Gastrointestinal Morphology Research Articles

Gastrointestinal morphology, tight junction gene expression, and microbiota of the Ossabaw obese pig model (816.1)

Obesity is characterized by chronic low‐grade inflammation, with reduced gastrointestinal (GI) barrier function hypothesized to be a contributing factor. Animal models are invaluable for understanding disease pathophysiology, with porcine models offering several advantages over rodents, including anatomical similarities to humans. A pilot study was undertaken to characterize GI differences in obese Ossabaw pigs vs. lean controls. Ossabaw gilts (n=8) were fed a high‐fat, high‐sugar diet ad libitum until 12 months of age and compared to lean Yorkshire controls (n=9). Plasma inflammatory markers (TNF‐α, IL‐6, and LPS‐binding protein) and intestinal morphology, tight junction protein gene expression, and mucosal microbiota populations were assessed. Preliminary results indicate that LPS‐binding protein concentrations tended to be greater (P=0.08) in obese vs. lean pigs (6233 vs.3802 µg/L). Blood TNF‐α concentrations were numerically, but not significantly increased in obese vs. lean pigs (39 vs. 29 ng/L; P=0.24). Obese pigs had greater (P=0.03) cecal crypt depth (494 vs. 430 µm) and tended to have greater (P=0.09) ileal villus height (477 vs. 400 µm) compared to lean controls. Our findings suggest a correlation between GI architecture, systemic inflammation, and obesity in high‐fat, high‐sugar fed Ossabaw pigs, supporting its use as a model of human obesity and metabolic syndrome.Grant Funding Source: Supported by USDA Hatch #ILLU‐538‐384

The comparative gastrointestinal morphology of five species of muroid rodents found in Saudi Arabia

Meriones rex (King jird), Meriones libycus (Libyan jird), Acomys dimidiatus (Eastern spiny mouse), Acomys cahirinus (Egyptian spiny mouse), and Dipodillus dasyurus (Wagner's dipodil) are five species of small rodents of the superfamily Muroidea with distributions in Eastern Africa, Egypt, and the desert regions of the Arabian Peninsula. Water is scarce in these regions and may result in relatively low-digestible food. The aim of the present study is to describe and compare the gastrointestinal tract morphology and morphometry of these five species in order to elucidate whether morphology is influenced by phylogeny or dietary preference. Each segment of the gastrointestinal tract of each species was macroscopically examined and the length and basal surface area of each segment was measured. Standard histologic procedures were performed to determine a surface enlargement factor to determine the mucosal luminal surface area. A unilocular-hemiglandular stomach was observed in all the species examined. The caeca of all the species were long and arranged into a loose spiral toward the caecal tip with the ileocaecal and caeco-colic openings positioned close together. Two rows of oblique folds could be observed in the proximal colon of all species except in D. dasyurus which had longitudinal folds. Morphometric analysis showed the largest stomach in A. cahirinus and the largest caecum and colon in M. libycus. All the species can be grouped in the family Muridae in two subfamilies and similarities were observed including the hemiglandular stomach and relatively large caecum. It could be concluded that phylogeny plays an important role in determining gastrointestinal morphology while diet plays a subordinate role in the desert rodents in the present study.

OP003 Circadian clock function maintains mucosal architecture and protects against intestinal inflammation in mice

Background: In the last years, the interest of circadian rhythms as regulators of intestinal inflammation has increased substantially. Consisting of a range of clock genes including Per1 and Per2, the molecular clock machinery is thought to be engaged in modulating intestinal barrier function and gut homeostasis, features which are highly disturbed in inflammatory bowel disease (IBD). Elucidating the precise role of clock genes in the intestine may therefore highlight new pathophysiological mechanisms and new therapeutic approaches. Methods: Here, we used Per1/Per2 mutant mice and wildtype controls to investigate the functional consequence of circadian disruption on gastrointestinal tract morphology and intestinal inflammation. Small and large intestines were evaluated histologically at basal conditions. Experimental chronic colitis was induced by cyclic administration of 2% dextran sulphate sodium (DSS) in the drinking water, and colitis severity was determined by mouse endoscopy and clinical scores (murine endoscopic index of colitis severity, disease activity index). Biopsies were taken and further investigated via RT-PCR, western blotting and immunofluorescence staining. Results: At baseline, Per1/2 mice displayed mucosal alterations in the small and large intestines, characterized by a diminished crypt length-to-width ratio and reduced numbers of goblet and Paneth cells. Strikingly, mutant mice exhibited severely increased clinical symptoms of colitis (e.g. body weight loss, rectal bleeding, and diarrhea) and gross lethality in response to DSS. BrdU labeling revealed increased numbers of proliferative intestinal epithelial cells (IEC) in Per1/2 mice, but a restricted migratory capacity along the crypt axis. Analyzing the fate of individual IEC, we detected elevated protein level of RIP3, a marker of necroptotic cell death, in IEC at the crypt base, indicating that aberrant cell death in the proliferative region of intestinal crypts is responsible for the observed morphological changes in Per1/2 mice. Together, these data suggest that Per1/Per2 deficiency modulates cell death events, and thus influences intestinal homeostasis. Conclusions: Our data render intact circadian rhythm crucially important for intestinal barrier function and maintenance. Thus, therapeutic interventions stabilizing circadian rhythm may be promising options for the treatment of IBD. OP004 Early combined immunosuppression for the management of Crohn’s disease: A community-based cluster randomized trial R. Khanna1, B.G. Levesque1,2, B. Bressler3, G. Zou1,4, L. Stitt1, G.R. Greenberg5, R. Panaccione6, A. Bitton7, P. Pare8, S. Vermeire9, G. D’Haens1,10, D. MacIntosh11, W.J. Sandborn1,2, M.K. Vandervoort1, J.C. Morris1, B.G. Feagan1,12 *. 1Robarts Clinical Trials Inc., Robarts Research Institute, Western University, London, Ontario, Canada, 2University of California, San Diego, Division of Gastroenterology, La Jolla, United States, 3St. Paul’s Hospital, Department of Gastroenterology, Vancouver, British Columbia, Canada, 4Western University, Department of Epidemiology and Biostatistics, London Ontario, Canada, 5Mount Sinai Hospital, Division of Gastroenterology, Toronto Ontario, Canada, 6University of Calgary, Division of Gastroenterology & Hepatology, Calgary Alberta, Canada, 7McGill University, Division of Gastroenterology, Montreal Quebec, Canada, 8Laval University, Hopital du St-Sacrement, Quebec City, Quebec, Canada, 9Department of Clinical and Experimental Medicine, KU Leuven, Translational Research in GastroIntestinal Disorders, Leuven, Belgium, 10University of Amsterdam, Academic Medical Center, Amsterdam, Netherlands, 11Dalhousie University, Division of Gastroenterology, Halifax, Canada, 12Western University, Department of Epidemiology and Biostatistics, Department of Medicine, London Ontario, Canada

Effect of Dietary Restriction and Hay Inclusion in the Diet of Slow-Growing Broilers

The objective of this study was to evaluate the effect of dietary restriction and inclusion of alfalfa (Medicago sativa L.) and Bermudagrass (Cynodon dactylon cv Coastal) hays in the diets of ISA Label JA57 slow-growing male broilers on performance, gastrointestinal tract characteristics, and economic viability. A total of 272 broilers at 21 days old were distributed in a randomized experimental design with four treatments, four replicates, and 17 birds per experimental unit. The treatments consisted of ad libitum concentrated feed (control intake), feed restriction (80% of the control intake), and feed restrictions with supplementation of alfalfa hay (80% of the control intake+20% alfalfa) or Bermudagrass hay (80% control intake+20% Bermuda). Dietary restriction, with and without hay inclusion, negatively affected (P<0.05) the weight gain of the birds; however, feed conversion was improved (P<0.05) for animals that underwent only restricted feeding, which also had the best economic indices. Birds subjected to dietary restriction and inclusion of hays showed changes (P<0.05) in the gastrointestinal organs and intestinal morphology.

Differential visceral pain sensitivity and colonic morphology in four common laboratory rat strains

What is the central question of this study? Does stress sensitivity and susceptibility to inflammation innate to certain rat strains make them vulnerable to bowel dysfunction? What is the main finding and its importance? Of four different rat strains, the Lewis rat, which displays both susceptibility to gastrointestinal inflammation and sensitivity to stress, exhibits the most aberrant gastrointestinal morphology and visceral pain sensitivity. Given the similarities to human functional bowel disorders, such as irritable bowel syndrome, this may make it a good model of this disease. Irritable bowel syndrome is a common, debilitating gastrointestinal (GI) disorder characterized by episodic exacerbations of symptoms such as abdominal pain, bloating and altered bowel habit. Contributory factors for the development of irritable bowel syndrome include genetics, childhood trauma and prior GI infection leading to chronic low-grade inflammation or immune activation. Additional considerations in comprehending the chronic relapsing pattern that typifies irritable bowel syndrome symptoms are the effects of both psychosocial and infection-related stresses. Background stress and immune profiles can influence gut permeability and visceral pain sensitivity. This study examined whether innate susceptibility to inflammation and stress sensitivity in four rat strains is associated with bowel dysfunction. The pain threshold to colorectal distension was assessed in Lewis, Fischer (F344) and spontaneously hypertensive rats and compared with Sprague-Dawley control animals. Colons were subsequently excised and morphologically assessed for total length, goblet cell hyperplasia and muscle and mucosal thickness. Lewis rats displayed visceral hypersensitivity compared with other strains. At a morphological level, the gastrointestinal tract from these rats displayed mucosal goblet cell hyperplasia and alterations in muscle layer thickness. The Lewis rat strain, which is reported to have increased susceptibility to GI inflammation in addition to stress sensitivity, had the most prominent features of physiological and morphological GI dysfunction. These data support the hypothesis that background strain is a key factor in the development and exacerbation of bowel dysfunction in rodent models.

Effects of Retinoids in Mouse Models of Colitis

In vitro and in vivo data have shown that retinoid treatment promotes an anti-inflammatory milieu with few adverse effects toward the gastrointestinal tract. The in vivo studies reported here further evaluate retinoid effects in 2 mouse models of inflammatory bowel disease. Chronic dextran sulfate sodium colitis was induced in age- and weight-matched C57Bl/6 mice by 4 cycles of dextran sulfate sodium administration (6-8 animals/group). At cycle 4, animals were administered 13-cis-retinoic acid (isotretinoin, 30 mg/kg) or vehicle (oral gavage) or 4-oxo-13-cis-retinoic acid (15 mg/kg, intraperitoneal) daily. T-cell transfer colitis was induced in CB17 SCID mice by transfer of naive CD4CD62L T cells and treated by transfer of regulatory CD4CD25 T cells (4-6 animals/group); isolated from BALB/c mice after treatment with isotretinoin or vehicle, as above, for 2 weeks. Assessments included endoscopic and histological scores, myeloperoxidase activity, serum cytokines, and plasma isotretinoin levels. Retinoid-treated animals with colitis showed comparable changes in myeloperoxidase activity, and endoscopic and histological scores, versus untreated animals with colitis. Modest and comparable changes were seen in body weight and colon length in animals injected with naive T cells from isotretinoin-treated donors versus those injected with T cells from vehicle-treated donors. Retinoid treatment was consistently associated with lower interleukin-12 levels, which, after the transfer of naive T cells from isotretinoin-treated donors, supported isotretinoin-mediated predisposition of naive T cells toward reduced proinflammatory cytokine expression. Colitis had no effect on isotretinoin exposure. Retinoids attenuate the proinflammatory cytokine response in vivo, with only modest effects on body weight and parameters of gastrointestinal morphology.

Gastrointestinal morphology and function in turkeys fed diets diluted with whole grain wheat

The aim of this study was to verify the hypothesis that moderate dilution of turkey diets with whole grain wheat (up to 22.5%) improves gastrointestinal function, thus contributing to sustained growth performance. A total of 900 male turkeys were allocated to 5 dietary treatments: basal diet (BD), BD diluted with low levels of ground and pelleted wheat or whole wheat, and BD diluted with high levels of ground and pelleted wheat or whole wheat (GH and WH, respectively). At successive stages of the experiment, diets containing 5 and 15%, 7.5 and 17.5%, 10 and 20%, 12.5 and 22.5% of wheat in different physical form were fed to turkeys aged 5 to 8, 9 to 12, 13 to 16, and 17 to 18 wk, divided into subgroups with low and high dietary levels of wheat, respectively. Dietary dilution with different levels of wheat did not reduce the BW gain of turkeys and did not deteriorate feed conversion despite a decrease in the amino acid content of diets. In comparison with BD, diet GH increased the thickness of the muscularis externa and the depth of cecal crypts (P < 0.05), increased Bacteria domain, and decreased Salmonella counts (P < 0.001), increased butyric acid concentrations, and decreased the levels of putrefactive compounds in the cecal digesta (P < 0.001). In comparison with BD, diet WH improved feed efficiency (P = 0.002) and contributed to significant (P < 0.01) changes in the parameters of gastrointestinal function, including lower pH of gizzard digesta, increased depth of jejunal crypts, lower ammonia concentrations, and lower pH of intestinal digesta, increased Bacteria and Bifidobacterium counts, decreased Salmonella counts, and higher concentrations of butyric acid and total short-chain fatty acids. In comparison with diet GH, diet WH enhanced the activity of bacterial α-glucosidase and β-glucosidase as well as α-galactosidase, reduced the activity of β-glucuronidase, and increased total fatty acid concentrations, mainly acetic acid levels, in the cecal digesta (P < 0.01). The observed changes indicate that diet supplementation with wheat grain enhances gastrointestinal function, thus improving feed conversion in turkeys.

Gastrointestinal morphological alterations in obese rats kept under hypercaloric diets

Hypercaloric diets have been successfully used as experimental models of obesity. This work compared morphological characteristics of inferior gastrointestinal organs. The experiment lasted 10 weeks, during which the rats’ food consumption, body weight, distance between the mouth and neck, distance between mouth and neck, distance between neck and tail, and abdominal circumference were evaluated weekly. After the sacrifice of the rats, 20 variables referring to inferior gastrointestinal morphology were assessed. The results comprised descriptive statistics of the data, analysis of main components, linear correlation, and t-tests. Significant differences were found between the two groups for the variables of abdominal circumference, retroperitoneal fat, ratio between retroperitoneal fat/animal weight, stomach weight, ratio between animal weight/intestine weight and mesentery/animal weight, length of small intestine, length of large intestine, and lateral line of the cecum. The data allow us to state that a hypercaloric diet can be responsible an increase in fat in the abdominal cavity as well as gastrointestinal morphological alterations, principally in stomach development.

English

The use of probiotics in feed for fish and its inclusion in intensive aquaculture to promote healthy gut is growing. The need for alternative measures that will perform closely and effectively to the use of antibiotics after its annulment in European Union (EU) in 2006 is an issue which call for concern. Several definitions of probiotics mainly for aquaculture were also dig out from published papers. Among them is a definition considered appropriate for aquaculture which is described as&rdquo; any microbial cell provided via the diet or rearing water that benefits the host fish, fish farmer or fish consumer, which is achieved, in part at least, by improving the microbial balance of the fish&rdquo;. In this context, they regard direct benefits to the host as immuno-stimulants, improved disease resistance, reduced stress response, improved gastro intestinal morphology and benefits to the fish farmer or consumer. The benefits to the fish farmer and consumers includes improved fish appetite, growth performance, feed utilization, improvement of carcass quality, flesh quality and reduced malformations. The mode of action with benefits of probiotics in aquaculture from published journals was also looked into. The use of probiotics is growing especially as new strains were being discovered that can withstand processing stress in feed manufacturing. But process optimization knowledge to effectively work with these additives is insufficient. Combination of strain isolated from the gastro-intestinal (GI) tracts of host animal had also being proving to be effective. Need to find proper parameters to work with probiotics will be of great importance to the feed industry in the near future and the stability of the strains of probiotics as a synbiotic relation with prebiotics. Examples and effects of known strains were also stated and the future perspective of probiotics for fish. &nbsp; Key words:&nbsp;Probiotic, fish farming, aquaculture, feed processing.

Comparative gastrointestinal morphology of three small mammalian insectivores: Acomys spinosissimus (Rodentia), Crocidura cyanea (Eulipotyphla), and Amblysomus hottentotus (Afrosoricida)

The gastrointestinal morphology was investigated in three mammalian insectivorous species, namely Acomys spinosissimus, Crocidura cyanea, and Amblysomus hottentotus. The aim of the study was to provide a comprehensive morphological comparison between the different species and to explore whether anatomical gastrointestinal adaptations are associated with the insectivorous diet of these species. The shape, proportional length, and proportional surface areas of the different gastrointestinal regions were recorded and compared in the three insectivores. Hematoxylin and Eosin (H&E) and Alcian Blue/Periodic Acid Schiff (AB/PAS) were used for morphological assessment. In all three species, the stomach was simple and uncompartmentalized. The internal aspect of the stomach in A. spinosissimus was hemi-glandular, containing stratified squamous epithelium in the fundus, with glandular epithelium in the body and pyloric region. However, C. cyanea and A. hottentotus had wholly glandular stomachs. Paneth cells were not observed in the intestinal tracts of C. cyanea and A. hottentotus. Acomys spinosissimus was the only species studied that had a cecum. The proximal colonic region of A. spinosissimus had V-shaped mucosal folds. Histologically, C. cyanea had villi throughout the entire gastrointestinal tract (GIT), whereas for A. hottentotus villi were not present in the most distal gastrointestinal regions. In both C. cyanea and A. hottentotus, longitudinal mucosal folds were present in the distal part of the colon. The GITs of C. cyanea and A. hottentotus showed little morphological differentiation namely, a simple, glandular stomach and the lack of a cecum.

No effect of short‐term exposure to high‐fibre diets on the gastrointestinal morphology of layer hens (Gallus gallus domesticus): body reserves are used to manage energy deficits in favour of phenotypic plasticity

Using layer hens, Gallus gallus domesticus, we compared the digestive capabilities of birds on a low-fibre diet (LF, 8.49% neutral detergent fibre; NDF), with those fed a high-fibre diet balanced for energy and protein to match the LF diet (high fibre balanced, HFB; NDF = 15.61%) and those fed a high fibre unbalanced (HFU) diet (NDF = 16.68%). The HFU diet had the lowest apparent dry matter (DM) metabolisability at 58.14 ± 6.46%, followed by HFB, 65.87 ± 3.50 and the LF diet, 70.49 ± 7.07%. Despite significant differences between apparent DM metabolisabilities of LF and HFU diets, no morphometric changes in the gastrointestinal tract (GIT) of layer hens were observed (including crop, gizzard, proventriculus, liver, large intestine, paired caeca and small intestine). Conversely, body mass losses were recorded for animals on HFU diet, while those on the LF and HFB diets actually gained body mass over the 14-day trials. We suggest that the body mass losses seen in the animals fed HFU diets were attributed to losses in adipose tissue, but this was not quantified. Assuming body mass losses were mainly in adipose tissue, we propose that adipose may act to buffer environmental challenges like shortfalls in nutrient acquisition when dietary energy requirements are not met. Compared with smaller birds (e.g. quail), the larger body size of the layer hens may offer them a greater safety margin in terms of body energy reserves before changes in the GIT might be needed to redress energy deficits associated with hard-to-digest, high-fibre diets.

Effect of feeding on the function and structure of the digestive system in juvenile southern catfish (Silurus meridionalis Chen)

Postprandial physiological and morphological responses to feeding were examined in juvenile southern catfish (Silurus meridionalis Chen) that had consumed a loach (Misgurnus anguillicaudatus Cantor) meal equivalent to 6% of the body mass of the catfish. The gastric evacuation rate (GER) peaked at 4h postfeeding, averaging 0.36g food weighth(-1), at which time 14% of the ingested meal had passed into the intestine. Less than 10% of the ingested meal remained in the stomach at 24h postfeeding. Pepsin activity peaked at 8h postfeeding, reaching a level approximately twofold higher than the prefeeding level. Pancreatic trypsin activity peaked at 16h postfeeding, reaching a level 4.5-fold higher than the prefeeding level. Peaks in lipase activity in both the proximal and middle intestinal segments occurred at 16h, reaching 2.8- and 2.4-fold higher levels than the prefeeding level, respectively, while the activity in the distal intestine segment reached a level 2.9-fold higher than the prefeeding level at 24h postfeeding. With respect to amylase activity, only the middle intestinal segment exhibited a change, first an increase and then a decrease, after feeding. Feeding also triggered an approximately 200% increase in the metabolic rate and resulted in 44.6kJkg(-1) being expended on specific dynamic action, equivalent to 16.1% of the meal's energy. In terms of organ size, the wet mass of the liver increased by 11% at 24h postfeeding, whereas the wet mass of the pancreas did not change. Except for a decrease in the thickness of the submucosa in the middle intestinal segment, the thickness of the intestinal fold, mucosa, submucosa, muscularis and serosa of each intestinal segment did not change significantly with feeding. These results suggest that the continuum of physiological responses observed with respect to metabolic increases, GER, regulation of pancreatic and intestinal digestive enzyme activities and liver wet mass to feeding corresponds to the changes in the demand on the digestive system in S. meridionalis. Moreover, species maintained stable gastrointestinal tract morphology during the short interval of repeated feeding.

A review of the nutrition of Australian peramelid marsupials

European settlement has had a dramatic impact on the distribution and abundance of peramelid (bandicoot and bilby) marsupials. Predation and competition from introduced species and altered habitat have been implicated in their decline or extinction. Bandicoots and bilbies inhabit a broad range of habitats in Australia. Research on the distribution, morphology, gastrointestinal histology, lactation, metabolism and nutritional physiology of extant peramelid species has increased in the last few decades. This paper provides a review that encompasses recent nutritional-based research. Peramelid research is mostly limited to only three species – Isoodon macrourus, Perameles nasuta and Macrotis lagotis – which prevents effective comparisons between species. Peramelids are broadly classified as omnivores and possess relatively uncomplicated gastrointestinal tracts. The caecum is the region of greatest diversity among species. The relatively large caecum of Chaeropus ecaudatus supports the theory that this species may have been the only herbivorous peramelid. The caecum of M. lagotis is less pronounced than other species and is continuous with the proximal colon. M. lagotis also has a longer total colon length, which aids water conservation to ensure survival in an arid environment. Temperate-zone species such as I. macrourus, I. obesulus and P. nasuta are more similar to each other with respect to gastrointestinal morphology than either C. ecaudatus or M. lagotis. Additional research on the morphometrics of the gastrointestinal tracts of P. gunnii, P. bougainville, P. eremiana, M. leucura and I. auratus would enable further comparisons to determine whether differences are a result of geographic distribution, habitat preference or variation between genera and/or individual species. Currently, histological information of the gastrointestinal tract is limited to the small intestine of P. nasuta and I. macrourus. The histology of the small intestine of the weaned juvenile I. macrourus more closely resembles that of P. nasuta pouch young than P. nasuta adults. The younger bandicoots possessed villi whereas in the adult P. nasuta and I. macrourus villi were arranged in a zig-zag formation. The reason for the zig-zag formation of the villi and the function it may serve remains unclear. Detailed nutritional research on captive M. lagotis, I. macrourus and P. nasuta indicate that the two temperate-zone species – I. macrourus and P. nasuta – are more similar to each other than to the arid-dwelling M. lagotis. Detailed nutritional studies are required on all species, both free-living and captive. Experimental diets do not always accurately reflect a natural diet, which means that results from captive studies may not reflect the situation for free-living animals. The hindgut of peramelids is the main region for retention of digesta, and presumably where microbial digestion occurs. However, no studies have been undertaken to examine the microflora of the gastrointestinal tract of bandicoots or the bilby. As captive husbandry is an important tool in conservation management, it should also improve their successful maintenance in captivity by the provision of diets that better meet their nutritional requirements.

Carriage of Shiga-toxigenic Escherichia coli by native marsupials in Australia

Shiga-toxigenic strains of Escherichia coli (STEC) are zoonotic pathogens with human health, meat processing and trade impacts. Cattle are the principal reservoirs of STEC, although other animals can be carriers. The STEC status of Australian native marsupials has not been formatively described to date. The aim of the current study was to investigate carriage of STEC by native Australian marsupials in Southeast Queensland. Faeces from a variety of marsupial species, stratified by gastrointestinal morphology and dietary type, were screened for stx1, stx2 and other STEC virulence genes by PCR. Positive samples were cultured to isolate STEC for characterisation. A number of macropods from both captive and wild habitats had evidence of STEC in their faeces. Rates of stx carriage by macropods (8.6%) were comparable, though generally low, compared to cattle. Eastern grey kangaroos had the highest rate of stx presence in faeces (10.3%). Hindgut-fermenting and monogastric marsupials had no evidence of STEC shedding. Based on virulence marker possession and serotype, the human pathogenic potential of isolates was low. This is the first report of Australian marsupials carrying STEC. Australian native macropods may act as reservoirs for STEC strains, but the potential significance to public health and/or livestock epidemiology remains questionable.

Management of Dermatitis Herpetiformis

The major treatment strategies for DH are gluten restriction or medical treatment with sulfones. Control of the cutaneous manifestations, but not the gastrointestinal changes, is rapid with dapsone. In addition to control of the cutaneous signs and symptoms of DH, dietary gluten restriction also induces improvement of gastrointestinal morphology and is possibly protective against the development of lymphoma.

Loss of Parietal Cell‐Expressed Sonic Hedgehog Results in Hypochlorhydria that is Associated with Altered Gastrointestinal Microbiota and Epithelial Morphology

Sonic Hedgehog (Shh) regulates gastric epithelial cell function and differentiation. Mice expressing a parietal cell-specific deletion of Shh (HKCre/ShhKO) develop both hypochlorhydria and hypergastrinemia due to disruption of parietal cell function. Histological evaluation revealed that compared to control mice, HKCre/ShhKO mice developed atypical colonic crypts (aberrant crypt foci) and distortion of the small intestinal mucosa, with short, broad and irregular villi and inflammatory infiltrate. Bacterial changes were quantified in stomach, luminal flushes and mucosal scrapping of terminal ileum, cecum, proximal and distal colon using 16S ribosomal DNA bacterial primers by qRT-PCR. Total gastric bacterial load was increased 10 fold in HKCre/ShhKO mice. Intestinal flushes from HKCre/ShhKO mice showed increased total bacteria in ileum when compared to wild type littermates. HKCre/ShhKO mice displayed significant decreases in gamma-Proteobacteria in ileum and Bifidobacteria in distal colon. Increased Actinobacteria levels in both the proximal and distal colon were observed. Mucosal scrapings from HKCre/ShhKO mice also showed an increase in total bacteria of the ileum, while decreases occurred in Actinobacteria in ileum and in beta-Proteobacteria in the distal colon. These data suggest that hypochlorhydria due to loss of gastric Shh results in altered microbiota in stomach and small and large intestine which may contribute to disrupted gastrointestinal morphology and function. Supported by NIH DK079979.

Rate of passage through the digestive tract of the kultarr (Antechinomys laniger)

The kultarr (Antechinomys laniger) is a small insectivorous marsupial that has undergone significant declines in geographical range. Limited studies have been undertaken on kultarr biology and therefore there is a lack of understanding of its basic biological and ecological requirements. Rate of passage in the kultarr, determined using mealworm cuticle as a marker in minced beef, was 1.6 ± 0.2 h and mean retention time was 3.9 ± 1.2 h. The rapid transit time was consistent for an animal of equivalent body mass, dietary preference and gastrointestinal tract morphology. Mean retention time was short, similar to that of other mammals with a small body mass. This study provides the first insight into gastrointestinal physiology of the little known kultarr.

Growth performance and gastrointestinal microbial ecology responses of piglets receiving Saccharomyces cerevisiae fermentation products after an oral challenge with Escherichia coli (K88)1

The effects of Saccharomyces cerevisiae fermentation products (YFP) on growth performance and gastrointestinal (GIT) microbial ecology in 90 weanling pigs orally challenged with Escherichia coli K88(+) (ETEC) were investigated. The YFP were an original YFP product (XPC) and a water-suspendable yeast fermentation prototype (WSYFP) from a commercial company. Treatments consisted of a negative control (NC, no in-feed or in-water additive), carbadox (AB, 55 mg of carbadox/kg of feed), XPC (in feed, 0.2%), and WSYFP (in water, 0.5, 1, or 2 g/pig per day), and each was allotted to 5 pens (3 pigs/pen). The diets met the 1998 NRC specifications. Pigs were acclimated to treatments for a 7-d period before an ETEC challenge. On d 8, blood was collected from pigs to determine the baseline packed cell volume (PCV) measurement, and pigs were orally challenged with ETEC. At various time points postchallenge, blood samples were taken, performance measures and fecal consistency scores were recorded, and gut digesta and tissue samples were taken to evaluate GIT morphology, microbial ecology, and metabolites. Preplanned contrasts were used for comparison. Pigs receiving YFP had greater ADFI than NC pigs on d 3 (424 vs. 378 g/d; P = 0.01) and d 7 (506 vs. 458 g/d; P = 0.03) postchallenge. This effect of YFP on ADFI was similar to that of AB on d 3, but pigs receiving AB ate more (576 vs. 506 g/d; P = 0.03) at d 7 than pigs receiving YFP. Pigs exhibited reduced (P < 0.001) PCV upon ETEC challenge; however, pigs receiving additives sustained a greater (P < 0.05) PCV at 72 h compared with the NC group. Compared with the NC pigs, pigs receiving YFP showed a smaller (P < 0.05) number of ileal mucosa adherent ETEC and prevalence of the order Enterobacteriales in the ileal digesta, which corresponded to less (5.09 vs. 6.97 mg/dL; P = 0.03) colonic ammonia on d 7 postchallenge. Most of the indices for ileal digesta bacterial richness and diversity were greater (P < 0.01) for YFP pigs compared with NC pigs. However, results also indicated that the influence of YFP on the piglet intestinal microenvironment might differ when given in feed or water during ETEC challenge. In conclusion, pigs receiving YFP showed a better appetite in the presence of ETEC, which, together with the greater ileal digesta bacteria richness and diversity and decreased ETEC adhering to the mucosa and reduced colonic ammonia, indicates a healthier GIT environment.

Effect of All-lac xcl 5x, Acid-pak 2x, Bio-mos® and Zinc Bacitracin on nutrient digestibility and gastrointestinal morphology of broiler chickens

An experiment was conducted with Ross broiler chickens from day-old to 42 d of age. A prebiotic (Bio-Mos®), probiotic (All Lac XCL 5x), organic acid (Acid pak 2x), individually or in combination were used to supplement an antibiotic growth promoter (Zinc Bacitracin). The chickens were challenge with Clostridium perfringens (CP) at 21, 22 and 23 days of age to determine the efficacy of these additives for replacing antibiotics in hindering the effects of CP on the villus surface area. Feed additives in this experiment prevented the negative effects of CP as the treated birds did not have lesions on their villus surfaces.

Riboflavin Depletion Impairs Cell Proliferation in Adult Human Duodenum: Identification of Potential Effectors

Riboflavin (vitamin B2) is an essential dietary component with a known function in oxidative metabolism. Our previous data using a rat model of riboflavin deficiency suggested that riboflavin also functions as a luminal signaling molecule regulating crypt development and cell turnover. Riboflavin deficiency is prevalent in both high- and low-income countries across the globe. This study aims to establish whether riboflavin deficiency has consequences for gastrointestinal (GI) morphology in adults and what the effects and effectors of any such alteration may be. Duodenal biopsies and blood samples were collected from a cross-section of gastroscopy patients. Crypt morphology and cell division were studied by immunohistochemistry, and biochemical riboflavin status was determined. Additionally a cell culture model of riboflavin deficiency was developed and analyzed using a combination of flow cytometry, and microarray and clonogenic assays. Duodenal crypts from subjects in the lowest quartile of riboflavin status were significantly shorter (P=0.023), less cellular (P=0.007), and had fewer cell divisions (P=0.034) than the crypts of subjects in the top quartile of riboflavin status. Following riboflavin depletion of colon cells in culture, cell cycle slowed. Microscopy revealed impaired mitosis and accumulation of aneuploid cells. Alterations in gene expression profiles reflected this alteration, with several mitosis-related genes altered, including AspM, cyclin B1, and Birc5 downregulated and Kif23 upregulated. Riboflavin depletion in vitro caused irreversible loss of proliferative potential of cells. Riboflavin depletion in adult humans impairs proliferation and proliferative potential of intestinal cells, which may have implications for gastrointestinal function.