降解饲料中单宁方法的研究进展

单宁是植物次生代谢产物,为多元酚类化合物,存在于高粱等植物性饲料原料中。饲料中存在较高质量浓度的单宁具有抗营养作用,在动物消化道中能与蛋白质和酶类形成难溶复合物,降低饲料的消化率。     

单宁对动物营养代谢的影响

单宁为水溶性酚类化合物，分子量500—3000道尔顿，具有较多的羟基和羧基，能与蛋白质、其它大分子物质（如淀粉、纤维素等）、矿物质形成复合物。豆科植物中以及油菜籽、高粱中，单宁含量较多，小麦中含量很少。豆类籽实中，单宁主要存在于种皮中，其含量多少与种皮颜色有关。白色豆实中单宁含量少，有色豆实中单宁含量多。单宁能抵御真菌、细菌和食草昆虫的侵害而保护植物。1单宁的抗营养作用单宁味苦涩，会降低饲料的适口性，并同饲料中蛋白质、碳水化合物和其它成分形成不易消化的复合物。单宁同蛋白质形成复合物的能力强于同碳水化合物…     

缩合单宁对反刍动物的营养作用

单宁是含酚植物次生代谢复合物、分子量为5 0 0～30 0 0的多酚类化合物,按其结构的不同可分为水解单宁(HT)和缩合单宁(CT)两大类。单宁的化学性质活泼,尤其是饲料中的单宁易与蛋白质结合,因此一直被认为是饲料中的抗营养因子。然而,由于反刍动物特殊的生理和消化特点,大多数日粮蛋白质在瘤胃中很快降解产生氨,瘤胃能够经过氮素循环重吸收其中的一部分,但有一部分氮(约2 5 %～35 % )被损失掉。这种氮的低效利用状况一方面要通过提高动物的氮保留能力来改善,另一方面就要通过能降低蛋白酶活性的天然植物化合物来实现,特别是缩合单宁。与水解…     

影响饲料适口性的几种因素

1抗营养因子 单宁。存在于高粱、大麦等谷物饲料和油菜籽等油料作物中。单宁具有苦涩味，进入动物体内后，能与胃肠蛋白质结合，分解出有强烈刺激性的没食子酸，影响适口性和采食量。     

单胃动物饲粮中的单宁

单胃动物（猪、鸡）的饲粮主要为植物性饲料组成，而大多数植物性饲料中均含有抗营养因子单宁。单宁属多酚化合物，又称鞣酸、单宁酸，能结合蛋白质和消化酶类，干扰消化过程，影响蛋白质和其它养分消化率与利用率，降低单胃动物生产性能。目前，我国猪、鸡饲养标准中尚未明确规定单宁或其它抗营养因子允许水平。本文主要阐述单宁的理化性质和消除单宁活性的主要途径。l单宁的理化性质单宁具有酚基，能与其它分子构成有效交联键。通常可将单宁分为可水解单宁（hydrolysabletannin）和缩合单宁（condensedtannin）。酸、碱或某些酶类分解可水…     

饲料蛋白质营养价值的评定方法及其研究进展

蛋白质营养在动物营养中占有非常重要的地位。我国蛋白质饲料紧缺，如何有效利用现有蛋白质饲料资源，提高蛋白质利用效率始终是重要的课题。而对饲料蛋白质的营养价值进行评定是合理利用蛋白质资源的基础工作。本文就饲料蛋白质营养价值的评定方法进行一下综述，仅供参考。1 饲料蛋白质的营养价值所谓饲料蛋白质的营养价值，可简单定义为单位饲料蛋白质满足动物需要的一种程度或度量。饲料蛋白质的营养价值与动物种类有关，随动物品种的不同而改变；另外，饲料蛋白质进入机体消化道后，其中的一部分随动物粪便排出，这一部分不能被动物利用…     

饲料抗营养因子的研究进展

植物性饲料是配合饲料最为广泛的原料之一，但都存在抗营养因了，有些是植物在进化过程中为适应复杂的生存环境、抵御外害，而产生的生物适应性物质，有些是在饲料加工、储存和使用过程中产生的与营养作用相反的物质。这些物质可以降低饲料的营养价值，影响动物生产性能的发挥。诸如蛋白酶抑制剂、单宁等可与蛋白质、碳水化合物结合形成不易消化的复合物，严重影响养分的消化、吸收利用。因此营养学者采用不同的加工方法，消除或降低有害成分的数量和毒害作用，保证饲料的质量标准。     

棉籽饼粕饲料中游离棉酚测定方法的研究

棉籽饼粕是一种富含营养物质的蛋白质饲料,含蛋白质40％以上、赖氨酸1．59％、蛋氨酸0．52％,可作为一种蛋白质资源用于动物饲料中,在一定程度上弥补了蛋白资源的不足。但是由于棉籽饼粕中含棉酚,对动物具有毒性,如果未经脱毒长期饲喂畜禽,则很易引起中毒甚至死亡。因此,游离棉酚常常是饲料生产中一项重要的监测指标。本文对棉籽饼粕饲料进行自然浸提,建立了游离棉酚含量的测定方法,并与国标法进行了比较。结果表明：此法操作简便,结果准确、可靠,可应用于基层单位大批量样品的检测。     

饲料原粮中的抗营养因子

抗营养因子是指饲料本身含有或从外界进入饲料中的阻碍营养的消化吸收的微量成分。抗营养因子可影响能量、蛋白质、矿物质和维生素的消化吸收。有些抗营养因子毒性很强，可造成动物中毒和死亡。1 影响蛋白质消化的抗营养因子1.1 主要抗营养物质：包括蛋白酶抑制因子、植物凝集素、皂素、单宁等。1.2 副作用：抗营养因子与消化酶结合，使其失去活性或减弱其活性。可与蛋白体结合，使粘膜发育异常。可与金属元素形成不溶性复合物。影响蛋白质、能量消化的抗营养因子、来源、抗营养作用及加工处理等详见表1。2 影响矿物质消化的抗营养因子2.1 …     

饲粮蛋白质水平对重庆黑山羊生产性能和血液生化指标的影响

以3～6月龄重庆黑山羊为试验动物。配制了粗蛋白质水平分别为8．23％、10．42％和12．52％的饲粮。进行了饲养试验、血清生化指标测定。结果表明：（1）随着饲粮中粗蛋白质水平的提高，各组山羊的日增重有增加的趋势，高蛋白质组极显著高于低蛋白质组（P〈0．01）、显著高于中蛋白质组（P〈0．05），中蛋白质组与低蛋白质组差异不显著（P〉0．05）；各组的日采食量有提高趋势，但各组间差异不显著（p〉O．05）；各组饲料转化率有提高趋势，高蛋白质组极显著高于低蛋白质组（P〈0．01），其余各组间差异不显著（P〉0．05）；     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

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。     

商会自治的基石——商会自治规范研究

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。     

獭兔睾丸的组织学观察

家兔作为一种实验动物 ,推动了繁殖技术的发展。本试验通过对不同年龄公獭兔的睾丸进行组织学观察、测定 ,研究精子的发生规律 ,为系统地进行繁殖生理工作提供依据。1　材料与方法选 60日龄、75日龄、90日龄 3个年龄公獭兔各5只 ,用外科手术法摘取两侧睾丸 ,放入 Bouin氏液中固定 ,二甲苯透明 ,石蜡包埋 ,切成 5～ 8μm切片 ,H.E.染色。在显微镜下观察 ,并进行定量组织学指标测定及差异性比较。2　结果和讨论2 .1　睾丸定量组织学指标的测定结果　见表 1。表 1　獭兔睾丸定量组织学指标　　　μm,个 /精细管60日龄 75日龄 90日龄曲细精管…     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

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。     

Observations of fracture of the anconeal process of the ulna of swine

Fractures of the anconeal process of 5 pigs ranging in age from 4 to 8 months were studied radiographically and histologically. Clinically, animals with a fracture of the anconeal process had a "tight," restricted gait. In pigs at 4.5 months of age, a radiolucent line through the base of the anconeal process was composed of fibrocartilage, fibrous connective tissue, and hyaline cartilage. Subperiosteal proliferation of woven bone was located along the cranial surface of the olecranon, adjacent to the base of the anconeal process. In older animals, the radiolucent line through the anconeal process contained variable amounts of fibrous connective tissue and fibrocartilage. The proliferation of subperiosteal bone at the base of the anconeal process formed a "buttress callus" which retained a radiolucent area between the callus and the proximal surface of the anconeal process. The latter region of radiolucency was continuous with the transversely oriented line that traversed the base of the anconeal process.     

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.     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

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.