Intestinal Nutrient Absorption Research Articles

Synthesis of Protein Hydrolysate from the Prepupae of <em>Hermetia illucens</em> using a Papain Enzymes

The aim of this study was to determine optimum enzyme concentration and hydrolysis time needed to hydrolyze black soldier fly prepupae into a protein hydrolysate. The prepupae were homogenized with aquadest and papain enzyme (0-9% on a weight basis) at pH 7 for 24-72 h at 55°C. At optimum conditions (enzyme concentration of 6% on a weight basis and hydrolysis time of 24 h), the yield of protein hydrolysate was 31% on a dry weight basis. The protein content increased from 39.7 to 61% (dry weight basis) whereas the lipid content in the protein hydrolysate decreased from 30.3 to 0.5% (dry weight basis). Hydrolysis of the prepupae with a papain enzyme increased the amino acid content from 15.4 to 47.1% on a weight basis. The black soldier fly prepupae contains 15 detectable amino acids primarily consists of glutamic acid (10.7%), alanine (10.7%), leucine (10%) and valine (9%). After hydrolysis with a papain enzyme, the composition of the amino acid changed and primarily consists of glutamic acid (17.3%), tyrosine (9.4%), leucine (9.4%) and alanine (8.9%). The protein hydrolysate may find application as a supplement for feed and food for a better absorption of nutrients in animal intestine.

Altered intestinal epithelial nutrient transport: an underappreciated factor in obesity modulated by diet and microbiota.

Dietary nutrients absorbed in the proximal small intestine and assimilated in different tissues have a profound effect on overall energy homeostasis, determined by a balance between body's energy intake and expenditure. In obesity, altered intestinal absorption and consequently tissue assimilation of nutrients may disturb the energy balance leading to metabolic abnormalities at the cellular level. The absorption of nutrients such as sugars, amino acids and fatty acids released from food digestion require high-capacity transporter proteins expressed in the intestinal epithelial absorptive cells. Furthermore, nutrient sensing by specific transporters/receptors expressed in the epithelial enteroendocrine cells triggers release of gut hormones involved in regulating energy homeostasis via their effects on appetite and food intake. Therefore, the intestinal epithelial cells play a pivotal role in the pathophysiology of obesity and associated complications. Over the past decade, gut microbiota has emerged as a key factor contributing to obesity via its effects on digestion and absorption of nutrients in the small intestine, and energy harvest from dietary fiber, undigested component of food, in the large intestine. Various mechanisms of microbiota effects on obesity have been implicated. However, the impact of obesity-associated microbiota on the intestinal nutrient transporters needs extensive investigation. This review marshals the limited studies addressing the altered structure and function of the gut epithelium in obesity with special emphasis on nutrient transporters and role of diet and microbiota. The review also discusses the thoughts and controversies and research gaps in this field.

Intrauterine growth restriction alters nutrient metabolism in the intestine of porcine offspring

BackgroundIntrauterine growth restriction (IUGR) has negative impacts on the postnatal survival, growth and development of humans and animals, with not only on newborns but also adulthood. However, the characteristics for nutrient digestion and absorption in IUGR offspring are still largely unknown. Therefore, the normal birth weight (NBW) and IUGR growing pigs were used in this study to investigate their differences in nutrient utilization, with an expectition for further nutritional optimization of the IUGR offspring during their later life.MethodsTwelve IUGR and 12 NBW growing pigs were fitted with catheters in their portal vein to measure blood flow rate as well as nutrients and metabolites in plasma. The digestibilities of nutrients in different intestinal segments, and bacterial fermentation in the large intestine were examined to reveal the characteristics of nutrients utilization in IUGR versus NBW pigs.ResultsThe rate of portal venous blood flow did not differ beween IUGR and NBW pigs. Plasma concentrations of total cholesterol, triglycerides and glucose were much lower but those of urea were higher in the portal vein of IUGR pigs, compared with the NBW pigs. The ileal digestibility of dry matter, gross energy and starch were lower in IUGR pigs than in NBW pigs. IUGR increased hindgut microbial diversity and bacterial fermentation activity in the caecum. In vitro cross-fermentation of ileal digesta by caecal microbes of NBW and IUGR pigs showed that gas production was much higher for IUGR ileal digesta regardless of the source of caecal inocula.ConclusionIUGR impairs the nutrient digestion and absorption in small intestine, reduces caecal microbial diversity and promotes bacterial fermentation in the large intestine during the growing phase. These findings aid in our understanding of nutrient metabolism in IUGR pigs and provide the basis for future nutritional interventions.

The duration of food withdrawal affects the intestinal structure, nutrients absorption, and utilization in broiler chicken.

Food withdrawal is usually used for accurate feed metabolizable energy (ME) assessment in poultry, but its effects on intestinal structure and the absorption of nutrients are unclear. In this study, broilers were fed ad libitum (CT) or withdrew food for 12 (FH12), 24 (FH24), 36 (FH36), or 48hours (FH48). We showed that food withdrawal increased the energy assimilation when compared with the CT. Food withdrawal improved the digestibility of ether extract and the level of lipid substances and fatty acid-derived β-hydroxybutyrate in serum. Compared to the CT, food withdrawal did not influence the digestibility of starch. Due to 12hours or longer food withdrawal duration increased glutamate oxidation and uric acid excretion, the analyzed digestibility of crude protein was underestimated, although the upregulated amino acid transporter genes. In addition, histological analysis showed that short-term food withdrawal (12hours) increased intestinal villus height, crypt depth, and proliferative cell, whereas prolonged food withdrawal (more than 24hours) impaired villus structure due to the decreased cell proliferation. Moreover, proteomics analysis revealed upregulated pathways in birds withdrawn food for 36hours involved in nutrient absorption and amino acid oxidation. In conclusion, food withdrawal changes nutrient absorption and utilization, especially for amino acid and ether extract, and results in increased ME. Both glutamate oxidation and fatty acid incomplete oxidation are involved in energy supply after refeeding. In contrast to short-term food withdrawal, prolonged food withdrawal impairs the intestinal structure and villus renewal. Our findings deserve attention from nutritionists who are analyzing food digestibility.

Dietary dandelion extract improved growth performance, immunity, intestinal morphology and microbiota composition of golden pompano Trachinotus ovatus

The gut microbiota plays an important role in growth performance, intestinal mucosal barrier, digestion and absorption of nutrients and immune responses. In this study, we investigated the effect of dietary dandelion extract (DE) on growth performance, expression of immune related genes in the spleen, intestinal morphology and microbiota of golden pompano (Trachinotus ovatus). Golden pompanos were fed three diets adding 0 (DE0), 0.50 (DE1), 1.00 (DE2) g/kg DE for 8 weeks. At the end of this trial, dietary 1.00 g/kg DE supplementation significantly increased weight gain rate and feed intake compared to those of the control group (P < 0.05). Meanwhile, dietary 1.00 g/kg DE supplementation significantly up-regulated transcription levels of glutathione peroxidase and interleukin 10 in the spleen of fish. However, dietary DE supplementation had no significant effect on transforming growth factor β1, glutathione reductase and catalase in the spleen of fish. Moreover, dietary 0.50–1.00 g/kg DE supplementation improved the richness and diversity of gut microbiota, increase the relative abundance of Actinobacteria and Firmicutes, and reduce the proportion of harmful microbial taxa. Furthermore, dietary DE improved intestinal morphology and immunity by increasing intestinal goblet cells numbers and decreasing epithelial lymphocyte numbers. In conclusion, dietary 1.00 g/kg DE supplementation was clearly beneficial for golden pompano by improving growth performance, gut morphology and microbiota and it could use as a functional feed additive in aquaculture.

The gut hormone GLP-2 predicts cardiovascular risk in patients with acute myocardial infarction

Abstract Background GLP-1 and GLP-2 (glucagon-like peptide-1/2) are gut derived hormones that are co-secreted from intestinal L-cells in response to food intake. While GLP-1 is known to induce postprandial insulin secretion, GLP-2 enhances intestinal nutrient absorption and is clinically used for the treatment of patients with short bowel syndrome. The relevance of the GLP-2 system for cardiovascular disease is unknown. Purpose The aim of this study was to assess the predictive capacity of GLP-2 for cardiovascular prognosis in patients with myocardial infarction. Methods Total GLP-2 levels, NT-proBNP concentrations and the Global Registry of Acute Coronary Events (GRACE) score were assessed at time of admission in 918 patients with myocardial infarction, among them 597 patients with NSTEMI and 321 with STEMI. The primary composite outcome of the study was the first occurrence of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke (3-P-MACE) with a median follow-up of 311 days. Results Kaplan-Meier survival plots (separated by the median of GLP-2 with a cut-off value of 4.4 ng/mL) and univariable cox regression analyses found GLP-2 values to be associated with adverse outcome (logarithmized GLP-2 values HR: 2.87; 95% CI: 1.75–4.68; p&amp;lt;0.0001). Further adjustment for age, sex, smoking, hypertension, hypercholesterolemia, diabetes mellitus, family history of cardiovascular disease, hs-Troponin T, NT-proBNP and hs-CRP levels did not affect the association of GLP-2 with poor prognosis (logarithmized GLP-2 values HR: 2.96; 95% CI: 1.38–6.34; p=0.0053). Receiver operating characteristic curve (ROC) analyses illustrated that GLP-2 is a strong indicator for cardiovascular events and proved to be comparable to other established risk markers (area under the curve of the combined endpoint at 6 months; GLP-2: 0.72; hs-Troponin: 0.56; NT-proBNP: 0.70; hs-CRP: 0.62). Adjustment of the GRACE risk estimate by GLP-2 increased the area under the receiver-operating characteristic curve for the combined triple endpoint after 6 months from 0.70 (GRACE) to 0.75 (GRACE + GLP-2) in NSTEMI patients. Addition of GLP-2 to a model containing GRACE and NT-proBNP led to a further improvement in model performance (increase in AUC from 0.72 for GRACE + NT-proBNP to 0.77 for GRACE + NT-proBNP + GLP-2). Conclusions In patients admitted with acute myocardial infarction, GLP-2 levels are associated with adverse cardiovascular prognosis. This demonstrates a strong yet not appreciated crosstalk between the heart and the gut with relevance for cardiovascular outcome. Future studies are needed to further explore this crosstalk with the possibility of new treatment avenues for cardiovascular disease. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Society of Cardiology (DGK), German Research Foundation (DFG)

Organic Cation Transporters in Human Physiology, Pharmacology, and Toxicology.

Individual cells and epithelia control the chemical exchange with the surrounding environment by the fine-tuned expression, localization, and function of an array of transmembrane proteins that dictate the selective permeability of the lipid bilayer to small molecules, as actual gatekeepers to the interface with the extracellular space. Among the variety of channels, transporters, and pumps that localize to cell membrane, organic cation transporters (OCTs) are considered to be extremely relevant in the transport across the plasma membrane of the majority of the endogenous substances and drugs that are positively charged near or at physiological pH. In humans, the following six organic cation transporters have been characterized in regards to their respective substrates, all belonging to the solute carrier 22 (SLC22) family: the organic cation transporters 1, 2, and 3 (OCT1–3); the organic cation/carnitine transporter novel 1 and 2 (OCTN1 and N2); and the organic cation transporter 6 (OCT6). OCTs are highly expressed on the plasma membrane of polarized epithelia, thus, playing a key role in intestinal absorption and renal reabsorption of nutrients (e.g., choline and carnitine), in the elimination of waste products (e.g., trimethylamine and trimethylamine N-oxide), and in the kinetic profile and therapeutic index of several drugs (e.g., metformin and platinum derivatives). As part of the Special Issue Physiology, Biochemistry, and Pharmacology of Transporters for Organic Cations, this article critically presents the physio-pathological, pharmacological, and toxicological roles of OCTs in the tissues in which they are primarily expressed.

Senescence-accelerated mouse prone 8 mice exhibit specific morphological changes in the small intestine during senescence and after pectin supplemented diet.

Impairment of gastrointestinal function and reduction of nutrient absorption associated with aging contribute to increased risk of malnutrition in the elderly population, resulting in physical weakness and vulnerability to disease. The present study was performed to examine the relationships between aging-associated morphological changes of the small intestine and nutrient malabsorption using senescence-accelerated mouse prone 8 (SAMP8) mice. Comparison of the morphology of the small intestine of young (22-week-old) and senescent (43-week-old) SAMP8 mice showed no significant changes in villus length, while the mRNA expression levels of secretory cell marker genes were significantly reduced in senescent mice. In addition, crypts recovered from the small intestine of senescent mice showed a good capacity to form intestinal organoids ex vivo, suggesting that the regenerative capacity of intestinal stem cells (ISCs) was unaffected by accelerated senescence. These results indicated that changes induced by accelerated senescence in the small intestine of SAMP8 mice are different from changes reported previously in normal aging mouse models. Biochemical analyses of serum before and during senescence also indicated that senescent SAMP8 mice are not in a malabsorption state. Furthermore, a diet supplemented with persimmon pectin had a mild effect on the small intestine of senescent SAMP8 mice. Intestinal villus length was slightly increased in the medial part of the small intestine of pectin-fed mice. In contrast, intestinal crypt formation capacity was enhanced by the pectin diet. Organoid culture derived from the small intestine of mice fed pectin exhibited a greater number of lobes per organoid compared with those from mice fed a control diet, and Lyz1 and Olfm4 mRNA levels were significantly increased. In conclusion, accelerated senescence induced exclusive changes in the small intestine, which were not related to nutrient malabsorption. Therefore, the SAMP8 strain may not be a suitable model to evaluate the effects of aging on intestinal homeostasis and nutrient absorption impairment.

Rice-shrimp culture: a better intestinal microbiota, immune enzymatic activities, and muscle relish of crayfish (Procambarus clarkii) in Sichuan Province.

Intestinal microbiota play an important role in the intestinal immunity and nutrient absorption, even muscle nutritional components, and the composition and function were affected by environment. In this study, the intestinal microbiota and immune enzyme, nutritional flavor of muscle of crayfish in rice field, and pond cultivation model were compared in summer and autumn. The results of Shannon diversity and Chao 1 index of intestinal microbiota based on 16S sequencing analysis showed that the diversity and abundance in autumn were higher than in summer. And the diversity and abundance of intestinal microbiota of different model in the same season were different. Four dominant phyla (relative abundance > 5% at least in one sample) of the intestinal microbiota were Bacteroidetes, Firmicutes, Proteobacteria, and Tenericutes. From summer to autumn, the intestinal immune enzyme activity of crayfish in both models showed a decreasing trend. In summer, the activity of catalase and alkaline phosphatase of crayfish cultured in the pond was significantly higher than that in rice field (P < 0.05). In autumn, the activity of catalase and lysozyme of crayfish cultured in rice field was significantly higher than that in pond (P < 0.05). The contents of umami and sweetish amino acids of muscle were higher in rice field than in pond, and the percentage of glutamic acid and alanine was significantly higher in rice field than in pond (P < 0.05). Thus, rice field model can make crayfish a more stable intestinal environment and a better intestinal immune enzyme activity and muscular flavor. Key points • The intestinal microbiota of crayfish in rice field had tended to stabilize from summer to autumn. • The crayfish had better nutrient absorption and stronger immune abilities in the rice field. • The crayfish cultured in rice field had higher overall umami concentration than in pond.

Organoids to Study Intestinal Nutrient Transport, Drug Uptake and Metabolism - Update to the Human Model and Expansion of Applications.

Intestinal transport and sensing processes and their interconnection to metabolism are relevant to pathologies such as malabsorption syndromes, inflammatory diseases, obesity and type 2 diabetes. Constituting a highly selective barrier, intestinal epithelial cells absorb, metabolize, and release nutrients into the circulation, hence serving as gatekeeper of nutrient availability and metabolic health for the whole organism. Next to nutrient transport and sensing functions, intestinal transporters including peptide transporter 1 (PEPT1) are involved in the absorption of drugs and prodrugs, including certain inhibitors of angiotensin-converting enzyme, protease inhibitors, antivirals, and peptidomimetics like β-lactam antibiotics. Here, we verify the applicability of 3D organoids for in vitro investigation of intestinal biochemical processes related to transport and metabolism of nutrients and drugs. Establishing a variety of methodologies including illustration of transporter-mediated nutrient and drug uptake and metabolomics approaches, we highlight intestinal organoids as robust and reliable tool in this field of research. Currently used in vitro models to study intestinal nutrient absorption, drug transport and enterocyte metabolism, such as Caco-2 cells or rodent explant models are of limited value due to their cancer and non-human origin, respectively. Particularly species differences result in poorly correlative data and findings obtained in these models cannot be extrapolated reliably to humans, as indicated by high failure rates in drug development pipelines. In contrast, human intestinal organoids represent a superior model of the intestinal epithelium and might help to implement the 3Rs (Reduction, Refinement and Replacement) principle in basic science as well as the preclinical and regulatory setup.

NPC1L1 Facilitates Sphingomyelin Absorption and Regulates Diet-Induced Production of VLDL/LDL-associated S1P.

Niemann-Pick C1-Like 1 (NPC1L1) is a cholesterol importer and target of ezetimibe, a cholesterol absorption inhibitor used clinically for dyslipidemia. Recent studies demonstrated that NPC1L1 regulates the intestinal absorption of several fat-soluble nutrients, in addition to cholesterol. The study was conducted to reveal new physiological roles of NPC1L1 by identifying novel dietary substrate(s). Very low-density lipoprotein and low-density lipoprotein (VLDL/LDL) are increased in Western diet (WD)-fed mice in an NPC1L1-dependent manner, so we comprehensively analyzed the NPC1L1-dependent VLDL/LDL components. Apolipoprotein M (apoM), a binding protein of sphingosine-1-phosphate (S1P: a lipid mediator), and S1P were NPC1L1-dependently increased in VLDL/LDL by WD feeding. S1P is metabolized from sphingomyelin (SM) and SM is abundant in WD, so we focused on intestinal SM absorption. In vivo studies with Npc1l1 knockout mice and in vitro studies with NPC1L1-overexpressing cells revealed that SM is a physiological substrate of NPC1L1. These results suggest a scenario in which dietary SM is absorbed by NPC1L1 in the intestine, followed by SM conversion to S1P and, after several steps, S1P is exported into the blood as the apoM-bound form in VLDL/LDL. Our findings provide insight into the functions of NPC1L1 for a better understanding of sphingolipids and S1P homeostasis.

Postsurgical Intestinal Rehabilitation Using Semisynthetic Glucagon‐Like Peptide‐2 Analogue (sGLP‐2) at a Referral Center: Can Patients Achieve Parenteral Nutrition and sGLP‐2 Independency?

Teduglutide, a semisynthetic analogue of glucagon-like peptide-2 (sGLP-2), increases intestinal absorption of fluids and nutrients, reducing the need for parenteral nutrition (PN). This report aims to describe our experience with sGLP-2 in a cohort of adult patients with short-bowel syndrome. This is a prospective observational study on adult patients initially evaluated in our specialized intestinal rehabilitation program that received sGLP-2 from June 2014 to March 2020. Autologous gastrointestinal reconstruction surgery (AGIRS) was performed in 108 patients; 68.5% (74 of 108) achieved intestinal sufficiency with standard medical therapy. Seventeen patients were treated with sGLP-2; 66.5% (8 of 12) received treatment for a mean time of 25.8 weeks (3.4-54.0) and could suspend PN. One patient reinitiated treatment due to renal lithiasis and acute renal failure. Currently, 7 of 12 patients (53.8%) continue without PN for a mean time of 165.6 weeks. Volume, energy, and days of PN were reduced in all patients. No serious adverse events were registered. Four of 7 patients (57.1%) who discontinued PN could also discontinue sGLP-2. Therefore, the use of sGLP-2 increased the overall success rate of PN independency after AGIRS to 76% (82 of 108). This study confirmed that sGLP-2 should be considered as part of the standard therapy for postsurgical medical rehabilitation treatment in patients with chronic intestinal failure. We add to the current knowledge that some patients can discontinue both PN and sGLP-2 in the long term, achieving complete recovery of their quality of life.

A review on the beneficial effect of thymol on health and production of fish

AbstractThe thymol molecule is a food additive, used to boost the growth, production and feed efficiency via improving the digestive secretion and activating the structure and function of digestive system. The major application of thymol essential oil is used in animal rations, particularly as a natural feed additive to decrease hazardous compounds in a wide range of animal species. Thymol essential oil plays an important role in improving the nutrient bioavailability, reproductive and productive performance, general health and immunity of livestock besides reducing problems of many animal diseases such as cancer and some other diseases. These roles may be attributed to the ability of thymol as anticancer, antimicrobial, antiviral, antioxidant, immunomodulators, anti‐inflammatory and antispasmodic factors through suppressing free radicals and harmful constituents from interacting with cellular biological components and its capability to manipulate the balance of the intestinal microbiota, increased digestion, metabolism and absorption of nutrients. This review elucidates the chemical structure and natural sources, physical proprieties and practical applications of thymol in fish nutrition.

Can intestinal absorption of dietary protein be improved through early exposure to plant-based diet?

Nutritional Programming (NP) has been studied as a means of mitigating the negative effects of dietary plant protein (PP), but the optimal timing and mechanism behind NP are still unknown. The objectives of this study were: 1) To determine whether zebrafish (Danio rerio) can be programmed to soybean meal (SBM) through early feeding and broodstock exposure to improve SBM utilization; 2) To determine if NP in zebrafish affects expression of genes associated with intestinal nutrient uptake; 3) To determine if early stage NP and/or broodstock affects gene expression associated with intestinal inflammation or any morphological changes in the intestinal tract that might improve dietary SBM utilization. Two broodstocks were used to form the six experimental groups. One broodstock group received fishmeal (FM) diet (FMBS), while the other was fed (“programmed with”) SBM diet (PPBS). The first ((+) Control) and the second group ((-) Control) received FM and SBM diet for the entire study, respectively, and were progeny of FMBS. The last four groups consisted of a non-programmed (FMBS-X-PP and PPBS-X-PP) and a programmed group (FMBS-NP-PP and PPBS-NP-PP) from each of the broodstocks. The programming occurred through feeding with SBM diet during 13–23 dph. The non-control groups underwent a PP-Challenge, receiving SBM diet during 36–60 dph. During the PP-Challenge, both PPBS groups experienced significantly lower weight gains than the (+) Control group. NP in early life stages significantly increased the expression of PepT1 in PPBS-NP-PP, compared to PPBS-X-PP. NP also tended to increase the expression of fabp2 in the programmed vs. non-programmed groups of both broodstocks. The highest distal villus length-to-width ratio was observed in the dual-programmed group, suggesting an increase in surface area for nutrient absorption within the intestine. The results of this study suggest that NP during early life stages may increase intestinal absorption of nutrients from PP-based feeds.

The scaffold protein p62 regulates adaptive thermogenesis through ATF2 nuclear target activation

During β-adrenergic stimulation of brown adipose tissue (BAT), p38 phosphorylates the activating transcription factor 2 (ATF2) which then translocates to the nucleus to activate the expression of Ucp1 and Pgc-1α. The mechanisms underlying ATF2 target activation are unknown. Here we demonstrate that p62 (Sqstm1) binds to ATF2 to orchestrate activation of the Ucp1 enhancer and Pgc-1α promoter. P62Δ69-251 mice show reduced expression of Ucp1 and Pgc-1α with impaired ATF2 genomic binding. Modulation of Ucp1 and Pgc-1α expression through p62 regulation of ATF2 signaling is demonstrated in vitro and in vivo in p62Δ69-251 mice, global p62−/− and Ucp1-Cre p62flx/flx mice. BAT dysfunction resulting from p62 deficiency is manifest after birth and obesity subsequently develops despite normal food intake, intestinal nutrient absorption and locomotor activity. In summary, our data identify p62 as a master regulator of BAT function in that it controls the Ucp1 pathway through regulation of ATF2 genomic binding.

Nitrate exposure induces intestinal microbiota dysbiosis and metabolism disorder in Bufo gargarizans tadpoles

Excess nitrate has been reported to be associated with many adverse effects in humans and experimental animals. However, there is a paucity of information of the effects of nitrate on intestinal microbial community. In this study, the effects of nitrate on development, intestinal microbial community, and metabolites of Bufo gargarizans tadpoles were investigated. B. gargarizans were exposed to control, 5, 20 and 100 mg/L nitrate-nitrogen (NO3–N) from eggs to Gosner stage 38. Our data showed that the body size of tadpoles significantly decreased in the 20 and 100 mg/L NO3–N treatment group when compared to control tadpoles. Exposure to 20 and 100 mg/L NO3–N also caused indistinct cell boundaries and nuclear pyknosis of mucosal epithelial cells in intestine of tadpoles. In addition, exposure to NO3–N significantly altered the intestinal microbiota diversity and structure. The facultative anaerobic Proteobacteria occupy the niche of the obligately anaerobic Bacteroidetes and Fusobacteria under the pressure of NO3–N exposure. According to the results of functional prediction, NO3–N exposure affected the fatty acid metabolism pathway and amino acid metabolism pathway. The whole-body fatty acid components were found to be changed after exposure to 100 mg/L NO3–N. Therefore, we concluded that exposure to 20 and 100 mg/L NO3–N could induce deficient nutrient absorption in intestine, resulting in malnutrition of B. gargarizans tadpoles. High levels of NO3–N could also change the intestinal microbial communities, causing dysregulation of fatty acid metabolism and amino acid metabolism in B. gargarizans tadpoles.

A human-like bile acid pool induced by deletion of hepatic Cyp2c70 modulates effects of FXR activation in mice

Bile acids (BAs) facilitate intestinal absorption of lipid-soluble nutrients and modulate various metabolic pathways through the farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5. These receptors are targets for therapy in cholestatic and metabolic diseases. However, dissimilarities in BA metabolism between humans and mice complicate translation of preclinical data. Cytochrome P450 family 2 subfamily c polypeptide 70 (CYP2C70) was recently proposed to catalyze the formation of rodent-specific muricholic acids (MCAs). With CRISPR/Cas9-mediated somatic genome editing, we generated an acute hepatic Cyp2c70 knockout mouse model (Cyp2c70ako) to clarify the role of CYP2C70 in BA metabolism in vivo and evaluate whether its activity modulates effects of pharmacologic FXR activation on cholesterol homeostasis. In Cyp2c70ako mice, chenodeoxycholic acid (CDCA) increased at the expense of βMCA, resulting in a more hydrophobic human-like BA pool. Tracer studies demonstrated that, in vivo, CYP2C70 catalyzes the formation of βMCA primarily by sequential 6β-hydroxylation and C7-epimerization of CDCA, generating αMCA as an intermediate metabolite. Physiologically, the humanized BA composition in Cyp2c70ako mice blunted the stimulation of fecal cholesterol disposal in response to FXR activation compared with WT mice, predominantly due to reduced stimulation of transintestinal cholesterol excretion. Thus, deletion of hepatic Cyp2c70 in adult mice translates into a human-like BA pool composition and impacts the response to pharmacologic FXR activation. This Cyp2c70ako mouse model may be a useful tool for future studies of BA signaling and metabolism that informs human disease development and treatment.

Vibrio parahaemolyticus infection impaired intestinal barrier function and nutrient absorption in Litopenaeus vannamei

The intestine is the primary target of pathogenic microbes during invasion. However, the interaction of Vibrio parahaemolyticus (V. parahaemolyticus) with intestinal epithelial cells and its effects on the intestinal function of Litopenaeus vannamei (L. vannamei) are poorly studied. Therefore, the aim of this study was to investigate the influence of V. parahaemolyticus infection on intestinal barrier function and nutrient absorption in L. vannamei. In the present study, a total of 90 shrimp were randomly divided into two groups including the control group and V. parahaemolyticus infection group (final concentration of 1 × 105 CFU/mL), with three replicates per group. The result showed that compared with the control group, V. parahaemolyticus infection increased (P < 0.05) serum diamine oxidase activity and endotoxin quantification, and down-regulated (P < 0.05) the mRNA levels of intestinal peroxinectin, integrin, midline fasciclin at 48 h and 72 h; V. parahaemolyticus infection decreased (P < 0.05) the mRNA expression of intestinal amino acid transporter (CAT1, EAAT3 and ASCT1) and glucose transporter (SGLT-1, GLUT) at 24 h, 48 h and 72 h, and increased (P < 0.05) serum glucose and amino acid (Asp, Thr, Ser, Glu, Gly, Ala, Val, Ile, Leu, Tyr, Phe, Lys, His and Arg) concentration at 24 h. The results indicated that V. parahaemolyticus infection increased intestinal permeability, inhibited absorption of glucose and amino acid in L. vannamei.

Birthweight determines intestinal microvasculature development and alters endothelial nitric oxide synthase density in young piglets.

Blood supply to enterocytes dictates intestinal health and nutrient absorption. These two aspects are impaired in low birthweight (LBW) piglets, but whether the perfusion to intestinal tissues is implicated as well is still unknown. Thus, structural changes in the microvasculature of LBW and normal birthweight (NBW) piglets were investigated during early postnatal development. Additionally, the presence of endothelial nitric oxide synthase (eNOS) in the intestinal mucosa was assessed given its important role to assure perfusion. A total of 22 pigs (11 LBW and 11 NBW) were sacrificed at days 0, 3, 8 and 19 of life. Body weight and intestinal length were recorded and a piece of the small intestine was sampled for immunohistochemical analysis of von Willebrand Factor (vWF, an endothelial cell marker) and eNOS. LBW piglets had a relatively (to body weight) longer intestine than their NBW counterparts. Age did not affect microvasculature, which was more abundant (85% larger vWF-positive area) in NBW than LBW pigs. However, an interaction age*BW was observed for eNOS-IR, showing that eNOS presence peaked in NBW piglets on the first day of life and subsequently decreased. This pattern was not observed in LBW piglets. The less abundant intestinal endothelial mass and the different pattern of eNOS expression observed in LBW piglets suggests microcirculation as a contributing factor in the impaired digestive functioning and gut health of LBW pigs. However, revealing whether the origin of this alteration is prenatal or postnatal, for example due to a lower milk intake, needs further study.

The prebiotic potential of brewers' spent grain on livestock's health: a review.

The increasing interest from the feed as a source of energy towards specific nutrient-yielding compounds in feeds is amongst the latest developments from scientific and industrial communities. Apart from brewers' spent grain (BSG) being relatively inexpensive feed source, nutritious with high crude protein and minerals, recent studies have explored its potential as a source of prebiotics. Prebiotics are certain feeds that are comprised of non-digestive polysaccharides that can be fed to animals and modulate the balance and activities of microbial populations in the gut. The BSG contains arabinoxylans and β-glucans whereby when consumed by animals, they promote the activity of beneficial bacteria particularly species from three genera of Bifidobacterium, Enterococcus, and Lactobacillus. The increased degradation of fibrous feed accelerates the production of short-chain fatty acids (SCFA) which serve as the primary energy sources for the anaerobic microbes. This elevated concentration of SCFA stimulates numerous physio-biological functions which include intestinal nutrients absorption, glucose balance, improvement of immunity, lipid metabolism, and suppression of pathogens such as Salmonella and Escherichia coli. To capitalize on the prebiotic potential of BSG, certain considerations need to be well taken care of and these include possible microbial dysfunctions such as rumen acidosis, different responses rates of animals due to variations in health status, age, and species as well as feed safety issues especially mycotoxin contamination which can jeopardize its inherited prebiotic benefits.