Assessment of the excretion time of electronic capsules placed in the intestinal lumen of cows with cecal dilatation-dislocation, healthy control cows, and cows with left displacement of the abomasum

OBJECTIVE To analyze the transit time from various locations in the intestines of cows with cecal dilatation-dislocation (CDD), healthy control cows, and cows with left displacement of the abomasum (LDA). ANIMALS 15 cows with naturally occurring CDD (group 1), 14 healthy control cows (group 2), and 18 cows with LDA (group 3). PROCEDURES 5 electronic transmitters were encased in capsules and placed in the lumen of the ileum, cecum, proximal portion of the colon, and 2 locations in the spiral colon (colon 1 and colon 2) and used to measure the transit time (ie, time between placement in the lumen and excretion of the capsules from the rectum). Excretion time of the capsules from each intestinal segment was compared among groups. RESULTS Cows recovered well from surgery, except for 1 cow with relapse of CDD 4 days after surgery and 2 cows with incisional infection. High variability in capsule excretion times was observed for all examined intestinal segments in all groups. Significant differences were detected for the excretion time from the colon (greater in cows with CDD than in healthy control cows) and cecum (less in cows with LDA than in cows of the other 2 groups). CONCLUSIONS AND CLINICAL RELEVANCE The technique developed to measure excretion time of capsules from bovine intestines was safe and reliable; however, the large variability observed for all intestinal segments and all groups would appear to be a limitation for its use in assessment of intestinal transit time of cattle in future studies.

Exposure to food allergens through inflamed skin promotes intestinal food allergy through the thymic stromal lymphopoietin-basophil axis.

BACKGROUND Exposure to food allergens through a disrupted skin barrier has been recognized as a potential factor in the increasing prevalence of food allergy. OBJECTIVE We sought to test the immunologic mechanisms by which epicutaneous sensitization to food allergens predisposes to intestinal food allergy. METHODS Mice were epicutaneously sensitized with ovalbumin or peanut on an atopic dermatitis-like skin lesion, followed by intragastric antigen challenge. Antigen-specific serum IgE levels and T(H)2 cytokine responses were measured by ELISA. Expression of type 2 cytokines and mast cell proteases in the intestine were measured by using real-time PCR. Accumulation of basophils in the skin and mast cells in the intestine was examined by using flow cytometry. In vivo basophil depletion was achieved by using diphtheria toxin treatment of Baso-DTR mice. For cell-transfer studies, the basophil population was expanded in vivo by means of hydrodynamic tail vein injection of thymic stromal lymphopoietin (TSLP) cDNA plasmid. RESULTS Sensitization to food allergens through an atopic dermatitis-like skin lesion is associated with an expansion of TSLP-elicited basophils in the skin that promote antigen-specific T(H)2 cytokine responses, increased antigen-specific serum IgE levels, and accumulation of mast cells in the intestine, promoting the development of intestinal food allergy. Critically, disruption of TSLP responses or depletion of basophils reduced the susceptibility to intestinal food allergy, whereas transfer of TSLP-elicited basophils into intact skin promoted disease. CONCLUSION Epicutaneous sensitization on a disrupted skin barrier is associated with accumulation of TSLP-elicited basophils, which are necessary and sufficient to promote antigen-induced intestinal food allergy.

Honey Bee Apis mellifera Parasites in the Absence of Nosema ceranae Fungi and Varroa destructor Mites

Few areas of the world have western honey bee (Apis mellifera) colonies that are free of invasive parasites Nosema ceranae (fungi) and Varroa destructor (mites). Particularly detrimental is V. destructor; in addition to feeding on host haemolymph, these mites are important vectors of several viruses that are further implicated as contributors to honey bee mortality around the world. Thus, the biogeography and attendant consequences of viral communities in the absence of V. destructor are of significant interest. The island of Newfoundland, Province of Newfoundland and Labrador, Canada, is free of V. destructor; the absence of N. ceranae has not been confirmed. Of 55 Newfoundland colonies inspected visually for their strength and six signs of disease, only K-wing had prevalence above 5% (40/55 colonies = 72.7%). Similar to an earlier study, screenings again confirmed the absence of V. destructor, small hive beetles Aethina tumida (Murray), tracheal mites Acarapis woodi (Rennie), and Tropilaelaps spp. ectoparasitic mites. Of a subset of 23 colonies screened molecularly for viruses, none had Israeli acute paralysis virus, Kashmir bee virus, or sacbrood virus. Sixteen of 23 colonies (70.0%) were positive for black queen cell virus, and 21 (91.3%) had some evidence for deformed wing virus. No N. ceranae was detected in molecular screens of 55 colonies, although it is possible extremely low intensity infections exist; the more familiar N. apis was found in 53 colonies (96.4%). Under these conditions, K-wing was associated (positively) with colony strength; however, viruses and N. apis were not. Furthermore, black queen cell virus was positively and negatively associated with K-wing and deformed wing virus, respectively. Newfoundland honey bee colonies are thus free of several invasive parasites that plague operations in other parts of the world, and they provide a unique research arena to study independent pathology of the parasites that are present.

Infra-Population and -Community Dynamics of the Parasites Nosema apis and Nosema ceranae, and Consequences for Honey Bee (Apis mellifera) Hosts

Nosema spp. fungal gut parasites are among myriad possible explanations for contemporary increased mortality of western honey bees (Apis mellifera, hereafter honey bee) in many regions of the world. Invasive Nosema ceranae is particularly worrisome because some evidence suggests it has greater virulence than its congener N. apis. N. ceranae appears to have recently switched hosts from Asian honey bees (Apis cerana) and now has a nearly global distribution in honey bees, apparently displacing N. apis. We examined parasite reproduction and effects of N. apis, N. ceranae, and mixed Nosema infections on honey bee hosts in laboratory experiments. Both infection intensity and honey bee mortality were significantly greater for N. ceranae than for N. apis or mixed infections; mixed infection resulted in mortality similar to N. apis parasitism and reduced spore intensity, possibly due to inter-specific competition. This is the first long-term laboratory study to demonstrate lethal consequences of N. apis and N. ceranae and mixed Nosema parasitism in honey bees, and suggests that differences in reproduction and intra-host competition may explain apparent heterogeneous exclusion of the historic parasite by the invasive species

Biochanin A and prunetin improve epithelial barrier function in intestinal CaCo-2 cells via downregulation of ERK, NF-κB, and tyrosine phosphorylation

The single-layered gut epithelium represents the primary line of defense against environmental stressors; thereby monolayer integrity and tightness are essentially required to maintain gut health and function. To date only a few plant-derived phytochemicals have been described as affecting intestinal barrier function. We investigated the impact of 28 secondary plant compounds on the barrier function of intestinal epithelial CaCo-2/TC-7 cells via transepithelial electrical resistance (TEER) measurements. Apart from genistein, the compounds that had the biggest effect in the TEER measurements were biochanin A and prunetin. These isoflavones improved barrier tightness by 36 and 60%, respectively, compared to the untreated control. Furthermore, both isoflavones significantly attenuated TNFα-dependent barrier disruption, thereby maintaining a high barrier resistance comparable to nonstressed cells. In docking analyses exploring the putative interaction with the tyrosine kinase EGFR, these novel modulators of barrier tightness showed very similar values compared to the known tyrosine kinase inhibitor genistein. Both biochanin A and prunetin were also identified as potent reducers of NF-κB and ERK activation, zonula occludens 1 tyrosine phosphorylation, and metalloproteinase-mediated shedding activity, which may account for the barrier-improving ability of these isoflavones.

Loss of Sirt1 function improves intestinal anti-bacterial defense and protects from colitis-induced colorectal cancer

Dysfunction of Paneth and goblet cells in the intestine contributes to inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC). Here, we report a role for the NAD+-dependent histone deacetylase SIRT1 in the control of anti-bacterial defense. Mice with an intestinal specific Sirt1 deficiency (Sirt1int-/-) have more Paneth and goblet cells with a consequent rearrangement of the gut microbiota. From a mechanistic point of view, the effects on mouse intestinal cell maturation are mediated by SIRT1-dependent changes in the acetylation status of SPDEF, a master regulator of Paneth and goblet cells. Our results suggest that targeting SIRT1 may be of interest in the management of IBD and CAC.

Mycobacterium avium Subsp. avium infection in four veal calves: differentiation from intestinal tuberculosis

Mycobacterium avium subsp. avium (Maa) is an intracellular pathogen belonging to the Mycobacterium avium-intracellulare complex (MAC). Reservoirs of MAC are the natural environment, wildlife and domestic animals. In adult bovine, MAC infections are typically caused by Mycobacterium avium subsp. paratuberculosis (Map). Maa infections in bovine are rarely reported but may cause clinical disease and pathological lesions similar to those observed in paratuberculosis or those induced by members of the Mycobacterium tuberculosis complex (MTBC). Therefore, differentiation of MAC from MTBC infection should be attempted, especially if unusual mycobacterial lesions are encountered. Four veal calves from a fattening farm dying with clinical signs of otitis media, fever, and weight loss were submitted for necropsy. Samples from affected organs were taken for histologic investigation, bacteriologic culture, and bacterial specification using PCR. Macroscopic thickening of the intestinal mucosa was induced by granulomatous enteritis and colitis. Intracytoplasmic acid-fast bacteria were detected by Ziehl-Neelsen stains and PCR revealed positive results for Mycobacterium avium subsp. avium. Clinical and pathological changes of Maa infection in veal calves had features of Mycobacterium avium subsp. paratuberculosis and the MTBC. Therefore, Mycobacterium tuberculosis complex infection should be considered in cases of granulomatous enteritis in calves.