Pathologic changes associated with induced small intestinal strangulation obstruction and nonstrangulating infarction in horses

Arteriovenous (ischemic strangulation obstruction, ISO) or venous (hemorrhagic strangulation obstruction, HSO) occlusions were created in the jejunum of 5 anesthetized horses and were left in situ for 1-, 2-, or 3-hour intervals. Segments were evaluated grossly for color, thickness, and motility. The horses were euthanatized, and the degree of mucosal slough, edema, congestion, and hemorrhage was determined histologically. Segments subjected to ISO became dark, but did not contain edema or hemorrhage. Segments subjected to HSO were characterized by progressive congestion, edema, and hemorrhage especially in the mucosal layer. Histologically, the mucosal epithelium was affected approximately equally by ISO or HSO, although more gross changes were evident in segments subjected to HSO.     

Pathologic changes in pigs with prednisolone-induced recrudescence of herpesvirus infection

In pigs inoculated with Aujeszky's disease virus (ADV), recrudescence of herpesvirus infection was induced by daily administration of 1,000 mg of prednisolone for 5 days at 2 (group A) or 5 (group B) months after the primary infection. At necropsy in group A pigs, ADV was recovered from nasal secretions 3 to 9 days after prednisolone treatment initiation and from the brain cortex 10 days after treatment initiation; ADV was not recovered from group B pigs. In pigs of both groups killed 10 days after treatment initiation, 2 types of characteristic lesions were found. One type was a nonsuppurative encephalitis that consisted of neuronal necrosis, neuronophagia, and formation of eosinophilic intranuclear inclusion bodies. The 2nd type had basophilic intranuclear inclusion bodies in the enlarged endothelial cells of the kidneys, liver, lungs, adrenal glands, and lymph node sinusoids. Cells containing intranuclear inclusion bodies had immature and mature herpesvirus particles. Therefore, the brain lesions containing the eosinophilic inclusion bodies were considered to be due to ADV. Basophilic inclusion bodies in the endothelial cells were due to porcine cytomegalovirus. These observations indicated that prednisolone treatment resulted in recrudescence of ADV and porcine cytomegalovirus infections.     

Histological development of the small intestinal mucosa in the ovine fetus.

Histological changes in the small intestine of 85 ovine fetuses were studied, with particular reference to the mucosa. In 24-day-old fetuses the endoderm of the intestine consisted of a single layer of epithelium. By the 26th day the epithelium was flattened and stratified. The first evidence of rudimentary villus formation was noted in 39-day-old fetuses. Intestinal glands were first observed at 56 days. Other mucosal structures were present by 101 days. At birth the intestinal mucosa was fully mature.     

Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa

Virkel, G., Carletti, M., Cantiello, M., Della Donna, L., Gardini, G., Girolami, F., Nebbia, C. Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa. J. vet. Pharmacol. Therap. 33 , 295–303. The intestinal mucosa plays a capital role in dictating the bioavailability of a large array of orally ingested drugs and toxicants. The activity and the expression of several xenobiotic metabolizing enzymes were measured in subcellular fractions from the duodenal mucosa of male veal calves and beef cattle displaying a functional rumen but differing in both age (about 8 months vs. 18 to 24 months) and dietary regimens (i.e., milk replacer plus hay and straw vs. corn and concentrated meal). Intestinal microsomes showed cytochrome P450 (CYP) 2B, 2C‐ and 3A‐mediated activities and the presence of the corresponding immunorelated proteins, but no proof of CYP1A expression and/or functions could be provided. Intestinal microsomes were also active in performing reactions typically mediated by carboxylesterases (indophenylacetate hydrolysis), flavin‐containing monooxygenases (methimazole S‐oxidation), and uridindiphosphoglucuronyltransferases (1‐naphthol glucuronidation), respectively. Cytosolic fractions displayed the glutathione S‐transferase (GST)‐dependent conjugation of 1‐chloro‐2,4‐dinitrobenzene; besides, the GST‐mediated conjugation of ethacrinic acid (GSTπ) or cumene hydroperoxide (GSTα) was matched by the presence of the corresponding immunorelated proteins. Conversely, despite the lack of measurable activity with 3,4‐dichloronitrobenzene, a protein cross reacting with anti‐rat GSTμ antibodies could be clearly detected. Although, as detected by densitometry, CYPs and GST isoenzymes tended to be more expressed in beef cattle than in veal calf preparations, there was a general poor correlation with the rate of the in vitro metabolism of the selected diagnostic probes.     

Synthesis of citrulline from ornithine by the small intestinal mucosa of cattle

Three segments of cattle small intestine (duodenum, upper jejuno‐ileum and lower jejuno‐ileum) were examined in an in vitro system for activity of ornithine carbamoyltransferase (OCT; EC 2.1.3.3) which is involved in the synthesis of citrulline (Cit) from ornithine (Orn). The mucosa of the three segments of small intestine was collected from Japanese black cattle, homogenized and then centrifuged. The supernatant fraction was used as the crude OCT enzyme solution. The OCT activity was assayed by the production of Cit from Orn determined directly by HPLC. The optimal pH and temperature for OCT activities in the duodenum, upper jejuno‐ileum and lower jejuno‐ileum of cattle small intestine were 7.47 and 39°C. Little difference was observed between the three segments. The OCT activity in cattle kidney was also examined for comparison, and almost no activity was found. The OCT activities in crude enzyme solutions of the three segments of small intestine were stable for up to one month of storage at ?20°C in Tris HCl buffer solution. Finally, the role of the small intestine in supplying Cit as a precursor for arginine synthesis in cattle kidney was discussed.     

The quantitative assessment of normal canine small intestinal mucosa.

Quanitative methods of assessing the architecture of small intestinal mucosa have been applied to biopsy material from normal dogs. Mucosal samples taken from four predetermined sites show that there are significant quantitative differences between the various levels of the small bowel. Animals of one year of age and older show no correlation between age or weight and mucosal dimensions. The significance of these findings, in relation to examination of biopsy material from cases of clinical small intestinal disease, is discussed.     

Thirty minutes transport causes small intestinal acidosis in pigs

Long duration (>10 hours) transport has been described as having either adverse or no effects on porcine health. However, the effect of short duration transport on porcine health is unknown. In the present paper, pigs fed ad libitum (n = 6) were transported for 30 minutes, anaesthetised, instrumented, and cardiovascular and gastrointestinal parameters were measured. Non-transported pigs (n = 6) served as controls. No significant differences between groups were found concerning blood flow in the arteria mesenterica cranialis, heart rate, cardiac output, pulmonal blood pressure, haemoglobin content and haematocrit value. Systolic systemic blood pressure was higher (though not significant), and diastolic systemic blood pressure was significantly higher in the transported pigs than in the controls. Small intestinal pH was significantly lower in transported pigs than in control pigs. We conclude that a 30-minute transport of fed pigs results in small intestinal acidosis. As small intestinal acidosis predisposes to bacterial translocation, even short duration transport should be avoided when possible.     

Pathologic changes caused by transplacental infection with an adenovirus-like agent in pigs

Five hysterectomy-derived colostrum-deprived pigs housed in individual cages with positive ventilation developed severe skin cyanosis and edema of the subcutaneous tissues in the submandibular, thoracic, and abdominal regions. The 5 pigs were killed 7 to 10 days after birth. Eosinophilic intranuclear inclusion bodies were found in endothelial cells of capillary and small blood vessels throughout the body. Ultrastructurally, nuclei of these affected endothelial cells contained small crystalline arrays of virus particles, which were considered to belong to the adenovirus-like group from their size and structure. The present results indicated that the porcine adenovirus-like agent might also have the ability to produce transplacental infection.     

Discussion of a biometrical model for the evaluation of feeding, age, and animal effects on transport properties of small intestinal mucosa

This paper is concerned with the question in which ways study results can depend on the choice of the statistical model and factors included in this model. This is shown using example data of a study dealing with the effects of an Enterococcus faecium as probiotic in the diet of pigs. We focused on the effects on transport properties of pig jejunum. The experimental design was the following: the sows and piglets were randomly assigned to two different feeding groups. The control group was fed a conventional diet and the experimental group was additionally supplemented with a probiotic preparation of Enterococcus faecium NCIMB 10415. The animals were divided into four age groups. Two samples of five animals of each feeding and age group were taken and mounted into conventional Ussing chambers. Glucose transport rates were measured by changes in short-circuit current (Isc) of the pig jejunum epithelium. The appropriate reference base for evaluation of effects of feeding or age on Isc is the variation between animals which are submitted to identical conditions relating to these factors. To refer explicitly to this variation a random animal effect has to be included in the statistical model of variance analysis. Otherwise the variation between animals could be underestimated. With the example data set conclusions for the factor "feeding" would be different depending on whether a random animal effect is included in the model or not.     

The quantitative assessment of mucosa in canine small intestinal malabsorption.

Histological sections from the small intestines of dogs showing clinical signs of small intestinal malabsorption have been examined using morphometric techniques. Weibel graticule measurements appear to be a useful adjunct to the subjective assessment of villus atrophy. Severe clinical signs of small intestinal malabsorption may be associated with a patchy distribution of lesions throughout the small bowel.     

饲料禁抗条件下仔猪肠道健康的营养干预手段

仔猪由于肠道发育不成熟,断奶应激导致仔猪肠道结构功能受损,增加仔猪的疾病易感性。维持肠道健康对仔猪生产非常重要,在目前饲料禁抗的背景下,营养干预是保障仔猪肠道健康的有效途径。文章主要综述功能氨基酸、抗菌肽、植物提取物、短链脂肪酸近年来在仔猪肠道健康研究中的进展,为仔猪生产中饲料抗生素的替代提供理论依据。     

The distribution and density of Clostridium difficile toxin receptors on the intestinal mucosa of neonatal pigs

Clostridium difficile is an enteric pathogen affecting a variety of mammals, but it has only recently been diagnosed as a cause of neonatal typhlocolitis in pigs. The most important virulence factors of C. difficile are 2 large exotoxins, toxin A (TcdA) and toxin B (TcdB). TcdA is a potent enterotoxin with effects on host tissues that are dependent upon receptor-mediated endocytosis of the intact toxin. TcdB is an effective cytotoxin, but it apparently does not bind receptors on intact mucosal epithelium. TcdB is much less toxic in vivo unless there is underlying damage to the mucosa, and it is not essential for the virulence of C. difficile. One hypothesis to explain the resistance of most species as neonates (e.g., humans and hamsters) is that they may lack significant numbers of TcdA receptors. The susceptibility of neonatal pigs suggests cells of the gastrointestinal mucosa express sufficient numbers of toxin receptors for lesion development. Immunohistochemical (IHC) assays documented specific binding of TcdA, but not TcdB, to the epithelium of the small and large intestine. The carbohydrate Galalpha1-3beta1-4GlcNAc-R has been described as an important receptor for TcdA. However, IHC indicated a distribution on cell surfaces much different from that of TcdA binding, suggesting a specific interaction of toxin with an alternative receptor.     

Dioxin residues in the edible tissue of finishing pigs after dioxin feeding

The aim of this study was to determine the contamination of finishing pigs with polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) after feeding either uncontaminated feed or feed contaminated with 0.75, 2 or 4 ng/kg toxic equivalents (TEQ; calculated by multiplying individual congener concentrations by congener-specific toxicity equivalency factors). The feed was mixed with pure substances of PCDD/Fs to get the intended contamination. Five groups of six piglets each were fed contaminated feed, one group of five piglets served as control. One group was fed contaminated feed (4 ng TEQ/kg) only for the rearing period (6 weeks), and another group for the first 8 weeks of the fattening period (4 ng TEQ/kg feed). The other groups received the contaminated feed during the 12-weeks fattening period. After slaughtering, the edible parts of the belly, loin and fore-end were collected and homogenized. The samples of group 2 and 4a were investigated uncooked as well as roasted. Fattening yield and feed conversion (kg feed/kg weight gain) of the animals of all groups were in the normal range (final weight 109.7 kg; feed conversion 2.55-2.69 kg). The PCDD/F-content in 1 kg fat of the belly, loin and fore-end in relation to the intake was between 0.016 (4 ng TEQ/kg feed for a 6-weeks rearing period) and 1.39% (fore-end; 2 ng TEQ/kg feed for 12-weeks fattening period). There was a decrease in dioxin residues after a 12-weeks period but not after a 4-weeks period of feeding an uncontaminated feed. When feed contaminated with 0.75, 2 and 4 ng TEQ/kg was given for a 12-weeks fattening period, the residue concentrations of PCDD/F-TEQ in 1 kg belly was 0.455, 1.07 and 1.55 ng, in 1 kg fore-end 0.04 ng, 0.32 ng and 0.34 ng and in 1 kg loin 0.015 ng, 0.07 ng and 0.30 ng respectively. Roasting had no influence on the dioxin-residues. The residues per g belly fat exceed the maximum limits for dioxin in food of 0.6 pg WHO-PCDD/F-TEQ/g fat (EC Recommendations 2002/201/EC), when feed containing 0.75 ng PCDD/F-TEQ/kg is given for 12 weeks. When feed containing 0.4 ng TEQ (maximum content; EC recommendations 2002/201/EC) is given for 12 weeks, approximately 0.55 pg TEQ/g fat can be expected in the food. This value is within the action level of 0.6 pg/g fat of porks. In conclusion, the results of the study allow prediction of dioxin residues in the edible tissue of pork, if the feed contamination is known and the amount of feed intake can be estimated.     

Culture and morphologic features of small intestinal mucosal explants from weaned pigs

Small intestinal explants from weaned pigs were cultured under a variety of conditions. Explants maintained villus-to-crypt ratio between 1:1 and 1.5:1 for 48 hours. The mucosal epithelium remained well preserved and retained good cellular morphologic features, as determined by light and electron microscopy. Between 48 and 72 hours, considerable mucosal degeneration was evident. Best results were obtained when the explants were cultured on a rocking platform placed in an atmosphere of 95% O2 and 5% CO2, using supplemented RPMI 1640 cell culture medium.     

Effect of segregated early weaning on postweaning small intestinal development in pigs

The effect of segregated early weaning (SEW) on postweaning small intestinal development was investigated in SEW and control (CON) pigs. Small intestines were collected from a total of 15 pigs killed at 11 (preweaning), 15 (3 d postweaning), and 34 d of age. At 3 d postweaning, the SEW and CON pigs had shorter villi (P<.01), deeper crypts (P<.01), and reduced (P<.01) ratios of villus height:crypt depth (V:C) compared with preweaning. Weaning also reduced specific activities of lactase (P<.01) in duodenum and ileum and alkaline phosphatase (ALP) (P<.05) in duodenum and jejunum. Sucrase activity in the three regions of the small intestine marginally decreased in both groups at 3 d postweaning. The mucosal protein:DNA ratio in duodenum and jejunum increased (P<.05) in SEW and CON pigs at 3 d postweaning compared with preweaning pigs. The SEW and CON treatments resulted in differences in postweaning gut development. At 15 d of age in SEW pigs, the mucosal protein:DNA ratio in duodenum and jejunum were 20 and 25.5% (P<.05) less, respectively, than those in CON pigs. However, at 34 d, these ratios in duodenum, jejunum, and ileum were 43.5 (P<.05), 24.3, and 32.9% (P<.05) greater, respectively, in SEW pigs than in CON pigs. Longer villi, shorter crypts (P<.01), and higher V:C ratios (P<.01) in jejunum and ileum were observed in SEW pigs vs CON pigs at 34 d of age. The specific activities of lactase in duodenum (P<.01) and jejunum (P<.05) and of ALP in duodenum (P<.01) were higher in SEW pigs. Sucrase activity in duodenum, jejunum, and ileum was 21.7, 46.3 (P<.05), and 11.2% greater in SEW pigs at 34 d of age. These results demonstrate differences in postweaning gut development between SEW and CON pigs. Furthermore, the number of intraepithelial lymphocytes in jejunum was greater (P<.001) in 34-d-old SEW pigs compared with CON pigs. Microscopy revealed a thick mucus coating over epithelial cells in the ileum of 34-d-old CON pigs that was not apparent in the SEW pigs. These observations are consistent with reduced pathogen exposure associated with SEW. We suggest that segregated early weaning advances postweaning gut maturation, which is consistent with improved growth and feed efficiency observed in SEW pigs.     

Dehydrogenase activity in small intestine mucosa in experimental coccidiosis in suckling pigs]

The activities of 3-beta-hydroxybutyrate dehydrogenase (EC. 1.1.1.30.; HBD) and isocitrate dehydrogenase (EC. 1.1.1.41; ICD) were evaluated microdensitometrically in the mucosa of duodenum, jejunum and ileum of 19 conventional piglets infected on the first day after parturition (DAP) with oocysts of Eimeria debliecki coccidium (infection dose of 200,000 oocysts). The two investigated enzymes are deposited in mitochondria which are dispersed in the supra-, para- and infranuclear region of absorption cells (Fig. 1). The synthesis of the two dehydrogenases was investigated in the small intestine mucosa in the period of 1st to 10th day after infection (DAI). The HBD and ICD activities were also followed in the small intestine of four control conventional piglets at the age of 2-5 days (Tab. I). The two dehydrogenases could be characterized by a topographic gradient; it means that their activity was increasing in the small intestine mucosa through duodenum in an aboral direction. The ICD activity is higher in the intestinal mucosa of healthy piglets (Figs. 2 and 3), where its topic concentration was more marked while the HBD activity is dispersed in enterocytes (Fig. 4). In infected piglets the density of the two enzymes was demonstrated to decrease already in the starting period of experimental infection, and it reaches the lowest values for the first time on DAI 5-6 (Fig. 5, Tab. II), then on DAIs 9 (HBD; Fig. 6, graph 11)) or 8 (ICD, Fig. 7 and 10). In the period of experimental infection no statistically significant predisposition to the hypoactivity of target dehydrogenases nor its marked shift were observed. Somewhat rapid resumption of synthesis was demonstrated as soon as on DAI 8 in ICD (Fig. 8); its activity on DAI 10 in the intestinal mucosa corresponded to the 93% activity of this dehydrogenase recorded in the small intestine of control piglets. The density of HBD to the same day (DAI 10) reached in the intestinal mucosa of infected piglets the values making only 44.7% of those demonstrated in the intestinal mucosa of the control group of animals.     

Abdominal adhesions after small intestinal surgery in the horse

One hundred thirteen of 172 horses (66%) undergoing exploratory celiotomy for a small intestinal lesion survived 4 or more days after surgery. Intra-abdominal adhesions causing clinical problems requiring additional surgery or euthanasia were documented in 25 horses (22.1%). Problems developed in significantly more males than females. The most common initial small bowel lesion was ileal impaction (12 horses); 21 horses underwent small intestinal resection or bypass. However, there was no significant difference in the incidence of intra-abdominal adhesions between horses that underwent intestinal resection or bypass and those that did not. Only 4 of the 25 horses (16%) with problems associated with postoperative adhesions survived. The mean interval between surgical procedures or between the initial procedure and euthanasia for all horses was 84 days (range, 7-512 days; median, 25 days). However, 70% of the subsequent celiotomies were performed within 60 days of the previous surgery. The mean interval between celiotomies was 221 days (range, 9-512 days) for the survivors and 61 days (range, 7-358 days) for the nonsurvivors. These results indicated that most of the problems related to postoperative intra-abdominal adhesions occurred within 2 months of the initial small intestinal surgery. Furthermore, the earlier development of postoperative adhesions was associated with a poorer prognosis for survival.