Alteration in intestinal morphologic features associated with extensive large-colon resection in horses

Light microscopy, morphometry, and scanning electron microscopy were used to examine the mucosal morphologic features of 7 intestinal specimens (3 from the small intestine; 4 from the large intestine) from each of 8 horses 1 year after sham operation (group 1; n = 3) or extensive large-colon resection (group 2; n = 5). Qualitative light microscopic examination did not reveal differences between groups, but morphometry revealed significantly (P less than 0.05) greater intercrypt area and distance in horses with colon resection and this was most pronounced in the cecum and remaining right ventral and dorsal colon. Crypt area and depth were similar for horses with colon resection and sham operation (P greater than 0.05). Qualitative evaluation of the scanning electron micrographs revealed more prominent crypt orifices in the large intestine of horses with colon resection. The larger intercrypt distance in the colon of horses with resection was not an obvious feature of the qualitative evaluation of the surface with scanning electron microscopy. Small intestinal morphologic features were variable and significant differences were not detected between horses with sham operation and colon resection. Horses adapted to extensive large-colon resection within 1 year by increasing the absorptive (intercrypt) surface area of the remaining large intestine.     

Accuracy of increased large-intestine wall thickness during ultrasonography for diagnosing large-colon torsion in 42 horses

Large-colon torsion is a common cause of colic in horses and has a worse prognosis and higher cost than other causes of surgical colic of the large colon. During large-colon torsion, the colon wall becomes thick due to vascular occlusion. Therefore, we hypothesized that detecting increased colon wall thickness during ultrasonography would be an accurate preoperative test for large-colon torsion. The sample population consisted of 42 horses that were admitted for surgical treatment of colic localized to the large colon. The diagnosis was confirmed at surgery or necropsy examination. Twelve (29%) of these horses were diagnosed with large-colon torsion. Duplicate ultrasonographic measurements of colon wall thickness were made at six abdominal locations and an average measurement was calculated. For four of these six sites, a significant difference (P < 0.005) was detected between horses with and without large-colon torsion. All four tests were moderately sensitive and highly specific for diagnosing large-colon torsion using five decision criteria. Using a ventral abdominal window, a colon wall thickness > or = 9 mm accurately predicted large-colon torsion in eight of the 12 horses (sensitivity, 67%; confidence interval [CI], 36-98%) and correctly predicted that large-colon torsion was absent in 28/28 horses (specificity 100%; CI, 98-100%). Intraobserver repeatability was assessed by evaluating the difference between the first and second measurements obtained, which was < or = 2 mm. Therefore, detecting increased large-colon wall thickness during ultrasonography is a reproducible and accurate preoperative test for large-colon torsion in horses with surgical colic localized to the large colon.     

Effects of concanavalin A on intestinal brush border enzyme activity in broiler chickens

1. The effects of Concanavalin A (Con A) on enzymes from the intestinal brush border were studied using membrane vesicles (BBMV) prepared from 3- and 6-week-old broiler chickens. 2. Maltase, sucrase, phytase, alkaline phosphatase and leucine aminopeptidase activities were assayed in BBMV in the absence (T0) or presence (T1) of Con A, or in the presence of casein (T2). Disaccharidase specific activities were assayed in the presence of Con A that had been pre-incubated with the enzyme (T3) or with the substrate (T4). 3. Con A significantly affected maltase and sucrase activities in 3-week-old broiler chicken intestinal BBMV. Pre-incubation of the lectin with the maltase or its substrate had no effect on enzyme activity. Pre-incubation of Con A with sucrose reduced enzyme activity. 4. Con A did not affect phytase, alkaline phosphatase or leucine aminopeptidase activities. 5. Maltase, alkaline phosphatase and leucine aminopeptidase activities were lower in 6-week-old than in 3-week-old broilers.     

Fiber digestion and voluntary intake in horses after adaptation to extensive large-colon resection

Each of 3 digestion trials (3 forage diets) was performed on 2 groups of horses 6 to 12 months after sham operation (group 1; n = 3) or large-colon resection (group 2; n = 5). Diets were alfalfa pellets, alfalfa hay, and grass hay. Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, and crude protein and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables determined were percentage of fecal water, total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. Large-colon resection decreased the digestion of plant cell wall because of decreased digestion of cellulose in alfalfa pellet and grass hay diets, but not in alfalfa hay diet. Insufficient digestible energy and/or protein from grass hay was obtained by horses with colon resection, and significant (P less than 0.05) weight loss was observed. Voluntary intake was significantly (P less than 0.05) increased by horses with colon resection. Of the diets studied, alfalfa hay was the most appropriate forage diet, compared with average grass hay and alfalfa pellet diet, for horses after extensive large-colon resection. Additionally, horses with colon resection may have higher levels of feed intake than do horses without colon resection.     

Digestion, fecal, and blood variables associated with extensive large colon resection in the horse

Nutritional alterations were evaluated in 9 horses before surgery and 3 weeks, 3 months, and 6 months (4 total trials) after sham operation (group 1; n = 3) or extensive large colon resection (group 2; n = 6). Feed and fecal analyses were performed to determine apparent digestion of dry matter, organic matter, crude protein, calcium, phosphorus, magnesium, potassium, manganese, zinc, copper, and iron, and true digestion of dry matter, organic matter, crude protein, total plant cell wall, hemicellulose, cellulose, and lignin. Additional fecal and metabolic variables included the percentage of fecal water (water in the feces), total fecal water, metabolic organic matter, metabolic crude protein, and metabolic nitrogen. A CBC and standard series of biochemical tests were performed. Large colon resection decreased (P less than 0.05) the true digestion of dietary crude protein and cellulose and apparent digestion of phosphorus, and it increased the fecal metabolic matter and water loss. Total fecal output increased 45% and total fecal water increased 55%. Phosphorus digestion was decreased (P less than 0.05) in group-2 horses, but effects of this were not detected on analysis of blood variables or on physical examination. Nevertheless, after extensive large colon resection, horses can regain body weight lost after surgery and have no overt physical changes when fed an alfalfa pellet diet that meets greater-than-maintenance requirements. Ad libitum water access is suggested, because these horses may have to consume 2 gal/day more than would normal horses.     

Serum tumor necrosis factor activity in horses with colic attributable to gastrointestinal tract disease.

Over a 24-month period, serum tumor necrosis factor (TNF) activity was determined in 289 horses with colic attributable to gastrointestinal tract disease. Serum TNF activity was quantitated by use of a modified in vitro cytotoxicity bioassay, using WEHI 164 clone-13 murine fibrosarcoma cells. Causes for colic, determined by clinical and laboratory evaluation, exploratory celiotomy, or necropsy included: gastrointestinal tract rupture (GTR); ileal impaction; small intestinal strangulating obstruction (SIO); proximal enteritis (PE); transient small intestinal distention; large-colon displacement; large-colon volvulus; large-colon impaction; colitis; small-colon obstruction; peritonitis; and unknown. Each diagnosis was placed into 1 of 3 lesion categories: inflammatory disorders (GTR, PE, colitis, peritonitis); strangulating intestinal obstruction (SIO, large-colon volvulus); and nonstrangulating intestinal obstruction (ileal impaction, transient small intestinal distension, large-colon displacement, large-colon impaction, small-colon obstruction, unknown). The prevalence of high serum TNF activity and/or mortality were evaluated. Differences were tested at significance level of P less than 0.05. Approximately 20% of the 289 horses has serum TNF activity greater than that found in clinically normal horses (greater than 2.5 U/ml). Twenty-three horses (8%) had marked increase in serum TNF activity (greater than or equal to 10 U/ml) which was more prevalent among horses with SIO and PE than in horses of other diagnostic groups, except those with GTR. Mortality and marked increase in serum TNF activity were greater in horses with intestinal inflammatory disorders or strangulating intestinal obstruction than in horses with nonstrangulating intestinal obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)     

乳鸽早期消化特性研究

试验通过研究2~10日龄乳鸽体重、消化器官重量、血清蛋白质代谢、胰腺和小肠黏膜消化酶活性等指标的变化规律,揭示乳鸽消化道早期发育特性。选取出壳后2、4、6、8、10日龄白卡奴乳鸽30羽(每个日龄6羽),屠宰取样。结果表明:1)日龄对乳鸽早期体重(含卵黄重)、腺胃、肌胃、肝脏、胰腺、小肠的器官重量和器官指数;血清总蛋白、白蛋白、尿酸、尿素氮含量;胰腺淀粉酶、脂肪酶、胰蛋白酶总活性,脂肪酶比活性,小肠黏膜二糖酶(蔗糖酶和麦芽糖酶)及碱性磷酸酶总活性和比活性均影响显著(P0.05)。其中,发育模式随日龄变化表现为线性增加的指标包括:肝脏、胰腺、小肠的器官指数(P0.01);体重,肌胃、腺胃、胰腺、肝脏、小肠的器官重量(P0.01);血清总蛋白和白蛋白含量(P0.01);胰腺淀粉酶、脂肪酶、胰蛋白酶总活性,胰腺脂肪酶比活性(P0.05);小肠黏膜二糖酶(麦芽糖酶和蔗糖酶)和碱性磷酸酶总活性和比活性(P0.01)。血清尿酸、尿素氮含量,胰蛋白酶比活性发育规律表现为线性下降(P0.05)。腺胃和肌胃的器官指数表现为先上升后下降(P0.05)。2)肠段对乳鸽小肠黏膜麦芽糖酶和蔗糖酶总活性影响显著(P0.05)。3)日龄与肠段的交互作用对麦芽糖酶总活性、蔗糖酶总活性和蔗糖酶比活性影响显著(P0.05)。结果提示,随着日龄变化,乳鸽机体蛋白质代谢能力不断增强,沉积水平不断提高,消化系统发育迅速,生长速度高于机体生长,自身胰腺和小肠黏膜水解酶活性不断增强,10日龄时,机体发育水平显著提高。因此,2~10日龄阶段是乳鸽出壳后消化生理机能趋于完善的重要阶段。     

Decreased activity of brush border membrane-bound digestive enzymes in small intestines from pigs experimentally infected with porcine epidemic diarrhea virus

Brush border membrane-bound digestive enzymes such as disaccharidases (lactase, sucrase, and maltase), leucine aminopeptidase N, and alkaline phosphatase were measured in jejunum from pigs experimentally infected with porcine epidemic diarrhea virus (PEDV). Three piglets from the infected and control groups were euthanized by electrocution and subjected to necropsy at 24, 36, 48, 60, and 72 hours post-inoculation (hpi). The infection of PEDV to jejunum resulted in significant decreases in brush border membrane-bound digestive enzymes such as disaccharidases (lactase, sucrase, and maltase), leucine aminopeptidase N, and alkaline phosphatase. PEDV replication results in massive destruction of villous enterocytes leading to a marked reduction of intestinal epithelial surface and brush border membrane-bound digestive enzyme activity. Reduced enzymatic activity and villous atrophy in the small intestine is thought to result in a maldigestive and malabsorptive diarrhea.     

Colopexy of the equine large colon: comparison of two techniques

A study was designed to evaluate 2 colopexy techniques (A and B) in 8 clinically normal horses to determine which technique would prevent recurrence of large-colon displacement and/or volvulus. For technique A, 35 cm of the lateral free band of the left ventral colon was sutured to the abdominal wall, 6 cm to the left of ventral midline. For technique B, the medial free band of the left ventral colon was sutured to the medial free band of the right ventral colon, and 8 cm of the lateral free band of the left ventral colon was sutured to the abdominal wall, 6 cm to the left of ventral midline. One horse from each group was euthanatized at 6 months, and another at 12 months after surgery. The position of the large colon, the integrity of the colopexy, and other adhesions within the abdominal cavity were evaluated. At necropsy, attempts were made to manually create displacement and volvulus of the large colon. The remaining horses in each group were anesthetized 6 months or 12 months after surgery, and the integrity of the colopexy was evaluated. After a 60-day recovery period, these horses were exercised for 2 months. Although each horse initially lost weight, the weight of all but 2 was acceptable at the conclusion of the study. Two horses that had technique-B colopexies had progressive weight loss serious enough to warrant euthanasia. Both colopexy techniques prevented manual creation of large-colon displacement and large-colon volvulus centered at the sternal and diaphragmatic flexures. Technique-A colopexy also prevented manual creation of volvulus of the large colon centered at its base.(ABSTRACT TRUNCATED AT 250 WORDS)     

胎儿宫内发育迟缓对新生仔猪小肠消化酶发育的影响

利用自然选择法从14窝初生仔猪选择14头正常仔猪和14头宫内发育迟缓（IUGR）仔猪，随机分成3组：初生组（DO）、母乳饲喂3d组（D3）和母乳饲喂7d组（D7），分别在0、3、7d屠宰以研究胎儿宫内发育迟缓对新生仔猪小肠消化酶发育的影响。初生时，正常仔猪小肠乳糖酶的总活性和比活性都显著高于IUGR仔猪。IUGR仔猪小肠氨基肽酶的总活性和比活性都低于正常仔猪，其中总活性的差异极显著。IUGR仔猪小肠的麦芽糖酶总活性显著低于正常仔猪，但比活性在2组间没有显著差异。2组间碱性磷酸酶的比活性和总活性都没有显著差异。生长至3日龄时，正常仔猪和IUGR仔猪间麦芽糖酶和碱性磷酸酶活性没有显著差异，而2组间乳糖酶总活性和氨基肽酶总活性的差异显著。7日龄时，正常仔猪和IUGR仔猪乳糖酶、麦芽糖酶、氨基肽酶和碱性磷酸酶活性均没有显著差异。试验结果表明宫内发育迟缓抑制了小肠乳糖酶和氨基肽酶的成熟，而麦芽糖酶和碱性磷酸酶表现出早熟。同时又表明，胎儿宫内发育迟缓仔猪的肠道功能发育在生后1周内能部分实现补偿生长，而且补偿生长的实现是随着日龄增加逐步完全的。     

Influence of alpha-linked glucose on sodium-glucose cotransport activity along the small intestine in cattle

Thirteen steers (378+/-23 kg) were used in a split-plot experimental design to evaluate the effect of small intestinal carbohydrate on sodium-glucose cotransport in brush border membrane vesicles prepared from five equidistant sites along the small intestine. The steers consumed 7.2+/-0.4 kg/d ground fescue hay and soybean meal-based supplement and were infused ruminally or postruminally with a partial alpha-amylase starch hydrolysate (914.5+/-8.3 g/d) for 7 d. On d 7, five equidistant 1-m small intestinal sections were harvested and frozen in liquid N for later preparation of brush-border membrane vesicles. Maltase activity of the homogenate and vesicle preparations changed (P < 0.001; lowest in the duodenum, highest in the jejunum) and alkaline phosphatase decreased (P < 0.001) along the small intestine. With respect to the original homogenates, the vesicle preparations were enriched 9.80+/-0.83- and 7.64+/-0.67-fold for alkaline phosphatase and maltase, respectively; enrichments were not different between treatments (P = 0.76 and 0.39, respectively). However, alkaline phosphatase and maltase enrichment changed (P < 0.001) along the small intestine. Recoveries of alkaline phosphatase and maltase activities (25.0+/-0.2% and 19.5+/-0.2%, respectively) in the vesicle preparation were not affected (P = 0.29 and 0.21, respectively) by treatment but changed (P < 0.001) along the intestine. Recovery of protein in the vesicle preparation was 2.60+/-0.01% and was not affected by treatment or intestinal site. Sodium-glucose cotransport activity (220+/-44 pmol x mg(-1) x s(-1)) was not affected (P = 0.34) by treatment but did change (P < 0.001; lowest in the ileum, highest in the proximal and mid-jejunum) along the small intestine. Apparent Km of the sodium-glucose cotransporter for glucose was 62.8+/-5.8 microM. The specific activity of maltase was highest in the jejunum, and sodium-glucose cotransport was highest in the first two jejunal sites. However, duodenal maltase activity was lowest and ileal sodium-glucose cotransport activity was lowest. Sodium-glucose cotransport activity may limit small intestinal starch assimilation in the distal small intestine. It does not seem that glucose arising from carbohydrate hydrolysis regulates activity of sodium-dependent glucose transport in cattle.     

Survival rates for horses undergoing stapled small intestinal anastomosis: 84 cases (1988-1997)

OBJECTIVE: To determine whether location and type of small intestinal anastomosis and other variables were associated with short- and long-term survival rates in horses undergoing stapled small intestinal anastomosis. DESIGN: Retrospective study. ANIMALS: 84 horses that underwent small intestinal anastomosis. PROCEDURE: Medical records from 1988 to 1997 were examined for horses that underwent stapled small intestinal anastomosis. Horses were allotted into 4 groups: jejunojejunostomy (n = 27), jejunoileostomy (11), jejunoileocecostomy with small intestinal resection (20), and jejunoileocecostomy without small intestinal resection (26). Survival rates and other variables were determined. RESULTS: Horses that underwent jejunoileocecostomy without resection had a significantly higher survival rate at all intervals than did horses in the other 3 groups. At 180 and 365 days after surgery, horses that underwent jejunojejunostomy had a significantly lower survival rate than those that underwent jejunoileocecostomy with intestinal resection. Horses that underwent jejunoileocecostomy with intestinal resection had a significantly higher survival rate at 1 year, compared with the combined jejunojejunostomy and jejunoileostomy groups. Preoperative heart rate was inversely associated with survival rate. Overall survival rates at discharge and 1 year were 81 and 56%, respectively. For horses that underwent small intestinal resection, survival rates at discharge and 1 year were 65 and 47%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Horses that underwent anastomosis of the small intestine to the cecum without resection had the highest survival rate, compared with horses that required intestinal resection. In some instances, resection and anastomosis involving the cecum had better prognosis than resections involving 2 segments of the small intestine.     

Short-term effect of acarbose on specific intestinal disaccharidase activities and hyperglycaemia in CBA diabetic mice

The purpose of this study was to examine the short-term effects of 75, 100 and 150 mg of acarbose mixed in 100 g standard laboratory chow on specific intestinal disaccharidase activities and on hyperglycaemia in diabetic CBA strain mice on standard diet. The small intestine was excised and divided into three segments, from pylorus to duodenum, and two equal lengths of the jejunum and ileum of control and diabetic mice with or without added acarbose. Specific maltase and sucrase activities were determined using maltose and sucrose as substrates respectively. Increased specific activities of maltase and sucrase were detected in the intestines of CBA mice on standard laboratory diet seven days after alloxan-induced diabetes. Feeding for 7 days with 75, 100 or 150 mg acarbose uniformly mixed in 100 g standard laboratory chow, induced a decrease in the specific maltase and sucrase activities, compared with diabetic mice on standard laboratory diet. Feeding with 75 mg acarbose mixed in 100 g standard laboratory chow caused a statistically significant decrease of maltase in the duodenum and of sucrase in duodenum and jejunum, without a antihyperglycaemic effect. Feeding with 100 or 150 mg caused statistically significant decreases in specific maltase and sucrase activities in duodenum, jejunum and ileum. An antihyperglycaemic effect was observed only in the group of diabetic mice fed with 100 mg acarbose. This indicates that the antihyperglycaemic effect of acarbose involves factors other than these, related only to its inhibitory effect on disaccharidase activities.     

Molecular characterisation of carbohydrate digestion and absorption in equine small intestine

Dietary carbohydrates, when digested and absorbed in the small intestine of the horse, provide a substantial fraction of metabolisable energy. However, if levels in diets exceed the capacity of the equine small intestine to digest and absorb them, they reach the hindgut, cause alterations in microbial populations and the metabolite products and predispose the horse to gastrointestinal diseases. We set out to determine, at the molecular level, the mechanisms, properties and the site of expression of carbohydrate digestive and absorptive functions of the equine small intestinal brush-border membrane. We have demonstrated that the disaccharidases sucrase, lactase and maltase are expressed diversely along the length of the intestine and D-glucose is transported across the equine intestinal brush-border membrane by a high affinity, low capacity, Na+/glucose cotransporter type 1 isoform (SGLT1). The highest rate of transport is in duodenum > jejunum > ileum. We have cloned and sequenced the cDNA encoding equine SGLT1 and alignment with SGLT1 of other species indicates 85-89% homology at the nucleotide and 84-87% identity at the amino acid levels. We have shown that there is a good correlation between levels of functional SGLT1 protein and SGLT1 mRNA abundance along the length of the small intestine. This indicates that the major site of glucose absorption in horses maintained on conventional grass-based diets is in the proximal intestine, and the expression of equine intestinal SGLT1 along the proximal to distal axis of the intestine is regulated at the level of mRNA abundance. The data presented in this paper are the first to provide information on the capacity of the equine intestine to digest and absorb soluble carbohydrates and has implications for a better feed management, pharmaceutical intervention and for dietary supplementation in horses following intestinal resection.     

Body and intestinal growth of broiler chicks on a commercial starter diet. 2. Development and characteristics of intestinal enzymes

1. Investigations were conducted into the development of intestinal enzyme function in broiler chickens on a commercial starter diet. The differences between intestinal regions and localisation of enzymes on the villus were assessed. 2. The specific activity of maltase, sucrase, aminopeptidase N (APN) and alkaline phosphatase (AP) at all intestinal sites decreased with age. There were also variations between intestinal sites although this variation depended on age. The specific activity of maltase was higher than that of the other enzymes examined, regardless of age and intestinal site. The total activities of the enzymes also increased with age at all intestinal sites. 3. Results of the localisation of enzymes on the crypt: villus axis showed that activity was expressed over a large proportion of the villus. There was an increase in the total villus activity of alpha-glucosidase (AG), APN and AP with age. Activity per unit villus surface area was similar between ages, except for jejunal AP. At hatch enzyme activity was expressed over 44.1, 55.8 and 63.3% of villus height in the duodenum, jejunum and ileum, respectively. At 21 d of age, corresponding values were 68.7, 65.6 and 77.2%. The point of peak activity from the crypt: villus junction increased with age. In the jejunum, most enterocytes were capable of secreting active enzymes within 1 h of formation. Cells maintained their secretory capabilities until they were more than 60 h old in the case of AG. 4. Although the specific activities of the enzymes were maximal at hatch, the digestive capacity of older birds may be sustained by an increase in total enzyme activity brought about by increased surface area. The pattern of enzyme activity along the gastrointestional tract (GIT) and crypt: villus axis is similar to that reported for some mammalian species.     

胰岛素和酶解配方奶粉对初生仔猪小肠生长发育的影响

为研究胰岛素和酶解配方奶粉是否促进初生仔猪小肠的组织生长和功能成熟,本试验比较了饲喂配方奶粉与饲喂配方奶粉补加胰素或酶解配方奶粉３ｄ后仔猪小肠的重量和长度,组织形态学结构,粘膜ＤＮＡ,ＲＮＡ和蛋白质含量,及小肠内容物中乳糖酶,麦芽糖酶和碱性磷酸酶活性。     

Impact of Yersinia enterocolitica enteritis on disaccharidase activity and small intestinal morphology in colostrum-deprived newborn piglets

The effect of enteritis on the development of the small intestine was examined in newborn, colostrum-deprived piglets infected with a human isolate of Y. enterocolitica (serotype 0:3, biotype 4) soon after birth. The piglets were killed 3 days (n = 6) or 5 days (n = 8) after infection, or antibiotic therapy was commenced on day 5 and the animals killed on day 14 (n = 5). Compared with the non-infected controls, infected animals had reduced mucosal lactase and sucrase, but not maltase activity, while after antibiotic therapy, previously infected piglets had a lower lactase and a higher maltase and sucrase activity. Lactase activity was significantly reduced in the duodenum and jejunum, and mean values were lower in the ileum, but the difference did not reach significance; maltase activity was greater at all ages from the distal jejunum to the mid-ileum; sucrase activity was reduced in all segments up to day 5 but after antibiotic therapy was increased in the jejunum and appeared early in the ileum. Enzyme profiles were more mature along the crypt-villus axis in some segments of the intestine in previously infected piglets. Sodium-potassium-ATPase activity was unchanged. There was a reduced villus height:crypt depth ratio, crypt hyperplasia and increased crypt cell proliferation. Morphological maturation, indicated by loss of vacuoles and location of the nucleus at the base of the enterocyte, proceeded distally from the duodenum to ileum from 3 to 14 days of age when only the ileum remained immature. In infected piglets, there was reduced vacuolation and earlier location of the nucleus at the base of the cell in the distal intestine. Accelerated maturity of specific disaccharidases and enterocyte morphology in infected piglets appears to be due to physical damage to the mucosa resulting in faster proliferation of crypt cells and migration of enterocytes. It is suggested that this may reduce macromolecular internalisation and impair the ability to utilise dietary carbohydrate and may have long-term effects on growth and immunological responses of the gut.     

Enterocyte digestive enzyme activity along the crypt-villus and longitudinal axes in the neonatal pig small intestine

Our objective was to examine the distribution of enterocyte digestive enzyme activity along the crypt-villus and longitudinal axes of the small intestine in formula-fed neonatal pigs between the ages of 14 and 18 d. The distended intestinal sac method was used to isolate 12 sequential fractions (F1 through F12) of epithelial cells. Enterocyte migration rate was measured in the proximal and distal intestine using in vivo bromodeoxyuridine labeling. Specific activities of representative villus cell marker enzymes of alkaline phosphatase, aminopeptidase N, sucrase, and lactase increased 6- to 17-fold from F12 (crypt cells) to F1 (villus cells), whereas the crypt cell marker [3H]thymidine incorporation increased 8- to 18-fold from F1 (villus cells) to F12 (crypt cells). Enterocyte migration rate was similar (3.2 vs 3.0 microm/h), whereas the villus height (547.4 vs 908.5 microm) and enterocyte life span (4.7 vs 10.2 d) were markedly lower (P < 0.05) in the proximal than in the distal segments, respectively. In general, the specific activities of all enzymes were lowest in the crypt fractions (F9 through F12) but increased markedly (ranging from 8- to 17-fold) from F12 to F1. The activity of aminopeptidase N was higher and that of sucrase was lower in the distal than in the proximal segment. The activities of the remaining enzymes were similar in the proximal and the distal segments. Our results suggest that the enterocyte life span in the distal small intestine is approximately twice as long as in the proximal small intestine. However, despite the difference in life span, the patterns of enzyme activities along the crypt-villus axis were generally similar in the proximal and the distal regions.     

小麦可溶性非淀粉多糖对肉仔鸡小肠粘膜二糖酶活性的影响

在体内、外研究了小麦可溶性非淀粉多糖(SNSP)对肉仔鸡小肠粘膜二糖酶活性的影响。取1日龄黄羽肉鸡105羽,随机分为3组,饲喂由玉米—豆粕、小麦—豆粕和玉米—豆粕加小麦SNSP提取物组成的3种日粮 ,分别于1、4、7、10、14、18和21日龄宰杀 ,取小肠粘膜 ,测定5种粘膜二糖酶的活性。体内试验结果表明 ,与玉米—豆粕日粮相比 ,小麦—豆粕日粮对肉仔鸡小肠粘膜乳糖酶、麦芽糖酶和纤维二糖酶活性抑制作用显著 (P<0.05)。玉米—豆粕加小麦SNSP提取物日粮对肉仔鸡小肠粘膜麦芽糖酶活性抑制作用显著 (P<0.05)。体外试验结果表明 ,小麦木聚糖显著降低乳糖酶、蔗糖酶、海藻糖酶和纤维二糖酶的活性 (P<0.05) ,极显著降低麦芽糖酶的活性 (P<0.01)。桦木木聚糖和小麦SNSP提取物分别显著降低蔗糖酶、海藻糖酶和纤维二糖酶的活性 (P<0.05) ,极显著降低麦芽糖酶的活性 (P<0.01)。研究结果表明 ,小麦SNSP无论在体内或在体外 ,均可抑制肉仔鸡小肠粘膜二糖酶活性。抑制小肠粘膜二糖酶活性是小麦SNSP抗营养作用的重要机制之一。