Dietary fibre and intestinal microflora: effects on intestinal morphometry and crypt branching

Fermented Rapeseed and Soybean Alone and in Combination with Macro Algae Inhibit Human and Pig Pathogenic Bacteria In Vitro

Higher plants produce secondary metabolites expressing antimicrobial effects as a defense mechanism against opportunistic microorganisms living in close proximity with the plant. Fermentation leads to bioconversion of plant substrates to these bioactive compounds and their subsequent release via breakdown of plant cell walls. Fermented feed products have recently started to become implemented in the pig industry to reduce overall disease pressure and have been found to reduce events such as post-weaning diarrhea. In this study, we investigate the antimicrobial potential of fermented soybean- and rapeseed-based pig feed supplements with and without added seaweed. The antimicrobial effect was tested in a plate well diffusion assay against a range of known human and livestock pathogenic bacteria. Further, we investigate the metabolite profiles based on liquid-chromatography mass-spectrometry (LC-MS) analysis of the fermented products in comparison to their unfermented constituents. We observed a pronounced release of potential antimicrobial secondary metabolites such as benzoic acids when the plant material was fermented, and a significantly increased antimicrobial effect compared to the unfermented controls against several pathogenic bacteria, especially Salmonella enterica Typhimurium, Listeria monocytogenes, Yersinia enterocolitica, and a strain of atopic dermatitis causing Staphylococcus aureus CC1. In conclusion, fermentation significantly enhances the antimicrobial properties of rapeseed, soybean, and seaweed, offering a promising alternative to zinc oxide for controlling pathogens in piglet feed. This effect is attributed to the release of bioactive metabolites effective against pig production-relevant bacteria.

Pectin Modulates Calcium Absorption in Polarized Caco-2 Cells via a Pathway Distinct from Vitamin D Stimulation

Pectin, a type of soluble fiber, promotes morphological changes in the small intestinal villi. Although its physiological significance is unknown, we hypothesized that changes in villus morphology enhance the efficiency of nutrient absorption in the small intestine and investigated the effect of pectin derived from persimmon on calcium absorption using polarized Caco-2 cells. In polarized Caco-2 cells, pectin altered the mRNA expression levels of substances involved in calcium absorption and the regulation of intracellular calcium concentration and significantly reduced calcium absorption. Although this was comparable to the results of absorption and permeability associated with the addition of active vitamin D, the simultaneous action of pectin and active vitamin D did not show any additive effects. Furthermore, as active vitamin D significantly increases the activity of intestinal alkaline phosphatase (ALP), which is known to be involved in the regulation of intestinal absorption of calcium and lipids, we also investigated the effect of pectin on intestinal ALP activity. As a result, it was found that, unlike the effect of active vitamin D, pectin significantly reduced intestinal ALP activity. These results suggest that pectin stimulates polarized Caco-2 cells through a mechanism distinct from the regulation of calcium absorption by vitamin D, modulating total calcium absorption from the elongated villi through morphological changes in the small intestine by suppressing it at the cellular level.

A diet rich in fermentable fiber promotes robust changes in the intestinal microbiota, mitigates intestinal permeability, and attenuates autoimmune uveitis

Therapeutic approaches for noninfectious uveitis have expanded greatly over the past 10 years, but are limited by potential side effects and limited efficacy. Thus, therapeutic approaches that include less toxic, potentially preventative strategies to manage noninfectious uveitis are essential areas of study. Diets rich in fermentable fiber are potentially preventative in various conditions such as metabolic syndrome and type 1 diabetes. We studied the effects of various fermentable dietary fibers in an inducible model of experimental autoimmune uveitis (EAU) and found that they differentially modulated uveitis severity. A high pectin diet was the most protective, reducing clinical disease severity through the induction of regulatory T lymphocytes and the suppression of Th1 and Th17 lymphocytes at peak ocular inflammation in either intestinal or extra-intestinal lymphoid tissues. The high pectin diet also promoted intestinal homeostasis as shown by changes in intestinal morphology and gene expression, as well as intestinal permeability. Pectin-induced modulation of intestinal bacteria appeared to be associated with protective changes in immunophenotype in the intestinal tract, and correlated with reduced uveitis severity. In summary, our current findings support the potential for dietary intervention as a strategy to mitigate noninfectious uveitis severity.

Intestinal plasticity and metabolism as regulators of organismal energy homeostasis

The small intestine displays marked anatomical and functional plasticity that includes adaptive alterations in adult gut morphology, enteroendocrine cell profile and their hormone secretion, as well as nutrient utilization and storage. In this Perspective, we examine how shifts in dietary and environmental conditions bring about changes in gut size, and describe how the intestine adapts to changes in internal state, bowel resection and gastric bypass surgery. We highlight the critical importance of these intestinal remodelling processes in maintaining energy balance of the organism, and in protecting the metabolism of other organs. The intestinal resizing is supported by changes in the microbiota composition, and by activation of carbohydrate and fatty acid metabolism, which govern the intestinal stem cell proliferation, intestinal cell fate, as well as survivability of differentiated epithelial cells. The discovery that intestinal remodelling is part of the normal physiological adaptation to various triggers, and the potential for harnessing the reversible gut plasticity, in our view, holds extraordinary promise for developing therapeutic approaches against metabolic and inflammatory diseases.

Selected commensals educate the intestinal vascular and immune system for immunocompetence

BACKGROUND

The intestinal microbiota fundamentally guides the development of a normal intestinal physiology, the education, and functioning of the mucosal immune system. The Citrobacter rodentium-carrier model in germ-free (GF) mice is suitable to study the influence of selected microbes on an otherwise blunted immune response in the absence of intestinal commensals.

RESULTS

Here, we describe that colonization of adult carrier mice with 14 selected commensal microbes (OMM¹² + MC²) was sufficient to reestablish the host immune response to enteric pathogens; this conversion was facilitated by maturation and activation of the intestinal blood vessel system and the step- and timewise stimulation of innate and adaptive immunity. While the immature colon of C. rodentium-infected GF mice did not allow sufficient extravasation of neutrophils into the gut lumen, colonization with OMM¹² + MC² commensals initiated the expansion and activation of the visceral vascular system enabling granulocyte transmigration into the gut lumen for effective pathogen elimination.

CONCLUSIONS

Consortium modeling revealed that the addition of two facultative anaerobes to the OMM¹² community was essential to further progress the intestinal development. Moreover, this study demonstrates the therapeutic value of a defined consortium to promote intestinal maturation and immunity even in adult organisms. Video Abstract.

A Fiber-Rich Diet and Radiation-Induced Injury in the Murine Intestinal Mucosa

Dietary fiber is considered a strong intestinal protector, but we do not know whether dietary fiber protects against the long-lasting mucosal damage caused by ionizing radiation. To evaluate whether a fiber-rich diet can ameliorate the long-lasting pathophysiological hallmarks of the irradiated mucosa, C57BL/6J mice on a fiber-rich bioprocessed oat bran diet or a fiber-free diet received 32 Gray in four fractions to the distal colorectum using a linear accelerator and continued on the diets for one, six or 18 weeks. We quantified degenerating crypts, crypt fission, cell proliferation, crypt survival, macrophage density and bacterial infiltration. Crypt loss through crypt degeneration only occurred in the irradiated mice. Initially, it was most frequent in the fiber-deprived group but declined to levels similar to the fiber-consuming group by 18 weeks. The fiber-consuming group had a fast response to irradiation, with crypt fission for growth or healing peaking already at one week post-irradiation, while crypt fission in the fiber-deprived group peaked at six weeks. A fiber-rich diet allowed for a more intense crypt cell proliferation, but the recovery of crypts was eventually lost by 18 weeks. Bacterial infiltration was a late phenomenon, evident in the fiber-deprived animals and intensified manyfold after irradiation. Bacterial infiltration also coincided with a specific pro-inflammatory serum cytokine profile. In contrast, mice on a fiber-rich diet were completely protected from irradiation-induced bacterial infiltration and exhibited a similar serum cytokine profile as sham-irradiated mice on a fiber-rich diet. Our findings provide ample evidence that dietary fiber consumption modifies the onset, timing and intensity of radiation-induced pathophysiological processes in the intestinal mucosa. However, we need more knowledge, not least from clinical studies, before this finding can be introduced to a new and refined clinical practice.

Fishmeal Replacement with Hermetia illucens Meal in Aquafeeds: Effects on Zebrafish Growth Performances, Intestinal Morphometry, and Enzymology

Fishmeal (FM) is still the most important protein source in aquafeeds. However, due to the reduction of wild fish stocks used for FM production, its manufacturing it is now unsustainable. Insect meal represents a valid alternative to FM, due to the low carbon footprint of its production and its high nutritional value. The aim of this study was to investigate the potentials of replacing FM with black soldier fly (Hermetia illucens) meal (HIM) in aquafeeds, using zebrafish as the animal model. Four diets were formulated with increasing HIM/FM replacement rate (the control diet contained 20% FM). Mortality rates, growth performances, and feed consumptions were measured, and fish intestine samples were collected for histological and enzymatic analysis. After 49 days, all groups almost tripled their initial body weight (cumulative body weight gain ranged between 143.9 and 155.2 mg), and no statistically significant differences among treatments were observed in relation to growth performances and histological traits. Contrarily, trypsin, alkaline phosphatases, and alpha amylase–glucoamylase activities were significantly reduced when the FM replacement rate was increased. In conclusion, HIM may represent an alternative to FM, since no adverse effects were observed when it was included up to 20% in the zebrafish diet, even when replacing 100% of the FM.

Prebiotics/Probiotics Mixture Induced Changes in Cecal Microbiome and Intestinal Morphology Alleviated the Loperamide-Induced Constipation in Rat

The aim of this study was to investigate the effect of a mixture of multi-strain probiotics and prebiotics on loperamide-induced constipation in Sprague-Dawley rats. A multi-strain probiotics alone (loperamide-induced group with multi-strain probiotics mixture group; Lop-Pro) and a mixture of multi-strain probiotics and prebiotics (loperamide-induced group with multi-strain probiotics and prebiotics mixture group; Lop-Pro/Pre) were administered orally after inducing constipation. The fecal water content was significantly higher (by 42%) in the Lop-Pro/Pre group (33.5%) than in the loperamide-induced group (Lop) (23.7%) (p<0.05). The intestinal mucosal thickness, crypt cell area, and interstitial cells of Cajal area were significantly higher in the Lop-Pro/Pre group compared to the Lop group by 16.4%, 20.6%, and 42.3%, respectively. Additionally, the total short-chain fatty acid content was significantly increased in the Lop-Pro and Lop-Pro/Pre groups by 56.4% and 54.2%, respectively, compared with the Lop group. The Lop-Pro and Lop-Pro/Pre groups recovered loperamide-induced alteration in Bacteroidetes and Verrucomicrobia abundance among intestinal microbiota, whereas the Lop-Pro/Pre group recovered Akkermansia, Lactobacillus, Clostridium, Bacteroides, and Oscillibacter abundance. Moreover, the relative abundance of Oscillibacter and Clostridium was significantly different in the Lop-Pro/Pre group compared to the Lop group. Collectively, administration of synbiotics rather than multi-strain probiotics alone is effective in alleviating constipation.

The prebiotic fiber inulin ameliorates cardiac, adipose tissue, and hepatic pathology, but exacerbates hypertriglyceridemia in rats with metabolic syndrome

Prebiotics ameliorate dysbiosis and influence metabolism and the immune system, but their effects on cardiovascular complications in metabolic disorders remain largely unknown. We here investigated the effects of the soluble fiber inulin on cardiac, adipose tissue, and hepatic pathology as well as on metabolic disorders in DahlS.Z-Leprfa/Leprfa (DS/obese) rats, an animal model of metabolic syndrome (MetS). DS/obese rats and their homozygous lean (DahlS.Z-Lepr+/Lepr+, or DS/lean) littermate controls were fed a purified diet containing 5% or 20% inulin from 9 to 13 wk of age. The high-fiber diet ameliorated hypertension, left ventricular inflammation, fibrosis and diastolic dysfunction; attenuated adipose tissue inflammation and fibrosis; and alleviated the elevation of interleukin-6 levels, without affecting insulin resistance, in DS/obese rats. In addition, high fiber intake ameliorated lipid accumulation, inflammation, and fibrosis; attenuated the reduction in AMPK activity; upregulated sterol regulatory element-binding protein-1c gene expression; and increased the expression of microsomal triglyceride transfer protein gene in the liver of DS/obese rats. It also mitigated increases in total and non-high-density lipoprotein cholesterol levels but increased the triglyceride concentration in serum in these rats. None of these parameters were affected by high dietary fiber in DS/lean rats. The proportion of regulatory T cells in adipose tissue was influenced by dietary fiber but not by genotype. Our results indicate that inulin exacerbates hypertriglyceridemia but alleviates hypertension and cardiac injury as well as adipose tissue and hepatic pathology in MetS rats.NEW & NOTEWORTHY Prebiotics ameliorate dysbiosis and influence metabolism and the immune system, but their effects on cardiovascular complications in metabolic disorders remain largely unknown. Inulin ameliorated hypertension, cardiac injury, and diastolic dysfunction without affecting obesity or insulin resistance in a rat model of metabolic syndrome. The favorable cardiac effects of inulin may be related to inhibition of systemic inflammation associated with a reduction in circulating interleukin-6 levels. Additionally, inulin exacerbated hypertriglyceridemia but alleviates adipose tissue and hepatic pathology in these animals, as well as increased the number of regulatory T cells in adipose tissue.

The effect of fucoidan or potassium permanganate on growth performance, intestinal pathology, and antioxidant status in Nile tilapia (Oreochromis niloticus)

Fucoidans are marine algal sulfated glycans that are widely used as dietary additives in aquaculture. These glycans are recognized as beneficial supplements for their antimicrobial, anti-inflammatory, anticancer, and antiviral properties. Potassium permanganate is another commonly used chemical that is used in aquaculture to treat infections in fish. Despite their widespread use, there are few data available regarding the potential sublethal toxicity associated with fucoidan and potassium permanganate treatments of fish. In this study, we investigated the effect of each compound on the growth, intestinal health, and antioxidant status of Nile tilapia (Oreochromis niloticus). Both compounds affected the growth of experimental fish compared with untreated fish. However, while growth parameters were positively associated with the dose of fucoidan administered, growth was negatively associated with the dose of potassium permanganate in Nile tilapia. Fucoidan treatment was observed to improve the intestinal health of fish based upon increases in intestinal villous area, intestinal villous length and width, and the intraepithelial lymphocyte number and decreases in the total intestinal bacterial count compared with untreated fish. Conversely, potassium permanganate induced intestinal epithelium proliferation and villous branching, a histopathological response typically observed with chemical irritants. Both fucoidan and potassium permanganate decreased levels of oxidative and nitrosative stress markers and enhanced the antioxidant status in multiple organs. Taken together, fucoidan dietary application improved the growth, intestinal health, and antioxidant status in Nile tilapia, supporting the use of this compound as a promising feed additive for aquaculture production. Conversely, potassium permanganate baths have negative effects on fish growth at higher doses and appeared to act as a gastrointestinal irritant in tilapia. This study improves knowledge regarding the biochemical and histological responses in Nile tilapia to two widely used aquaculture-related treatments.

Sending signals - The microbiota's contribution to intestinal epithelial homeostasis

The intestine is inhabited by a diverse range of microorganisms, which requires the host to employ numerous barrier measures to prevent bacterial invasion. However, the intestinal microbiota additionally acts symbiotically with host cells to maintain epithelial barrier function, and perturbation to this interaction plays a pivotal role in intestinal pathogenesis. In this review, we highlight current findings of how the intestinal microbiota influences host intestinal epithelial cells. In particular, we review the roles of numerous microbial-derived products as well as mechanisms by which these microbial products influence the regulation of intestinal epithelial population dynamics and barrier function.

Canola meal in nursery pig diets: growth performance and gut health

An experiment was conducted to determine the effects of including canola meal (CM) in nursery pig diets on growth performance, immune response, fecal microbial composition, and gut integrity. A total of 200 nursery pigs (initial body weight = 7.00 kg) were obtained in two batches of 100 pigs each. Pigs in each batch were housed in 25 pens (four pigs per pen) and fed five diets in a randomized complete block design. The five diets were corn-soybean meal (SBM)-based basal diets with 0%, 10%, 20%, 30%, or 40% of CM. The diets were fed in three phases: phase 1: day 0 to 7, phase 2: day 7 to 21, and phase 3: day 21 to 42. Diets in each phase were formulated to similar net energy, Ca, and digestible P and amino acid contents. Feed intake and body weight were measured by phase. Immune response and gut integrity parameters were measured at the end of phases 1 and 2. Fecal microbial composition for diets with 0% or 20% CM was determined at the end of phase 2. Overall average daily gain (ADG) responded quadratically (P < 0.05) to increasing dietary level of CM such that ADG was increased by 17% due to an increase in the dietary level of CM from 0% to 20% and was reduced by 16% due to an increase in the dietary level of CM from 20% to 40%. Pigs fed diets with 0% or 40% CM did not differ in overall ADG. Dietary CM tended to quadratically decrease (P = 0.09) serum immunoglobulin A (IgA) level at the end of phase 2 such that serum IgA level tended to reduce with an increase in dietary CM from 0% to 20% and to increase with an increase in dietary CM from 20% to 40%. Dietary CM at 20% decreased (P < 0.05) the relative abundance of Bacteroidetes phylum and tended to increase (P = 0.07) the relative abundance of Firmicutes phylum. Dietary CM linearly increased (P < 0.05) the lactulose to mannitol ratio in the urine by 47% and 49% at the end of phases 1 and 2, respectively, and tended to linearly decrease (P < 0.10) ileal transepithelial electrical resistance at the end of phase 1 by 64%. In conclusion, CM fed in the current study could be included in corn-SBM-based diets for nursery pigs 20% to improve the growth performance and gut microbial composition and reduce immune response. Also, the CM used in the current study could be included in corn-SBM-based diets for nursery pigs at 30% or 40% without compromising growth performance. Dietary CM increased gut permeability, implying that dietary CM at 20% improves the growth performance of weaned pigs through mechanisms other than reducing gut permeability.

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.

Dietary Oat Bran Reduces Systemic Inflammation in Mice Subjected to Pelvic Irradiation

Patients undergoing radiotherapy to treat pelvic-organ cancer are commonly advised to follow a restricted fiber diet. However, reducing dietary fiber may promote gastrointestinal inflammation, eventually leading to deteriorated intestinal health. The goal of this study was to evaluate the influence of dietary fiber on radiation-induced inflammation. C57BL/6J male mice were fed a High-oat bran diet (15% fiber) or a No-fiber diet (0% fiber) and were either irradiated (32 Gy delivered in four fractions) to the colorectal region or only sedated (controls). The dietary intervention started at 2 weeks before irradiation and lasted for 1, 6, and 18 weeks after irradiation, at which time points mice were sacrificed and their serum samples were assayed for 23 cytokines and chemokines. Our analyses show that irradiation increased the serum cytokine levels at all the time points analyzed. The No-fiber irradiated mice had significantly higher levels of pro-inflammatory cytokines than the High-oat irradiated mice at all time points. The results indicate that a fiber-rich oat bran diet reduces the intensity of radiation-induced inflammation, both at an early and late stage. Based on the results, it seems that the advice to follow a low-fiber diet during radiotherapy may increase the risk of decreased intestinal health in cancer survivors.

Targeting gut microbiota and barrier function with prebiotics to alleviate autoimmune manifestations in NOD mice

AIMS/HYPOTHESIS

Adopting a diet containing indigestible fibre compounds such as prebiotics to fuel advantageous bacteria has proven beneficial for alleviating inflammation. The effect of the microbial changes on autoimmunity, however, remains unknown. We studied the effects of prebiotic xylooligosaccharides (XOS) on pancreatic islet and salivary gland inflammation in NOD mice and tested whether these were mediated by the gut microbiota.

METHODS

Mother and offspring mice were fed an XOS-supplemented diet until diabetes onset or weaning and were compared with a control-fed group. Diabetes incidence was monitored, insulitis and sialadenitis were scored in histological sections from adult mice, and several metabolic and immune variables were analysed in mice before the development of diabetes. Gut barrier function was assessed using an in vivo FITC-dextran permeability test. The importance of XOS-mediated gut microbial changes were evaluated in antibiotic-treated mice fed either XOS or control diet or given a faecal microbiota transplant from test animals.

RESULTS

Diabetes onset was delayed in the XOS-fed mice, which also had fewer cellular infiltrations in their pancreatic islets and salivary glands. Interestingly, insulitis was most reduced in the XOS-fed groups when the mice were also treated with an antibiotic cocktail. There was no difference in sialadenitis between the dietary groups treated with antibiotics; the mice were protected by microbiota depletion regardless of diet. Faecal microbiota transplantation was not able to transfer protection. No major differences in glucose-insulin regulation, glucagon-like peptide-1, or short-chain fatty acid production were related to the XOS diet. The XOS diet did, however, reduce gut permeability markers in the small and large intestine. This was accompanied by a more anti-inflammatory environment locally and systemically, dominated by a shift from M1 to M2 macrophages, a higher abundance of activated regulatory T cells, and lower levels of induction of natural killer T cells and cytotoxic T cells.

CONCLUSIONS/INTERPRETATION

Prebiotic XOS have microbiota-dependent effects on salivary gland inflammation and microbiota-independent effects on pancreatic islet pathology that are accompanied by an improved gut barrier that seems able to heighten control of intestinal diabetogenic antigens that have the potential to penetrate the mucosa to activate autoreactive immune responses.

Laxative effects of triple fermented barley extracts (FBe) on loperamide (LP)-induced constipation in rats

BACKGROUND

Constipation, a common health problem, causes discomfort and affects the quality of life. This study intended to evaluate the potential laxative effect of triple fermented barley (Hordeum vulgare L.) extract (FBe), produced by saccharification, Saccharomyces cerevisiae, and Weissella cibaria, on loperamide (LP)-induced constipation in Sprague-Dawley (SD) rats, a well-established animal model of spastic constipation.

METHODS

Spastic constipation was induced via oral treatment with LP (3 mg/kg) for 6 days 1 h before the administration of each test compound. Similarly, FBe (100, 200 and 300 mg/kg) was orally administered to rats once a day for 6 days. The changes in number, weight, and water content of fecal, motility ratio, colonic mucosa histology, and fecal mucous contents were recorded. The laxative properties of FBe were compared with those of a cathartic stimulant, sodium picosulfate. A total of 48 (8 rats in 6 groups) healthy male rats were selected and following 10 days of acclimatization. Fecal pellets were collected one day before administration of the first dose and starting from immediately after the fourth administration for a duration of 24 h. Charcoal transfer was conducted after the sixth and final administration of the test compounds.

RESULTS

In the present study, oral administration of 100-300 mg/kg of FBe exhibited promising laxative properties including intestinal charcoal transit ratio, thicknesses and mucous producing goblet cells of colonic mucosa with decreases of fecal pellet numbers and mean diameters remained in the lumen of colon, mediated by increases in gastrointestinal motility.

CONCLUSION

Therefore, FBe might act as a promising laxative agent and functional food ingredient to cure spastic constipation, with less toxicity observed at a dose of 100 mg/kg.

Quantification of epithelial cell proliferation, cell dynamics, and cell kinetics in vivo

The measurement of cell proliferation in vivo is usually carried out by the examination of static measures. These comprise the mitotic index or labeling indices using incorporation of DNA synthesis markers such as bromodeoxyuridine or tritiated thymidine, or intrinsic markers, such as Ki67 and proliferative cell nuclear antigen (PCNA). But static measures only provide a 'snapshot' of cell proliferation. Rate measures, including double labeling methods and the metaphase arrest method, can actually measure cell production rates but they are far less utilized at present. Transit times and migration rates can also be measured using pulse and chase labeling or by following the transit of labeled cells through the tissue. Simple indices of cell division can easily be confounded by concomitant changes in the compartment size and many alleged markers of proliferation have serious shortcomings, as the markers may be involved in multiple aspects of cell regulation. The complexities of studying proliferation in vivo are illustrated here with a focus on the gastrointestinal tract. Some of these methods can help elucidate the role of the stem cells and their relationship to label retaining cells. WIREs Dev Biol 2017, 6:e274. doi: 10.1002/wdev.274 For further resources related to this article, please visit the WIREs website.

Ameliorating effects of herbal formula hemomine on experimental subacute hemorrhagic anemia in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Hemomine (HM) is an herbal mixture consisting of 5 varieties of the hematopoietic herbal extracts (Angelica gigas Nakai, Cnidium officinale Makino, Paeonia lactiflora Pall., Rehmannia glutinosa Liboschitz ex Stueudel, Glycyrrhiza uralensis Fischer).

AIM OF THE STUDY

Anemia has been treated with iron supplements, whereas it could cause adverse side effects such as digestive discomfort. In the present study, HM was applied to SHA rats to test for several activities so as to verify its therapeutic potentials on anemia and digestive discomfort.

MATERIALS AND METHODS

Sprague-Dawley rats were assigned to seven groups: (Two controls, two references (ferric hydroxide polymatose (FM) and ferritin extract glycerin hydrate (FA)), three different concentrations of HM, n=8 per groups), and induced subacute hemorrhagic anemia (SHA) through blood exsanguinations once a day for 7 days.

RESULTS

The SHA animal model showed changes in the markers related to classic iron-deficient and regenerative anemia in this experiment. However, the SHA related anemic signs were dose-dependently inhibited by the administration of HM 2, 1, and 0.5ml/kg for 7 days, and more favorably than the equal dosages of FM and FA. In addition, FM and FA showed the typical constipation signs, including reduction of in thickness of the colonic mucosa, in contrast, HM 2, 1, and 0.5ml/kg groups had no effects on the gastrointestinal motilities and the colonic mucous components when compared to the controls. The results suggested that the HM significantly showed to have therapeutic effects in the experimental SHA in rats, and is more potent than the commercial iron supplement through the proliferation of hematopoietic stem cells with reduced digestive discomfort.

CONCLUSIONS

Therefore, Hemomine may prove to be a promising hematopoietic and therapeutic agent for anemia.

Prenatal caprine milk oligosaccharide consumption affects the development of mice offspring

SCOPE

The composition of the gastrointestinal (GIT) microbiota, particularly in early life, influences the development of metabolic diseases later in life. The maternal microbiota is the main source of bacteria colonising the infant GIT and can be modified by dietary prebiotics. Our objective was to determine the effects of prenatal consumption of prebiotic caprine milk oligosaccharides (CMO) on the large intestine of female mice, milk composition, and offspring's development.

METHODS AND RESULTS

C57BL/6 mice were fed either a control diet, CMO diet, or galacto-oligosaccharide diet from mating to weaning. From weaning, some pups nursed by CMO, GOS, and control-dams were fed the control diet for 30 days. CMO or GOS-fed dams had increased colon length and milk protein concentration compared to control-fed dams. At weaning, pups from CMO-fed dams had increased body weight and colon length and increased proportions of colonic Bifidobacterium spp compared to the pups from control-fed dams. Thirty days after weaning, pups from CMO-fed dams had increased visceral fat weight compared to pups from control-fed dams.

CONCLUSION

Consumption of CMO by the dams during gestation and lactation improved the development of the pups, and the relative abundance of bifidobacteria and butyric acid in the colon, at weaning.

Morphoquantitative analysis of the Ileum of C57BL/6 mice (Mus musculus) fed with a high-fat diet

Due to the increase in overweight and obesity in humans, various studies have been conducted in recent years that demonstrate the detrimental effects on tissues and organs. The aim of this study was to assess the morphoquantitative changes produced in the ileum of mice, associated with high-fat diets. Fourteen male C57BL/6 mice, 5 months old, were fed two types of diets for 14 weeks. The control group (C) was fed a standard diet (10% fat, AIN-93M) and the experimental group (E) was fed a high-fat diet (42% fat, AIN-93M-AG). The assessments included: body weight, calorie consumption, food efficiency, biochemical analysis of plasma lipids, diameter, total wall thickness, thickness of the tunica mucosa and tunica muscularis, length and width of the intestinal villi, depth of the intestinal crypts and number of goblet cells per mm(-2) (NA). For the statistical analysis the Student's t-test was used, considering a P value less than 0.05. The mice in the E group presented greater weight gain (P = 0.028), higher levels of total and LDL cholesterol (P = 0.03 and P = 0.01, respectively), and length of the intestinal villi (P = 0.000). The width of the intestinal villi and the NA of PAS-positive goblet cells presented significantly lower values (P = 0.037 and P = 0.039, respectively) than the C group. The observed changes could be related to the higher demand for fat absorption and to possible alterations in the intestinal microflora and inflammation by action of high-fat diets.

Diet and Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) are increasingly becoming interested in nonpharmacologic approaches to managing their disease. One of the most frequently asked questions of IBD patients is what they should eat. The role of diet has become very important in the prevention and treatment of IBD. Although there is a general lack of rigorous scientific evidence that demonstrates which diet is best for certain patients, several diets-such as the low-fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diet; the specific carbohydrate diet; the anti-inflammatory diet; and the Paleolithic diet-have become popular. This article discusses the diets commonly recommended to IBD patients and reviews the supporting data.

Soybean Oil Is More Obesogenic and Diabetogenic than Coconut Oil and Fructose in Mouse: Potential Role for the Liver

The obesity epidemic in the U.S. has led to extensive research into potential contributing dietary factors, especially fat and fructose. Recently, increased consumption of soybean oil, which is rich in polyunsaturated fatty acids (PUFAs), has been proposed to play a causal role in the epidemic. Here, we designed a series of four isocaloric diets (HFD, SO-HFD, F-HFD, F-SO-HFD) to investigate the effects of saturated versus unsaturated fat, as well as fructose, on obesity and diabetes. C57/BL6 male mice fed a diet moderately high in fat from coconut oil and soybean oil (SO-HFD, 40% kcal total fat) showed statistically significant increases in weight gain, adiposity, diabetes, glucose intolerance and insulin resistance compared to mice on a diet consisting primarily of coconut oil (HFD). They also had fatty livers with hepatocyte ballooning and very large lipid droplets as well as shorter colonic crypt length. While the high fructose diet (F-HFD) did not cause as much obesity or diabetes as SO-HFD, it did cause rectal prolapse and a very fatty liver, but no balloon injury. The coconut oil diet (with or without fructose) increased spleen weight while fructose in the presence of soybean oil increased kidney weight. Metabolomics analysis of the liver showed an increased accumulation of PUFAs and their metabolites as well as γ-tocopherol, but a decrease in cholesterol in SO-HFD. Liver transcriptomics analysis revealed a global dysregulation of cytochrome P450 (Cyp) genes in SO-HFD versus HFD livers, most notably in the Cyp3a and Cyp2c families. Other genes involved in obesity (e.g., Cidec, Cd36), diabetes (Igfbp1), inflammation (Cd63), mitochondrial function (Pdk4) and cancer (H19) were also upregulated by the soybean oil diet. Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil.

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

Dose-dependent effects of a soluble dietary fibre (pectin) on food intake, adiposity, gut hypertrophy and gut satiety hormone secretion in rats

Soluble fermentable dietary fibre elicits gut adaptations, increases satiety and potentially offers a natural sustainable means of body weight regulation. Here we aimed to quantify physiological responses to graded intakes of a specific dietary fibre (pectin) in an animal model. Four isocaloric semi-purified diets containing 0, 3.3%, 6.7% or 10% w/w apple pectin were offered ad libitum for 8 or 28 days to young adult male rats (n = 8/group). Measurements were made of voluntary food intake, body weight, initial and final body composition by magnetic resonance imaging, final gut regional weights and histology, and final plasma satiety hormone concentrations. In both 8- and 28-day cohorts, dietary pectin inclusion rate was negatively correlated with food intake, body weight gain and the change in body fat mass, with no effect on lean mass gain. In both cohorts, pectin had no effect on stomach weight but pectin inclusion rate was positively correlated with weights and lengths of small intestine and caecum, jejunum villus height and crypt depth, ileum crypt depth, and plasma total glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) concentrations, and at 8 days was correlated with weight and length of colon and with caecal mucosal depth. Therefore, the gut's morphological and endocrine adaptations were dose-dependent, occurred within 8 days and were largely sustained for 28 days during continued dietary intervention. Increasing amounts of the soluble fermentable fibre pectin in the diet proportionately decreased food intake, body weight gain and body fat content, associated with proportionately increased satiety hormones GLP-1 and PYY and intestinal hypertrophy, supporting a role for soluble dietary fibre-induced satiety in healthy body weight regulation.

Laxative effects of fermented rice extract in rats with loperamide-induced constipation

Constipation is a common problem in males and females. The aim of the present study was to evaluate the laxative effects of fermented rice extract (FRe) on rats with loperamide-induced constipation. FRe (100, 200 and 300 mg/kg) was administered orally once per day for six days following 1 h loperamide treatment. The laxative effects of FRe were compared with those of sodium picosulfate (S. picosulfate). Following the induction of constipation in the rats, a marked decrease was observed in the fecal pellet number and water content discharged over 24 h, the surface mucus thickness in the colonic lumen, intestinal charcoal transit ratio, thickness of the colonic mucosa and the number of mucus-producing cells, while an increase was observed in the number of fecal pellets remaining in the colonic lumen and their mean diameter, as compared with the normal vehicle control rats. These conditions were significantly alleviated following the administration of the three doses of FRe when compared with the loperamide control group. However, the alleviating effects were lower than those of S. picosulfate, with the exception of the intestinal charcoal transit ratio. Similar effects on the intestinal charcoal transit ratio were detected for the three doses of FRe when compared with the S. picosulfate-treated rats. In conclusion, the results indicated that FRe exhibits a laxative effect without causing diarrhea, as compared with sodium picosulfate; thus, FRe may be effective as a complementary medicine in patients suffering from lifestyle-induced constipation.

The effect of hibernation on the morphology and histochemistry of the intestine of the greater mouse-eared bat, Myotis myotis

Seasonal variations in morphometry and histochemistry of the intestine have been examined in the active and hibernating greater mouse-eared bat, Myotis myotis, using histological and histochemical techniques. The results of morphometric analyses indicated that hibernation affected the villus height, villus width, crypt depth and crypt width of the duodenum, jejunum and ileum. Histochemical analysis showed that goblet cells of the small and large intestine contain acidic and neutral mucosubstances. According to the results obtained with Alcian Blue (pH 5.8)/PAS staining, hyaluronic acid is dominant in the goblet cells of the small and large intestine during both the hibernation and active periods. Chondroitin sulfate and dermatan sulfate, which are sulfated GAGs, were dominant, and very little heparan sulfate, heparin and keratan sulfate were present. Moreover, sulfated glycoproteins were also detected in the goblet cells of the small intestine in the active animals. The present study demonstrates that hibernation altered the examined morphometric and histochemical parameters of the intestine.

Fructo-oligosaccharides and iron bioavailability in anaemic rats: the effects on iron species distribution, ferroportin-1 expression, crypt bifurcation and crypt cell proliferation in the caecum

The present study investigated the effects of fructo-oligosaccharides (FOS) on the bioavailability of Fe from ferric pyrophosphate (FP), a water-insoluble compound, in Fe-deficient anaemic rats that were subjected to a Hb repletion assay. Male Wistar rats (n 64) were fed adequate or low (8 mg/kg) Fe diets for 15 d followed by 1 or 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as ferrous sulphate (FS), FP or FP that was mixed with 7·5% FOS in the form of yacon flour or Raftilose P95 (RAF), a purified source of FOS. The effects of FOS were observed within the 1st week of the repletion period. Fe bioavailability was improved by FOS supplementation, as measured by Hb regeneration efficiency and hepatic Fe stores, which were more pronounced in the RAF group. Moreover, RAF supplementation resulted in a higher biological value relative to that of the FP group. FOS supplementation resulted in caecal enlargement, in addition to acidification and Fe species redistribution in the caecal contents relative to the control rats. These effects occurred concomitantly with decreased ferroportin (FPN)-1 expression in the caecal mucosa, which was similar in magnitude to that observed in the FS group. Caecum mucosal morphometry was influenced by FOS supplementation, whereas crypt fission and cell proliferation were highest in the caecum of the RAF group. These results reinforce the effects of FOS as Fe bioavailability enhancers in anaemic rats that are sustained by early changes in their caecal environment (decreased mucosal FPN-1 expression and increased Fe absorbability, crypt fission and cellularity).

Synergistic effect of fermented rice extracts on the probiotic and laxative properties of yoghurt in rats with loperamide-induced constipation

Aim. The objective was to evaluate the synergistic effects of fermented rice extracts (FRe) on the laxative and probiotic properties of yoghurt in rats with loperamide-induced constipation. Methods. After constipation induction, yoghurt containing FRe (BFRe; 0.05%, 0.1%, or 1%) was administered orally once per day for 6 days. Results. Loperamide treatment caused marked decreases in fecal pellet numbers and water content discharged, as well as in the surface mucosal thickness of the colonic lumen, intestinal charcoal transit ratio, thickness, and number of mucous-producing goblet cells in the colonic mucosa, whereas it increased the remnant fecal pellet number and the mean diameter of the colonic lumen. However, this loperamide-induced constipation was ameliorated by treatment with FRe, yoghurt single formula, or 0.05%, 0.1%, or 1% BFRe (10 mL/kg). Additionally, the viable numbers of Lactobacillus in the cecal contents and feces were markedly higher than those in constipated rats. Moreover, greater probiotic and laxative effects were detected in BFRe-treated rats than in rats treated with equivalent doses of yoghurt or FRe single formula. Conclusion. The results suggest that addition of FRe to liquid yoghurt will enhance the probiotic and beneficial laxative effects of yoghurt in the digestive tract, without causing side effects.

Pectin of Prunus domestica L. alters sulfated structure of cell-surface heparan sulfate in differentiated Caco-2 cells through stimulation of heparan sulfate 6-O-endosulfatase-2

Although previous reports have suggested that pectin induces morphological changes of the small intestine in vivo, the molecular mechanisms have not been elucidated. As heparan sulfate plays important roles in development of the small intestine, to verify the involvement of heparan sulfate (HS) in the pectin-induced morphological changes of the small intestine, the effects of pectin from Prunus domestica L. on cell-surface HS were investigated using differentiated Caco-2 cells. Disaccharide compositional analysis revealed that sulfated structures of HS were markedly changed by pectin administration. Real-time RT-PCR showed that pectin upregulated human HS 6-O-endosulfatase-2 (HSulf-2) expression and markedly inhibited HSulf-1 expression. Furthermore, inhibition analysis suggested that pretreatment with fibronectin III1C fragment, RGD peptide, and ERK1/2 inhibitor suppressed pectin-induced HSulf-2 expression. These observations indicate that pectin induced the expression of HSulf-2 through the interaction with fibronectin, α5β1 integrin, and ERK1/2, thereby regulating the sulfated structure of HS on differentiated Caco-2 cells.

Long-term intake of pea fiber affects colonic barrier function, bacterial and transcriptional profile in pig model

The objective of this study was to investigate the effect of long-term intake of pea fiber (PF) on colonic health and the underlying mechanism. Fifty weaned piglets were randomly allocated into 2 groups receiving control and fibrous diet with inclusion of PF from weaning to Day 160 postweaning, with 5 pens in each group and 5 pigs in each pen. Compared with control diet, long-term intake of PF diet induced deeper crypt and increased colonic barrier-related protein expression of mucin and sIgA. As indicated by the increased lactobacillus content, pigs fed PF diet had a stimulating effect on bacterial fermentation in the colon, thus a higher concentration of colonic total short chain fatty acid and acetic acid were observed. DNA microarray results suggested that feeding PF diet inhibited 77% of genes (40 downregulated and 12 upregulated genes) related to colonic cancer, immune response, and lipid metabolism, involving in signal pathway such as intestinal immune network for IgA production, peroxisome proliferator-activated receptor signaling pathway and nutrient metabolism-related pathways. Collectively, our results suggested that long-term intake of PF would improve colonic function via altering colonic barriers, colonic immune and metabolism-related protein or gene expressions.

Non-effect of an antibiotic treatment on dietary fiber-induced goblet cell proliferation in the ileum of rats

We examined the effect or not of an antibiotic treatment on dietary fiber-induced goblet cell proliferation in the rat ileum. The number of goblet cells in the ileum increased when rats consumed dietary fiber. However, this effect was maintained with a concurrent treatment of antibiotics, suggesting that the fiber effect on goblet cell response would remain irrespective of a bacterial component such as endotoxin.

Cellulose supplementation early in life ameliorates colitis in adult mice

Decreased consumption of dietary fibers, such as cellulose, has been proposed to promote the emergence of inflammatory bowel diseases (IBD: Crohn disease [CD] and ulcerative colitis [UC]) where intestinal microbes are recognized to play an etiologic role. However, it is not known if transient fiber consumption during critical developmental periods may prevent consecutive intestinal inflammation. The incidence of IBD peaks in young adulthood indicating that pediatric environmental exposures may be important in the etiology of this disease group. We studied the effects of transient dietary cellulose supplementation on dextran sulfate sodium (DSS) colitis susceptibility during the pediatric period in mice. Cellulose supplementation stimulated substantial shifts in the colonic mucosal microbiome. Several bacterial taxa decreased in relative abundance (e.g., Coriobacteriaceae [p = 0.001]), and other taxa increased in abundance (e.g., Peptostreptococcaceae [p = 0.008] and Clostridiaceae [p = 0.048]). Some of these shifts persisted for 10 days following the cessation of cellulose supplementation. The changes in the gut microbiome were associated with transient trophic and anticolitic effects 10 days following the cessation of a cellulose-enriched diet, but these changes diminished by 40 days following reversal to a low cellulose diet. These findings emphasize the transient protective effect of dietary cellulose in the mammalian large bowel and highlight the potential role of dietary fibers in amelioration of intestinal inflammation.

Ileal endogenous amino acid losses: response of broiler chickens to fiber and mild coccidial vaccine challenge

The effects of mild coccidial vaccine (5× dose) challenge and fiber levels on ileal endogenous amino acid (EAA) losses was determined in 26-d-old broiler chickens using the regression method. Birds were fed semipurified diets containing 3 levels of casein (40, 80, or 120 g/kg of diet) as the only source of dietary protein at 2 levels of fiber (purified cellulose at 25 or 75 g/kg of diet). One half of the experimental birds were gavaged with coccidial vaccine on d 20. The 3 levels of casein were used to determine EAA losses for each replicate cage of birds. The design of the study was a randomized complete block employing a factorial arrangement of treatments with 2 levels of coccidial challenge (control or unchallenged, and challenged) and 2 levels of fiber, with 6 replicate cages per treatment and 8 birds per cage. Birds were killed on d 26 and contents from the entire ileum were flushed with distilled water and stored at -20°C until processed. Ileal EAA losses were determined from the ordinate intercept, at zero amino acid (AA) intake, of the regression of ileal digesta AA concentration in milligrams per kilogram of DM intake against dietary AA intake in milligrams per kilogram of DM. The effect of fiber level on EAA losses, expressed in milligrams per kilogram of DM intake, were higher (P < 0.05) for most of the AA in birds fed 25 g of fiber/kg of diet. Coccidial vaccine challenge decreased (P < 0.05) EAA losses for 8 of the 18 AA. A significant interaction between fiber level and coccidial vaccine challenge was obtained for all AA except His and Lys. Coccidial vaccine challenge resulted in increased (P < 0.05) NaPi-IIb expression. The results suggest that ileal EAA loss is higher in challenged birds fed the diet containing 25 g of fiber/kg of diet. Changes in EAA losses as a result of dietary fiber level and coccidial infection are important in amino acid nutrition of the broiler chicken.

Fiber fermentability effects on energy and macronutrient digestibility, fecal traits, postprandial metabolite responses, and colon histology of overweight cats

Considering the different potential benefits of divergent fiber ingredients, the effect of 3 fiber sources on energy and macronutrient digestibility, fermentation product formation, postprandial metabolite responses, and colon histology of overweight cats (Felis catus) fed kibble diets was compared. Twenty-four healthy adult cats were assigned in a complete randomized block design to 2 groups of 12 animals, and 3 animals from each group were fed 1 of 4 of the following kibble diets: control (CO; 11.5% dietary fiber), beet pulp (BP; 26% dietary fiber), wheat bran (WB; 24% dietary fiber), and sugarcane fiber (SF; 28% dietary fiber). Digestibility was measured by the total collection of feces. After 16 d of diet adaptation and an overnight period without food, blood glucose, cholesterol, and triglyceride postprandial responses were evaluated for 16 h after continued exposure to food. On d 20, colon biopsies of the cats were collected under general anesthesia. Fiber addition reduced food energy and nutrient digestibility. Of all the fiber sources, SF had the least dietary fiber digestibility (P < 0.05), causing the largest reduction of dietary energy digestibility (P < 0.05). The greater fermentability of BP resulted in reduced fecal DM and pH, greater fecal production [g/(cat × d); as-is], and greater fecal concentration of acetate, propionate, and lactate (P < 0.05). For most fecal variables, WB was intermediate between BP and SF, and SF was similar to the control diet except for an increased fecal DM and firmer feces production for the SF diet (P < 0.05). Postprandial evaluations indicated reduced mean glucose concentration and area under the glucose curve in cats fed the SF diet (P < 0.05). Colon mucosa thickness, crypt area, lamina propria area, goblet cell area, crypt mean size, and crypt in bifurcation did not vary among the diets. According to the fiber solubility and fermentation rates, fiber sources can induce different physiological responses in cats, reduce energy digestibility, and favor glucose metabolism (SF), or improve gut health (BP).

Reduced gut bacterial translocation in European sea bass (Dicentrarchus labrax) fed mannan oligosaccharides (MOS)

The objective of this study was to determine the effect of mannan oligosaccharides derived from the outer cell wall of a select strain of Saccharomyces cerevisiae (Bio-Mos, Alltech Inc, USA) on mucus production, selected mucus immune parameters activity, gut morphology and in vivo and ex vivo gut bacterial translocation for European sea bass (Dicentrarchus labrax). Specimens were fed 4 g kg⁻¹ dietary MOS level of inclusion in a commercial sea bass diet for eight weeks. At the end of this period, anterior gut mucosal folds height, width and folds surface area were increased by MOS supplementation (P < 0.05, n = 240). Posterior gut presented shorter folds (P < 0.05, n = 240) but wider that those fed control diet (P < 0.05, n = 240) resulting in increased total surface area (P < 0.05, n = 240). For rectum, feeding MOS reduced fold length (P < 0.05, n = 240). Gut morphological analyses showed an enhancement in the number of cells secreting acid mucins by area unit, higher density of eosinophilic granulocytes (ECGs) in the mucosa for fish fed MOS together with an improvement in gut mucus lysozyme activity which could be related to the reduced in vivo and ex vivo gut bacterial translocation found. No differences were found for the skin mucus immune parameters evaluated.

Histological Changes in the Small Intestinal Epithelium in Fattening Pigs Fed Selected Feed Additives

The production experiment was conducted on 48 fattener pigs fed complete diets supplemented with the antibiotic flavomycin (group C), the probiotic Bactocell® (Pedicoccus acidilactici, strain MA18/5M) at the amount of 0.01% in the first and second stage of fattening (group E1), and the prebiotic BIO-MOS® (Saccharomyces cerevisiae, strain 1026) at the amount of 0.1% in the first stage of fattening (group E2). Serial sections of the duodenum, jejunum and ileum were prepared post mortem. Haematoxylin and eosin and immunohistochemical (Ki-67, PCNA) staining procedures were performed. The effect of the feed additives on the morphological characteristics and proliferation capacity of small intestinal crypt epithelium varied when mitotic indices in groups were compared. In comparison with group C, the enterocytes were higher in group E2 in the jejunum (P ⪬ 0.01) and smaller in the ileum (P ⪬ 0.01). Administration of the Ki-67 antibody resulted in fewer positive reactions in the jejunum in group E1 than in group C (P ⪬ 0.01). Enterocyte proliferation in crypt epithelium decreased after the administration of the probiotic or the prebiotic vs. the antibiotic, but the absence of significant differences between the groups may suggest that these feed additives have no adverse effect on the mucosal epithelial cells.

Multifaceted transcriptional regulation of the murine intestinal mucus layer by endogenous microbiota

The intestinal mucus layer and endogenous microbiota are strongly intertwined and this contributes to the maintenance of the epithelial barrier and ultimately of gut homeostasis. To understand the molecular foundations of such relationship, we investigated if the nature of the microbiota transcriptionally regulates mucus layer composition in vivo. We found that the expression of mucins 1 to 4 and trefoil factor 3 was down-regulated in the ileum and colon of conventional and reconventionalized mice compared with germ-free animals. Conversely, very limited colon-restricted changes in transmembrane mucins were detected in mice colonized with human adult or baby microbiota. Moreover, by microarray analysis, the murine endogenous microbiota was found to modulate genes putatively involved in mucin secretion. These findings show that a well-established microbial community participates in the regulation of the gut mucus layer and that its composition and adequacy to the host are key factors in this process.