天蚕素和合生素对AA肉鸡小肠黏膜形态和小肠免疫细胞的影响

为研究日粮中添加天蚕素、合生素对AA肉鸡小肠黏膜形态及免疫细胞的影响,试验选用480只1日龄健康AA肉鸡,随机分为4组,每组4个重复,每个重复30只鸡。对照组（Ⅰ组）饲喂基础日粮,试验组（Ⅱ~Ⅳ组）分别在基础日粮中添加0.5%天蚕素、0.3%合生素、0.5%天蚕素+0.3%合生素。试验期42 d。结果显示,与Ⅰ组相比,Ⅳ组十二指肠、回肠绒毛高度极显著升高（P<0.01）;Ⅱ组空肠和回肠、Ⅲ组小肠各段隐窝深度显著或极显著降低（P<0.05;P<0.01）;Ⅱ、Ⅲ组小肠各段和Ⅳ组十二指肠、回肠绒毛高度/隐窝深度显著或极显著升高（P<0.05;P<0.01）;Ⅱ组空肠绒毛宽度显著降低（P<0.05）,Ⅲ组十二指肠和空肠、Ⅳ组空肠和回肠绒毛宽度均极显著降低（P<0.01）;Ⅱ、Ⅲ组空肠黏膜厚度显著升高（P<0.05）,Ⅳ组小肠各段黏膜厚度均极显著升高（P<0.01）。Ⅱ组回肠上皮内淋巴细胞数量显著升高（P<0.05）,Ⅲ组十二指肠、Ⅳ组小肠各段上皮内淋巴细胞数量极显著升高（P<0.01）;Ⅲ组十二指肠、Ⅳ组十二指肠和回肠杯状细胞数量极显著升高（P<0.01）;Ⅳ组空肠肥大细胞数量显著升高（P<0.05）。综上所述,天蚕素、合生素单独或联合添加均能改善AA肉鸡小肠黏膜结构,促进小肠黏膜免疫细胞增殖,联合添加效果最佳。     

Effects of Cecropin and Synbiotics on the Intestinal Mucosal Morphology and Intestinal Mucosal Immune Cells of AA Broilers

In order to investigate the effects of cecropin and synbiotics on the intestinal mucosal morphology and intestinal mucosal immune cells of AA broilers. 480 of 1-day-old healthy AA broilers were chosen and randomly divided into 4 groups with 4 replicates per group and 30 broilers per replicate. The broilers in group Ⅰ(control group) were fed basal diet,while that in groups Ⅱ to Ⅳ were fed the basal diet supplemented with 0.5% cecropin,0.3% synbiotics,0.5% cecropin+0.3% synbiotics,respectively. The trial lasted for 42 days. The result showed that compared with group Ⅰ,the villus height of duodenum and ileum in group Ⅳ were extremely significantly increased (P<0.01).The crypt depth of jejunum and ileum in group Ⅱ,and that of small intestine in group Ⅲ were significantly or extremely significantly decreased (P<0.05;P<0.01).The villus height/crypt depth of small intestine in groups Ⅱ and Ⅲ,and that of duodenum and ileum in group Ⅳ were significantly or extremely significantly increased (P<0.05;P<0.01).The villus width of jejunum in group Ⅱ was significantly decreased (P<0.05),while the villus width of duodenum and jejunum in group Ⅲ,that of jejunum and ileum in group Ⅳ were extremely significantly decreased (P<0.01).The mucous thickness of jejunum in groups Ⅱ and Ⅲ were significantly increased (P<0.05),while that of small intestine in group Ⅳ was extremely significantly increased (P<0.01).The number of the intraepithelial lymphocyte of ileum in group Ⅱ was significantly increased (P<0.05),and that of duodenum in group Ⅲ and small intestine in group Ⅳ were extremely significantly increased (P<0.01).The number of the goblet cell of duodenum in group Ⅲ,duodenum and ileum in group Ⅳ were extremely significantly increased (P<0.01).The mast cell of jejunum in group Ⅳ was significantly increased (P<0.05).In conclusion,both the cecropin and synbiotics could improve the small intestine mucosal structure and promote the small intestine mucosal immunocompetent cells proliferation in AA broiler, and the effect of combined utilization would be better.     

Passage of ribonucleic acid along the intestine of sheep.

Sheep (Flemish female x Texel male, 55 kg BW), fitted with a PVC cannula in the dorsal rumen and single T-shaped PVC cannulas in the proximal duodenum, distal duodenum, mid-jejunum and terminal ileum were fed hay or hay-concentrate diets at various levels of nitrogen and cell walls (NDF) (22 to 32 g N/d; 150 to 699 g NDF/d). Co-EDTA and Cr-NDF were used as markers to measure the flow rate of digesta. Ribonucleic acid (RNA) intestinal digesta and in rumen bacteria was determined with orcinol after extraction with sodium chloride, precipitation with tungstophosphoric acid and alkaline hydrolysis. The RNA:total N ratio in bacteria, harvested from the rumen, amounted to 0.70 (CV 4.4%). The apparent digestibility of RNA in different sections of the intestine was higher than of total N. About 6% of RNA entering the duodenum disappeared between the proximal and distal duodenum. At jejunum, the net disappearance of RNA amounted to 68% of the quantity which entered the proximal duodenum. A higher result of 71% was obtained at the ileum. Total net disappearance of RNA between the proximal duodenum and rectum averaged 75%. Sixteen percent of RNA leaving the ileum was apparently digested in the large intestine. The true digestibility of RNA between the proximal duodenum and the terminal ileum, as estimated by multiple regression analysis, amounted to 78%. Of the amount of RNA entering the ileum, 24% was of endogenous origin. At ileum, the RNA passage was positively related to the ileal flow of NDF (R2 = 0.67) and N (R2 = 0.94). The passage of RNA increased by 3 mg RNA per g ileal indigestible NDF. Ileal endogenous N consisting of approximately 2% of endogenous RNA-N. In conclusion, the digestion capacity in the first part of the small intestine is high. Rising flows of indigestible cell walls and nitrogen increase the loss of ileal RNA. Further, using RNA as a microbial marker to assess the amount of microbial protein entering the duodenum of ruminants, digesta samples should be collected immediately post pylorus at the proximal duodenum, in order to avoid underestimation of the microbial protein synthesis in the rumen.     

CCK and GLP-1 release in response to proteinogenic amino acids using a small intestine ex vivo model in pigs

The impact of individual amino acids (AA) on gut hormone secretion and appetite regulation in pigs remains largely unknown. The aim of the present study was to determine the effect of the 20 proteinogenic AA on the release of the anorexigenic hormones cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) in postweaning pigs. Six 25-d-old male piglets (Domestic Landrace × Large White; body weight = 6.94 ± 0.29 kg) were humanely killed for the collection of intestinal segments from the duodenum, jejunum, and ileum. Tissue samples from the three intestinal segments were used to determine which of the regions were more relevant for the analysis of gut peptides. Only the segments with the highest CCK and GLP-1 secretion and expression levels were evaluated with the 20 individual AA. Tissue segments were cut open, cleaned, and stripped of their muscle layer before identical circular samples were collected and incubated in 24-well plates for 1 h (37 °C, 5% v/v CO₂). The culture broth consisted of a glucose-free KRB buffer containing no added AA (control) or with the addition of 10 mM of 1 of the 20 proteinogenic AA. Following incubation, tissues and supernatant were collected for gene expression and secretion analysis of CCK and GLP-1 levels. CCK secretion and mRNA expression were higher (P < 0.05) in duodenum when compared with proximal jejunum or ileum, whereas GLP-1/proglucagon levels were higher in ileum vs. duodenum (P < 0.05) and jejunum (P < 0.05, for GLP-1 only) in postweaning pigs. Based on these results, the effect of AA on CCK and GLP-1 secretion was studied in the duodenum and ileum, respectively. None of the AA tested stimulated both anorexigenic hormones. Of all the essential AA, Ile, Leu, Met, and Trp significantly (P < 0.05) stimulated GLP-1 from the ileum, while only Phe stimulated CCK from the duodenum. Of the nonessential AA, amide AA (Gln and Asn) caused the release of CCK, while Glu and Arg increased the release of GLP-1 from the ileum. Interpreting the results in the context of the digestion and absorption dynamics, non-bound AA are quickly absorbed and have their effect on gut peptide secretion limited to the proximal small intestine (i.e., duodenum), thus, mainly CCK. In contrast, protein-bound AA would only stimulate CCK release from the duodenum through feedback mechanisms (such as through GLP-1 secreted mainly in the ileum).     

In vitro effects of tachykinins on the smooth musculature of horse gut

The contractile effects of the tachykinins eledoisin, substance P and neurokinin A and B were investigated in vitro on circular and longitudinal muscle strips from horse duodenum, ileum and colon. Circular smooth muscle of the small intestine was highly responsive, large intestine circular smooth muscle less so, while longitudinal muscle from all gut segments was much less sensitive. pD₂ values and intrinsic activities on small intestine circular muscle indicated differences in receptor distribution between the duodenum and ileum: NK₃ and a smaller number of NK₂ receptors being present in the duodenum, and NK₂ receptors predominating in the ileum. Notwithstanding this, eledoisin and neurokinin B were the most active substances on duodenum and ileum, respectively. These findings suggest that tachykinins may play a role in equine gastrointestinal pathophysiology.     

维生素A在泌乳奶牛消化道内的动态变化研究

选择3头条件一致的荷斯坦奶牛,安装永久性的瘤胃瘘管、十二指肠瘘管和回肠瘘管,用Co-ETDA做标记物。采用3×3拉丁方设计研究了不同维生素A添加水平对奶牛瘤胃、十二指肠、回肠和血液中维生素A浓度的影响,以及维生素A在小肠中的吸收情况,研究结果表明：瘤胃、十二指肠、回肠和血液中维生素A浓度随着维生素A剂量增加而极显著上升（P〈0.01）,其中回肠末端维生素A浓度上升的幅度随着添加剂量的增加而加大,其余三者中维生素A浓度上升的幅度随着添加剂量的增加而逐步降低。小肠中维生素A的吸收量随着维生素A剂量的增加而极显著上升（P〈0.01）,但上升的幅度随着添加剂量的增加而逐步降低。     

Morphology of the small intestine of weaned piglets and a novel method for morphometric evaluation

The intestinal morphology of 7-week-old pigs was investigated by light (LM) and scanning electron microscopy (SEM). The piglets were fed either a semisynthetic or a cereal-based diet. The shapes of the intestinal villi and crypts of the duodenum, jejunum and ileum were examined. The villi were predominantly tongue-shaped. In the duodenum they were also ridged, branched and folded, and in the jejunum they were also leaf-like and ridged. At places with lymph follicles, the surface of the ileum was rugged with meandering fold-like villi. The crypts of the three segments of the small intestine were mainly coiled and sometimes branched. A novel morphometric evaluation method was introduced using the enlargement factors of each villus and crypt surface. The enlargement factor for the villus surface of the duodenum, jejunum and ileum was 3.13, 3.72 and 2.71, respectively. The factor for the crypt surface of the duodenum, jejunum and ileum was 9.07, 8.94 and 6.53, respectively. Furthermore, the relative proliferation rate and the epithelial renewal index were calculated for the first time. The relative proliferation rate of the duodenum, jejunum and ileum was 32.88, 34.78 and 50.77 proliferations per mm crypt perimeter, respectively. The diets consumed had an influence on the epithelial renewal index being higher for piglets fed the cereal-based diets.     

Developmental changes in morphometry of the small intestine and jejunal sucrase activity during the first nine weeks of postnatal growth in pigs

The objective of this study was to investigate the development of small intestinal size and digestive capacity of the jejunum in growing pigs. The weight, length, surface area, and mucosa weight of the small intestine were measured when pigs were 1, 3, 5, and 9 wk of age. Sucrase and alkaline phosphatase (ALP) activities of the jejunal brush-border membrane, prepared by differential centrifugation and Mg2+ precipitation, were determined at the respective postnatal stages. Body weights increased 7-fold from 2.7 kg at 1 wk to 23.32 kg at 9 wk postnatal. Body weight gains were greater (P < 0.05) from wk 3 to 5 than from wk 1 to 3. Weights of the small intestine and of the intestinal mucosa increased faster (P < 0.05) from 3 to 5 wk than from 1 to 3 wk; the slowest increase occurred from 5 to 9 wk. Weights of the duodenum, jejunum, and ileum, and mucosa from the respective sections increased (P < 0.05) as pigs grew from 3 to 9 wk. Mucosa weight relative to the weight of the section was greater (P < 0.05) for the duodenum and jejunum than for the ileum at 9 wk of age. Between the ages of 3 and 9 wk, the increase in mucosa weight was highest for the jejunum followed by the duodenum and the ileum. The increase was greatest for the duodenum followed by the jejunum and the ileum when mucosal weight was expressed per unit of appropriate intestinal section weight. There was a 55-fold increase in jejunal sucrase activity from 1 to 9 wk; the greatest rate of increase occurred between 5 and 9 wk. Total jejunal ALP activities in pigs at 9 wk was greater (P < 0.05) than at 5 wk, which in turn was greater than at 1 wk of age. In summary, increases in BW during the first 9 wk of postnatal growth in pigs are accompanied by significant developmental changes in digestive capacity including intestinal weights, length, and area as well as jejunal brush-border sucrase and ALP activities.     

Propionic acid disappearance from the foregut and small intestine of the beef steer

Studies were conducted to determine the disappearance of propionic acid from the rumen and across the small intestine. Four crossbred beef steers, fitted with ruminal, duodenal and ileal cannulas, were given pulsed-continuous infusions of a nonabsorbable liquid phase marker (CrEDTA) and buffered propionic acid to achieve ruminal propionate productions (RPP) of 142 (basal), 567 and 997 mmol/h. Liquid flows from the rumen, and at the duodenum and ileum (2.75, 3.57 and .92 liters/h, respectively) were not affected by RPP (P greater than .23), although significant differences existed between sites (P = .001), reflecting a net addition of liquid between the rumen and duodenum and a net removal of liquid within the small intestine. Propionate disappearance from the rumen was 40 to 57% irrespective of RPP, with the complement passing from the rumen. Of the propionate that exited the rumen, 93 to 97% disappeared prior to entering the duodenum. Overall removal of RPP prior to the duodenum was 97 to 99% irrespective of RPP. Passage of propionic acid at the duodenum and at the ileum did not differ (P greater than .76) across all RPP, and the overall mean passages did not differ from zero (P greater than .34); similar results were observed for other VFA. These observations indicate that essentially all RPP is removed prior to entering the small intestine. Additionally, net propionate disappearance across the small intestine was undetectable and likely biologically irrelevant. Therefore, VFA absorption does not appear to be a limiting biological process in the beef steer.     

日粮中添加复合微生态制剂对蛋种鸡肠道pH及微生物的影响

研究日粮中添加复合微生态制剂对蛋种鸡小肠肠道长度、pH及盲肠微生物的影响,试验选用1日龄海兰褐蛋种鸡320只,随机分为4个组,进行16周的试验。试验组日粮是在对照组日粮基础上分别添加50、100、200 g/t的复合微生态制剂组成。试验结果表明:① 与对照组相比, 21日龄时,添加复合微生态制剂组显著降低了蛋种鸡十二指肠、空肠、回肠的相对长度(P<0.05);42日龄时,试验2组的回肠相对长度显著低于对照组(P<0.05); 112日龄时, 试验1组空肠和回肠的相对长度显著低于对照组 (P<0.05),试验3组十二指肠的相对长度显著低于对照组(P<0.05)。②试验1、2组蛋种鸡21日龄空肠和回肠的pH显著低于对照组(P<0.05),试验3组蛋种鸡21、42、112日龄十二指肠、42日龄空肠的pH也显著降低 (P<0.05) 。③添加复合微生态制剂可显著提高蛋种鸡21日龄盲肠乳酸菌的数量(P<0.05),其中试验2组乳酸菌的数量最多,与对照组相比,提高了11.76%,其次是试验3组和试验1组;添加复合微生态制剂对于42和112日龄蛋种鸡的盲肠微生物无显著影响。结果提示,日粮中添加复合微生态制剂能缩短蛋种鸡小肠肠道相对长度,同时降低肠道pH并能改善肠道菌群,对雏鸡的健康生长有促进作用。本试验中添加100 g/t的复合微生态制剂为适宜添加量。     

羔羊小肠pH及主要消化酶发育规律的研究

对小尾寒羊羔羊小肠不同部位(十二指肠、空肠和回肠)pH及淀粉酶、胰蛋白酶、糜蛋白酶、脂肪酶和乳糖酶的活性进行了测定，结果表明：羔羊小肠不同部位内容物pH不同，回肠pH显著高于空肠，空肠和回肠pH显著高于十二指肠，羔羊1月龄后，小肠各段pH变化不大；小肠不同部位淀粉酶和胰蛋白酶、糜蛋白酶及脂肪酶活性不同，空肠段淀粉酶、胰蛋白酶、糜蛋白酶及脂肪酶活性高于十二指肠和回肠段，随着羔羊日龄的增长，小肠淀粉酶、胰蛋白酶、糜蛋白酶及脂肪酶活性增加，3月龄后各消化酶活性变化差异不显著(P＜O．05)；羔羊小肠不同部位乳糖酶活性不同，空肠乳糖酶活性显著高于十二指肠和回肠，随着羔羊日龄的增长，小肠乳糖酶活性逐渐降低。     

The small intestine of the adult New Hampshire chicken: an immunohistochemical study

The presence and distribution of glucose-dependent insulinotropic polypeptide or gastric inhibitory polypeptide (GIP), gastric-releasing peptide (GRP) and glucagon immunoreactivity were studied in the small intestine of the New Hampshire chicken using immunohistochemistry. This is the first report of the presence of GIP-immunoreactive (ir) cells in avian small intestine. GIP, GRP and glucagon immunoreactivity was localized in the epithelium of the villi and crypts of the duodenum, jejunum and ileum. In particular, both in the duodenum and in the jejunum immunoreactive endocrine cells to GIP, GRP and glucagon were observed. In the ileum, we noticed GIP-ir and glucagon-ir cells. GRP-ir was found in nerve fibres of all three segments of the small intestine. The distribution of these bioactive agents in the intestinal tract of the chicken suggests that GIP and glucagon may play a role in the enteropancreatic axis in which intestinal peptides modulate pancreas secretion.     

Effects of nitric oxide donor and nitric oxide synthase inhibitor on ruminal contractions in conscious sheep

The present study was planned to evaluate a role of nitric oxide (NO) in the regulation of regular ruminal contractions in conscious sheep. Intravenous infusion of S-nitroso-acetyl-DL-penicillamine (SNAP) at doses of 3-30 nmol kg(-1) min(-1)for 30 minutes inhibited both the amplitude and frequency of ruminal contractions in a dose-dependent manner. However, intravenous infusion of Nomega-nitro-L-arginine-methyl ester (L-NAME) at doses of 0.3-3.0 micromol kg(-1) min(-1)did not alter the basal tone of intraruminal pressure and the amplitude of ruminal contractions. The frequency of contractions was slightly inhibited by L-NAME infusion at 1.0 micromol kg(-1)min(-1). The effects of L-NAME were abolished by simultaneous infusion of L -arginine at 30 micromol kg(-1) min(-1). These results suggest that exogenous NO can diminish the ruminal contractions, while endogenous NO is not involved in the regulatory mechanism of basal tone and regular phasic contractions of the rumen in healthy sheep.     

The effect of pectin on amino acid digestibility and digesta viscosity, motility and morphology of the small intestine, and on N-balance and performance of young pigs

Two experiments were carried out using a balanced feed mixture composed of wheat, corn, soyabean meals, casein, and crystalline amino acids (AA) and supplemented with 0, 4, or 8% of apple pectin. The daily dietary allowance provided pigs with the same level of nutrients, apart from the pectin. One experiment was conducted on pigs (within 25 to 40 kg BW) with the post valve T-caecum (PVTC) cannula to determine AA digestibility and ileal digesta viscosity. In the second experiment, the N-balance was measured twice on male pigs at about 20 and 28 kg BW using 6 animals per diet and feed intake and body weight were measured twice during the 28 d. After 40 d of feeding the diets, the pigs were sacrificed and the small intestines were weighed and sampled. The added pectin decreased standardized ileal AA digestibility (on average up to 5% dig. units) and increased digesta viscosity from about 1 to 88 mPa s. The higher pectin level did not affect motility of the duodenum and mid-jejunum, measured as responses to electrical field stimulation and to acetylcholine. However, the response of the duodenum to electrical field stimulation was after feeding the diet with 4% pectin increased compared with other diets. Pectin supplementation did not alter the weight and the length of the small intestine, but induced changes in the intestinal morphology. Muscle layer width increased significantly in the duodenum, the mid-jejunum, and the ileum while villi length increased in the duodenum and ileum. The addition of pectin decreased N retention and increased the F/G ratio but did not affect significantly the ADG of the pigs.     

能量限制对三黄鸡补偿生长及肠道结构的影响

本试验旨在研究能量限制对三黄鸡补偿生长及肠道结构的影响,选用72只15日龄三黄母鸡,随机分为3个组:自由采食组(对照组)、15%能量限制组(试验1组)和30%能量限制组(试验2组),限饲15 d(30日龄)、补偿生长14 d(44日龄)和35 d(65日龄)后分别屠宰,取其十二指肠、空肠、回肠,测量其肠壁厚度、绒毛高度和隐窝深度。结果表明:1)限饲降低三黄鸡平均日增重(P0.05),但料重比与对照组相比差异不显著(P0.05)。补偿生长后,试验组与对照组组间的末重、平均日增重、料重比均差异不显著(P0.05)。2)限饲增加了十二指肠、空肠、回肠绒毛高度及回肠绒毛高度/隐窝深度(P0.05)。补偿生长后,十二指肠肠壁厚度变薄(P0.05),空肠和回肠绒毛高度增加(P0.05)。本试验表明,能量限制显著降低三黄鸡限饲期生长性能,补偿生长35 d后表现出完全补偿生长效应;能量限制在一定程度上改善了三黄鸡的小肠肠道形态结构,增加了十二指肠、空肠、回肠绒毛高度。     

Expression of monocarboxylate transporter 1 (MCT1) in the dog intestine

In this study, the expression and distribution of monocarboxyolate transporter 1 (MCT1) along the intestines (duodenum, jejunum, ileum, cecum, colon and rectum) of dogs were investigated at both the mRNA and protein levels. The expression of MCT1 protein and its distribution were confirmed by Western blotting and immunohistochemical staining using the antibody for MCT1. We identified mRNA coding for MCT1 and a 43-kDa band of MCT1 protein in all regions from the duodenum to the rectum. Immunoreactive staining for MCT1 was also observed in epithelial cells throughout the intestines. MCT1 immunoreactivity was greater in the large intestine than in the small intestine. MCT1 protein was predominantly expressed on the basolateral membranes along intestinal epithelial cells, suggesting that MCT1 may play an important role in lactate efflux and transport of short-chain fatty acids (SCFAs) to the bloodstream across the basolateral membranes of the dog intestine.     

Electromyoenterography During Normal Gastro-Intestinal Activity, Painful or Non-painful Colic and Morphine Analgesia, in the Horse

The electrical potentials were recorded from the antrum, the duodenum, the ileum and the first part of the colon of ponies under (a) normal resting conditions, (b) during nonpainful colic and (c) after intravenous morphine administration.

The normal pony, at rest, had five contractions of the antrum per minute. On the small intestine, the basal electrical activity decreased from the duodenum (14-15/min) to the ileum (10-11/min). The small bowel also had three types of motility: peristaltic waves, rhythmic segmentations and random contractions. On the colon, bursts of potentials indicating intense motor activity occurred at the rate of 20 to 30 per hour. Morphine given intravenously (IV) greatly increased the frequency of the electrical potentials of the antrum and the longitudinal bands of the colon.

During non-painful colic, hyperactivity of the cranial small intestine was continuous. Spasms of the jejunum occurred every minute and could not be relieved by morphine (IV).

When colic was painful, jejunal spasms announced the crisis of intense abdominal pain. After morphine (IV) the spasms and pain disappeared; the jejunum remained hyperactive, the motility of the colon was increased while the antrum became quiet.

     

Surgical diseases of the small intestine.

Surgical disorders of the gastrointestinal tract of cattle occur occasionally, and veterinarians are challenged to determine an accurate diagnosis and treatment for these conditions. Although surgical diseases most commonly occur in the forestomachs (dislocated abomasum, reticuloperitonitis) and the colons (cecal dilatation), this article focuses on lesions in the small intestine (duodenum, jejunum, ileum).     

Morphologic evaluation of IgM cells of the canine small intestine by fluorescence microscopy.

Biopsies of small intestine from 7 dogs were examined by fluorescence microscopy to determine the number of IgM-containing cells in the lamina propria. Biopsies were taken from duodenum, jejunum, and ileium. (Cell counts were made by 2 persons to demonstrate reproducibility.) There were 452.24 +/- 60.09 cells per mm2 in the duodenum 572.68 +/- 62.13 cells per mm2 in the jejunum, and 107.47 +/- 59.57 cells per mm2 in the ileum. All sections were cut at 6 micrometer. The ileum had fewer cells than either duodenum or jejunum (P = 0.000038 and 0.00001, respectively), whereas duodenum and jejunum did not differ significantly in numbers of cells (P = 0.17528). Quantifying autofluorescent cells in the same sites showed no significant differences among the 3 tissues (P = 0.24697). The autofluorescent cells differed in intensity and morphology from the IgM cells. These two observations tend to support the contention that the autofluorescent cells did not bias the IgM cell counts at the 3 sites. Total autofluorescence (cells, collagen, and vessels) was higher in the ileum than in either the jejunum or the duodenum (P = 0.04967 and 0.03050, respectively). However, all 3 categories counted (IgM cells, autofluorescent cells, and autofluorescent structures) had significant dog-tissue interactions. This will necessitate determining normals for each age-sex-breed category of dog studied.     

Morphometric study of the layers of the canine small intestine at five sampling sites

The histology of the canine intestine has not been accurately defined. To establish the precise thickness of its different layers, whole wall samples of the small intestine were removed from 41 cadavers at five standardised sampling sites (duodenum, proximal jejunum, distal jejunum, proximal ileum and distal ileum). The total thickness was estimated by morphometry, as was the thickness of the mucosa, muscularis mucosae, submucosa and muscularis externa. In addition, the size of the lymphoid aggregates in the submucosa and the thickness of the circular and longitudinal layers within both the muscularis mucosae and the muscularis externa were estimated. The total intestinal thickness depended very much upon the thickness of the mucosa and submucosa. The mucosa decreased progressively from proximal to distal parts of the small intestine (47% reduction). The thickness of the submucosa, however, changed little from the duodenum to the distal jejunum, but increased significantly in the ileum; this change was positively correlated with the amount of lymphoid tissue. Sex influenced the thickness of the intestinal wall, with males displaying higher thickness values along the small intestine. Conversely, no correlation between bodyweight and intestinal thickness was found for any of the five sampling sites. This study gives absolute and relative values for the thickness of the layers of the dog intestine which might help in the diagnosis of small intestinal pathology from postmortem samples and/or endoscopic biopsies.