尼龙袋法评定鹿常用饲料的营养价值

用３头装有永久性瘤胃瘘管的成年公梅花鹿，采用尼龙袋法，评定了４９种７３个样品鹿常用饲料的干物质有效降解率（ＤＭＤ，下同），蛋白质有效降解率（ＣＰＤ，下同），有机物有效降解率（ＯＭＤ，下同）。结果表明，尼龙袋法能较好地评定梅花鹿饲料的ＤＭＤ、ＣＰＤ、ＯＭＤ和反映饲料品质差异；同类不同种饲料及同种饲料因收获期不同、处理不同、部位不同其ＤＭＤ、ＣＰＤ、ＯＭＤ差异较大；同种不同产地饲料间的ＤＭＤ、ＣＰＤ亦有差别。     

单胃动物与禽类饲料蛋白质营养价值评定手段的局限

依据系统整体营养调控理论，重点讨论了现行单胃动物和禽类饲料蛋白质在营养价值评定手段上，忽视了蛋白质自身能量、蛋白质吸收耗及肽营养三大问题，并与未来蛋白质营养价值的评定进行了展望。     

尼龙袋法评定单胃动物饲料营养价值研究进展

饲料营养价值的准确评价是研究动物营养需要和进行日粮配方的前提和基础。在评定饲料营养价值的方法中,尼龙袋法（Nylon Bag Technique）和动物的消化过程紧密结合,其测定结果同体内试验具有良好的可比性,且重复性好、操作相对简单,便于大批样品的研究,在评定饲料营养价值（特别是蛋白质和氨基酸营养）方面被广泛采用．Orskov和McDonald等还提议建立尼龙袋法的饲料养分标准数据库。     

体外发酵产气技术在饲料营养价值评定中的应用

体外产气技术是反刍动物饲料营养价值评定中常用的方法之一。文章比较了体内法、瘤胃尼龙袋法和体外法在反刍动物营养价值评定中的特点,并着重从体外产气技术的技术细节、测定装置和应用范围进行了全面的论述,为该技术的标准化和自动化提供参考。     

反刍动物饲料营养价值体外评定方法

介绍体外产气法、两步法(短期瘤胃法)、人工瘤胃持续发酵法(长期瘤胃法)、酶解法、溶解度法和近红外反射光谱技术(NIRS)等的基本原理、优缺点和应用情况。     

粗饲料营养价值评定研究进展

粗饲料是反刍动物营养的主要来源。随着反刍动物营养学研究的不断进步,有关粗饲料资源的开发、利用和研究也在不断深入和推进。粗饲料作为反刍动物营养的主体,合理、有效地利用来源丰富的粗饲料资源对于反刍动物的科学饲养有着重要意义。在反刍动物日粮中,粗饲料通常占40%～80%,甚至更高,因此,对粗饲料进行营养价值评定显得尤为重要。粗饲料营养价值评定是了解饲料营养价值的重要环节,是组织动物生产,制定饲养计划,满足动物营养需要的基础。本期我们特别邀请了东北农业大学的张永根教授对国内外关于粗饲料营养价值评定的研究进展进行了较全面的论述,在评价饲料营养价值的基础上合理利用饲料资源,希望能对业内相关工作者起到参考和借鉴的作用。     

反刍动物饲料营养价值体外评定方法进展

此文论述了评价反刍动物饲料营养价值的几种主要体外方法,包括体外产气法、两步法（短期瘤胃法）、人工瘤胃持续发酵法（长期瘤胃法）、酶解法、溶解度法以及近红外反射光谱技术（NIRS）等。主要介绍了这几种方法的基本原理、优缺点、发展及应用情况。     

中国反刍动物饲料营养价值评定研究进展

本文在查阅357篇相关度比较高的公开发表论文和学位论文的基础上,从中筛选出有代表性的、测定信息较为完整的饲料营养价值评定文献67篇。归纳和总结了中国近年来在反刍动物饲料常规养分、瘤胃有效降解率、小肠消化率等指标评定上具有代表性的成果。此外,本文还提出了目前反刍动物饲料营养价值评定中存在的问题和针对这些问题的一些建议,为该领域的广大科研工作者和生产者提供参考。     

反刍动物饲料营养价值评定及模型应用

反刍动物饲料营养价值评定包括饲料营养成分评定和饲料营养物质可利用性评定两个方面,其中,评定反刍动物饲料营养物质可利用性的方法主要有体内法、半体内法和体外法,因各自的特点分别应用于不同的研究领域.反刍动物饲料营养价值评定模型的应用,又使这些评定方法得到进一步深入和扩展.文章综述了反刍动物饲料营养价值评定的主要方法以及几种营养价值评定模型的应用研究进展.     

反刍动物饲料营养价值的评定

反刍动物饲料包括各种粗饲料及精饲料,为了满足反刍动物的营养需要,必须对饲料营养价值进行评定.饲料的营养价值评定包括饲料营养成分评定和饲料营养物质的可利用性评定两个方面,一方面需要测定饲料的营养物质含量,另一方面需要了解这些营养物质在畜体内的代谢转化过程及产生的结果,这样可较全面深入和完善地评定饲料的营养价值.本文就反刍动物饲料营养价值常用的评定方法进行了分析和比较,为开展进一步研究提供了参考.     

The evaluation of the mobile nylon bag technique for determining the apparent protein digestibility in a wide variety of feedstuffs for pigs

Studies were conducted with four (50 to 70 kg) barrows to evaluate the mobile nylon bag technique (MNBT) for determining the apparent protein digestibility (AD) in a variety of feedstuffs. One-gram samples of each feedstuff, ground through a 1.0-mm mesh screen, were enclosed in nylon bags (25 X 40 mm; 48 microns mesh). Following predigestion (.01 N HCl; 4,000 Folin Intestinal Pepsin Units/liter), four bags of each sample were inserted into each pig via a duodenal T-cannula. The indigested contents were pooled within pig and feedstuff prior to crude protein analysis. The AD of each feedstuff was determined previously with four barrows according to the conventional method (CM), based on a 5-d total collection of feces following a 14-d adaptation period. The following results, AD (%), were obtained with the MNBT (n = 4) and CM (n = 4), respectively. Barley, 70.1 vs 81.2 (P less than .05); corn, 72.3 vs 82.1 (P less than .05); wheat, 79.6 vs 86.4 (P less than .05); corn gluten feed, 73.9 vs 70.9; rice bran, 57.3 vs 57.4; wheat middlings, 70.8 vs 79.4 (P less than .05); soybean meal, 89.9 vs 93.0; a mixture of soybean meal and hulls, 86.9 vs 88.8; coconut expeller, 65.0 vs 69.8; fababeans, 79.5 vs 78.5; peas, 87.6 vs 88.1; meat meal, 83.2 vs 84.0; complete diet (4.3% crude fiber), 76.3 vs 83.6 (P less than .05); and complete diet (13.6% crude fiber), 56.5 vs 55.0.(ABSTRACT TRUNCATED AT 250 WORDS)     

瘤胃尼龙袋法测定10种饲料过瘤胃淀粉量和淀粉瘤胃降解率

以3头安装有永久性瘤胃瘘管的利木赞×鲁西黄牛杂交阉牛为试验动物,采用尼龙袋法对大麦、麸皮、玉米、玉米DDGS、苹果粕、大豆皮、豆粕、苜蓿干草、青贮饲料、羊草等10种饲料原料中淀粉的瘤胃降解率和过瘸胃淀粉含量进行测定.结果表明,10种饲料的过瘤胃淀粉量依次为60.37、17.98、216.23、9.23、14.18、6.13、18.22、8.11、3.78 g/kg和2.77 g/kg;其淀粉瘤胃降解率依次为90.57%、92.32%、64.37%、78.95%、84.18%、86.30%、70.93%、66.43%、72.19%和65.08%.总之,大麦等能量饲料的过瘤胃淀粉含量较高,苜蓿等粗饲料的过瘤胃淀粉含量较低,副产品饲料和蛋白质饲料过瘤胃淀粉含量居中.     

ORIGINAL ARTICLE: Ruminal and total tract phosphorus release from feedstuffs in cattle measured using the mobile nylon bag technique

Phosphorus (P) excretion in manure is a concern for dairy and beef producers. Excess P released into surface water runoff can lead to eutrophication and algal blooms in streams and lakes. One approach to reducing P excretion is to reduce dietary P. Data regarding P release from feedstuffs is limited and more precise formulations based on specific feed P release in the digestive tract may be one way to lower excreted P. In this experiment, the mobile nylon bag technique was used to determine the disappearance of P in corn silage, alfalfa hay, Coastal bermudagrass hay, and Tifton‐85 bermudagrass hay in steers after ruminal (24 h), ruminal + pepsin/HCl (rumen + PHCl), and ruminal + pepsin/HCl + intestinal (rumen + PHCl + I) incubation. Ruminal disappearance of P differed (p < 0.05) between feedstuffs and by site of incubation. Total tract (rumen + PHCl + I) P disappearance for corn silage, alfalfa hay, Coastal bermudagrass hay, and Tifton‐85 bermudagrass hay were 90.6%, 93.7%, 83.8% and 84.0% respectively. The range in P release (approximately 7%) indicates that considering P availability when balancing rations could have a measurable impact on subsequent P excretion from ruminants. More data concerning P availability as affected by other feed ingredients or plant species, maturity, and/or quality are needed to more accurately define P release from ruminant feeds.     

生物技术在改善纤维饲料营养价值中的应用

在世界各地存在着大量可用作饲料的植物和作物残渣,但都具有共同的营养特点:蛋白质、可溶性碳水化合物、矿物质和胡萝卜素含量低,而粗纤维含量高。纤维饲料中的粗纤维包括纤维素、半纤维素和木质素,其中纤维素和半纤维素能够被草食动物的瘤胃微生物充分降解利用,但由于木质素和纤维素之间镶嵌在一起形成坚固的酯键,阻碍了瘤胃微生物及单胃动物对纤维素的降解,导致纤维性饲料消化率低,最终影响了动物的生产性能。如何提高纤维饲料的利用率已成为众多科学家的研究热点。有关纤维饲料的处理方法有多种,包括物理、化学和生物方法。近几年随着生…     

Determination of undegradable intake protein digestibility of forages using the mobile nylon bag technique

Two experiments were conducted using 2 ruminally and duodenally fistulated steers to determine the digestibility of undegradable intake protein (UIP) of smooth bromegrass (Bromis inermis), birdsfoot trefoil (Lotus coniculatus L.), and heat-treated alfalfa (Medicago sativa) using the mobile nylon bag technique. Undegradable intake protein was determined using neutral detergent insoluble CP at a single in situ incubation time point based on 75% of the total mean retention time estimated from IVDMD plus a 10-h passage lag. In Exp. 1, UIP (% DM) of smooth bromegrass in June and July were 1.82 and 1.71, respectively (P = 0.11). Undegradable intake protein (% DM) of birdsfoot trefoil increased from 1.30 in June to 1.94 in July (P < 0.01). Total tract indigestible protein of smooth brome-grass and birdsfoot trefoil increased in July (P < 0.05). Digestibility of UIP decreased in July for smooth brome-grass (P < 0.01) but tended to increase for birdsfoot trefoil (P = 0.07). In Exp. 2, alfalfa from plots fertilized with low (66 kg of N/ha) or high (200 kg of N/ha) amounts of N were dried to simulate 3 preservation methods: dehydrated (100 degrees C, 10 h), sun-cured (50 degrees C, 15 h), and lyophilized (-50 degrees C, 72 h) alfalfa. Undegradable intake protein (% DM) was estimated as in Exp. 1 and was 3.13, 2.10, and 1.84 for dehydrated, sun-cured, and lyophilized alfalfa, respectively. Total tract indigestible protein (% DM) was increased (P < 0.05) for dehydrated alfalfa (1.66) compared with sun-cured (1.54) or lyophilized (1.57) alfalfa. As a result of greater UIP flow to the lower tract, digestibility (%) of UIP was greater (P < 0.01) for dehydrated (46.4) than for sun-cured (25.6) or lyophilized (14.7) alfalfa. Heat-treated alfalfa samples increased net UIP absorption in the lower tract because 1.47, 0.56, and 0.27 percentage units of UIP (% DM) of dehydrated, sun-cured, and lyophilized alfalfa, respectively, disappeared. Overall, the digestibility of the UIP of these forages was low in the lower tract.     

体外产气法与尼龙袋法评定粗饲料干物质降解率的相关性分析

为寻求可在实验室条件下简单地评定饲料降解性能的方法,试验以玉米秸秆及不同尿素、石灰比例复合处理的玉米秸秆为发酵底物,对饲料体外产气量和尼龙袋瘤胃干物质降解率作了相关性分析。统计分析表明,体外产气量与体内干物质降解率呈高度正相关,相关系数分别为:对照组0.967、料A0.964、料B0.999和料C0.994。结果证明,在对饲料降解性能及潜在可降解能力作快速、定性判断时,体外产气法可以代替尼龙袋法。     

Evaluation of mobile nylon bag technique for determining apparent ileal digestibilities of protein and amino acids in growing pigs

The mobile nylon bag technique (MNBT) may offer a simple, rapid means for assessing ileal AA digestibility of pig feed ingredients. In the present study, the effects of washing bags recovered from digesta, the amount and fineness of feeds, and feed trypsin inhibitor activity on apparent ileal digestibilities (AID) of CP and AA were determined with the MNBT. Twenty-four ileorectal anastomosed pigs (Yorkshire x Chinese Black barrows, 30 kg initial BW), of which 12 were fitted with duodenal T-cannulas, were used. Not washing the bags recovered from ileal digesta resulted in a reduction (P < 0.05) in apparent ileal digestibilities of CP and AA determined by MNBT. Washing the bags for more than 4 min overestimated (P < 0.05) the apparent ileal digestibilities of CP and AA compared with those determined with the anastomosed pigs. Sample size and fineness of grinding also affected (P < 0.05) apparent ileal digestibilities of CP determined by MNBT. The apparent ileal digestibilities of CP determined by MNBT were reduced (P < 0.05) when sample size exceeded 0.75 g and when feed was ground through screens with a mesh size of more than 1.0 mm. The closest agreement between results obtained by MNBT and a conventional ileal digestibility assay occurred when 0.75 g of feed ground through a 1.0-mm mesh screen was used per bag and bags were washed for 2 min after retrieval from digesta. Further studies are warranted to investigate the use of the mobile nylon bag technique for predicting the ileal digestibilty of AA for feeds containing antinutritional factors.     

Determination of the digestibility of lignocellulose material using the bag (nylon bag) method

A trial was performed on wethers to study the digestibility of various lignocellulose materials (LCM) by the nylon bag method. The animals were fed good meadow hay ad lib. with unlimited access to water and mineral lick. The trial showed that LCM digestibility was not influenced by different weights of substrate sample. However, digestibility increased with the time for which the LCM were left to ferment in rumen. Almost 90% or more dry matter of the different substrates (pure sulphate cellulose, barley straw and treated beech sawdust) was digested within 48-hour fermentation in rumen. The situation is similar when the substrates are left to ferment in vitro for 96 hours. The high correlation coefficients calculated from the digestibility values of the substrates in vitro and in vivo testify to this fact. The only exception is untreated beech sawdust in which no such a high correlation was found, mainly owing to its low digestibility. However, this should be verified in other kinds of untreated wood (aspen, maple, ash), but with a higher digestibility. It should be stated that silk with a 50 mu mesh is the best material for the production of the bags.