饲粮淀粉来源对肉仔鸡淀粉消化和肠道发育的影响

目的研究饲粮淀粉源对肉仔鸡生长性能、淀粉消化性能以及肠道发育的影响。方法选取360只1日龄AA肉仔鸡健雏,随机分为3个处理组,分别饲喂3种不同淀粉来源饲粮(玉米、小麦、碎米),每个处理6个重复,饲养至28 d,分离肠道,测定各肠段长度,肠道内容物淀粉含量及饲料淀粉含量。结果不同淀粉源饲粮对试验期末肉仔鸡体重、平均日增重和采食量影响显著(P<0.05);碎米组饲粮在肉仔鸡小肠中的停留时间(152.76 min)显著高于玉米饲粮组(126.17 min)和小麦饲粮组(133.30 min)(P<0.05),淀粉消化速率低于玉米组(1.97 h-1)和小麦组(1.57h-1);碎米组十二指肠、空肠、回肠长度均低于玉米和小麦组。结论不同淀粉源饲粮引起了肉仔鸡早期生长性能,淀粉消化能力和肠道发育情况的变化。[营养学报,2012,34(4):340-343,348]     

不同肠段对槲皮素、芦丁吸收的比较研究

为了比较不同肠段对槲皮素及芦丁的吸收情况 ,选用Wistar大鼠 72只 ,随机分为对照组、槲皮素组及芦丁组 ,每组分别进行十二指肠、空肠、回肠及结肠灌流。灌流液分别为 1%的二甲基亚砜溶液 (溶剂 )、2 0 μmol L槲皮素、芦丁溶液。灌流结束后 ,采用高效液相色谱仪分析灌流液中槲皮素或芦丁的含量。结果发现 :十二指肠、空肠、回肠、结肠对槲皮素及芦丁均有吸收 ,芦丁的吸收率显著低于槲皮素。槲皮素单位长度吸收率 :结肠 >回肠 >十二指肠 >空肠 ,单位面积吸收率 :回肠 >空肠 >十二指肠 >结肠。槲皮素肠道灌流后 ,高效液相色谱图中出现新的未知峰 ,推测其为肠粘膜代谢后形成的衍生物重新分泌进入肠腔所致。     

类高血糖素多肽-Ⅱ对短肠大鼠残留小肠葡萄糖吸收的影响

目的:研究类高血糖素多肽-Ⅱ(GLP-Ⅱ)对短肠大鼠残留小肠葡萄糖吸收的影响. 方法:75%小肠切除大鼠随机分成空白对照组(SB组)、类高血糖素多肽-Ⅱ组(SB/GLP-Ⅱ组),另设一组正常进食大鼠作为SB组的对照组.术后第1天起进食标准大鼠饲料,术后第6天进行体内小肠循环灌流实验,测定大鼠回肠的单位长度及单位重量的葡萄糖吸收数据. 结果:灌洗段回肠长度各组无差异,SB组湿重/长度比值显著高于正常组,但显著低于SB/GLP-Ⅱ组.灌洗段回肠每厘米45 min葡萄糖吸收量正常组和SB组无差异,SB/GLP-Ⅱ组显著高于SB组 (P<0.05).正常组灌洗段回肠每克湿重葡萄糖吸收率显著高于SB组,但SB组和SB/GLP-Ⅱ组无差异(P＞ 0.05). 结论:GLP-Ⅱ能显著促进短肠大鼠残留小肠单位长度的葡萄糖吸收.     

中链三酰甘油对短肠综合征大鼠脂肪代谢和肠道代偿的影响

目的:研究肠内营养(EN)中添加中链三酰甘油(MCT)对广泛肠切除术后大鼠脂肪代谢和肠道代偿的影响.方法:体质量220～250 g SD大鼠27只,随机分为三组.假手术对照组(Con组)行空肠横断吻合,长链三酰甘油(LCT)短肠组(LSB组)和中、长链甘油三酯(MCT/LCT)短肠组(MSB组)均行85%中段小肠切除.各组大鼠于术后第2～14天,分别给予等氮和等热量的EN支持,其中Con组和LSB组EN的脂肪均为LCT,MSB组EN的脂肪含50% LCT和50%MCT.术后每天监测体质量变化;术后第12～14天检测脂肪吸收率;术后第15天处死动物,取血检测血浆总游离脂肪酸及必需脂肪酸水平,称量空肠及回肠重量、空肠及回肠黏膜重量,检测空肠及回肠黏膜DNA及蛋白质含量;行小肠病理检查,测量空肠及回肠黏膜绒毛高度、隐窝深度和黏膜厚度,并检测空肠和回肠黏膜增殖细胞核抗原(PCNA)和细胞凋亡情况.结果:大鼠广泛肠切除术后出现明显的肠道代偿.MSB组的脂肪吸收率、血清总游离脂肪酸及必需脂肪酸水平显著高于LSB组;MSB组在体质量、肠黏膜重量、肠黏膜DNA及蛋白质含量、肠黏膜病理(绒毛高度、隐窝深度和黏膜厚度)、肠黏膜细胞增殖及凋亡与LSB组比均无显著性差异.结论:添加50% MCT的EN较单纯LCT的EN更能增加短肠综合征大鼠对脂肪的吸收,增加血清游离脂肪酸水平,而不影响肠道代偿.     

小肠的吸收功能

人们吃的食物,不管是五谷杂粮,还是肉蛋蔬菜、都要经过胃肠道的消化,里面含的各种营养素才能被机体吸收利用。担负吸收营养物质任务的,是小肠。 小肠分为十二指肠、空肠和回肠三部分,长达5～6米,弯弯曲曲地盘在腹腔内。十二指肠的壁上有一个小小的窟窿眼,是肝脏和胰腺导管开口之处,胆汁、胰液通过这个孔眼进入十二指肠;空肠位于小肠前三分之一,食物到这里变成液体状态;回肠占小肠三分之二,食糜在这里停留时间最长。     

兔小肠吸收纳豆激酶及其分布特征研究

目的研究兔小肠吸收纳豆激酶及其分布特征。方法双夹心酶联免疫吸附试验(ELISA)检测血浆中纳豆激酶;链霉菌抗生物素蛋白-生物素-过氧化物酶复合物(SABC)免疫组织化学技术观察小肠吸收纳豆激酶分布。结果颈总动脉血栓模型兔十二指肠注射纳豆激酶液体发酵粗酶液,高剂量组(4500IU/kg·bw)注射1、1.5、2、3h和低剂量组(2500IU/kg·bw)注射1.5、2、3h,血浆中纳豆激酶检测阳性。免疫组化染色结果表明,正常兔口服纳豆激酶粗制液后,空肠纹状缘深棕色阳性吸收颗粒最多,上皮细胞胞浆中有深棕色阳性吸收颗粒,十二指肠与回肠纹状缘有棕色、弥漫性的阳性吸收颗粒,吸收强度为空肠>回肠>十二指肠。结论纳豆激酶可经小肠吸收进入血浆。     

谷氨酸钠对铝在体外吸收的影响

目的　了解谷氨酸钠对铝吸收的影响。方法　 1 8只 SD雄性大鼠 ,体重 (2 50±1 5) g,被翻转的离体十二指肠、空肠、回肠 ,在其内腔充满 p H 7.3的缓冲液 (其组成为 Tris- HCl1 5.5mmol,Na Cl1 2 0 .7mmol,KCl5.6mmol,Ca Cl2 2 .5mmol,Mg Cl2 1 .2 mmol,glucose1 1 .5mmol)后 ,置于 p H7.3含待测液的生理盐水中 ,待测物分别为 2 0 mmol Al Cl3,2 0 mmol Al Cl3+2 0mmol柠蒙酸钠和 2 0 mmol Al Cl3+2 0 mmol谷氨酸钠。恒温 (37± 0 .1 )℃培养 0 .5h,培养期间通入95% O2 和 5% CO2 气体。然后用石墨炉无火焰原子吸收分光光度计 ,分别测定肠内腔液和肠的铝含量。结果　对照组 (Al Cl3)十二指肠、空肠、回肠对铝的吸收率 (鲜肠重计 )分别为 3.59± 0 .55,3.41± 0 .61和 3.1 9± 0 .68(μg/g) ,参照组 (Al+柠檬酸钠 )分别为 4.92± 0 .73,4.47± 0 .56和4.37± 0 .77(μg/g) ,试验组 (Al+谷氨酸钠 )分别为 4.75± 0 .68,4.45± 0 .59和 4.32± 0 .63(μg/g) ,参照组与试验组的十二指肠、空肠、回肠铝吸收率与对照组相比有显著差异。如将肠段重换算成干重 ,则参照组和试验组仅十二指肠铝的吸收率与对照组相比有显著差异 (其吸收率为 :2 7.51±1 .88和 2 8.67± 2 .1 6对 2 4 .98± 1 .75(μg/g) ,而空肠、回?     

纳米三氧化二铁在大鼠小肠的吸收转运研究

目的 探索三氧化二铁纳米颗粒(Fe₂O₃ NPs)经口暴露后在大鼠小肠中的吸收转运特点及机制。方法 26只雄性SD大鼠按体重随机分为吸收曲线组和重复灌胃组[对照组(超纯水);实验组(200 mg/(kg·bw)]。前者采眼眶血测定铁离子含量并绘制吸收曲线计算药动学参数。重复灌胃组连续灌胃28天后处死大鼠采集胃液、肠液后进行体外模拟消化实验、检测转运相关基因表达、铁离子含量和纳米颗粒分布情况。结果 Fe₂O₃ NPs在人工模拟胃肠液及大鼠胃肠液中释放的铁离子随消化时间延长而增加且符合二室曲线代谢模型。与对照组相比,实验组大鼠各肠段铁离子转运相关基因和肠上皮胞吞相关基因表达升高(P<0.05);各肠段铁离子含量升高(P<0.05),且各肠段铁离子含量和纳米颗粒的沉积数量均表现为十二指肠>空肠>回肠。结论 本研究中,单次灌胃Fe₂O₃ NPs后大鼠的口服吸收率低,消除较快。Fe₂O₃ NPs在大...     

大鼠肠缺血-再灌注损伤后细菌易位发生部位的实验研究

目的:探讨肠道缺血-再灌注损伤对不同肠段细菌易位的影响。方法:将大鼠随机分为对照组(行假手术)和肠道缺血-再灌注组(分别于再灌注后1、6和24 h取材)。检测空肠、回肠和结肠的细菌、内毒素易位情况,各段肠系膜静脉中的肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)水平。结果:对照组和肠道缺血-再灌注1 h组各肠段系膜淋巴结细菌培养均阴性,再灌注后24 h组空肠、回肠系膜淋巴结细菌易位率明显高于对照组和结肠系膜淋巴结(P0.05);两组大鼠各段肠系膜静脉血培养、内毒素测定均为阴性;肠道缺血-再灌注后1 h和6 h组大鼠TNF-α浓度明显高于对照组(P0.05);各段肠系膜静脉血IL-6浓度均明显高于对照组(P0.05),再灌注后6 h组,空肠、回肠的肠系膜静脉血IL-6浓度明显高于结肠(P0.05)。结论:肠道缺血-再灌注损伤可造成肠道细菌易位,空、回肠更易遭受肠缺血-再灌注损伤的打击,从而发生细菌易位。     

赖氨酸、苯丙氨酸、酪氨酸和缬氨酸对大鼠回肠锌吸收动力学作用的研究

用原位灌流的大鼠回肠研究了赖氨酸、苯丙氨酸、酪氨酸和缬氨酸对锌吸收动力学的作用。赖氨酸对大鼠回肠锌吸收动力学常数以及快速相和慢速相半衰期、回肠锌吸收率均无影响。苯丙氨酸、酪氨酸和缬氨酸能增加回肠锌吸收率。其中苯丙氨酸组K_921)、K_(12)、K_(02)的值均高于对照组。缬氨酸组K_(21)和K_(12)值高于对照,并且快速相T_(1/2)缩短。酪氨酸组K_(21)值较对照组高,而K_(12)、K_(02)值以及快速相、慢速相半衰期无改变。本研究的结果提示:苯丙氨酸、酪氨酸、缬氨酸能促进锌在大鼠回肠的吸收。氨基酸对锌吸收的促进作用与其对锌的配合物稳定常数有关。     

Manganese source affects manganese transport and gene expression of divalent metal transporter 1 in the small intestine of broilers

In the present study, two experiments were conducted to investigate the effect of Mn source on Mn transport and the expression of a Mn transporter, divalent metal transporter 1 (DMT1), in the small intestine of broilers. In Expt 1, in situ ligated duodenal loops from Mn-deficient chicks (29-d-old) were perfused with solutions containing 0-8.74 mmol Mn/l from either MnSO4, or one of two organic chelates of Mn and amino acids with moderate (OM) or strong (OS) chelation strength (Q(f)) up to 30 min. In Expt 2, Mn-deficient intact broilers (14-d-old) were fed a control diet (12.45 mg Mn/kg) or the control diet supplemented with 100 mg Mn/kg as one of all Mn sources for 14 d. The uptake kinetics of Mn from different Mn sources in the ligated duodenal loops followed a saturable process as determined by regression analysis of concentration-dependent uptake rates. The maximum transport rate (Jmax) and K(m) values, and DMT1 mRNA levels in the ligated duodenal loops were higher (P < 0.01) for OM and OS than for MnSO4. DMT1 mRNA levels were much higher (P < 0.01) in the duodenum than in the jejunum and ileum. Both DMT1 mRNA levels in the duodenum and plasma Mn contents from the hepatic portal vein of intact chicks on day 14 post-feeding increased (P < 0.05) in the following order: control < MnSO4 < OM < OS. These results indicated that organic Mn sources with stronger Q(f) showed higher Mn transport and absorption, and DMT1 might be involved in the regulation of organic Mn transport in the proximal small intestine of broilers.     

Site of zinc absorption in dog small intestine

An in vivo intestinal perfusion technique was used to study the absorption of zinc from the duodenum, proximal jejunum and distal ileum of six dogs (group 1). Net absorption of zinc from the duodenum before and after ligation of the common bile duct averaged 596 and 574 ng.min-1.cm-1, respectively. Zinc absorption was greater (P less than 0.01) from the duodenum than from the jejunum (251 ng.min-1.cm-1) or ileum (404 ng.min-1.cm-1). Four other dogs (group 2) experienced perfusion of approximately equal segments of the duodenum (in two animals the common bile duct was ligated, and in another two it was not), proximal jejunum and distal ileum for 4 h. No change in absorption of zinc with time was noted, nor was any difference in absorption by the duodenum with and without ligation of the common bile duct observed. The data indicate that the duodenum has the greatest capacity for zinc absorption, followed by the distal ileum and proximal jejunum, and that pancreatic secretions do not appear to be necessary for adequate zinc absorption in the dog duodenum.     

Determination of the site of zinc absorption in rat small intestine.

We have studied net uptake of zinc from segments of rat duodenum, jejunum, and ileum using in vivo intestinal perfusion. We have also evaluated the effect of pancreatic and bile secretions on duodenal zinc absorption. Segments of duodenum, jejunum, and ileum and duodenum with bile and pancreatic duct obstruction, 10 cm in length, were studied in six rats each. Percentage absorption of zinc as determined by atomic absorption spectrophotomety was greater from the ileum (60.1%) when compared to duodenum (19.1%) or jejunum (20.2%). Exclusion of bile and pancreatic secretions from the lumen increased zinc absorption in the duodenum (32.0%). Postperfusion mucosal zinc content comprised 29.0% of absorbed zinc from jejunum, 7.4% from ileum, 5.2% from duodenum, and 2.7% from duodenum with bile and pancreatic duct obstructed, indicating rapid transport of zinc across epithelial cells after uptake from the duodenum and ileum. Our data indicate that the ileum has the greatest capacity for zinc absorption.     

DIGESTION AND ABSORPTION OF DISACCHARIDES IN MAN

Lactose absorption occurs in the duodenum and proximal jejunum, maltose in the jejunum and proximal ileum, and sucrose in the distal jejunum and ileum. Very little hydrolysis of these disaccharides occurs in the intestinal lumen of man.     

Dietary phytic acid and wheat bran enhance mucosal phytase activity in rat small intestine

The aim of this work was to investigate the influence of dietary phytic acid (PA) on intestinal phytase activity in growing rats by in vitro determination of phytase activity in the three segments of the small intestine (duodenum, jejunum and ileum), and by in vivo intestinal perfusion of a solution rich in PA (diluted soymilk). Using the in vitro method, duodenal and jejunal activities were enhanced significantly by adaptation to purified PA (+44 and +145% respectively, compared with control rats). For the rats adapted to the wheat bran (WB) diet, the induction of intestinal phytase by the substrate compared with the control values (P < 0.001) was observed only in ileum. Using soymilk in perfusions, rats consuming PA or WB diets hydrolyzed more phytate (P < 0.001 and P < 0.05, respectively) than controls. Further, Mg absorption from diluted soymilk was not affected by food adaptation, whereas Ca absorption was greater in the PA and WB groups (P < 0.001 and P < 0.05, respectively) than in the control group. Thus, intake of pure PA by rats enhances phytase in the upper parts of the small intestine (duodenum and jejunum), whereas the WB diet activates ileal phytase. Furthermore, the induction of phytase activity is greater in magnitude in rats fed synthetic PA than that observed in rats fed the WB diet. The enhancement of phytase improves intestinal Ca absorption, thus showing the capacity of the small intestine to adapt to diets rich in PA and poor in Ca.     

大鼠肠道碘吸收速率及不同日龄的影响

目的：建立肠道碘吸收速率模型，观察不同日龄大鼠的肠道碘吸收速率变化及其特点，为给婴幼儿合理、适宜地补碘提供基础资料。方法：Ｗｉｓｔａｒ成年大鼠２０只，雌雄各半，采用原位肠道灌流方法，建立肠道碘吸收速率模型。根据模型方法，观察出生后１３、１６、２１、３０、４５日龄幼鼠（每组１２只左右）空肠与回肠的碘吸收速率变化及其特点。结果：肠腔内灌流液碘浓度随时间的延长，早期呈快速下降，然后浓度降低速度减慢，该吸收特点符合二房室模型，肠腔内碘浓度的变化可用一双指数曲线数学式表达Ｘ１（ｔ）＝Ａｅ－αｔ＋Ｂｅ－βｔ。根据数学式计算出Ｋ１２、Ｋ２１、Ｋ０２值及快速相和慢速相的生物半减期。成年大鼠肠道碘吸收快速相生物半减期（ＦＰ１／２）约为２～３分钟，慢速相生物半减期（ＳＰ１／２）约为４０～６０分钟。成年雄鼠空肠碘吸收能力高于雌鼠，１３、１６、２１日龄雌鼠肠道碘吸收能力低于４５日龄鼠，但差异均无显著性。不同日龄雄鼠间肠道碘吸收速率未见规律性变化。结论：大鼠肠道碘吸收速率模型为二房室模型；大鼠空、回肠对碘的吸收速率很快；幼龄雌鼠吸收碘的能力略低，雄鼠未见年龄别变化；成年雌鼠肠道吸收碘的能力稍低于雄鼠。提示雌性易于发生相对缺碘     

Folate-binding protein and the absorption of folic acid in the small intestine of the suckling rat

The folate in milk is largely bound to high-affinity folate-binding protein (FBP). With an in vivo intestinal loop technique, we examined the absorption of folic acid bound to FBP (FA-FBP) in the small intestine of the suckling rat. In contrast to unbound folic acid (FA), FA-FBP is absorbed more avidly in the ileum than in the jejunum (p less than 0.025) and its absorption is not inhibited by 1 mmol sulfasalazine/L. Folate-binding activities in the mucosa of the proximal (duodenum and jejunum combined) and distal (ileum) small intestine were also examined and found to be 0.32 and 1.31 pmol/mg protein, respectively (p less than 0.001). A 6-h fast produced a 42% decrease in folate-binding activity in the distal small intestine (p less than 0.01) but did not change activity in the proximal portion. Collectively, these observations suggest that FA-FBP is absorbed by a mechanism that is distinct from that responsible for the absorption of FA and that absorption does not require prior dissociation of the vitamin-binding protein complex.