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植物性饲料中60%～80%的磷是以不被单胃动物利用或利用率极低的植酸磷形式存在。植酸是一种很强的络合剂,易与多种必需矿物元素离子,如钙、镁、铁、锰、锌等络合,形成难溶性植酸-金属络合物,从而影响这些矿物元素的吸收利用,使其生物学效价明显降低。植酸也可与蛋白质分子进行有效地络合,使蛋白质溶解性大大降低。同时它还能和动物消化道中的消化酶结合,使其活性降低,最终降低蛋白质、淀粉及脂类等营养物质消化吸收的利用率。植酸酶可以水解植酸磷,消除或降低其抗营养作用,释放出磷供动物利用,可以提高植物性饲料中磷的利用率,因此饲粮中添… 相似文献
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动物常规植物性饲料中约有60％～70％的磷是以植酸磷的形式存在于稳定的植酸盐复合物中,这些磷只有在植酸分解酶的作用下才能游离出来供动物吸收利用。单胃动物除成年禽外消化道中缺乏植酸酶,因而对植酸磷的利用率极低。许多研究证明,猪只能利用玉米中磷的10％～20％,豆饼中磷的25％～35％,家禽除成年禽外对植酸磷的利用率还略低于猪。饲料中大量的植酸磷不仅不能被利用而随粪便排入环境,造成 相似文献
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尹尧 《畜牧兽医科技信息》2015,(5)
<正>植酸的抗营养作用普遍存在于饲料中,它不仅与磷形成动物难于消化的植酸磷,也可与蛋白质和各种矿物质形成络合物,影响动物对饲料中磷、蛋白质和各种矿物质的利用。本文针对饲料中植酸的抗营养作用作一综述。1植酸的性质及分布植酸又称肌酸,化学名称环己六醇六磷酸酯,分子式C6H18O24P6,为淡黄色至淡褐色奖状液体。植酸广泛存在于植物体内,特别是禾谷类籽粒中,也集中存在于谷粒外层中,故麸皮、米糠中植酸含量较高。豆类、棉菜籽及其饼粕中也含有 相似文献
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植酸酶对畜禽动物磷吸收的作用 总被引：3，自引：0，他引：3
植酸酶作为一种环保型饲料添加剂不仅可以改善畜禽动物对饲料中植酸盐的水解提高植酸磷的利用率,降低粪尿磷排出量,减少环境污染,还可以促进饲料中蛋白质,淀粉的消化及矿物质元素的吸收。本文对植酸酶的来源,类型,作用方式及在动物饲料中的作用进行了概述。 相似文献
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植酸酶对肉鸡矿物质代谢的影响 总被引：3，自引：0，他引：3
植物性饲料是家禽饲料中的主要成分。植物性饲料中三分之二的磷以植酸盐的形式存在。由于单胃动物的消化道内缺少植酸酶,以植酸形式存在的植酸磷很少被单胃动物所利用。一方面,饲料生产中需要添加价值昂贵的商品磷源,另一方面,由于动物(特别是单胃动物)不能或很少利用植物饲料中的植酸磷,大量未被动物吸收利用的植酸磷随粪便排出体外,既造成了磷资源的浪费,同时又给环境造成了污染。畜禽粪便中磷对环境的污染已成为一些国家畜牧业发展的制约因素。 Nelson(1968a)首次报道了添加植酸酶可提高仔鸡对磷的利用率,但当时由于植酸酶的提取成本高、产量少、植酸酶的研究与应用未能引起人们的足够重视。近些年来,非植酸磷对环境的 相似文献
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谷物原料中约2/3的磷是以有机植酸磷形式存在的。已证实植酸磷不能为单胃动物利用。然而,添加植酸酶可使植酸磷水解,磷游离出来,而被动物吸收。减轻对环境污染植物饲料原料中磷可利用率提高,饲料中磷的添加量就可以减少,这样,经粪便排出的磷便随之下降。1988年荷兰家禽排出的磷量约1.36万吨。自1984年起,他们采用低磷禽饲料 相似文献
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NaPi-Ⅱ型协同转运载体蛋白与磷吸收的关系 总被引：1，自引：0，他引：1
大部分磷(60%～80%)以不能被动物消化的植酸磷的形式存在,只能被动物排出体外,造成浪费;另一方面,由于动物不能利用植酸磷,在饲料中又不得不人为添加更多的工业合成磷,而这些添加的磷不能完全被吸收利用,60%的无机磷被排出体外,造成严重的环境污染.目前,规模化畜禽养殖业中过量磷的排泄导致的环境污染,已成为全球关注的热点问题.作为一种非再生资源,磷在饲料工业中具有举足轻重的地位,是继蛋白质和能量以外第三种最昂贵的饲料原料.了解磷的吸收作用机制对提高磷在生产上的利用和减少其带来的环境污染具有重要意义,而NaPi-Ⅱ型协同转运载体蛋白是对磷在小肠中的吸收有重要影响的一种载体蛋白. 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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以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献