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本文主要论述有关磷生物学效价的研究及对磷生物学效价的影响因素,包括对研究方法所采取的标准物、测定指标以及植酸、钙磷水平与VD等因素对磷效价的影响和一些近期发展起来的提高磷生物学效价减少饲料中无机磷添加量的途径与方法,以便降低饲料成本与畜禽粪便中磷的排放,降低畜禽业对环境的污染,发展绿色、环保型畜牧业。 相似文献
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磷(P)是日粮中不可缺少的重要营养元素。无论无机还是有机磷,他们的生物学效价都会不同。因此,了解生物学效价的知识和评定方法对选择饲料磷的来源,最大限度地发挥动物和家禽的生产性能,避免粪便过量的磷排泄具有极为重要的意义。本文的目的是对一些评定无机磷酸盐和有机饲料原料磷的生物学效价的常规方法做一介绍,并对他们的物理和化学特性加以描述。 磷是动物所必需的主要矿物元素之一。磷、钙,对于动物骨骼系统的生长和发育具有重要作 相似文献
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不同蛋氨酸来源的相对生物学效价 总被引：2，自引：0，他引：2
贵刊 2 0 0 3年第九期登载的《液体蛋氨酸羟基类似物的生物学效价》一文 ,我们认为有必要对其中有关生物学效价评定方法的一些观点提出质疑 ,供大家进一步讨论。评定液体蛋氨酸羟基类似物 (MHA -FA)相对于蛋氨酸 (DLM)的生物学效价与评定其他任何营养物质一样 ,梯度添加效应试验并用线性或指数回归分析是最敏感 ,也是唯一能够准确反映动物生长与生产规律和评定营养物质生物学效价的方法。对此动物营养界已有定论。动物对限制性营养物质如蛋氨酸的生长反应呈曲线式并遵循报酬递减规律。在蛋氨酸缺乏的日粮中 ,随着梯度添加DLM或MHA -F… 相似文献
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近日,中国农业科学院北京畜牧兽医研究所动物营养学国家重点实验室承担的科技部创新方法工作专项"猪禽饲料能量生物学效价评定方法的创新研究"项目通过验收。饲料有效能值是制定畜禽饲养标准及优化饲料配方的首要技术参数。饲料能量生物学效价的评定是动物营养学科中世界性的"老大难"问题。传统的动物试验法存在着耗时、费力、重演性差的弊端。欧洲及美国、日本等发达国家虽然曾在体外消化技术方面进行过种种尝试,但一直缺 相似文献
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我国是畜禽养殖大国，由于猪、鸡等单胃动物对植酸磷的利用率偏低，所以常常添加磷酸盐来满足动物对磷的需要，但经代谢周转的磷和未被消化吸收的磷约占摄入磷量一半以上被排出体外，畜禽粪便磷污染问题日益严重。纳米技术的出现将人们为提高磷酸盐利用率的研究扩展到磷酸盐物理性状、化学结构和生物利用性三者之间的关系上来，可为研发高效磷源，降低饲料磷含量，减轻磷污染提供一条思路。目前，纳米营养素的研究主要集中于微量元素方面，对饲料中常量元素磷的纳米化研究还未见报道。因此，本试验旨在探索性地研究纳米磷酸氢钙的利用效果并对其磷的生物学效价进行评定。 相似文献
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蛋白质饲料供应不足乃世界性问题,我国蛋白质饲料紧缺亦日趋严重,实现对饲料蛋白质营养价值的准确、客观评定是合理利用蛋白质饲料资源的先决条件。因此,如何客观评价饲料蛋白质氨基酸营养价值,是各国学者一直关注和研究的主要课题。近年的研究表明,满足畜禽蛋白质的需要实质上是满足其氨基酸的需要,蛋白质的营养实质是氨基酸的营养。在畜禽饲养及营养学中,评定蛋白质的生物学效价的方法已逐渐被摒弃,研究重点已转到蛋白质中各种必需氨基酸生物学效价评定方面,即以可利用氨基酸为基础评定饲料蛋白质的营养价值。1体外法测定氨基酸生物学效价… 相似文献
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肉仔鸡体外消化模拟技术评定不同剂量植酸酶作用效果的研究 总被引：2，自引：0，他引：2
对肉仔鸡体外消化模拟技术评定不同剂量植酸酶在玉米-豆粕日粮中作用效果的可行性进行了检验.在体外条件下,分别测定了添加与不添加植酸酶的6种玉米-豆粕日粮磷体外消化率和无机磷释放量.结果表明：磷体外消化率和无机磷释放量随植酸酶添加水平的增加而增加（P＜0.01）,添加不同剂量的植酸酶日粮,磷体外消化率和无机磷释放量与肉仔鸡日增重、采食量、回肠磷消化率、胫骨灰分和磷的沉积以及胫骨灰分中磷的含量等指标均存在强相关（R^2=0.971,0.990,0.962,0.903,0.866,0.986和R^2=0.970,0.987,0.976,0.898,0.859,0.984）.利用肉仔鸡体外消化模拟技术,可以评定和预测玉米-豆粕日粮中添加不同剂量植酸酶对肉仔鸡生产性能和磷利用的影响. 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
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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献