单宁对反刍动物养分利用的营养机制

植物饲料中适量的单宁含量对反刍动物养分利用有其积极作用.本文从分析单宁的理化性质入手,详细综述了植物饲料中单宁的营养作用机制、抗营养作用、去除措施以及研究展望,以期为有效利用含单宁的植物饲料提供理论参考.     

单宁对反刍动物的营养作用

单宁是一类广泛分布于植物中的多酚类聚合物,是一类重要的抗营养因子。近年来,研究表明饲料中含有适量的单宁对反刍动物有一定的营养作用。本文旨在对单宁的抗营养作用、营养机制以及研究进展就行阐述,为动物生产中有效利用单宁提供理论参考。关键词单宁;反刍动物;抗营养作用;营养机制。     

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。     

单宁对反刍动物的抗营养作用机理及其消除措施

本文从分析植物单宁的理化性质入手,综述了植物饲料中单宁的抗营养作用机制及去除措施。     

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。     

植物单宁调控乳酸菌特性的研究进展及其在生产中的应用

单宁是植物的一种次级代谢产物,能够结合蛋白质形成复合物,在微生物发酵中有特殊生理作用。目前国内外学者对单宁结构、生物学特性和抑菌作用进行了深入研究。本文系统阐述了植物单宁对乳酸菌生长特性的调控作用,包括植物单宁抑菌性、不同种类乳酸菌对植物单宁适应性和代谢途径等,并对单宁在反刍动物营养与饲草加工利用中的应用进行了展望。     

抑制植物性饲料中抗营养因子的方法

植物性饲料是配合饲料最为广泛的原料之一 ,但都存在抗营养因子 ,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。本文就加工工艺中的几种常见调制方法对植物中抗营养因子的…     

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。     

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。     

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...     

Patterns of selection of Acacia karroo by goats and changes in tannin levels and in vitro digestibility following defoliation

Patterns of browse selection by Boer goats in a representative Acacia karroo community in the eastern Cape were studied. The rate of intake of browse was positively related to the leaf mass per unit length of the shoot. The ease of harvesting leaf material, as determined by the height off the ground, modified the rate of intake. Generally, following browsing, tannin levels increased significantly and in vitro digestibility decreased significantly. These changes in tannin content and digestibility differed in magnitude according to the plant size and age of the shoot and leaf. Generally, the leaf and shoot intake was negatively related to tannin content and positively related to digestibility, thus influencing patterns of selection for different plant parts and size classes of A. karroo. However, some of the results are contradictory.     

Comparative aspects of plant tannins on digestive physiology,nutrition and microbial community changes in sheep and goats: A review

Comparative aspects of plant tannins on digestive physiology, nutrition and microbial community in sheep and goats are discussed in the context of differences due to feed intake, digestibility, utilization of nutrients and microbial community. The purpose of this review was to present an overview of the potential benefits of tannin‐containing diets for sheep and goats and specie differences in their response to tannins. It is well established that moderate level of tannins in the diet (3%–4% tannins DM) can precipitate with soluble proteins and increase protein supply to the sheep, but comparative aspects of tannin‐containing diets in sheep and goats on animal performance, digestive physiology, rumen microbial changes and potential benefits to sustainable animal production by those compounds have received little attention. In addition, developing plant‐based tannin‐containing diets for control of rumen microbiota and rumen fermentation (e.g., methane gas) would be expected to have a greater impact on the ruminant health, productivity and emission of greenhouse gasses. The positive impacts of the plant tannin compounds mainly depend on their influence on the gut microbiome diversity and ability to generate fermentation end products (short‐chain fatty acids) that have diverse biological roles. Diets which contain optimal levels of tannins have potential benefits for sustainability of small ruminant production systems. However, there is a need for an improved understanding of the utilization of tannin‐containing forages to improve their management. This implies investigations of animal responses to tannin‐containing forages or browse species and, in particular, a better understanding of the interactions that can arise between sheep and goats on digestion, DMD, rumen fermentation and microbial community changes. This knowledge could help to improve current feeding systems in terms of efficiency of feed use and environmental impacts (reduce methane gas production) and thus contribute to the development of a sustainable sheep and goat production.     

Influence of macronutrients and polyethylene glycol on intake of a quebracho tannin diet by sheep and goats

We determined if supplemental macronutrients or polyethylene glycol (PEG) influenced intake of a tannin diet. Sheep (lambs 5 mo age, 36 kg) and goats (kids 7 mo age, 32 kg) were fed supplements high in either energy or protein or offered a choice between the two supplements before and after receiving a meal containing 15% quebracho tannin. The effect of PEG, a compound that attenuates the negative effects of tannins, was assessed by offering PEG while animals consumed the tannin diet for 4 h/d. Intake of the tannin diet was influenced by both macronutrients and PEG. Animals that chose their own supplements or that received the high-protein supplement, consumed more of the tannin diet than animals fed the high-energy supplement: 34 and 36 vs 31 g/kg(0.75) (lambs) and 41 and 39 vs 34 g/kg(0.75) (kids), respectively (P < 0.05). Animals supplemented with PEG ate much more of the tannin diet than unsupplemented animals: 70 vs 39 g/kg(0.75) (lambs) and 63 vs 34 g/kg(0.75) (kids), respectively (P < 0.001). Sheep and goats consumed more tannin food when given PEG than when supplemented with macronutrients (51 and 38 g/kg(0.75), P < 0.001). Sheep and goats offered a choice between supplements consumed more CP than animals fed the high-energy supplement and more ME than animals fed the high-protein supplement (P < 0.05). In so doing, they selected a combination of foods that yielded a more balanced intake of macronutrients, while achieving high levels of intake of the tannin food. Sheep and goats can be used as an environmentally safe and economically sound means to reduce the abundance of tannin-rich vegetation. Macronutrients and PEG enhance use of tannin-containing plants, which may increase production of alternate forages and create a more diverse mix of species in a plant community.     

Effect of condensed tannin ingestion in sheep and goat parotid saliva proteome

Saliva appears as a defence mechanism, against potential negative effects of tannins, in some species of animals which have to deal with these plant secondary metabolites in their regular diets. This study was carried out to investigate changes in parotid saliva protein profiles of sheep (Ovis aries) and goats (Capra hircus), induced by condensed tannin ingestion. Five Merino sheep and five Serpentina goats were maintained on a quebracho tannin enriched diet for 10 days. Saliva was collected through catheters inserted on parotid ducts and salivary proteins were separated by two-dimensional gel electrophoresis. Matrix-assisted Laser desorption ionization - time of flight (MALDI-TOF) and liquid chromatography tandem mass spectrometry (LC-MS/MS) were used to identify the proteins whose expression levels changed after tannin consumption. Although no new proteins appeared, quebracho tannin consumption increased saliva total protein concentration and produced changes in the proteome of both species. While some proteins were similarly altered in both species parotid salivary protein profile, sheep and goats also presented species-specific differences in response to tannin consumption.     

谷精草有效成分分析及体外抗菌活性测定

采用试管法和圆形滤纸层析法分析鉴定了谷精草的化学成分,结果表明:谷精草含有生物碱、酚性成分、有机酸、黄酮及其甙类、挥发油、植物甾醇、鞣质等化学成分。用纸片法和试管法对谷精草水提取液进行了体外抗菌作用试验,结果表明:谷精草水提取液对金色葡萄球菌、链球菌、巴氏杆菌、沙门氏菌、大肠杆菌等兽医临床常见病原微生物都有较强的抗菌作用,抑菌圈直径分别为12.16±0.33mm,15.36±0.29mm,13.57±0.61mm,8.63±0.26mm,9.88±0.72mm;谷精草水提取液对金色葡萄球菌、链球菌、巴氏杆菌、沙门氏菌、大肠杆菌的最低抑菌浓度(MIC)分别为0.125g/ml、0.063g/ml、0.125g/ml、0.5g/ml、0.25g/m;最低杀菌浓度(MBC)分别为0.25g/ml、0.125g/ml、0.25g/ml、1g/ml、1g/ml。     

Use of condensed tannin extract from quebracho trees to reduce methane emissions from cattle

Our objective was to determine if condensed tannin extract from quebracho trees (Schinopsis quebracho-colorado; red quebracho) could be used to reduce enteric methane emissions from cattle. The experiment was designed as a repeated 3 x 3 Latin square (4 squares) with 3 treatments (0, 1, and 2% of dietary DM as quebracho tannin extract) and 3 28-d periods. Six spayed Angus heifers (238 +/- 13.3 kg of initial BW) and 6 Angus steers (207 +/- 8.2 kg of initial BW) were each assigned to 2 squares. The measured condensed tannin content of the extract was 91%, and the basal diet contained 70% forage (DM basis). Feeding quebracho tannin extract had no effect on BW, ADG, or nutrient intakes. Furthermore, it had no effect on DM, energy, or fiber (ADF and NDF) digestibility, but apparent digestibility of CP decreased linearly (P < 0.001) by 5 and 15% with 1 and 2% quebracho tannin extract, respectively. There were no effects of quebracho tannin extract on methane emissions (g/d, g/kg of DM, % of GE intake, or % of DE intake). Feeding up to 2% of the dietary DM as quebracho tannin extract failed to reduce enteric methane emissions from growing cattle, although the protein-binding effect of the quebracho tannin extract was evident.     

Self-regulation of intake of polyethylene glycol by sheep fed diets varying in tannin concentrations

Tannins occur in many plant species, and they often suppress intake by reducing nutrient availability or by causing malaise. Polyethylene glycol (PEG) binds to tannins and may thereby increase the availability of macronutrients and decrease malaise. Supplemental PEG increases intake of tannin-containing plants by sheep, goats, and cattle. Given the strong response to supplemental PEG, we speculated that animals might self-regulate their intake of PEG when offered foods high in tannins. The objective of the first experiment was to determine if the amount of supplemental PEG (0, 25, 50, 75, or 100 g; molecular weight, 3,350) affected intake by lambs of a food (milo-tannin mix) containing 20% quebracho tannin. There was a linear relationship (Y = 272 + 1.2X; R2 = .86; P = .023) between the amount of supplemental PEG ingested and the subsequent intake of milo-tannin food by lambs. The objective of the second experiment was to determine whether lambs self-regulated intake of PEG when fed a ration that contained 0, 5, 10, 15, or 20% quebracho tannin and whether they adjusted their intake of PEG when tannin was removed from the diet. There was a positive relationship between the amount of PEG ingested and intake of food and tannin (P = .0001). Lambs fed high-tannin diets ate more PEG than controls (P = .03). Lambs fed the 20% tannin diet ate the most PEG, and controls ate the least PEG. Tannin limited intake of the diets, but PEG attenuated the response to a great degree (P = .065). Immediately after tannin was removed from the ration, lambs that formerly had been fed the 20% tannin ration ate more PEG than lambs fed the other rations (P = .0075). Ten of the lambs (5 from the 20% tannin group, 1 from the 15% tannin, and 2 each from the 10 and 5% groups) continued to eat PEG for 7 d after tannin was removed from their ration. When they were tested again 6 wk after the trial and offered tannin-free diets, their intake of PEG had decreased.