Transient changes of enzyme activities and expression of stress proteins in the small intestine of piglets after weaning

To determine the transient effects of weaning on the small intestine, 16 piglets were slaughtered at days 0, 1, 4 and 7 after weaning. Jejunal samples were collected to examine different enzyme activities and mRNA expressions of two stress protein families, namely, heat-shock proteins (HSP) and trefoil factors (TFF). Results showed that the activities of ceruloplasmin, alkaline phosphatase and lactate dehydrogenase, were significantly changed at Day 1 and/or Day 4. The mRNA expressions of HSP10, HSP60 and HSP90 showed a pattern of increased expression with time after weaning. Expression significantly differed between Day 0 and Day 7 after weaning. The mRNA expression of HSP70 was significantly increased on Day 1 only. Similarly, the mRNA expressions of TFF1 and TFF2 were significantly increased on Day 7 compared with those on Day 0. Expression of TFF3 was not affected by time after weaning. In conclusion, the present study indicated that weaning induced transient injury to small intestinal morphology and function. Particularly it changed enzyme activities and gene expression of stress proteins in the small intestine of piglets. At first time, a change in the gene expression of HSP10 and a gene overexpression of TFF1 in the small intestine of piglets after weaning was found.     

Ferrous iron uptake by rat duodenal brush border membrane vesicles: Effects of dietary iron level and competing minerals (Zn, Mn, and Ca)

We sought to confirm a recent report that Fe⁺² uptake into rat brush-border membrane vesicles is markedly increased by short-term consumption of iron-deficient diet, with no additional enhancement as the animal becomes functionally iron-deficient with continuing dietary Fe deprivation. In addition, we investigated whether previously observed in vivo absorption interactions of iron, zinc, and manganese occur in the brush border membrane vesicles uptake process, and whether short-term or long-term consumption of an iron-deficient diet affects the interaction at the uptake level. We did not observe any differences in Fe⁺² uptake between normal and iron-deficient brush border membrane vesicles, even when the iron status contrast was intensified by feeding a high iron versus iron-deficient diet for 3 weeks. Equimolar Zn⁺² and Mn⁺² decreased Fe⁺² uptake by 29 to 50% and 11 to 39%, respectively. Iron deficiency did not alter these effects. Equimolar Fe⁺² decreased Zn⁺² uptake by 13 to 22%. Calcium, included as a negative control, did not affect Fe⁺² uptake. Thus, some competition between Fe⁺² and similar divalent cations does occur at the level of the brush border membrane; the exact nature of this competition remains to be determined.     

Effects of dietary zinc levels on the activities of enzymes, weights of organs, and the concentrations of zinc and copper in growing rats

Zinc (Zn) is an essential nutrient that is required in humans and animals for many physiological functions, including immune and antioxidant function, growth, and reproduction. The present study was performed to investigate the effects of three Zn levels, including Zn adequate (35.94 mg/kg, as a control), Zn deficiency (3.15 mg/kg), and Zn overload (347.50 mg/kg) in growing male rats for 6 wk. This allowed for evaluation of the effects that these Zn levels might have on body weight, organ weight, enzymes activities, and tissues concentrations of Zn and Cu. The results showed that Zn deficiency has negative effects on growth, organ weight, and biological parameters such as alkaline phosphatase (ALP) and Cu−Zn superoxide dismutase (Cu−Zn SOD) activities, whereas Zn overload played an effective role in promoting growth, improving the developments of organs and enhancing immune system. Hepatic metallothionein (MT) concentration showed an identical increase tendency in rats fed both Zn-deficient and Zn-overload diets. The actual mechanism of reduction of Cu concentration of jejunum in rats fed a Zn-overload diet might involve the modulation or inhibition of a Cu transporter protein by Zn and not by the induction of MT.     

Comparison of angiotensin-converting enzyme, malonaldehyde, zinc, and copper levels in preeclampsia

Preeclampsia is a syndrome of unknown etiopathogenesis. Recent studies carried out on preeclampsia have focused on the increase in free radicals in the feto-placental unit with poor perfusion. It is believed that the renin-angiotensin system (RAS) has a role in the poor perfusion of the placenta. It is uncertain whether there is a pre-existing impairment in RAS in pre-eclamptic pregnant women or not. In the present study, we measured angiotensin-converting enzyme (ACE), malonaldehyde (MDA), zinc, and copper levels in the placental tissue of 16 pre-eclamptic pregnant women and compared them with those in 20 healthy pregnant women. Whereas ACE activity and MDA were found to be high in the placentas of pre-eclamptic patients, zinc and copper levels were low and there was a negative correlation between ACE activity and zinc concentration. These findings suggest that high ACE activity might play a role in the increase in tissue hypoxia and consequent lipid peroxidation through vasoconstriction; zinc deficiency in the placental tissue might cause insufficiency of superoxide dismutase, an antioxidant enzyme. Furthermore, deficiency in placental zinc also plays a role in the biosynthesis of connective tissue, maintaining its integrity, which might have an impact on the structure of the spiral arteries     

Effects of increased cellular zinc levels on gene and protein expression in HT-29 cells

High cellular zinc concentrations lead to impairments in ATP synthesis and cell cycle control particularly in neurons and epithelial cells. The molecular basis for these dysfunctions is still not fully elucidated. Here we analyzed the effects of a high zinc exposure (10ppm) on gene and protein expression in the human epithelial cell line HT-29. Of the 1176 genes analyzed with cDNA arrays, nine differentially expressed genes were identified. Proteome analysis based on 1310 detected proteins identified 11 molecular targets. Most of the identified genes/proteins have not been linked to cellular zinc status before (e.g. PEC-60, R-ras3). More than half of the targets participate in ATP production or stress response. Therefore, it appears that higher zinc concentrations mediate their effects mainly via impairments in cellular energy metabolism and stress response.This work was in part supported by the Degussa Bio Actives GmbH, Freising-Weihenstephan, Germany.     

不同温度敏感性棉花纤维发育相关酶活性变化对低温的响应

选用纤维比强度形成存在温度敏感性差异的两个棉花品种（科棉1号：温度弱敏感型品种,苏棉15：温度敏感型品种）为材料,于2006—2007年在江苏南京设置大田分期播种试验,使棉纤维发育处于不同的温度条件,研究低温对棉纤维发育相关酶（蔗糖酶、蔗糖合成酶、磷酸蔗糖合成酶、β-1,3-葡聚糖酶）活性及相应基因表达的影响.结果表明：由晚播造成的低温（棉纤维发育期日均最低温分别为21.1、20.5和18.1 ℃）影响了纤维发育相关酶的活性变化,从而影响了棉纤维素累积和纤维比强度的形成.低温提高了纤维中蔗糖酶和β-1,3-葡聚糖酶的活性,降低了蔗糖合成酶和磷酸蔗糖合成酶的活性.低温使Expansin、蔗糖合成酶基因的高表达时间延长,β-1,3-葡聚糖酶基因的表达峰值出现时间延迟,且表达量降低.两个棉花品种的纤维素合成相关酶对低温的响应存在差异,温度敏感型品种（苏棉15）的酶活性的变化幅度明显高于温度弱敏感型品种（科棉1号）, 可能是导致不同棉花品种纤维比强度形成存在温度敏感性差异的主要原因.     

逆境条件下小麦种子活力与种子萌发相关酶活性及其基因表达的关系

分析不同基因型小麦品种逆境萌发过程中种子萌发相关酶活性及基因表达差异,明确在逆境条件下,种子活力与种子萌发相关酶活性及基因表达量的关系.通过标准发芽试验和逆境(冷浸、人工老化、干旱胁迫)发芽试验,测定4个小麦品种种子活力、萌发过程中可溶性总糖和可溶性蛋白含量、α-淀粉酶活性、半胱氨酸蛋白酶活性及相关基因表达量.结果表明:干旱、人工老化和冷浸胁迫3种逆境对种子活力都有一定影响.不同萌发条件下,可溶性总糖含量呈现先小幅度升高后小幅度降低再迅速升高的趋势;而可溶性蛋白含量随着萌发时间的延长呈现逐渐下降的趋势.α-淀粉酶活性整体呈现逐渐升高的趋势,但在冷浸胁迫处理后,豫农949和轮选061的α-淀粉酶活性在萌发60 h后出现下降.半胱氨酸蛋白酶活性整体呈先降低后升高的趋势,但在干旱胁迫条件下,豫农949、豫麦49-198和轮选061的半胱氨酸蛋白酶活性呈现先升高后降低再升高的趋势.不同逆境萌发条件下,α-AMY(α-淀粉酶基因)表达量整体呈先上升后下降的趋势.冷浸胁迫处理后,轮选061的α-AMY表达量高于对照,在其他逆境萌发条件下,4个品种的α-AMY表达量均低于对照;人工老化处理后,长4738的CP(半胱氨酸蛋白酶基因)表达量与对照差异不显著,在其他逆境萌发条件下,4个品种的CP表达量均高于对照.种子萌发期间,不同萌发条件下α-淀粉酶和半胱氨酸蛋白酶活性与其基因表达并没有直接关系,α-淀粉酶活性与可溶性总糖含量达到显著正相关,半胱氨酸蛋白酶活性与可溶性蛋白含量的相关性不显著.在标准发芽条件下,α-淀粉酶活性与活力指数呈显著正相关,而在逆境萌发过程中,其相关性不显著.冷浸胁迫处理后,半胱氨酸蛋白酶活性与活力指数呈显著正相关,但在标准发芽、干旱胁迫、人工老化处理后,其相关性不显著.     

复合噬菌体裂解酶对白羽肉鸡肠道菌群结构和肝脏抗氧化酶指标的影响

【背景】噬菌体裂解酶具有良好的安全性与抑菌特性,有望替代抗生素作为一种饲料添加剂应用于改善畜禽肠道菌群和预防动物疾病。【目的】以白羽肉鸡为饲喂对象,分别饲喂复合噬菌体裂解酶与抗生素制剂,评估噬菌体裂解酶对畜禽肠道菌群的影响及其作为替抗饲料添加剂的应用潜能。【方法】以3日龄健康白羽肉鸡为饲喂对象,在基础饲粮上添加由噬菌体裂解酶TSPphg和噬菌体裂解酶MMPphg获得的复合噬菌体裂解酶制剂(200 mg/kg)与50μg/g的金霉素制剂,分别进行比较饲喂管理。利用第三代测序技术对28 d时白羽肉鸡肠道菌群进行高通量测序,借助生物信息学分析肠道菌群多样性和优势菌群(丰度前10)相对丰度,揭示各分组组间与组内差异,并对肝脏主要氧化酶活性进一步比较。【结果】饲喂复合噬菌体裂解酶和金霉素制剂对白羽肉鸡肠道菌群有一定影响,均降低了肠道菌群相对丰度与多样性,而且Shannon指数与空白组相比存在显著差异(P<0.05)。优势菌群中,复合噬菌体裂解酶组相较于金霉素组和空白组,拟杆菌门的相对丰度发生了显著上升,而厚壁菌门的相对丰度发生了显著下降(P<0.05)。同时,在属水平上,粪杆菌属的相...     

Turnover of mouse intestinal brush border membrane proteins and enzymes in organ culture: A direct evaluation from studies on the evolution of enzyme activities during the culture

The turnover of mouse intestinal brush border membrane enzymes has been studied by kinetic analysis of the evolution of enzyme activities during organ culture. By comparing the results obtained in these studies with the predictions from a mathematical model of enzyme synthesis and degradation in orgen cultures, it has been possible to reach the following conclusions: (1) There is no degradation of brush border membrane enzymes during culture and the rate of synthesis of each enzyme is directly measurable from the kinetics of total enzyme accumulation (tissue + media). (2)_Brush border membrane enzymes are released in culture media by two complementary processes. The first one involves a differential solubilization of enzymes but its exact nature cannot be exactly stated. The second one involves a microvesiculation of brush border membranes, the importance of which in vivo is seen in the possible conciliation between unitary membrane synthesis and heterogeneous turnover of membrane components.     

Evaluation of the relationship among gene expressions and enzyme activities with antioxidant role and presenilin 1 expression in Alzheimer's disease

It is known that oxidative stress originating from reactive oxygen species plays a role in the pathogenesis of Alzheimer's disease. In this study, the role of antioxidant status associated with oxidative stress in Alzheimer's disease was investigated. Peripheral blood samples were obtained from 28 healthy individuals (as control) and 28 Alzheimer's patients who met the National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association criteria. Catalase, glutathione S-transferase and paraoxonase 1 enzyme activities in blood plasma and glutathione S-transferase enzyme activities in erythrocytes were determined by spectrophotometer. Catalase, glutathione S-transferase and presenilin 1 gene expressions in leukocytes were determined using qRT-PCR. Data were analysed with SPSS one-way anova , a LSD post hoc test at p < 0.05. The activity of each enzyme was significantly reduced in Alzheimer's patients compared to control. The catalase gene expression level did not change compared to the control. Glutathione S-transferase and presenilin 1 gene expression levels were increased compared to the control.     

Testicular atrophy, zinc concentration, and angiotensin-converting enzyme activity in the testes of vitamin a-deficient rats

Angiotensin-converting enzyme (ACE) as a part of the renin angiotensin system (RES) regulates blood pressure and fluid and electrolyte homeostasis, and the enzyme is considered to have a function in reproduction. Reduced enzyme activities have been observed in atrophied testes as a results of zinc and pituitary deficiencies. Vitamin A deficiency causes atrophy of testes. The present study was conducted on three groups of male, 3-wk-old, Wistar rats. After 54 d of the experimental period, testicular weights of the vitamin A-deficient rats (Agroup, allowed free access to vitamin Adeficient diet) was significantly lower than its pair-fed, PF (given restricted amount control diet) and A+ (allowed free access to control diet) groups. Zinc concentrations and both soluble and particulate ACE activities in the testes of vitamin A-deficient rats (Agroup) were significantly lower than the other two groups. No significant differences were observed regarding zinc concentration, particulate ACE, and total ACE activities in the testes of PF and A+ groups. Vitamin A deficiency did not significantly affect the enzyme activity in the lung. From the observations of the present study, we speculate that testicular atrophy in vitamin A deficiency may have resulted from lower zinc concentration and decreased ACE activity in that organ.     

Effects of a blend of essential oils and an enzyme combination on nutrient digestibility,ileum histology and expression of inflammatory mediators in weaned piglets

The aim of this study was to test the hypothesis of an improved gut environment of post-weaning piglets when administered a blend of essential oils (EO; thymol and cinnamaldehyde) and an enzyme combination (xylanase and β-glucanase (XB)) either alone or in combination. To assess the effect of dietary treatments, faecal nutrient digestibility and microbial counts, as well as ileum histology and gene expression of inflammatory mediators were evaluated. One hundred and ninety-two weaned piglets were allocated into four experimental treatments, and fed the basal diet (CTRL) either without or with EO, XB or their combination (EO+XB) for a 42-day period. The experiment concerning digestibility was designed with two periods (period I: days 15 to 21; period II: days 29 to 35) and the faeces were collected on days 20, 21, 34 and 35. On day 42, six piglets from each treatment were slaughtered. It was found that EO, XB and EO+XB supplementation did not affect (P>0.05) the growth performance of the piglets from days 0 to 42. Moreover, no dietary effect on faecal score was observed. Faecal digestibility of dry matter, organic matter, ash, dietary fibre, lipid, CP and NDF were increased from period I to period II (P<0.01 to P=0.06), while no effect (P>0.05) of EO, XB or their combination on the faecal digestibility was observed at both periods. Compared with the CTRL diet, dietary XB reduced the faecal Lactobacillus and Escherichia coli counts but increased the Lactobacillus to Coliforms ratio on day 42 (P=0.02, 0.03 and 0.03, respectively), and all the additives supplementations decreased the counts of faecal Coliforms on day 42 (P<0.01). XB supplementation increased the villus to crypt ratio (P=0.04) and reduced the mucosal macrophages number (P<0.01) in the ileum compared with the CTRL group, and dietary EO or EO+XB decreased the number of lymphatic follicles (P=0.01 and P<0.01, respectively) and mucosal macrophages (P=0.02 and P<0.01, respectively). In addition, the interleukin (IL)-1α was downregulated in piglets treated with EO+XB compared with the EO group (P=0.02). In conclusion, the administration of EO, XB or their combination was effective in improving ileum histology, and EO+XB supplementation might benefit the modulation of the expression of ileum inflammatory cytokines in piglets.     

Effect of fibre sources on performance,serum parameters,intestinal morphology,digestive enzyme activities and microbiota in weaned pigs

ABSTRACT

This study was conducted to evaluate the effects of wheat bran (WB) as insoluble fibre source, and sugar beet pulp (SBP) as soluble fibre source, on performance, serum parameters and intestinal health in weaned pigs. A total of 90 weaned pigs (BW: 7.33 ± 1.24 kg) were randomly assigned to three dietary treatments: (1) a control diet (CON) based on corn and soybean meal; (2) CON + 6% WB; (3) CON + 6% SBP. Each treatment had five replicate pens with six pigs per pen. The experimental period was divided into two phases (d 0 to 14 and d 14 to 28). Pigs in group WB tended to have greater avarage daily gain than those in group SBP. Compared with CON, SBP reduced (p < 0.05) the apparent total tract digestibility (ATTD) of dry matter, organic matter (OM), gross energy and neutral detergent fibre on d 14 and 28, while WB decreased (p < 0.05) the ATTD of OM on d 28. Pigs in group SBP had higher (p < 0.05) glucagon-like peptide 1 concentration than the other groups on d 14 and 28. The villus height to crypt depth (V:C) ratio of duodenum and jejunum in pigs fed diet WB were greater (p < 0.05) than in group SBP. The WB increased (p < 0.05) the V:C ratio of ileum compared with CON or SBP. Compared with SBP, WB increased (p < 0.05) the sucrase activity in the duodenum. Moreover, pigs in WB had higher (p < 0.05) activities of maltase and sucrase in the jejunum compared with CON or SBP. The abundances of Ruminococcaceae and Prevotellaceae were increased (p < 0.05) in WB, while the Lachnospiraceae abundance was increased (p < 0.05) in SBP. WB increased (p < 0.05) concentrations of acetate, butyrate and total short-chain fatty acids (SCFA), while SBP increased (p < 0.05) concentrations of acetate and total SCFA when compared with CON. In conclusion, WB was beneficial to performance in weaned pigs by improving morphology, enzyme activities and microbiota when compared with SBP, highlighting that effects of fibre depends on the fibre sources.     

The growth performance,intestinal digestive and absorptive capabilities in piglets with different lengths of small intestines

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.     

Accumulation of copper in the kidney of pigs fed high dietary zinc is due to metallothionein expression with minor effects on genes involved in copper metabolism

A study was conducted to determine the effect of high dietary zinc (Zn) oxide on trace element accumulation in various organs with special emphasis on the kidney. A total of 40 weaned piglets were allocated into two groups with 16 and 24 piglets each receiving a diet containing normal (NZn; 100 mg Zn/kg) or high (HZn; 2,100 mg Zn/kg) Zn concentration, respectively. After two weeks, eight piglets from each treatment were killed and organ samples were taken. Eight piglets from the remaining 16 pigs fed HZn diets were changed to NZn diets (CZn). All remaining piglets were killed after another two weeks for organ sampling. Trace element concentration was determined in the jejunum, liver, kidney, pancreas, bone (metacarpal IV), spleen, lung, thymus, tonsils and lymph nodes of jejunum, ileum and colon. Kidney mRNA expression of Zn transporter ZnT1 and ZIP4, genes involved in Cu metabolism (Ctr1, Atox1, SOD1, ATP7A, CCS, CP) and divalent metal ion transport (DMT1) and binding (MT-1a, MT-2b, MT-3) were determined. The Zn concentration in jejunum, liver, pancreas tissue and metacarpal IV was higher (P < 0.05) in HZn group compared with NZn and CZn groups. Trace element concentration in organs of CZn pigs was similar to those fed NZn diets. Zn concentration in muscle, lung and lymphatic organs as thymus, tonsils, spleen and lymph nodes of jejunum, ileum and colon did not differ between the groups. Zn and Cu were positively correlated (R = 0.67; P < 0.05) in the kidney. No significant differences for Cu chaperones, Cu transporters and Cu-dependent factors were determined despite decreased expression of Atox1 after two weeks and increased Ctr1 expression over time in the HZn group. Expression of MT-1a, MT-2b and MT-3 were significantly higher in HZn fed pigs with most pronounced effects for MT-1a > MT-2b > MT-3. Gene expression of MTs in pigs fed CZn diets did not differ from pigs fed NZn diets. The data suggest that high dietary Zn feeding in pigs leads to Cu co-accumulation in the kidney of pigs with minor effect on genes relevant for Cu metabolism. In addition, the organ Zn and Cu accumulation is reversible after two weeks of withdrawal of high dietary Zn.     

不同水位时期东洞庭湖湿地土壤微生物生物量碳氮和酶活性变化

为从土壤微生物的角度分析东洞庭湖不同植被类型湿地土壤质量状况,本研究选取了苔草、芦苇和柳树3种典型植被类型为对象,在平水期、丰水期和枯水期对其土壤微生物生物量碳(MBC)、氮(MBN)和酶活性进行监测,并分析其主要影响因子.结果 表明:1)3个水位时期,各植被类型湿地土壤MBC、MBN、蔗糖酶和纤维素酶活性(枯水期纤维...     

刺芹侧耳两种保护酶基因的克隆、分析及温度对其表达量的影响

为了探究温度胁迫下刺芹侧耳中过氧化氢酶和铜锌超氧化物歧化酶基因的作用,本研究通过RT-PCR方法对刺芹侧耳转录组数据库检索得到的过氧化氢酶（CAT）和铜锌超氧化物歧化酶（Cu/Zn-SOD）基因进行克隆,并利用荧光定量PCR分析在高低温胁迫下CAT和Cu/Zn-SOD基因的表达量,以探讨刺芹侧耳中这两种保护酶基因在高、低温胁迫下的响应特征。结果表明,克隆得到的CAT和Cu/Zn-SOD基因开放阅读框长度分别为1 581bp和582bp,分别编码526个和193个氨基酸,分子量分别为59.6kDa、19.62kDa,等电点分别为6.35、6.31。在高温（35℃）和低温（4℃）两组处理中,CAT和Cu/Zn-SOD基因的表达量及酶活均在处理48h时达到最高且与对照组呈现显著差异,说明两种基因在刺芹侧耳抵御高低温胁迫的过程中具有重要作用。本研究结果初步研究了温度胁迫下刺芹侧耳中CAT与Cu/Zn-SOD基因的生物学功能,为进一步解析刺芹侧耳抵抗温度胁迫的机理奠定基础。