Gastrointestinal Functionality Research Articles

Biomarkers of gastrointestinal functionality in animal nutrition and health

Effective gastrointestinal functionality is crucial in determining animal health, welfare and performance. A new definition of gastrointestinal functionality has been recently presented and it has identified the key components that contribute to effective gastrointestinal functionality and health. These components are: diet, effective structure and function of the gastrointestinal barrier, host interaction with the gastrointestinal microbiota, effective digestion and absorption of feed, effective immune status, and neuroendocrine function of the gut. Each of these components are linked to each other by several complex mechanisms and pathways, however, having identified some key components of gastrointestinal functionality offers the opportunity to evaluate potential biomarkers that can allow us to measure the functionality of the gastrointestinal system in farm animals. Numerous and rapidly evolving methodologies are producing an ever-increasing number and types of biomarkers, each with their own distinct advantages and disadvantages. Moreover, differences in models and methodologies make it difficult to extrapolate finding across species and to make meaningful comparisons, even when studies seem quite similar. This review will highlight the intrinsic challenges in choosing what biomarker to measure, where and when to measure it. Because of the complexity of the interactions between the key components of gastrointestinal functionality, we propose that the use of a single biomarker might not be feasible, rather we propose the development of a panel of biomarkers of gastrointestinal functionality that needs to be indicative not only of effective functionality and health of the gastrointestinal tract, but also of animal performance, health and welfare.

The Utilization of Prebiotics, Probiotics, Organic Acids and Antibiotics in Monogastric Animals

The gastrointestinal microbiota is a complex ecosystem made up of a multitude of bacterial species, some of which are potentially pathogenic, while others are considered good for the host. The beneficial microorganisms that live in the hindgut influence gastrointestinal functionality and the host’s health in general. Nowadays, many dietary supplements are available to be fed to young farm animals such as broilers, turkeys, piglets and calves in order to improve their intestinal health and growth performance. Despite the fact that non-pharmacological feed additives in general do not reach the efficacy of antibiotics as growth promoters, the proper choice and use of a dietary supplement may improve livestock productivity. Nevertheless, it has to be considered that dietary supplements usually increase the feed price, which means that the cost-benefit ratio of feed additives should always be determined. Keywords: gastrointestinal microbiota; dietary supplements; livestock productivity

Holistic Lipidomics of the Human Gut Phenotype Using Validated Ultra-High-Performance Liquid Chromatography Coupled to Hybrid Orbitrap Mass Spectrometry.

As lipids are assigned a plethora of biological functions, it is evident that dysregulated lipid metabolism signifies a key element in many pathological conditions. With this rationale, this study presents a validated lipidomics platform to map the fecal lipidome, which integrates unique information about host-gut microbiome interactions, gastrointestinal functionality, and dietary patterns. This particular method accomplished coverage across all eight lipid categories: fatty acyls, glycerolipids, phosphoglycerolipids, polyketides, prenols, saccharolipids, sphingolipids, and sterols. Generic extraction of freeze-dried feces was achieved by solid-liquid extraction using methanol and methyl tert-butyl ether. Extracted components were separated by liquid chromatography, whereby the selected ethylene-bridged hybrid phenyl ultra-high-performance liquid chromatography stationary phase allowed fast separation of both individual lipid species and categories. Detection was achieved by high-resolution full-scan Q-Exactive Orbitrap mass spectrometry and covered a broad m/z scan range (67-2300 Da). Method validation was performed in a targeted fashion to evaluate the analytical performance across all lipid categories, revealing excellent linearity (R2 ≥ 0.9921), acceptable repeatability (coefficients of variance ≤15.6%), and stable recovery (coefficients of variance ≤11.9%). Method suitability for untargeted fingerprinting was verified, demonstrating adequate linearity (R2 ≥ 0.90) for 75.3% and acceptable repeatability (coefficients of variance ≤30%) for 84.5% of about 9000 endogenous fecal compounds. Eventually, the potential of fecal lipidomics was exemplified within a clinical context of type 2 diabetes, thereby revealing significant perturbations [orthogonal partial least-squares discriminant analysis Q2(Y) of 0.728] in the fecal lipidome between participants with normal blood glucose levels (n = 26) and those with type 2 diabetes (n = 17).

Protein‐loaded sodium alginate and carboxymethyl cellulose beads for controlled release under simulated gastrointestinal conditions

AbstractNetwork characteristics of sodium alginate and carboxymethyl cellulose, in relation to the controlled release of bovine serum albumin under simulated gastrointestinal conditions, have been examined. Small‐deformation dynamic oscillation in‐shear, compression testing and optical microscopy were employed to monitor the structural characteristics of polysaccharide beads as excipients for protein entrapment. Work focused on gastrointestinal functionality and controlled release utilising variable acidity and counterion addition in preparations. Beads were found to shrink in gastric and swell in intestinal conditions, thus emphasising the disparate effect of experimental conditions. Changes in mechanical properties reflected alterations in gel microstructure, with beads becoming relatively strong in the gastric environment. In contrast, networks were weakened in the intestinal environment resulting in bead disintegration towards the end of digestion time. This type of structural behaviour allows the controlled delivery of the protein, as a model bioactive, in a particular part of the gastrointestinal tract.

Roles of the gut in the metabolic syndrome: an overview.

The metabolic syndrome is a cluster of risk factors (central obesity, hyperglycaemia, dyslipidaemia and arterial hypertension), indicating an increased risk of diabetes, cardiovascular disease and premature mortality. The gastrointestinal tract is seldom discussed as an organ system of principal importance for metabolic diseases. The present overview connects various metabolic research lines into an integrative physiological context in which the gastrointestinal tract is included. Strong evidence for the involvement of the gut in the metabolic syndrome derives from the powerful effects of weight-reducing (bariatric) gastrointestinal surgery. In fact, gastrointestinal surgery is now recommended as a standard treatment option for type 2 diabetes in obesity. Several gut-related mechanisms that potentially contribute to the metabolic syndrome will be presented. Obesity can be caused by hampered release of satiety-signalling gut hormones, reduced meal-associated energy expenditure and microbiota-assisted harvest of energy from nondigestible food ingredients. Adiposity per se is a well-established risk factor for hyperglycaemia. In addition, a leaky gut mucosa can trigger systemic inflammation mediating peripheral insulin resistance that together with a blunted incretin response aggravates the hyperglycaemic state. The intestinal microbiota is strongly associated with obesity and the related metabolic disease states, although the mechanisms involved remain unclear. Enterorenal signalling has been suggested to be involved in the pathophysiology of hypertension and postprandial triglyceride-rich chylomicrons; in addition, intestinal cholesterol metabolism probably contributes to atherosclerosis. It is likely that in the future, the metabolic syndrome will be treated according to novel pharmacological principles interfering with gastrointestinal functionality.

Gastrointestinal Functionality of Aquatic Animal (Oreochromis niloticus) Carcass in Water Allows Estimating Time of Death.

Postmortem changes have been previously studied in some terrestrial animal models, but no prior information is available on aquatic species. Gastrointestinal functionality was investigated in terms of indices, protein concentration, digestive enzyme activity, and scavenging activity, in an aquatic animal model, Nile tilapia, to assess the postmortem changes. Dead fish were floated indoors, and samples were collected within 48 h after death. Stomasomatic index decreased with postmortem time and correlated positively with protein, pepsin-specific activity, and stomach scavenging activity. Also intestosomatic index decreased significantly and correlated positively with protein, specific activity of trypsin, chymotrypsin, amylase, lipase, and intestinal scavenging activity. In their postmortem changes, the digestive enzymes exhibited earlier lipid degradation than carbohydrate or protein. The intestine changed more rapidly than the stomach. The findings suggest that the postmortem changes of gastrointestinal functionality can serve as primary data for the estimation of time of death of an aquatic animal.

The effects of red grape pomace inclusion in grower diet on amino acid digestibility, intestinal microflora, and sera and liver antioxidant activity in broilers

The objective of this study was to evaluate the effect of dietary red grape pomace (RGP) on amino acid digestibility (AIAAD), intestinal microflora, and antioxidant activity in the sera and liver. Sixty-six broilers were housed in battery cages. They were allocated to six cages corresponding to two dietary treatments with three replicates of each treatment. The treatments were administered from 10 to 36 days and included a control diet and a diet containing 1.5% RGP dry powder with the other components remaining unchanged, compared to the control. The RGP had a significant (P < 0.05) positive effect on the apparent metabolizable energy. The majority of coefficients of AIAAD were higher in the RGP. The ileal digestibility of threonine, serine, proline, and glycine was significantly (P < 0.05) higher in RGP. RGP had a positive effect (P < 0.05) on the content of Lactobacillus in the lower part of the ileum. The blood sera of broilers fed RGP had significantly (P < 0.05) lower 2,2-diphenyl-1-picrylhydrazyl (DPPH) and uric acid content. The RGP at a concentration of 15 g/kg in the grower diet did not affect the growth of broilers, and RGP is suitable for broiler diets to improve gastrointestinal tract functionality.

Histochemical and biometric study of the gastrointestinal system of Hyla orientalis (Bedriaga, 1890) (Anura, Hylidae).

This study was carried out to assess the localization of hyaluronic acid (HA) and the distribution of glycoproteins in the gastrointestinal system of adult Hyla orientalis. Histochemical analysis of the gastrointestinal system in H. orientalis showed that mucous content included glycogene and/or oxidable dioles [periodic acid/Schiff (PAS)+], neutral or acid-rich (PAS/AB pH 2.5+), sialic acid residues (KOH/PAS+) and acid sulphate [Aldehyde fuchsin (AF)+] glycoproteins. However the mucus content was not the same in stomach, small and large intestine. The mucus content of stomach included only glycogene and/or oxidable dioles and sialic acid residues. Besides these histochemical methods, the localization of HA was detected using biotinylated hyaluronic acid binding protein labeled with streptavidin-fluorescein isothiocyanate (FITC). In the extracellular matrix of the submucosa, the reaction for HA was evident. Since HA was located in submucosa beneath the epithelial layer of gastrointestinal system, it has a significant role in hydric balance, and essential to provide the gastrointestinal system integrity and functionality. According to biometric results, there were statistical differences between small and large intestine in terms of the amount of material stained positive with PAS/AB, PAS, KOH/PAS and AF/AB. Additionally, number of goblet cells in the small and large intestine was significantly different.

Probiotic/prebiotic supplementation of antiretrovirals improves gastrointestinal immunity in SIV-infected macaques.

HIV infection results in gastrointestinal (GI) tract damage, microbial translocation, and immune activation, which are not completely ameliorated with suppression of viremia by antiretroviral (ARV) therapy. Furthermore, increased morbidity and mortality of ARV-treated HIV-infected individuals is associated with these dysfunctions. Thus, to enhance GI tract physiology, we treated SIV-infected pigtail macaques with ARVs, probiotics, and prebiotics or with ARVs alone. This synbiotic treatment resulted in increased frequency and functionality of GI tract APCs, enhanced reconstitution and functionality of CD4+ T cells, and reduced fibrosis of lymphoid follicles in the colon. Thus, ARV synbiotic supplementation in HIV-infected individuals may improve GI tract immunity and thereby mitigate inflammatory sequelae, ultimately improving prognosis.

Black Pepper and Health Claims: A Comprehensive Treatise

For millennia, spices have been an integral part of human diets and commerce. Recently, the widespread recognition of diet-health linkages bolsters their dietary importance. The bioactive components present in them are of considerable significance owing to their therapeutic potential against various ailments. They provide physiological benefits or prevent chronic ailment in addition to the fundamental nutrition and often included in the category of functional foods. Black pepper (Piper Nigrum L.) is an important healthy food owing to its antioxidant, antimicrobial potential and gastro-protective modules. Black pepper, with piperine as an active ingredient, holds rich phytochemistry that also includes volatile oil, oleoresins, and alkaloids. More recently, cell-culture studies and animal modeling predicted the role of black pepper against number of maladies. The free-radical scavenging activity of black pepper and its active ingredients might be helpful in chemoprevention and controlling progression of tumor growth. Additionally, the key alkaloid components of Piper Nigrum, that is, piperine assist in cognitive brain functioning, boost nutrient's absorption and improve gastrointestinal functionality. In this comprehensive treatise, efforts are made to elucidate the antioxidant, antimicrobial, anti-inflammatory, gastro-protective, and antidepressant activities of black pepper. Moreover, the synergistic interaction of black pepper with different drugs and nutrients is the limelight of the manuscript. However, the aforementioned health-promoting benefits associated with black pepper are proven in animal modeling. Thus, there is a need to conduct controlled randomized trials in human subjects, cohort studies, and meta-analyses. Such future studies would be helpful in recommending its application in diet-based regimens to prevent various ailments.

Investigation of alginate gel inhomogeneity in simulated gastro-intestinal conditions using magnetic resonance imaging and transmission electron microscopy

The inhomogeneity of alginate gel beads prepared by an external diffusion method has been characterised using spatially resolved nuclear magnetic resonance or “magnetic resonance imaging” (MRI) and transmission electron microscopy (TEM). The beads exhibited various degrees of inhomogeneity although reducing the length of exposure to the gelling bath and the presence of non-gelling ions decreased gel inhomogeneity. In order to gain information regarding the gastro-intestinal functionality of these beads for in vivo applications, they were exposed to simulated gastro-intestinal conditions. The increased polymer concentration at the edge of the beads was shown to persist throughout our gastro-intestinal model despite the centre of the bead becoming progressively more porous in nature. The porosity of the alginate gels has been quantified by image analysis of transmission electron micrographs and shown to depend on both location within the bead and gastro-intestinal conditions. We suggest that such changes in porosity of these alginate beads during simulated gastro-intestinal conditions may make these an attractive option for controlled delivery applications in vivo.

Investigation of alginate beads for gastro-intestinal functionality, Part 1: In vitro characterisation

This paper summarises the work undertaken to characterise the physico-chemical properties of alginate gel beads in simulated gastro-intestinal (GI) conditions. Two types of alginate beads were investigated: “strong” (strongly gelled) and “weak” (weakly gelled) beads prepared by long and short exposure to a calcium chloride gelling bath, respectively. The beads were found to shrink in gastric conditions and swell in intestinal conditions due to changes in electrostatic forces in the gel matrix at the different pH and ionic strength conditions. We found a good correlation between the NMR transverse relaxation time ( T 2) of the water protons within the gel and alginate concentration which was dependant on environmental conditions. T 2 shortening was observed in gastric conditions reflecting the formation of a more dense gel network on shrinking. In intestinal conditions, T 2 increased reflecting the formation of a more open, porous gel network on swelling. This was corroborated by electron microscopy which clearly depicted the changes in gel density in simulated GI conditions. The mechanical properties of the beads similarly reflected the changes in the gel microstructure with the beads becoming stronger in gastric conditions and weaker in intestinal conditions, respectively. The beads were shown to eventually disintegrate towards the end of the intestinal phase which may make these alginate gel beads an attractive option as controlled delivery devices in the gastro-intestinal tract. The in vivo behaviour of the beads within the GI tract is investigated using non-invasive magnetic resonance imaging in the second paper of this series.

Investigation of alginate beads for gastro-intestinal functionality, Part 2: In vivo characterisation

This paper summarises work undertaken to visualise and characterise alginate gel beads, in vivo, in the human gastro-intestinal tract using magnetic resonance imaging (MRI). Two types of alginate beads were investigated: “strong” (strongly gelled) and “weak” (weakly gelled) beads, each prepared by long and short exposures to a calcium chloride gelling bath, respectively. Ten volunteers attended the study centre, on two different occasions, and consumed a different bead type on each visit. Before consuming the bead meal, the volunteers consumed 50 ml of Calogen ® (a fatty preload) which converted gastric motility to a fed pattern and delayed the emptying of the non-nutrient model bead meal from the stomach. Gastric emptying of the bead meal was dominated by the fatty preload, with the median half-emptying time 48 min for both bead types. Gastric sieving of the strong beads occurred with the percentage of the meal remaining at 60 min significantly higher for the strong bead meal compared to the weak bead meal. Both types of gelled beads were clearly visualised by MRI in both the stomach and the small intestine, with beads being more visible in the ileum compared to the jejunum and duodenum. The water proton transverse relaxation time, T 2, of the beads was measured in the stomach. After an initial increase, T 2 decreased slightly over time from the initial in vivo measurement. In the first paper of this series, we correlate in vitro T 2 shortening with formation of a more dense gel network. These in vivo investigations suggest that changes in the gel beads, within the GI tract, could be monitored using T 2.

Investigation of ionically crosslinked chitosan and chitosan–bovine serum albumin beads for novel gastrointestinal functionality

AbstractThe objective of the work was to determine whether chitosan–tripolyphosphate (TPP) systems can be used to develop safe gel particles for in vivo applications. In particular, we are interested in the use of chitosan systems capable of swelling at low pH in vitro as potentially swellable, satiety‐enhancing ingredients. The formation of homogeneous chitosan‐TPP gel beads was improved by reducing the pH of the TPP gelling bath from 8.5 to 4.0 thus increasing the cationic nature of chitosan and the crosslink density. However, the mechanical strength of this system was reduced compared to the basic system. This has been related to tightening of the gel network by increased shrinking of this system. Although release studies have shown that decreasing the pore size of the gel, by increasing the crosslink density through increasing the TPP concentration, is a good way to trap our model release polymer (dextran), in simulated gastrointestinal conditions, these ionic gel beads showed marked shrinking. We propose that this is due to screening of the charge on the chitosan molecule in the presence of salt and/or an excess of TPP which encourages ionic interactions. We conclude that these ionic gels are an unfeasible alternative satiety‐enhancing ingredient to covalently crosslinked systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Cloning and expression analysis of three digestive enzymes from Atlantic halibut ( Hippoglossus hippoglossus) during early development: Predicting gastrointestinal functionality

The objective of the present study was to describe the histological and physiological development of the gastrointestinal system in Atlantic halibut from the time of first-feeding until metamorphosis. At first-feeding, the gastrointestinal (GI) tract is divided into anterior, mid and hindgut regions. The liver is present, as is the pancreas. During development the pancreas changes from a compact organ to a diffuse tissue interspersed through much of the mesentery surrounding the GI tract. Functional gastric glands are not present until approximately 66 days post-hatch (dph). Using primers based upon winter flounder digestive enzyme gene sequences, we were able to amplify partial sequences for bile salt-activated lipase (BAL), trypsinogen (TRP), and pepsinogen (PEP) from RNA extracted from whole larvae and juveniles using Reverse Transcription-PCR (RT-PCR). PCR products were sequenced and the sequences used to design halibut gene-specific primers for BAL and PEP. RT-PCR analysis revealed that BAL and TRP gene expression was evident at least from the time of first-feeding but PEP gene expression was not detectable until 80 dph. In situ hybridization using molecular probes from winter flounder sequences localized expression of BAL and TRP to the exocrine pancreas. PEP expression was only localized to the glandular regions of the stomach. These data provide a first step toward understanding the molecular events governing the ontogeny of digestive capacity in Atlantic halibut.

Functional Activities of Lactobacillus Probiotics: Genetic Mandate

The lactobacilli are important inhabitants of the intestinal tract of man and animals. Considerable evidence has implicated them in a number of potentially beneficial roles including immunostimulation, pathogen exclusion, production of bioactive materials, and general intestinal health. Opportunities now abound for incorporation of lactobacilli into functional foods, dietary adjuncts, and health-related products. Over the past decade, developments in the molecular taxonomy of lactobacilli have identified six distinct species within the group previously designated Lactobacillus acidophilus. It remains an important challenge to understand the intestinal roles, activities, and interactions of the individual species, as well as the group at large. In this context, genetic characterization and manipulation of lactobacilli are essential to unequivocally define their contributions to the intestinal microbiota and ultimately control their unique and potentially beneficial properties. This presentation will examine gene systems and regulatory controls of lactobacilli that may be important to their activity, stability, and gastrointestinal functionality. The genetic tools and strategies currently available for characterization and manipulation of lactobacilli will be discussed relative to future targets for probiotic applications. From this framework, new opportunities for the development of safe and effective probiotics will be presented.