饲料中抗营养因子——单宁的含量分析方法

针对近年来单宁在动物营养上的最新研究成果，本文重点阐述了饲料中缩合单宁、可水解单宁和总酚类化合物的分析方法。旨在为更好地利用含单宁饲料提供参考。     

氮素对羽叶决明缩合单宁及相关酶活性的影响

缩合单宁对牧草品质的影响极大,适量的缩合单宁含量对于提高牧草的利用率和营养品质非常重要。研究以豆科牧草羽叶决明Cassia nictitoms为材料,分析了氮素梯度处理后茎和叶中缩合单宁的含量及其生物合成酶二氢黄酮醇还原酶(DFR)活性的变化特征。结果表明,羽叶决明叶片的缩合单宁含量高于茎,随氮素的增加,叶片中缩合单宁含量从14.78%下降到1.14%;茎中从4.62%开始降低,达到0.98%后趋于稳定;DFR活性表现出与缩合单宁相似的变化规律,二者在叶和茎中都呈显著(P0.01)的二次曲线关系。植株粗蛋白含量测定发现,随氮素的增加粗蛋白含量无显著增加(P0.05)。因此,适当增加氮素的使用量可以达到减少缩合单宁含量,从而提高羽叶决明的利用率和营养品质。     

饲料中单宁对动物的影响

单宁是在多种植物中普遍存在的一种抗营养因子,饲料中的单宁含量过高会对动物产生很大的影响,适量的单宁则能促进动物的健康和生产。     

缩合单宁对反刍动物瘤胃发酵的影响与研究进展

缩合单宁作为一种常见的抗营养因子,存在于众多饲草植物中。近年来在反刍动物上的研究发现缩合单宁在提高过瘤胃蛋白、控制甲烷排放以及调控瘤胃发酵方面表现出营养作用。本文综述了缩合单宁对瘤胃微生物区系结构、pH、甲烷产量、氨态氮以及微生物蛋白含量的影响,并提出了缩合单宁新的研究方向和应用前景。     

单宁酸的生理功能及其在畜禽生产中的研究进展

单宁是一种广泛存在于植物中的多酚类天然产物,从结构与活性上又分为水解单宁和缩合单宁。水解单宁因其独特的化学特性和生理活性,可作为添加剂在动物生产中运用,缩合单宁酸具有较强的抗营养吸收作用,被定义为饲料中的抗营养因子。本文主要介绍了单宁酸的营养作用,并整理了其在猪、鸡生产中的研究进展。     

单宁对反刍动物的影响及其含量测定

针对近30年来有关单宁在反刍动物营养作用方面的研究进展,从单宁的理化性质、单宁对反刍动物的影响作用、单宁在饲用植物中的含量及其影响单宁含量的因素和单宁测定方法4个方面作了比较全面的评述。     

单宁的抗营养作用机理及处理措施

单宁是植物饲料中主要的抗营养因子之一,其限制了植物饲料在动物生产中的运用。本文就单宁的分布与含量、理化性质、抗营养的作用机理及处理措施作一综述。     

植物缩合单宁对草食动物的抗寄生虫性

植物缩合单宁广泛存在于众多植物种群,具有抵御动物摄食的化学防卫功能.近年来植物缩合单宁因其抗寄生虫性受到愈来愈多的关注,相关研究为动物肠胃道寄生虫防控提供了新的途径,它有望成为传统化学驱虫剂的替代物质.本文在总结了迄今研究成果的基础上,将植物缩合单宁的抗寄生虫机制归纳为营养免疫假说和代谢阻断假说,并详细阐述了影响植物缩合单宁抗寄生虫性的各种因素.     

缩合单宁的生物功能及其在动物生产中的应用

植物提取物缩合单宁是广泛分布于自然界的多酚类聚合物,具有抗氧化、抗炎、抗菌、抗寄生虫、抗病毒等多种生理功效。长期以来,缩合单宁被视为饲料"抗营养因子",近年来发现,低剂量缩合单宁能够促进动物生长,增强机体抗氧化能力和免疫力,调节肠道微生态平衡,提高生产性能。本文综述了缩合单宁的化学结构、提取和纯化方法及其在单胃动物、反刍动物和水产动物养殖中的应用研究进展,以期为缩合单宁的饲料化利用和抗生素替代品的开发提供依据。     

饲料中抗营养因子--单宁的含量分析方法

针对近年来单宁在动物营养上的最新研究成果,本文重点阐述了饲料中缩合单宁、可水解单宁和总酚类化合物的分析方法。旨在为更好地利用含单宁饲料提供参考。     

豆科牧草研究进展

豆科牧草的属间、属内、种间与种内均存在着巨大的遗传变异，利用这种变异，通过育种与选择，已培育出可良好地适应广泛的环境与管理条件的品种，遗传操作为此提供了更为广阔的空间，在豆科牧草固氮方面，对固氮过程、氮向伴生禾草的传送途径及残余氮对后继农作物的价值均有了进一步的理解。对包括施氮、采摘策略和影响混播草地中禾本科－豆科牧草平衡的胁迫等相互作用因素均已给予了阐明。在禾草／白三叶草草地为基础的家畜生产系统中，氮素的损失及其对环境产生的不良作用低于大量施氮的禾草草地系统。与禾草相比，豆科牧草无是用作放牧、青贮或用作干草，其物理、化学和解剖学等方面的特性均可增加家畜的嗜食性和自由采食量。由于豆科牧草的营养价值、可利用营养成分和采食特征，在单一豆科牧草或豆科牧草比重较大的禾草－豆科牧草混播草地上采食的不同种类、不同类型家畜的个体生产性能均优于在禾草草地上采食者。值得注意的是浓缩单宁在动物营养中的有益作用，这类单宁存在于诸如百脉根（Lotus corniculatus）、红豆草（Onobrychis viciifolia）和冠状岩黄芪（Hedys-crum coroharium）等植物中，其防止家畜患膨胀病，通过使较多的氨态氮到达小肠而提高氮的利用，并减轻绵羊肠道中线虫的作用。显然，培育含浓缩单宁的转基因豆科牧草是植物育种者现阶段的主要目标之一。此外，豆科牧草亦有许多其他用途，例如，在葡萄园中用作保护性植被，禾谷类作物的下层植被和为制药业提供次生化合物等。豆科牧草以其植物多态性和花朵的颜色等亦在美化景观和自然保护区中发挥着作用。可以预见，豆科牧草的作用在温带可持续农业中的作用将会增加，充分发掘现有的知识和相关研究成果，及有效的技术将是未来豆科牧草利用的主要特色。     

Effects of tannins in animal nutrition

Tannins are watersoluble plant polyphenols that precipitate proteins. According to their chemical structure they can be divided into condensed tannins and hydrolysable tannins. Altogether, tannins are reported to have various physiological effects like anti-irritant, antisecretolytic, antiphlogistic, antimicrobial and antiparasitic effects. Phytotherapeutically tannin-containing plants are used to treat nonspecific diarrhoea, inflammations of mouth and throat and slightly injured skins. Studies with ruminants have also demonstrated that the denaturing properties of tannins can possibly be used to improve protein supply to the small intestine. Besides anthelmintic effects of condensed tannins have been observed in sheep and goats. On the other hand high tannin concentrations resulted in reduced animal performances and health disorders as well in ruminants as in monogastriers. Further scientific research is therefore needed to clarify whether tannins can be effectivly used in livestock feeding, for example in prophylaxis of diarrhoea or parasitic control.     

CPB-LAR-GFP表达载体的构建及其在紫花苜蓿愈伤组织中的表达

以无色花青素还原酶编码基因LAR为靶序列,构建携带绿色荧光蛋白GFP和抗除草剂bar基因的双标记选择植物表达载体,通过农杆菌介导法对紫花苜蓿进行遗传转化,经PCR检测和PPT筛选出抗性愈伤组织,转基因紫花苜蓿愈伤组织的缩合单宁含量比对照高30.8%。试验证明重组基因已转化至紫花苜蓿愈伤组织中并发挥生理功能,为研究缩合单宁合成与代谢的分子调控机制和培育具有抗除草剂和抗臌胀病的牧草新品种奠定基础。     

Ruminal fermentation and degradation patterns, protozoa population, and urinary purine derivatives excretion in goats and wethers fed diets based on two-stage olive cake: effect of PEG supply

Three experiments were conducted in Granadina goats and Segure?a wethers fed at maintenance level to evaluate the effect of including a mixture of barley and a new by-product derived from olive oil extraction (two-stage dried olive cake) on ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to the animals to evaluate the effects of tannins contained in the by-product. The experimental diets were as follows: alfalfa hay and alfalfa hay plus a concentrate, formulated with two-stage dried olive cake, barley, and a mineral-vitamin mixture either with or without the addition of polyethylene glycol to the drinking water. The inclusion of two-stage dried olive cake in the diet resulted in an increase of condensed tannins. Ruminal VFA concentration in goats and wethers increased (P < 0.05) and ammonia N (NH3-N) concentration decreased (P < 0.05). The inclusion of two-stage dried olive cake decreased (P < 0.001) urinary allantoin excretion only in wethers. Ruminal degradation profiles and fractional passage rates were similar in goats and wethers. The polyethylene glycol supply increased (P < 0.001) DM and N degradation rates in both animal species but did not modify the fractional passage rate. Ruminal fermentation patterns were also similar in goats and wethers and were affected by polyethylene glycol supply. In general, Entodiniomorphida and Holotricha protozoa counts were higher (P < 0.05) in the rumen of goats than of wethers. Protozoa count in wethers responded more to polyethylene glycol supply than in goats. The present work presents the first data obtained from a comparative study with sheep and goats concerning urinary excretion of purine derivatives. The excretion was similar in both animal species when fed alfalfa hay; however, polyethylene glycol affected only urinary allantoin excretion in wethers. Results suggest a greater sensitivity of wethers than of goats to two-stage olive cake condensed tannins.     

红豆草抗寄生虫活性研究进展

红豆草属多年生豆科牧草,适口性好、固氮能力强,营养丰富且富含缩合单宁。红豆草特有的抗寄生虫活性不仅对动植物寄生虫病有较好的防控作用,在提高动物生产性能和预防其他疾病的发生方面也具有明显作用,是现代化农业和畜牧业可持续发展的重要牧草,应用前景广阔。针对红豆草的抗寄生虫活性研究进展进行了综述,旨在为红豆草的研究提供指导。     

The possible role of methionine in the detoxification of faba bean (Vicia faba L.) tannins in chick diets

1. A metabolism trial was designed to investigate the role of methionine as a specific detoxifying agent of the condensed tannins present in faba beans (Vicia faba L.).

2. A 5 x 5 factorial approach was employed where 5 concentrations of dietary methionine were obtained (ranging from 3.9 to 12.15 g/kg diet dry matter) by the addition of DL‐methionine, and 5 concentrations of condensed tannins (ranging from 0.5 to 19.7 g/kg diet dry matter) by altering the ratio of tannin‐free and tannin‐containing faba bean hulls added to a basal diet.

3. The intake of condensed tannins had a significant, depressive effect on apparent available nitrogen (P< 0.001) and nitrogen corrected apparent metabolisable energy (AME_n ) (P< 0.001). There was no interaction between methionine and tannin (P>0.05). Thus the depressive effect of tannin was independent of methionine levels in the diet.

4. Methionine does not act as a specific detoxifier of faba bean condensed tannins.     

饲料中添加缩合单宁对凡纳滨对虾生长性能、体成分、血清生化及抗氧化指标的影响

本试验旨在研究饲料中添加缩合单宁对凡纳滨对虾生长性能、体成分、血清生化及抗氧化指标的影响.选择初体重约为1.38 g的凡纳滨对虾600尾,随机分为5组,每组3个重复,每个重复40尾.5组对虾投喂缩合单宁添加量分别为0(CT0组,作为对照组)、0.5(CT 0.5组)、1.0(CT1组)、2.0(CT2组)、4.0 g/...     

Preference for condensed tannins by sheep in response to challenge infection with Haemonchus contortus

Herbivores prefer feeds that supply required nutrients and avoid those with excess nutrients and plant secondary compounds (PSC). Nevertheless, PSC such as condensed tannins can provide beneficial medicinal effects to herbivores as they act against infective diseases such as parasitism. The objectives of this study were to determine: (1) if parasitized lambs increased preference for a tannin-rich feed after they experienced the beneficial antiparasitic effects of condensed tannins relative to parasitized lambs that did not experience such benefits, and (2) if preference for the tannin-rich feed in the former group decreased when parasite burdens subsided. Twenty two lambs were familiarized with beet pulp and beet pulp+8% quebracho tannins (beet pulp+tannins) and choices were given between the two feeds (initial preference tests). Subsequently, all animals were dosed with 10,000 L(3) stage larvae of Haemonchus contortus. Twenty-two days later, animals were exposed to beet pulp (Control group; n=11) or beet pulp+tannins (Treatment group; n=11) during 24 d. After exposure (during a parasitic infection) animals in both groups were given choices between the two feeds. Lastly, animals in both groups received an antiparasitic drench and were again given a choice between both feeds (after a parasitic infection). Lambs preferred beet pulp to beet pulp+tannins throughout the study (P<0.001) and no difference in preference for the tannin-rich feed was detected between groups during initial preference tests (P>0.05). However, during a parasitic infection, intake of and preference for the tannin-rich feed was higher for lambs that experienced the beneficial effects of condensed tannins while parasitized (Treatment) than for lambs that did not (Control) (P<0.05). When parasitic infections were terminated by chemotherapy, differences between groups disappeared (P>0.05). Preference by the Treatment group for the tannin-rich feed was lower after than during a parasite infection (P<0.05). In contrast, preference by the Control group did not change during these periods (P>0.05). Lambs in the Treatment group displayed lower FEC than lambs in the Control group (Group × Sampling Date; P<0.05). These results show lambs learned about the antiparasitic effects of condensed tannins and increased their preference for the tannin-rich feed, which subsided after chemotherapy, indicating preference was due to parasite infection. These findings suggest management that allows animals to select tannin-rich feeds can enable parasitized animals to self-medicate.     

植物单宁及其对动物的作用研究进展

对植物中单宁含量、单宁对动植物的影响及降低单宁含量的方法进行了综述。植物单宁是广泛存在于植物体内的一类多元酚化舍物,是植物进化过程中由碳水化舍物代谢衍生出来的一种自身保护性物质。一般认为单宁在维管植物中有两种存在形式既水解单宁和缩合单宁。单宁的含量与基因、部位、植物生长阶段、植物病虫害等有关;植物含有高度单宁可保护植物...