Bovine intelectins: cDNA sequencing and expression in the bovine intestine

Intelectins (Itlns) are lectins with potential roles in innate immunity, capable of binding bacteria via galactofuranose residues. Itlns also function as intestinal receptors for the antimicrobial glycoprotein lactoferrin (Lf). Since Lf binds strongly to enterohemorrhagic Escherichia coli O157:H7 (EHEC), we aimed to determine the expression of Lf receptor in terminal rectum, the site of predilection of EHEC in cattle. We sequenced two bovine intelectins (Itln1 and Itln2) and showed that both were expressed in abomasum and rectum, but expression appeared minimal in the jejunum. There was significantly higher expression of Itln2 in terminal rather than proximal rectum. Lactoferrin was expressed in all samples examined. Thus, we have demonstrated two novel bovine Itlns and shown that they are expressed along with Lf in the gastrointestinal tract, where they may interact with microbial pathogens.     

山东主要刺参养殖区幼参肠道抗生素耐药菌及耐药基因分布特征

为解析目前刺参(Apostichopus japonicus)苗种携带耐药菌及耐药基因现状,本研究从烟台、威海、青岛3个刺参主要养殖区的6家养殖场采集了幼参,对其肠道内容物中常用抗生素的耐药菌数量、占比和种类进行检测。利用荧光定量PCR技术,对样本中4类抗生素的7种耐药基因分布情况进行分析。结果显示,所检测的6个采样点中均有6种抗生素耐药菌的检出,从耐药菌占比来看,耐药菌占比最高的种类是乙酰甲喹、萘啶酸和四环素耐药菌,占比分别为0.05%~40.06%、2.16%~39.94%和0.06%~23.15%,氟苯尼考、庆大霉素和链霉素耐药菌的占比均不高,占比范围为0.01%~4.15%。由所分离到的98株耐药菌的鉴定结果可以看出,可培养的抗生素耐药菌分为4门5纲30属,主要集中在弧菌属、芽孢杆菌属和嗜冷杆菌属,占检出率的15.30%、13.27%和12.25%。基于属水平的不同抗生素耐药菌种类的分布统计结果显示,各采样点耐药菌种类差异较大,而且弧菌属、芽孢杆菌属和嗜冷杆菌属中均存在同一菌属中有耐多种抗生素的情况。对6个样本7种抗生素耐药基因的丰度检测结果显示,同一类抗生素的不同耐药基因的含量差异显著,除氨基糖苷类抗生素耐药基因aadA的相对拷贝数比例和链霉素以及庆大霉素耐药菌占比之间存在显著相关性(P<0.05)外,其他抗生素耐药基因的丰度与耐药菌占比之间相关性不显著(P>0.05)。研究表明,苗期刺参中存在一定的携带耐药菌和耐药基因的风险。     

Poultry fat decreased fatty acid transporter protein mRNA expression and affected fatty acid composition in chickens

Background: A study was undertaken to examine the effects of poultry fat (PF) compared with those of soybean oil (SBO) on intestinal development, fatty acid transporter protein (FATP) mRNA expression, and fatty acid composition in broiler chickens. A total of 144 day-old male commercial broilers were randomly allocated to 2 treatment groups (6 replicates of 12 chicks for each treatment) and fed isocaloric diets containing 3.0% PF or 2.7% SBO at 0 to 3 wk and 3.8% PF or 3.5% SBO at 4 to 6 wk, respectively. Results: PF had no influence on intestinal morphology, weight, or DNA, RNA, or protein concentrations at 2, 4, and 6 wk of age. However, compared with SBO, PF significantly decreased FATP mRNA abundance at 4 wk (P=0.009) and 6 wk of age (P<0.001); decreased liver fatty acid-binding protein (L-FABP) mRNA abundance at 6 wk of age (P=0.039); and decreased C18:2 (P=0.015), C18:3 (P<0.001), C20:2 (P=0.018), Σ-polyunsaturated fatty acids (Σ-PUFA) (P = 0.020), and the proportion of PUFA (P<0.001) in the intestinal mucosa and decreased C18:2 (P=0.010), C18:3 (P<0.001), C20:2 (P<0.001), Σ-PUFA (P=0.005), and the proportion of PUFA (P<0.001) in breast muscle at 6 wk of age. Conclusions: PF decreases FATP and L-FABP mRNA expression and decreased the proportion of PUFA in the intestinal mucosa and breast muscle.     

Changes in Hemostatic Indices in Foals Naturally Infected With Strongylus vulgaris

Strongylus vulgaris has been found endemic in equine populations subject to parasite control by targeted selective anthelmintic therapy. This study investigated hemostasis in foals naturally infected with S. vulgaris and monitored this response over the course of progressing infection stages. The hemostatic indices D-dimer, antithrombin III (ATIII), fibrinogen, prothrombin time (PT), and activated partial thromboplastin time were evaluated in weekly blood samples for up to 50 weeks in 12 foals born into a herd with high prevalence of S. vulgaris. Results were compared with weekly S. vulgaris antibody enzyme-linked immunosorbent assay values in all foals using a linear mixed effects model with repeated measures and to total numbers of S. vulgaris larvae in nine foals at necropsy with Pearson linear correlation. In the first week of life, all evaluated indices of hemostasis were significantly different from those observed in the rest of the study weeks, corresponding to previously demonstrated aberrancies in neonates. Significant changes were seen for D-dimer in weeks 11–24, 26–27, 30, and 39 compared with week 2, for PT in weeks 12–13 compared with week 6, and for ATIII in week 15 compared with week 4. Strongylus vulgaris antibody levels were statistically associated with D-dimer (P = .0076) and fibrinogen (P = .0004) concentrations. Naturally acquired infection with S. vulgaris was associated with changes suggestive of mild activation of coagulation, fibrinolysis, and inflammation. The results of this study may help elucidate the pathogenesis of the endarteritis, thromboembolism, and nonstrangulating intestinal ischemia that is observed in horses with S. vulgaris infection.     

黄羊胃肠组织形态学研究

采用石蜡切片方法对健康成年黄羊胃,肠进行了组织形态学观察。结果表明,瘤胃,网胃和瓣胃的胃壁构造基本相同。粘膜上皮都是复层扁平上皮,浅层细胞角化,瘤胃粘膜上形成许多大小不等的舌状乳头。无粘膜肌层;网胃粘膜形成许多皱襞。在皱襞上和网孔底上有许多圆锥状乳头。     

Characterisation of chloride currents in the jejunum and colon of pigs

Chloride secretion in the intestines of pigs of different age (32 days and 4 months) was examined using the Ussing chamber technique. After stimulating chloride secretion by carbachol and forskolin, alternative chloride channels and finally Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) channels were blocked. While basal short-circuit currents (I_sc) were higher in the jejunum than in the colon of the piglets of 32 days, it was inverse for the 4-month-old fatteners. In the jejunum responses to stimulation and final levels of I_sc were higher in the piglets than in the fatteners. The decrease in I_sc after blocking CFTR channels was smaller in the fatteners than in the piglets in both intestinal segments. In conclusion, 32-day-old piglets show a higher basal chloride secretion as well as a higher response to stimulation in the jejunum than 4-month-old pigs.     

A diet moderately deficient in zinc induces limited intestinal alterations in weaned pigs

The aim of this work was to test the hypothesis that a moderate zinc deficiency induces intestinal alterations in weaned piglets. A diet based on maize and soybean meal was formulated without supplemental zinc (33 ppm, zinc-deficient) or with added zinc (113 ppm, control). These diets were pair-fed for 18 or 27 d to intra-litter pairs of piglets weaned at 21 d of age. The feed intake and growth, plasma concentrations of zinc and alkaline phosphatase (ALP) activity, and morphometry, enzyme activities and the microflora of the mid-jejunum were investigated. Feed intake and growth were similar between diets and diarrhoea was not observed. By contrast, plasma zinc and ALP activity were much lower in zinc-deficient piglets at slaughter (P < 0.001). The weight of organs was unaffected, except colonic tissue that was lighter in piglets fed the zinc-deficient diet (P < 0.05). Neither villus-crypt intestinal architecture nor mucosal enzyme activities were altered. Jejunal counts of lactic acid bacteria and coliforms tended to be higher in the zinc-deficient pigs (P ≤ 0.10). In conclusion, feeding a diet moderately deficient in zinc for 18–27 d induced limited intestinal alterations in weaned pigs.     

The presence of EGF- and IGF-1-receptors in the small intestine of fetal, neonatal and weaned piglets

During development, gut morphology and functions change. Some of these are mediated by milk-borne factors, e.g. insulin-like growth factor-1 (IGF-1) and epidermal growth factor (EGF), of which the effects are in part dictated by the distribution of their receptors (R).

EGFR- and IGF-1R-immunoreactivity (IR) was evaluated in samples of the fetal, neonatal and weaned porcine small intestine.

EGFR-IR first appeared in the neonatal duodenum and was located basolaterally in villar and to a lesser extent in cryptal enterocytes. In weaned pigs, EGFR appeared apically in enterocytes with a region-dependent distribution along the villus–crypt axis. IGF-1R-IR was observed in smooth muscle cells in each age group. From the last trimester of gestation onward IGF-1R-IR was seen at the apical and basolateral side of villar enterocytes and in submucosal arterioles.

Thus, the age- and region-dependent presence of EGFR and IGF-1R has to be taken into account when evaluating effects of EGF and IGF-1 on growth or repair.     

原麝胃肠形态特征的初步研究

本项研究结果表明:原麝的胃肠形态位置与羊的相似。麝胃属复胃,分瘤胃、网胃、瓣胃和皱胃。原麝瘤胃的后腹盲囊明显大于后背盲囊,瘤胃柱仅前柱较发达;网胃小房的皱褶低如线状,房底缺次级皱褶;瓣胃页有24片,不分级;皱胃含有腺体。皱胃旋褶有17片。原麝肠的特点是在回肠乳头的腹侧有一憩室,内有由集合淋巴小结形成的Peyer氏斑(板);结肠近袢卷曲成圆盘状。     

短链脂肪酸介导的肠上皮和抗炎调节研究进展

哺乳动物体中的肠道菌群是细菌生态系统的组成部分,从动物出生时起,这些微生物就对免疫系统的发育、功能和调节起着非常重要的作用。当前,越来越多的研究集中在微生物对宿主细胞代谢的影响上。短链脂肪酸(SCFA)作为肠道菌群的一种代谢产物,对肠道稳态的维持具有重要作用。SCFA是肠道上皮细胞的重要燃料,能增强肠屏障功能。作为信号分子,SCFA可以通过细胞表面G蛋白偶联受体(GPCR)发出信号,从而激活控制免疫功能的信号级联反应;还可以通过底物转运蛋白进入细胞,抑制组蛋白脱乙酰化酶(HDAC),最终达到降低肠道炎症反应。本文综述了微生物SCFA的产生及其对肠道黏膜的影响,并通过激活细胞表面GPCR以及抑制组蛋白去乙酰化酶(HDACs)来调节免疫反应的作用。