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采取分组对比的方法（对照组，肺动脉高压综合征（PHS）发病组，维生素C治疗组）分别检测试验鸡只肝组织、肠黏膜、心肌线粒体中的NO含量和NOS的活性。结果显示，对于发生PHS的快大型黄羽肉鸡，其肝脏、心肌和肠黏膜线粒体NO含量呈现先显著上升后显著下降的变化趋势（P〈0．05）。线粒体NOS活力的变化趋势则与NO一致。与对照组相比，维生素C治疗组各指标则呈现相反的变化，说明其能有效地阻止快大型黄羽肉鸡发生PHS这一过程。 相似文献
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肺动脉压升高是肉鸡肺动脉高压综合征(PHS)的重要发病机制。近年来研究表明一氧化氮(NO)在PHS发生发展中发挥着重要作用。本文论述了NO对肉鸡PHS发病过程的影响。一氧化氮合酶(NOS)和NO活性在PHS早期升高而后期下降。NO具有强大的扩张血管的作用,但在PHS过程中,NO合成相对不足,导致肺血管舒缩失衡,引起肺动脉压升高。肺血管重构是肉鸡肺动脉高压综合征的重要病理学变化特征,而NO可促进肺小动脉平滑肌细胞凋亡,在一定程度上抑制肺血管重构的形成。NO作为自由基对机体造成的损伤也是引起PHS的原因之一。在肉鸡日粮中补充NO前体物L-精氨酸可以增加内源性NO的生成,有助于降低PHS的发病率。 相似文献
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试验旨在研究饲料中添加香菇多糖对黄羽肉鸡免疫功能及生长性能的影响。选取1日龄体重接近的黄羽肉鸡180只,随机分为6个组,每个组3个重复,每个重复10只鸡。空白对照组：饲喂基础饲粮;25 mg/kg香菇多糖组：在基础饲粮中添加25 mg/kg的香菇多糖;50 mg/kg香菇多糖组：在基础饲粮中添加50 mg/kg香菇多糖;100 mg/kg香菇多糖组：在基础饲粮中添加100 mg/kg香菇多糖;150 mg/kg香菇多糖组：在基础饲粮中添加150 mg/kg香菇多糖;200 mg/kg香菇多糖组：在基础饲粮中添加200 mg/kg香菇多糖,试验期为42 d。结果表明,在饲料中连续14～42 d添加150～200 mg/kg的香菇多糖可以显著提高黄羽肉鸡血清一氧化氮（NO）、白介素-2(IL-2)、干扰素-γ(IFN-γ)、溶菌酶（LZM）含量和免疫器官指数（P<0.05）,在饲料中连续42 d添加50～150 mg/kg可显著提高黄羽肉鸡的平均日增重、特定生长率和饲料转化率（P<0.05）。综上,在饲料中添加适宜剂量的香菇多糖可以显著提高黄羽肉鸡血清NO、IL-2、IFN-γ... 相似文献
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半胱胺添加水平对黄羽肉鸡生长性能、肉质及机体抗氧化能力的影响 总被引：2，自引：0，他引：2
本试验在22～63日龄黄羽肉鸡日粮中添加不同水平的半胱胺,研究半胱胺对黄羽肉鸡生长性能、肉质及机体抗氧化能力的影响.选用750只21日龄黄羽肉鸡(母鸡)随机分为3组,每组5个重复,每个重复50只鸡.预饲1周后,在肉鸡基础日粮中分别添加0、60和120 mg/kg半胱胺,鸡饲养至63日龄结束.结果表明,在黄羽肉鸡日粮中添加120 mg/kg半胱胺可显著提高22～42日龄肉鸡的平均日增重和平均日采食量(P<0.05),对22～42日龄肉鸡的料重比及43～63日龄肉鸡的平均日增重、平均日采食量及料重比无显著影响(P>0.05);添加60 mg/kg半胱胺可显著提高63日龄黄羽肉鸡肌肉pH45 min、肌内脂肪含量和肌肉嫩度(P<0.05),显著降低宰后45 min 肌肉亮度(L*45 min)(P<0.05),添加60和120 mg/kg半胱胺可显著提高63日龄黄羽肉鸡肌肉系水力(P<0.05);添加60 mg/kg半胱胺可显著提高63日龄黄羽肉鸡血清和肌肉中谷胱甘肽含量(P<0.05),显著提高肌肉中谷胱甘肽过氧化物酶的活性和总抗氧化能力(P<0.05),肌肉中巯基含量有提高趋势,丙二醛含量有降低趋势;添加60 mg/kg 半胱胺可显著提高63日龄黄羽肉鸡肌肉中超氧化物歧化酶、谷胱甘肽过氧化物酶、腺苷一磷酸脱氨酶1、过氧化物酶体增生物激活受体-γ基因的表达(P<0.05).结果提示:在22～63日龄黄羽肉鸡日粮中添加120 mg/kg半胱胺能显著提高22～42日龄鸡的生长性能(P<0.05);在22～63日龄黄羽肉鸡只粮中添加60 mg/kg半胱胺能显著提高63日龄鸡的肌内脂肪含量、肌肉嫩度、肌肉pH及系水力,提高机体抗氧化能力(P<0.05). 相似文献
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试验旨在研究饲粮中添加有机铬对热应激下黄羽肉鸡生产性能、血液酶活力和肠道形态的作用。选择180只32日龄雄性黄羽肉鸡,随机分为常温组、热应激组和有机铬组,每组6个重复,每重复10只鸡。常温组和热应激组饲喂基础饲粮,有机铬组在基础饲粮中添加1.2 mg/kg的有机铬。常温组环境为26℃,热应激组和有机铬组环境温度为35℃,试验共14 d。结果表明：热应激显著降低了黄羽肉鸡的45 d体重、32～45 d的平均日增重和平均日采食量（P<0.05）,显著升高了料重比和死淘率（P<0.05）,显著升高了血液谷丙转氨酶（ALT）、谷草转氨酶（AST）、乳酸脱氢酶（LDH）、肌酸激酶（CK）的活力（P<0.05）,显著降低了空肠和回肠的绒毛高度和绒毛高度/隐窝深度（P<0.05）;饲粮添加1.2 mg/kg的有机铬显著提高了黄羽肉鸡的45 d体重、32～45 d的平均日增重和平均日采食量（P<0.05）,显著降低了料重比（P<0.05）,显著降低了血液AST和CK的活力（P<0.05）,显著提高了空肠的绒毛高度、回肠的绒毛高度/隐窝深度值（P<0.05... 相似文献
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肉鸡肺高压综合征(PHS,pul monary hyper-tension syndrome)又称肉鸡肺动脉高压综合征,在世界范围内的其发病率为4.2%,每年约有70亿肉鸡遭受此病的侵害,估计全世界因此病所造成的经济损失每年达10亿美元。因此引起了国内外学者对该病的广泛关注。以往认为白羽肉鸡常发此病,但随着集约化生产程度的提高、对生长速度的过分追求,快大型黄羽肉鸡该病的发生也有日渐增多之势。所以,越来越引起重视。前人对自由基在肉鸡PHS的发生、发展过程中的作用及其对自由基的清除已作了大量的研究工作,但自由基变化的同时往往伴随着能量的改变,PHS发生过… 相似文献
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选21d健康的黄羽肉鸡120只,随机分成4组。A组为对照组,饲喂基础日粮;B、C和D组为试验组,分别饲喂在基础日粮中添加0.2%、0.5%和0.8%谷氨酰胺的饲粮,试验期14d,在高温(33±2℃)下观察黄羽肉鸡血液超氧化物岐化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和丙二醛(MDA)含量的变化,以研究谷氨酰胺对黄羽肉鸡血液抗氧化能力的影响。试验结果表明:高温下日粮中添加0.5%和0.8%谷氨酰胺可显著提高28d和35d黄羽肉鸡的血液GSH-Px活力(P<0.05),显著降低血液中MDA含量(P<0.05);添加谷氨酰胺对血液SOD活力无显著影响(P>0.05)。提示谷氨酰胺是通过提高体内GSH-Px活性,抑制脂质过氧化反应以增强机体的抗氧化能力。 相似文献
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试验选用360只岭南黄肉鸡，研究谷维素对生长性能和脂肪代谢的影响，试验鸡分为3个组，每组3个重复。试验分为2个阶段，1。21日龄阶段各组分别饲喂含谷维素0、25和75mg／kg的日粮，22～49日龄阶段各组分别饲喂含谷维素0、30和90mg/kg的日粮。试验结果表明，日粮中添加谷维素对黄羽肉鸡生长性能无显著影响；在0～21日龄阶段，日粮中添加75mg／kg谷维素可使黄羽肉鸡血清中的总胆固醇含量下降20．77％（P〈0．05），甘油三酯下降27．66％（P〈0．05）；在22。49日龄阶段，日粮中添加60和90mg／kg谷维素可使血清中的高密度脂蛋白分别增加30．45％（P〈0．05）和27．16％（P〈0．05），添加90rag／rag谷维素使血清中甘油三酯降低33．85％（P〈0．05）。 相似文献
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本试验旨在研究厚朴总酚对黄羽肉鸡生长性能、肉品质和抗氧化功能的影响。试验选取1日龄黄羽肉鸡360只,随机分为5组,每组6个重复,每个重复12只。对照组饲喂基础饲粮;抗生素组1～28日龄饲喂基础饲粮+20 mg/kg抗敌素和12 mg/kg黄霉素,29～56日龄饲喂基础饲粮+12 mg/kg黄霉素;厚朴总酚添加组分别饲喂在基础饲粮中添加50、150和250 mg/kg厚朴总酚的饲粮。试验期56 d。结果表明:1) 29～56日龄和1～56日龄,50 mg/kg厚朴总酚添加组黄羽肉鸡平均日采食量显著高于抗生素组(P0.05),黄羽肉鸡料重比随厚朴总酚添加水平的提高呈现二次变化(P0.05)。2) 56日龄时,50和150 mg/kg厚朴总酚添加组黄羽肉鸡胸肌pH(45 min和24 h)与抗生素组相比显著提高(P0.05),且150 mg/kg厚朴总酚添加组黄羽肉鸡胸肌肉色45 min红度值显著高于其他各组(P0.05),150 mg/kg厚朴总酚添加组黄羽肉鸡胸肌滴水损失(24 h)和失水率显著低于对照组和抗生素组(P0.05)。3) 28日龄时,150 mg/kg厚朴总酚添加组黄羽肉鸡血清超氧化物歧化酶(SOD)和过氧化氢酶活性与抗生素组差异不显著(P0.05),且血清SOD活性显著高于其他组(P0.05); 56日龄时,150 mg/kg厚朴总酚添加组黄羽肉鸡肝脏丙二醛含量显著低于对照组(P0.05)。综上所述,饲粮中添加厚朴总酚能提高黄羽肉鸡生长性能,改善肉品质,增强抗氧化功能,且以150 mg/kg的添加水平为佳。 相似文献
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以意大利蜜蜂（Apis mellifera ligustica)为实验材料，应用755B型分光光度计，测定了蜜蜂幼虫、刚出房的工蜂、哺育工蜂及采集蜂的血淋巴中K^ 和Na^ 含量，结果表明：不同发育阶段的蜜蜂血淋巴中所含K^ 和Na^ 含量有所差异。 相似文献
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《Research in veterinary science》2013,94(3):1367-1379
This paper investigates the in vitro effect of dexamethasone on bovine CD25highCD4+, CD25lowCD4+ and CD25−CD4+ T cells. Only a small percentage of bovine CD25highCD4+ (2–4%) and CD25lowCD4+ (1–2%) cells expressed Foxp3. Dexamethasone caused considerable loss of CD25−CD4+ cells, but it increased the relative and absolute numbers of CD25highCD4+ and CD25lowCD4+ lymphocytes, while at the same time reducing the percentage of Foxp3+ cells within the latter subpopulations. Considering all these, as well as the intrinsically poor Foxp3 expression in bovine CD25+CD4+, it can be concluded that the drug most probably increased the number of activated non-regulatory CD4+ lymphocytes. It has been found that changes in cell number were at least partly caused by proapoptotic effect of the drug on CD25−CD4+ cells and antiapoptotic effect on CD25highCD4+ and CD25lowCD4+ cells. The results obtained from this study indicate that the involvement of CD4+ lymphocytes in producing the anti-inflammatory and immunosuppressive effect of dexamethasone in cattle results from the fact that the drug had a depressive effect on the production of IFN-γ by CD25−CD4+ cells. Secretion of TGF-β and IL-10 by CD4+ lymphocytes was not involved in producing these pharmacological effects, because the drug did not affect production of TGF-β and, paradoxically, it reduced the percentage of IL-10+CD4+ cells. 相似文献
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The role of CD4+CD25+ regulatory T cells in viral infections 总被引：5，自引：0，他引：5
Vahlenkamp TW Tompkins MB Tompkins WA 《Veterinary immunology and immunopathology》2005,108(1-2):219-225
Many virus infections result in the suppression of one or more functions of the immune system. Multiple mechanisms have been proposed to explain viral-induced immunosuppression, including an imbalance in the cellular Th1/Th2 or cytokine profile, induction of anergy, depletion of effector cells and most recently the activation of CD4+CD25+ regulatory T (T reg) cells. CD4+CD25+ T reg cells are a subset of circulating CD4+ T cells with suppressive properties. CD4+CD25+ T reg cells were first identified in mice as cells capable of maintaining self-tolerance by suppressing autoreactive T cells. This review focuses on interactions between CD4+CD25+ T reg cells and viral pathogens. Most cases in which CD4+CD25+ T reg cells participate in response to infection reported so far involve chronic or persistent viral infections. Examples have been growing recently and include members of different viral families including retroviridae, herpesviridae and picornaviridae. It is currently not known how microbes are recognized by CD4+CD25+ T reg cells and whether exoantigen-specific T reg cells are of the same lineage as self-reacting natural T reg cells or represent peripherally induced counterparts derived from CD4+CD25- T cells. The findings that T reg cells influence the functional immunity during viral infections, however, might indicate that, in some cases, virus-specific T reg cells not only influence immune pathology or prevent pathogen elimination but also can promote a generalized state of immunosuppression in vivo such that the host is more susceptible to secondary infections with other pathogens or has reduced resistance to tumors. Conceivably, the activities of T reg cells might be one of the contributing reasons why it has been difficult so far to produce effective vaccines against some persisting viral infections. 相似文献
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P. Wongyanin S. Buranapraditkun K. Chokeshai-usaha R. Thanawonguwech S. Suradhat 《Veterinary immunology and immunopathology》2010,133(2-4):170-182
Increases in numbers or activities of regulatory T lymphocytes (Tregs) have been linked to the establishments of several persistent infections. It has been previously shown that porcine reproductive and respiratory syndrome virus (PRRSV) can negatively modulate the host immune responses, resulting in persistent infection and secondary immunodeficiency. Recently, the existence of porcine CD4+CD25+ Tregs has been demonstrated. We investigated the effect of PRRSV on the CD4+CD25+ Tregs. The CD4+CD25+Foxp3+ T lymphocytes in the peripheral blood mononuclear cells (PBMCs) were identified, using the anti-human anti-Foxp3 monoclonal antibody. In vitro culture of porcine PBMC in the presence of PRRSV, but not classical swine fever virus, significantly increased the numbers of Foxp3+ lymphocytes, particularly in the CD4+CD25high subpopulation. The time-course study revealed that PRRSV significantly increased the numbers of viral-specific CD4+CD25highFoxp3+ subpopulation in the culture starting from 12 h through the end of the observation period. Consistent to the results obtained by flow cytometry, enhanced Foxp3 gene expression was observed in the PBMC cultured with PRRSV in a time-course manner. The presence of monocyte-derived DC in the co-culture significantly enhanced the induction of CD4+CD25+ Foxp3+ T lymphocytes. The PRRSV-induced CD4+CD25high T lymphocytes exhibited suppressive activity when co-cultured with PHA-activated, autologous peripheral blood leukocytes, indicating the suppressive activity of the PRRSV-specific Tregs. In addition, PRRSV exposure significantly increased the numbers of PRRSV-specific CD4+CD25+Foxp3+ subpopulation in the PBMC of infected pigs at 10 days post-infection. In summary, the results indicated that PRRSV could increase the numbers of viral-specific, inducible regulatory T lymphocytes in the porcine PBMC, both in vitro and in vivo. The findings suggested the novel immunomodulatory mechanism induced by PRRSV. 相似文献