little is known about the roles of aspartate, alanine, and fatty acids as energy sources for these cells. Therefore, this study simultaneously determined the oxidation of the amino acids and glucose as well as short- and long-chain fatty acids in enterocytes of developing pigs. Jejunal enterocytes were isolated from 0-, 7-, 14- and 21-day-old piglets, and incubated at 37 °C for 30 min in Krebs-Henseleit bicarbonate buffer (pH 7.4) containing 5 mM D-glucose and one of the following: D-[U-¹⁴C]glucose, 0.5-5 mM L-[U-¹⁴C]glutamate, 0.5-5 mM L-[U-¹⁴C]glutamine, 0.5-5 mM L-[U-¹⁴C]aspartate, 0.5-5 mM L-[U-¹⁴C]alanine, 0.5-2 mM L-[U-¹⁴C]palmitate, 0.5-5 mM [U-¹⁴C]propionate, and 0.5-5 mM [1-¹⁴C]butyrate. At the end of the incubation, ¹⁴CO₂ produced from each ¹⁴C-labeled substrate was collected. Rates of oxidation of each substrate by enterocytes from all age groups of piglets increased (P < 0.05) gradually with increasing its extracellular concentrations. The rates of oxidation of glutamate, glutamine, aspartate, and glucose by enterocytes from 0- to 21-day-old pigs and of alanine from newborn pigs were much greater (P < 0.05) than those for the same concentrations of palmitate, propionate, and butyrate. Compared with 0-day-old pigs, the rates of oxidation of glutamate, aspartate, glutamine, alanine, and glucose by enterocytes from 21-day-old pigs decreased (P < 0.05) markedly, without changes in palmitate oxidation. Oxidation of alanine, propionate, butyrate and palmitate by enterocytes of pigs was limited during their postnatal growth. At each postnatal age, the oxidation of glutamate, glutamine, aspartate, and glucose produced much more ATP than alanine, propionate, butyrate and palmitate. The degradation of glutamate was initiated primarily by glutamate-pyruvate and glutamate-oxaloacetate transaminases. Our results indicated that amino acids (glutamate plus glutamine plus aspartate) are the major metabolic fuels in enterocytes of 0- to 21-day-old pigs.

Glutamine, glutamate, and aspartate differently modulate energy homeostasis of small intestine under normal or low energy status in piglets

Weaning stress may cause reduced energy intake for maintenance of mucosal structure. Gln, Glu, and Asp are major energy sources for the small intestine. This study investigated whether Gln, Glu, and Asp improve the intestinal morphology via regulating the energy metabolism in weaning piglets. A total of 198 weaned piglets were assigned to 3 treatments: Control (Basal diet + 1.59% L-Ala); T1 (Basal diet + 1% L-Gln + 0.5% L-Glu + 0.1% L-Asp); T2 (Low energy diet + 1% L-Gln + 0.5% L-Glu + 0.1% L-Asp). Jejunum and ileum were obtained on d 5 or 21 post-weaning. T1 enhanced growth performance. T1 and T2 treatments improved small intestinal morphology by increasing villus height, goblet cell number and decreasing crypt depth. Days post-weaning affected the efficacy of T2, but not T1, on energy metabolism. At normal energy supplementation, Gln, Glu, and Asp restored small intestinal energy homeostasis via replenishing the Krebs' cycle and down-regulating the AMPK (adenosine monophosphate activated protein kinase) pathway. As these are not sufficient to maintain the intestinal energy-balance of piglets fed with a low energy diet on d 5 post-weaning, the AMPK, glycolysis, beta-oxidation, and mitochondrial biogenesis are activated to meet the high energy demand of enterocytes. These data indicated that Gln, Glu, and Asp could restore the energy homeostasis of intestinal mucosa of weaning piglets under normal energy fed. Low energy feeding may increase the susceptibility of piglets to stress, which may decrease the efficacy of Gln, Glu, and Asp on the restoration of energy balance. These findings provide new information on nutritional intervention for insufficient energy intake in weaning piglets.

Glutamate attenuates lipopolysaccharide induced intestinal barrier injury by regulating corticotropin-releasing factor pathway in weaned pigs

Objective

The purpose of this study was to evaluate the protection of glutamate (GLU) against the impairment in intestinal barrier function induced by lipopolysaccharide (LPS) stress in weaned pigs.

Methods

Twenty-four weaned pigs were divided into four treatments containing: i) non-challenged control, ii) LPS-challenged control, iii) LPS+1.0% GLU, and iv) LPS+2.0% GLU. On day 28, pigs were treated with LPS or saline. Blood samples were collected at 0, 2, and 4 h post-injection. After blood samples collection at 4 h, all pigs were slaughtered, and spleen, mesenteric lymph nodes, liver and intestinal samples were obtained.

Results

Dietary GLU supplementation inhibited the LPS-induced oxidative stress in pigs, as demonstrated by reduced malondialdehyde level and increased glutathione level in jejunum. Diets supplemented with GLU enhanced villus height, villus height/crypt depth and claudin-1 expression, attenuated intestinal histology and ultrastructure impairment induced by LPS. Moreover, GLU supplementation reversed intestinal intraepithelial lymphocyte number decrease and mast cell number increase induced by LPS stress. GLU reduced serum cortisol concentration at 4 h after LPS stress and downregulated the mRNA expression of intestinal corticotropin-releasing factor signal (corticotrophin-releasing factor [CRF], CRF receptor 1 [CRFR1], glucocorticoid receptor, tryptase, nerve growth factor, tyrosine kinase receptor A), and prevented mast cell activation. GLU upregulated the mRNA expression of intestinal transforming growth factor β.

Conclusion

These findings indicate that GLU attenuates LPS-induced intestinal mucosal barrier injury, which is associated with modulating CRF signaling pathway.

Oxidation of amino acids, glucose, and fatty acids as metabolic fuels in enterocytes of post-hatching developing chickens

This study determined the oxidation of amino acids, glucose and fatty acid in enterocytes of developing chickens. Jejunal enterocytes were isolated from 0-, 7-, 21-, and 42-d-old broiler chickens, and incubated at 40°C for 30 min in Krebs-Henseleit bicarbonate buffer (pH 7.4) containing 5 mM D-glucose and one of the following: 0.5-5 mM L-[U-14C]glutamate, 0.5-5 mM L-[U-14C]glutamine, 0.5-5 mM L-[U-14C]aspartate, 0.5-5 mM L-[U-14C]alanine, 0.5-2 mM [U-14C]palmitate, D-[U-14C]glucose, 0.5-5 mM [U-14C]propionate, and 0.5-5 mM [1-14C]butyrate. 14CO2 produced from each 14C-labeled substrate was collected for determination of radioactivity. Among all the substrates studied, glutamate had the greatest rate of oxidation in enterocytes from 0- to 42-d-old chickens. Glutamate transaminases, rather than glutamate dehydrogenase, may be primarily responsible for initiating glutamate degradation. Rates of amino acid and fatty acid oxidation by cells increased (P < 0.05) with increasing their extracellular concentrations from 0.5 to 5 mM. Rates of glutamate and glucose oxidation in enterocytes decreased (P < 0.05) with increasing age, and rates of glutamine, aspartate, propionate, and butyrate oxidation were lower (P < 0.05) in 42-d-old chickens than in 0-d-old chickens. By contrast, oxidation of palmitate at 2 mM increased (P < 0.05) by 118% in cells from 42-d-old chickens, compared with 0-d-old chickens. Compared with glutamate, oxidation of glutamine, aspartate, alanine, propionate, butyrate, and palmitate was limited in cells from all age groups of chickens. Collectively, these results indicate that glutamate is the major metabolic fuel in enterocytes of 0- to 42-d-old chickens.

Insulin signaling and antioxidant proteins in adipose tissue explants from dairy cows challenged with hydrogen peroxide are altered by supplementation of arginine or arginine plus methionine

Arginine (Arg) and methionine (Met) can elicit anti-inflammatory and antioxidant effects in animals. Unlike Met, however, it is unknown if the supply of Arg can impact key aspects of adipose tissue (AT) function in dairy cows. Since Met and Arg metabolism are linked through the synthesis of polyamines, it is also possible that they have a complementary effect on aspects of AT function during a stress challenge. In this experiment, subcutaneous AT was harvested from four lactating multiparous Holstein cows (~27.0 kg milk per day, body condition score 3.38 ± 0.23) and used for incubations (4 h) with the following: control medium with an "ideal" profile of essential amino acids (IPAA; CTR; Lys:Met 2.9:1), IPAA plus 100 μM H2O2 (HP), H2O2 plus greater Arg supply (HPARG; Lys:Arg 1:1), or H2O2 plus greater Arg and methionine (Met) supply (HPARGMET; Lys:Met 2.5:1 and Lys:Arg 1:1). Western blotting was used to measure abundance of 18 protein targets associated with insulin and AA signaling, nutrient transport, inflammation, and antioxidant response. Reverse transcription polymerase chain reaction (RT-PCR) was used to assess effects on genes associated with Arg metabolism. Among the protein targets measured, although abundance of phosphorylated (p) AKT serine/threonine kinase (P = 0.05) and p-mechanistic target of rapamycin (P = 0.04) were lowest in HP explants, this effect was attenuated in HPARG and especially HPARGMET compared with CTR. Compared with HP, incubation with HPARG led to upregulation of the AA transporter solute carrier family 1 member 3 (L-glutamate transporter; P = 0.03), the reactive oxygen species detoxification-related enzyme glutathione S-transferase mu 1 (GSTM1; P = 0.03), and fatty acid synthase (P = 0.05). Those effects were accompanied by greater abundance of solute carrier family 2 member 4 (insulin-induced glucose transporter) in explants incubated with HPARG and also HPARGMET (P = 0.04). In addition, compared with other treatments, the peak response in abundance of the intracellular energy sensor 5'-prime-AMP-activated protein kinase was detected with HPARGMET (P = 0.003). There was no effect of Arg or Arg plus Met on the mRNA abundance of genes associated with Arg metabolism (ARG1, NOS2, AMD1, SMS, and SRM). Overall, supplementation of Arg alone or with Met partially alleviated the negative effects induced by H2O2. More systematic studies need to be conducted to explore the function of Arg supply with or without Met on AT function.

Therapeutic effect of Moringa oleifera leaves on constipation mice based on pharmacodynamics and serum metabonomics

ETHNOPHARMACOLOGICAL RELEVANCE

Moringa oleifera is native to India, and has been introduced to China in recent years. Moringa oleifera leaves (MOL), as Ayurvedic medicine, has efficacy of Pachana karma (digestive) and Virechana karma (purgative). Folium Sennae (FS), Rhubarb (RB), Aloe vera (AV), Hemp seed (HS) are commonly used as laxatives in Traditional Chinese Medicine (TCM), which have different characteristics. However, the intensity of the diarrheal effect of MOL and its mechanism of action are unclear.

AIM OF THE STUDY

The methods of pharmacology and omics were used to compare the purgative effects of MOL and FS, RB, AV, HS, and their effects on metabolomics, to analyze the purgative characteristics and related mechanisms of MOL.

MATERIALS AND METHODS

C57BL/6J mouse model of constipation was established by feeding low-fiber food. Feces parameters and colon pathology were used to evaluate the effect of FS, RB, AV, HS and MOL. And mass spectrometry-based serum metabolomics was performed. The differential metabolites of these herbs in the treatment of constipation were obtained by OPLS-DA analysis. Furthermore, pathway analysis was conducted based on different metabolites.

RESULTS

Moringa leaves can adjust the stool number, wet fecal weight and fecal water content to varying degrees to achieve laxative effects, and recover colon muscle thickness and mucus. Analysis of metabolomics results showed that 71 metabolites from LC-MS datasets between model group and control group were obtained. 29, 12, 44, 29 and 20 metabolites were significantly reversed by FS, RB, AV, HS, MOL compared with model group respectively. According to the metabolic pathways, RB and AV may be clustered into a similar category, and MOL, FS and HS showed similarity of metabolic characteristics.

CONCLUSION

The purgative effect of MOL is inferior to that of FS, and stronger than that of AV, RB and HS. The metabolic pathway for constipation is more similar to that of FS. MOL has a long-lasting and mild effect of laxative, increasing defecation volume and water content of feces, and may become a fewer side effects medicine to treat constipation.

Comparative transcriptome and metabolome analysis reveal glutathione metabolic network and functional genes underlying blue and red-light mediation in maize seedling leaf

BACKGROUND

Light quality severely affects biosynthesis and metabolism-associated process of glutathione. However, the role of specific light is still unclear on the glutathione metabolism. In this article, comparatively transcriptome and metabolome methods are used to fully understand the blue and red-light conditions working on the glutathione metabolism in maize seedling leaf.

RESULTS

There are 20 differently expressed genes and 4 differently expressed metabolites in KEGG pathway of glutathione metabolism. Among them, 12 genes belong to the glutathione S-transferase family, 3 genes belong to the ascorbate peroxidase gene family and 2 genes belong to the ribonucleoside-diphosphate reductase gene family. Three genes, G6PD, SPDS1, and GPX1 belong to the gene family of glucose 6-phosphate dehydrogenase, spermidine synthase, and glutathione peroxidase, respectively. Four differently expressed metabolites are identified. Three of them, Glutathione disulfide, Glutathione, and l-γ-Glutamyl-L-amino acid are decreased while L-Glutamate is increased. In addition, Through PPI analysis, two annotated genes gst16 and DAAT, and 3 unidentified genes 100381533, pco105094 and umc2770, identified as RPP13-like3, BCAT-like1and GMPS, were obtained. By the analysis of protein sequence and PPI network, we predict that pco105094 and umc2770 were involved in the GSSG-GSH and AsA-GSH cycle in the network of glutathione metabolism.

CONCLUSIONS

Compared to red light, blue light remarkably changed the transcription signal transduction and metabolism of glutathione metabolism. Differently expressed genes and metabolic mapped to the glutathione metabolism signaling pathways. In total, we obtained three unidentified genes, and two of them were predicted in current glutathione metabolism network. This result will contribute to the research of glutathione metabolism of maize.

Colonization resistance: metabolic warfare as a strategy against pathogenic Enterobacteriaceae

The intestine is home to a large and complex bacterial ecosystem (microbiota), which performs multiple beneficial functions for the host, including immune education, nutrition, and protection against invasion by enteric pathogens (colonization resistance). The host and microbiome symbiotic interactions occur in part through metabolic crosstalk. Thus, microbiota members have evolved highly diverse metabolic pathways to inhibit pathogen colonization via activation of protective immune responses and nutrient acquisition and utilization. Conversely, pathogenic Enterobacteriaceae actively induce an inflammation-dependent disruption of the gut microbial ecosystem (dysbiosis) to gain a competitive metabolic advantage against the resident microbiota. This review discusses the recent findings on the crucial role of microbiota metabolites in colonization resistance regulation. Additionally, we summarize metabolic mechanisms used by pathogenic Enterobacteriaceae to outcompete commensal microbes and cause disease.

Identifying Suitable Supplements to Improve Piglet Survival during Farrowing and Lactation

Piglet mortality during parturition and prior to weaning is an ongoing economic and welfare issue. This review collates the current literature describing the effects of specific dietary supplements on key parameters affecting piglet survival. Four distinct parameters were identified as having a direct impact on the survival of piglets to weaning: stillbirth rate, birth weight and weight variation, daily gain and weaning weight, and colostrum and milk quality. In the primary stage, relevant literature from the past 5 years was reviewed, followed by a secondary review of literature older than 5 years. The focal parameters benefitted from different supplements. For example, stillbirth may be reduced by supplements in late gestation, including forms of arginine, alpha-tocopherol-selenium, uridine, and Saccharomyces cerevisiae yeast culture, whereas average daily gain and weaning weight were related closely to supplements which improved colostrum and milk quality, most commonly fats and fatty acids in the form of n-3 polyunsaturated fatty acids, soybean oil, and fish oil, and polysaccharides, such as ginseng polysaccharide. Therefore, an effective supplement plan for piglet mortality reduction must consider the circumstances of the individual system and target one or more of the highlighted parameters.