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酶是生物细胞原生质合成的一类具有高度催化活性的蛋白质,因其来源于生物体,所以通常称其为“生物催化剂”。酶广泛分布在动、植物和微生物体内,动物体内物质(碳水化合物、脂肪、蛋白质等)的新陈代谢,都必须在酶的参与下进行,没有酶就没有新陈代谢,也就没有生命活动。 相似文献
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酶是动物体内各种物质化学变化的催化剂,几乎所有的反应都是在酶的催化下进行的。据有关资料报道,饲料中添加酶制剂,既能增进禽体健康、补充动物体内酶源的不足、消除饲料中某些抗营养因子、促进畜禽生产,又可以提高饲料利用率,还对控制禽场的环境污染有明显作用。将两种或几种酶复合添加,效果更好。 相似文献
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酶是一种由活细胞产生的具有生物催化反应能力的蛋白质催化剂,在动物体内消化与新陈代谢过程中起着重要的作用。酶具有高效性,专一性,无毒副作用,不产生残留等特点。它广泛存在于动物、植物和微生物体内,是生物体维持正常的生理生化功能必不可少的成分。畜禽消化道内缺乏植酸酶,纤维素酶以及其他的一些非淀粉多糖酶,因而许多营养学 相似文献
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酶制剂的适当选择与高效使用 总被引：6，自引：0，他引：6
一、酶及其作用 酶是一种由活细胞产生的生化反应的蛋白质催化剂,在动物体内消化与新陈代谢过程中起着非常重要的作用。生物体内生化代谢途径中的酶可分为氧化还原酶类、转移酶类、水解酶类、裂合酶类、异构酶类和合成酶类共6类。工业上应用的酶制剂大多数为水解酶,按作用底物的不同,可分为淀粉酶、蛋白酶、脂肪酶、果胶酶、木聚糖酶、β-葡聚糖酶、纤维素酶、植酸酶、核糖核酸酶等。动物能分泌到消化道内的酶主要属于蛋白 相似文献
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1酶的分类及其作用
酶是一种由活细胞产生的生化反应的蛋白质催化剂,在动物体内参与消化与新陈代谢的过程,并起着非常重要的作用。生物体内生化代谢途径中的酶可分为氧化还原酶类、转移酶类、水解酶类、裂合酶类、异构酶类和合成酶类共6类。工业上应用的酶制剂大多数为水解酶,按作用底物的不同,又可分为淀粉酶、蛋白酶、脂肪酶、果胶酶、木聚糖酶、β-葡聚糖酶、纤维素酶、植酸酶、核糖核酸酶等。动物能分泌到消化道内的酶主要属于蛋白酶、 相似文献
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正确认识与合理使用饲用酶制剂 总被引：2，自引：0，他引：2
1饲用酶制剂的概念1.1酶的功能和特点酶是一种由活细胞产生的具有生物催化反应能力的蛋白质催化剂,在动物体内消化与新陈代谢过程中起着重要的作用。酶的基本功能是其催化活性,可加速多种生物化学反应,饲料中的营养物质、抗营养因子的分解反应就是靠酶来催化的。酶催化反应的特 相似文献
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饲用酶制剂在家禽饲养中的应用段修军（扬州大学农学院动科系２２５００９）酶，旧称酵素，是生物体内各种物质化学变化的催化剂，也是生物体自身所产生的一种活性物质。动物体内的各种化学变化几乎都在酶的催化作用下进行。酶制剂是通过各种特殊微生物发酵而获得的生物化... 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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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
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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