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液态蛋氨酸羟基类似物(HMB)是一种有效的反刍动物蛋氨酸(MET)源，它比MET更能抵抗瘤胃微生物的降解，过瘤胃率40％以上。反刍动物日粮中添加HMB能改善动物生产性能，降低饲料成本，并对动物健康和环境保护有利。 相似文献
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蛋氨酸羟基类似物(MHA Methionine Hydroxy Analoge或HMB 2-Hydroxy-4-(Methythio)Butanoic Acid)是一种有效的反刍动物用活性蛋氨酸源:已有研究证明蛋氨酸羟基类似物是一种现成的反刍动物用蛋氨酸源。一些机构的研究已分别证实了蛋氨酸羟基类似物在瘤胃中的存留、吸收、转化情况,血浆中L-蛋氨酸的含量,以及蛋氨酸羟基类似物在牛乳、肌肉组织中的利用情况(Belasco,1972;1980,Pat-terson和Kung,1988,Koenig等,1996,Webb,1997)。1 过瘤胃率最低达40％ 在AgCanada所做的研究证实蛋氨酸羟基类似物被反刍动物摄入后,瘤胃通过率最少达40％(Koenig等,1996)。另外弗吉尼亚工学院研究发现蛋氨酸羟基类似物实际上可 相似文献
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《今日畜牧兽医》2002,(3)
当前，饲料工业中广泛应用的蛋氨酸添加剂可分为两种：消旋蛋氨酸（DL－Methionine，简称蛋氨酸即DLM）和消旋蛋氨酸羟基类似物（DL－MethionineHydroxyAnalogue，简称MHA）。虽然，蛋氨酸和蛋氨酸羟基类似物都有液体和固体产品，但市场上常见的是固体消旋蛋氨酸（DLM）和液体蛋氨酸羟基类似物自由酸（MHA－FA）。从分子结构看，蛋氨酸（DLM）分子碳链α位为一个氨基（—NH２），而MHA—FA分子相应位置上则为一个羟基（—OH），故MHA—FA不是蛋氨酸。理论上MHA—FA在动物体内须经转氨酶的作用，用其他来源的氨基代替其分… 相似文献
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蛋氨酸添加剂对肉用仔鸡生产性能的影响 总被引：3，自引：0，他引：3
蛋氨酸是家禽玉米 -豆粕型日粮的第一限制性氨基酸 ,在家禽特别是肉鸡日粮中添加工业合成蛋氨酸才能满足其需要。市售蛋氨酸添加剂有固体蛋氨酸 (纯度为 99% )和液体蛋氨酸羟基类似物 (纯度为 88% )两种。有关液体蛋氨酸羟基类似物的生物学效价目前还存在争议 :一种意见认为在等摩尔含量的基础上 ,液体蛋氨酸羟基类似物可以代替固体蛋氨酸 ;另一种意见则认为液体蛋氨酸羟基类似物本身不是蛋氨酸 ,当进入动物体后需经化学转化才可形成蛋氨酸 ,进而参与代谢。许多试验结果亦表明 ,液体蛋氨酸羟基类似物的相对生物学效价较低 ,只有固体蛋氨酸的… 相似文献
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液体蛋氨酸羟基类似物的生物学效价 总被引：4，自引：0，他引：4
蛋氨酸是畜禽必需氨基酸 ,特别在禽饲料中常常是第一限制性氨基酸。两种化学结构不同的蛋氨酸可以满足这种添加需求 ,一种是众所周知的粉状DL -蛋氨酸 (DLM) ,另一种是液体蛋氨酸羟基类似物 (MHA) ,它与DLM分子结构相似 ,称作DL - 2 -羟基 - 4- (甲硫基 ) -丁酸或者DL -蛋氨酸羟基类似物。几十年来 ,由于研究参数的复杂性 (例如营养水平、日粮组成和动物生产阶段 ) ,研究结果没有完全揭示蛋氨酸的吸收方式和吸收率。本文的目的在于总结两类蛋氨酸产品在试验条件和生产条件下生物效价的比较研究资料 ,供应用时参考。1 MHA单体、二聚… 相似文献
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蛋氨酸在畜牧业中应用已有30多年历史,但主要应用干猪、禽等单胃家畜。奶牛是反刍动物,其瘤胃微生物可以合成各种氨基酸,对必须氨基酸的需求不如猪、禽那样严格。但1963年以来的研究表明:在奶牛日粮中添加蛋氨酸及其羟基类似物,可以提高 相似文献
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液体蛋氨酸羟基类似物对鸭的相对生物学效价 总被引：1，自引：1，他引：0
饲料工业中常用的蛋氨酸添加剂有两种 :固体状的消旋蛋氨酸 (ＤＬ -Ｍｅｔｈｉｏｎｉｎｅ ,简称蛋氨酸 )和液体状的消旋蛋氨酸羟基类似物游离酸 (ＤＬ -ＭｅｔｈｉｏｎｉｎｅＨｙｄｒｏｘｙＡｎａｌｏｇｕｅＦｒｅｅＡｃｉｄ ,以下简称ＭＨＡ -ＦＡ)。与蛋氨酸不同 ,ＭＨＡ -ＦＡ分子中α-氨基 ( -ＮＨ2 )被α -羟基 ( -ＯＨ)取代 ,见图 1。因此 ,它不是蛋氨酸 ,只是一种具有蛋氨酸活性的蛋氨酸类似物。理论上 ,ＭＨＡ -ＦＡ在动物体内须经转氨酶的作用 ,用其它来源的氨基代替其分子上的羟基 ,才能形成蛋氨酸并参与蛋白质的合成。ＤＬ -蛋氨… 相似文献
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蛋氨酸是动物的一种重要的必需氨基酸。蛋氨酸羟基类似物可在动物体内转化为蛋氨酸并发挥其营养作用。此外，它还可用做反刍动物的过瘤胃蛋白源和仔猪日粮的酸化剂，能抑菌杀菌、减少热应激，并可减少氮的排泄，保护环境。本文重点从蛋氨酸羟基类似物的消化吸收机制、对动物的主要生物学作用和生物学效价的评定3方面进行综述。 相似文献
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<正>蛋氨酸在畜牧业中的应用已有40多年的历史,但主要应用于猪、禽等单胃家畜禽,绵山羊做为反刍动物,其瘤胃微生物可以通过营养的生物重组而合成各种氨基酸,因此,其对氨基酸的需求就不及猪、禽那样严格。但是随着对反刍动物营养研究的深入,人们发现在绵羊或山羊的日粮中添加蛋氨酸及其羟基类似物,可以提高绵羊的产毛量和毛质,对奶山羊而言可提高其产奶量和乳脂率。本文目的在于对蛋氨酸及其羟基类似物对绵山羊生产性能的影响及其作用的机制的有关研究做一概述。 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