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维生素E是机体内具有广泛生理功能的重要脂溶性维生素和营养性抗氧化剂,广泛存在于体内储脂器官和生物膜上,具有免疫调节、阻止自由基对组织攻击和维持膜结构的稳定等重要作用。有关维生素E缺乏对雏鸡红细胞影响方面的研究未见有文献报道。本试验用人工建立的维生素E缺乏症雏鸡模型,通过对雏鸡红细胞G-6-PD活性和血红蛋白(Hb)含量的检测,旨在探讨维生素E缺乏对雏鸡红细胞的影响,为揭示维生素E缺乏对雏鸡红细胞的损伤机制提供依据。 相似文献
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自由基与多不饱和脂肪酸反应启动一个被称为生命系统中脂质过氧化反应以及食物氧化酸败的连锁反应过程.多不饱和脂肪酸更易氧化,导致有毒产物的形成.由于胚胎组织中不饱和脂肪酸含量较高,在肉种鸡日粮中使用抗氧化剂可以改善雏鸡的氧化状态.带壳蛋被认为具有抗氧化酸败的作用,然而研究表明食用蛋中的卵黄脂质在储存时易被氧化,这种氧化受到储存时间、温度及卵黄脂肪酸不饱和程度的影响.因此有许多在蛋鸡饲料中添加抗氧化剂来保持其营养价值的试验研究.文献表明,卵黄中的VE具有抗氧化活性,对孵化期的胚胎以及初生的雏鸡均有较好的保护作用.然而这些研究均未考虑到维生素对孵化率的影响.由于经济方面的因为.维生素的实际使用量明显低于研究中的建议使用量,因此,它在胚胎中的积极作用以及雏鸡的抗氧化作用在生产中的应用价值不是很大.其他抗氧化剂如角黄素等与VE具有协同作用,然而,这些高成本的物质可能限制了它们在肉种鸡上的应用.本文综述了肉种鸡和产蛋鸡营养中的维生素(特别是VE)对胚胎组织和卵黄脂抗氧化性的影响. 相似文献
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由于VE的商业化应用,研究的重点集中在以围绕提高机体免疫力的最佳用量上,有关研究结果综述如下:①产蛋母鸡饲料中添加150~450iu/kgVE,其雏鸡接种流产布氏菌疫苗后,抗体产生显著提高。②雏鸡添加150~300iu/kgVE后,人工感染大肠杆菌,其体液和细胞免疫水平均显著提高。③VE可降低法氏囊和脾脏的前列腺素水平,其机理可能与抗氧化特性有关。④雏鸡接种新城疫疫苗的同时,饲料中再添加300mg/kgVE,可产生高效价的循环抗体。⑤接种鸡新城疫和巴氏杆菌疫苗后,饲料添加300iu/KgVE,可有效提高雏鸡对病毒和细菌抗原的免疫应答。VE直接作用于T细胞,当接种的抗原浓度较高时,VE的作用效果就更明显。补充VE对提高免疫应答的理想时期应在雏鸡免疫系统发育时期,即1日龄至4周龄,⑥雏鸡接种柔嫩艾美耳球虫后,添加100iu/KgVE,可降低死亡率,并增加体重。⑦添加178iu/kgVE会使隐性感染IBD的商品雏鸡免疫应答提高,这是由于免疫竞争的结果。在机体的免疫系统受到刺激时,摄入高含量的VE对改善机体的免疫力有明显效果。 相似文献
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维生素E缺乏对雏鸡脾脏淋巴细胞Caspase-3活性及Caspase-3mRNA表达的影响 总被引:1,自引:0,他引:1
用低维生素E(VE)和添加不饱和脂肪酸的日粮饲喂雏鸡建立VE缺乏雏鸡模型,采用比色法和半定量RT-PCR法分别检测脾脏淋巴细胞Caspase-3活性及Caspase-3 mRNA的表达水平。结果显示,VE缺乏组雏鸡脾脏淋巴细胞Caspase-3活性和Caspase-3 mRNA丰度高于对照组,组间差异均极显著(P<0.01)。结果表明,Caspase-3活性及Caspase-3 mRNA丰度的改变,是VE缺乏雏鸡脾脏淋巴细胞凋亡的调控机制之一。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献