瘤胃投饲不同形式蛋氨酸对肉牛营养物质消化率和血液指标的影响

选择安装瘤胃、十二指肠前端和回肠末端瘘管的肉牛4头,采用4×4拉丁方设计,研究瘤胃投饲不同形式蛋氨酸对肉牛营养物质消化率和血液指标的影响,瘤胃投饲蛋氨酸添加剂分别为0(Ⅰ组)、DL Met(Ⅱ组)、动物油包被Met(Ⅲ组)和吸附MHA(Ⅳ组)。试验结果表明,Ⅲ组日增重、可消化氮、沉积氮、沉积氮/可消化氮分别比Ⅰ组提高12 18%(P<0 05)、5 90%(P<0 05)、126 1%(P<0 05)和113 7%(P<0 05);Ⅲ组尿中尿素氮显著低于Ⅰ组(P<0 05)。Ⅲ组氮和NDF在小肠的表观消化率分别比Ⅰ组提高10 8%(P<0 05)和30 06%(P<0 05)。Ⅲ组血浆尿素氮显著低于Ⅰ组(P<0 05)。Ⅲ组和Ⅳ组血浆TAA、EAA、BCAA、Ser和Met均显著低于Ⅰ组(P<0 05);Ⅱ组、Ⅲ组和Ⅳ组血浆Asp显著低于Ⅰ组(P<0 05)。本试验条件下最佳保护蛋氨酸为动物油包被蛋氨酸。     

瘤胃投饲不同形式蛋氨酸对肉牛微生物氨基酸的影响

选择安装瘤胃、十二指肠前端和回肠末端瘘管的肉牛4头,采用4×4拉丁方设计,研究瘤胃投饲不同形式蛋氨酸对肉牛微生物氨基酸的影响,投饲蛋氨酸添加剂分别为0( 组)、DL-Met( 组)、动物油包被Met( 组)和吸附MHA( 组)。试验结果表明, 组不仅显著提高瘤胃液中微生物(LAM)中Phe和Met的含量(P<0.05),降低Asp含量(P<0.05),而且显著提高瘤胃食糜中微生物(SAM)Leu和Ile的含量(P<0.05); 组显著提高LAM中Phe和Met的含量(P<0.05),降低SAM中Ile的含量(P<0.05)。 组和 组显著提高十二指肠微生物Ile、Leu、Phe和Met的流通量(P<0.05)。     

瘤胃保护性蛋氨酸稳定性的研究

采用不同比例的动物油包被蛋氨酸制成瘤胃保护性蛋氨酸I(RPMetⅠ)、瘤胃保护性蛋氨酸Ⅱ(RPMetⅡ)和瘤胃保护性蛋氨酸III(RPMetⅢ)。通过人工唾液消化试验、体内尼龙袋试验和人工真胃液消化试验,检验DL蛋氨酸(DLMet)、商品过瘤胃蛋氨酸(BypassMet)和瘤胃保护性蛋氨酸(RPMetⅠ、RPMetⅡ和RPMetⅢ)的稳定性。试验结果表明,三种动物油包被蛋氨酸的稳定性均好于商品过瘤胃蛋氨酸和DL-蛋氨酸;不同比例的动物油包被对瘤胃保护性蛋氨酸稳定性的影响差异显著(P<0.05)。     

过瘤胃保护蛋氨酸稳定性及其评定方法的研究

本研究应用双外流连续培养系统和瘤胃尼龙袋法检验动物油包被蛋氨酸在瘤胃中的稳定性。根据动物油添加比例不同(分别添加20%、30%和40%),保护性蛋氨酸分为过瘤胃保护蛋氨酸I(RPMet-I)、过瘤胃保护蛋氨酸II(RPMet-II)和过瘤胃保护蛋氨酸III(RPMet-III)。试验结果表明:与未包被蛋氨酸相比,动物油包被蛋氨酸在瘤胃中的释放率显著降低(P<0.05);动物油添加比例不同对于过瘤胃保护蛋氨酸的稳定性影响显著(P<0.05)。不同形式保护性蛋氨酸在双外流连续培养系统中的降解趋势与在瘤胃中的降解趋势相似,且应用双外流连续培养系统测定各个时间点保护性蛋氨酸的释放率简单、稳定,与瘤胃尼龙袋法相比各个时间点的释放率均存在强相关回归关系(n=5,P<0.01),因此该系统适宜于评定保护性氨基酸的稳定性。     

瘤胃投饲不同形式蛋氨酸对肉牛小肠氨基酸流量和消化率的影响

选择安装瘤胃、十二指肠前端和回肠末端瘘管的健康肉牛4头,采用4×4拉丁方设计,研究瘤胃投饲不同形式蛋氨酸对肉牛小肠氨基酸消化率的影响。投饲蛋氨酸添加剂分别为0(Ⅰ组)、DL-Met(Ⅱ组)、动物油包被Met(Ⅲ组)和吸附MHA(Ⅳ组)。结果表明:试牛总氨基酸在小肠的表观消化率平均为69.88%±0.83%,其中必需氨基酸(EAA)为74.61%±1.23%,非必需氨基酸(NEAA)为64.25%±0.51%。Lys和His在小肠的表观消化率最高,分别为80.14%±1.11%和80.15%±1.23%,Gly和Pro在小肠的表观消化率最低,分别为53.52%±0.30%和55.53%±2.03%。Ⅲ组ThrI、le、Tyr、Phe、Pro、Cys在小肠的表观消化率显著高于Ⅰ组(P<0.05),而Ala则相反。Ⅳ组ThrI、le、Phe、Cys在小肠的表观消化率显著高于Ⅰ组(P<0.05)。与Ⅰ组相比,Ⅱ组只显著增加了Phe在小肠的表观消化率(P<0.05)。     

商品蛋氨酸在家禽上的应用

8对科学研究得出的生物利用率数值应在实际情况下提出质疑 从科学试验得出的液体MHA—FA的生物利用率数值，在实际现场条件下可以很容易地采用一个简单方法对其提出质疑：将DL—met和液体MHA—FA分别添加到同一未补充饲料的两个批次中，DL—met的剂量为液体MHA—FA的65％。     

过瘤胃养分包被壁材人工唾液、瘤胃稳定性及小肠释放性能的研究

为探讨不同包被壁材在瘤胃中的稳定性及小肠释放性能,试验选用4只装有永久性瘤胃瘘管及十二指肠前端瘘管的健康崂山奶山羊去势公羊,分别测定中性羧甲基纤维素钠、单硬脂酸甘油酯、乙基纤维素、海藻酸钠、酸性羧甲基纤维素钠、乙酸纤维素、脂肪粉、聚乙二醇和血粉等9种包被壁材的人工唾液12 h消失率、瘤胃48 h降解率及小肠消失率。结果表明:脂肪粉不仅人工唾液及瘤胃降解率低,而且小肠消失率高,是最为理想的过瘤胃养分包被壁材;单硬脂酸甘油脂和血粉在人工唾液及瘤胃稳定性略差,用作包被壁材时应适当加大包被比例或增加包衣厚度;乙基纤维素和乙酸纤维素瘤胃降解率和小肠消失率均较低,包被时应注意包衣厚度,防止由于包被过度而影响养分释放与吸收。     

瘤胃保护性蛋氨酸稳定性检验研究

根据氨基酸过瘤胃保护原理 ,将硬脂酸 (C1 8)、膨润土和蛋氨酸按一定比例制成包被蛋氨酸 ,通过体外法和半体内法检验该包被蛋氨酸在瘤胃中的稳定性以及在小肠中的消化率。试验结果表明 ,包被蛋氨酸在人工唾液、瘤胃液及真胃液中的溶解度分别为10 .2 1%、12 .2 1%和 18.68%。经人工唾液、瘤胃尼龙袋、真胃液和两级离体消化试验 ,结果表明 ,包被蛋氨酸样品在人工唾液和瘤胃液中较为稳定 ,蛋氨酸的释放率分别为 14 .73%和 2 2 .0 5 % ;在真胃液中也具有较好的可消化性 ,蛋氨酸的释放率为 90 .10 % ,两级离体消化试验中蛋氨酸释放率为 91.5 2 %。瘤胃尼龙袋法和真胃液体外法计算结果显示 ,样品中的蛋氨酸在试羊整个消化道内释放率为 89.0 3%。     

蛋氨酸羟基类似物的生产工艺及其在动物营养中的应用

蛋氨酸羟基类似物(MHA)作为蛋氨酸(Met)替代物被广泛应用于饲料添加剂中.MHA因其特殊的结构性质,不仅具备Met的营养功能,而且可以发挥Met不具备的酸化剂、抗生素等功能.随着我国畜牧和饲料添加剂行业的发展,MHA合成方法的研究及应用必将得到进一步的关注,因此,本文概述了MHA的生产工艺及其在动物营养中的应用.     

过瘤胃蛋氨酸添加剂的研究

本研究选用动物油和氢化棕榈油包理处理蛋氨酸，制成颗粒状过瘤胃蛋氨酸添加剂。通过人工唾液消化试验、体内尼龙袋试验、人工真胃液消化试验及真胃液体外消化试验，检验其稳定性；通过真胃瘘管试验测定了真胃液AA含量。并选用12只育成期内蒙古细毛羊，进行了消化代谢试验。试验结果表明，过瘤胃蛋氨酸添加剂，在人工唾液和瘤胃内较稳定，而在人工真胃液和真胃液中具有易溶解和消化的特点。其中动物油包被蛋氨酸效果最佳，营养物质消化率、N沉积率（P<0.01）、真胃液蛋氨酸和总氨基酸水平均明显高于其他处理。     

奶牛和肉牛日粮淀粉和葡萄糖的营养调控及其评定的建议

谷物饲料干物质中的淀粉含量多在50%以上,全株玉米青贮的淀粉含量亦有30%。牛的玉米日粮生淀粉消化率比熟淀粉低,但熟淀粉由于瘤胃消化率很高,所以瘤胃后的可消化淀粉量很低。生糖前体能量(瘤胃丙酸 肠可消化淀粉)能明显提高产奶量和乳蛋白率,但导致乳脂率下降。须对生糖前体能量进行评定和调节,以提高产奶效率。对真胃灌注不同梯度的葡萄糖或淀粉均显着地提高了Kf和体脂肪及体蛋白质沉织,因此我国肉牛饲养标准提出的Kf(%)=11.7645 55.756(IDOM/FNDF)仍适用,但可进一步增加IDOM中的淀粉调控。     

宏基因组测序分析野生林麝瘤胃、小肠和大肠微生物组成和抗生素抗性基因

本试验旨在研究野生林麝(Moschus berezovskii)瘤胃、小肠和大肠微生物组成和抗生素抗性基因.采集野生林麝消化道3个区段(瘤胃、小肠和大肠)的内容物进行宏基因组测序,并进行常规物种注释和抗生素抗性基因功能注释.结果表明:3个区段共有优势菌门为厚壁菌门(Firmicutes)和变形菌门(Proteobact...     

0~56日龄陕北白绒山羊解剖特点及胃肠道参数变化规律探究

试验旨在研究0~56日龄羔羊胃肠道全重、相对净重、容积、长度等参数的变化规律。试验选用24只陕北白绒山羊,按照完全随机试验设计分为8组,每组3只,分别在0、3、7、14、21、28、42、56日龄屠宰、取样,测定各阶段羔羊体况发育情况及胃肠道全重、相对净重、容积及长度等参数。结果显示,除了皱胃外,各胃室相对净重均快速增长,7日龄后增速较高,在56日龄时,瘤胃相对净重从0日龄的29.34%提升到52.53%,网胃从11.83%到14.77%,瓣胃从6.54%上升到9.34%,而皱胃相对净重从52.29%下降到23.36%;小肠各部位净重均保持增长,十二指肠相对净重在0~56日龄整个阶段均保持在3.5%左右,而空肠均保持在90%左右,回肠相对净重在14日龄之前保持在1%左右,在14日龄之后保持在5%左右;大肠的各部位全重迅速增大,盲肠从0日龄的5.29 g增长到56日龄的43.31 g,结肠从11.67 g增长到200.45 g,直肠从3.03 g增长到53.02 g,前期增长缓慢,从28日龄开始,大肠各部位全重迅速增重。综上所述,28日龄是羔羊全面发育的一个界点,28日龄后,其消化道参数快速增长,特别是具有纤维物质消化能力的瘤胃、回肠、盲肠、结肠等部位,结合各方面因素可以预测,28日龄断奶具有可行性。     

不同粗精比日粮对绵羊小肠中瘤胃微生物蛋白质利用的影响

用4只装有瘤胃瘘管、十二肠瘘管和回肠瘘管的去势(公母各半)萨福克羊体重平均为(45.5±5.2)kg,在不同粗精比日粮条件下 ,研究瘤胃细菌、纤毛虫体蛋白质在小肠内的利用率。结果表明 :到达十二指肠的瘤胃细菌和纤毛虫的量 ,随日粮中精饲料水平的提高而显著减少(P<0.05)。与此相反 ,过瘤胃饲料蛋白质的量则显著增加(P<0.05)。小肠内的细菌利用率显著受日粮变化的影响 ,而纤毛虫利用率则不易受日粮影响且显著地高于细菌的利用率(P<0.05)。小肠内被吸收的细菌和纤毛虫对微生物氮的贡献率在全试验组中平均为50 %。     

Propionic acid disappearance from the foregut and small intestine of the beef steer

Studies were conducted to determine the disappearance of propionic acid from the rumen and across the small intestine. Four crossbred beef steers, fitted with ruminal, duodenal and ileal cannulas, were given pulsed-continuous infusions of a nonabsorbable liquid phase marker (CrEDTA) and buffered propionic acid to achieve ruminal propionate productions (RPP) of 142 (basal), 567 and 997 mmol/h. Liquid flows from the rumen, and at the duodenum and ileum (2.75, 3.57 and .92 liters/h, respectively) were not affected by RPP (P greater than .23), although significant differences existed between sites (P = .001), reflecting a net addition of liquid between the rumen and duodenum and a net removal of liquid within the small intestine. Propionate disappearance from the rumen was 40 to 57% irrespective of RPP, with the complement passing from the rumen. Of the propionate that exited the rumen, 93 to 97% disappeared prior to entering the duodenum. Overall removal of RPP prior to the duodenum was 97 to 99% irrespective of RPP. Passage of propionic acid at the duodenum and at the ileum did not differ (P greater than .76) across all RPP, and the overall mean passages did not differ from zero (P greater than .34); similar results were observed for other VFA. These observations indicate that essentially all RPP is removed prior to entering the small intestine. Additionally, net propionate disappearance across the small intestine was undetectable and likely biologically irrelevant. Therefore, VFA absorption does not appear to be a limiting biological process in the beef steer.     

瘤胃保护性赖氨酸过瘤胃效果的评价

本研究采用瘤胃尼龙袋法和运动尼龙袋法测定了不同比例棕榈油脂肪粉包被赖氨酸的瘤胃降解率及小肠释放率,结果发现:以30%、40%、50%和60%的棕榈油脂肪粉对赖氨酸进行包被而制备的RPLys-Ⅰ、RPLys-Ⅱ、RPLys-Ⅲ和RPLys-Ⅳ,48 h瘤胃降解率依次为62.42%、55.12%、50.34%和47.21%;24h小肠消失率依次为80.27%、67.05%、64.92%和54.80%。综合分析认为,棕榈油脂肪粉包被比例以50%为宜。     

Combinations of high-moisture harvested sorghum grain and dry-rolled corn: effects on site and extent of digestion in beef heifers

To determine the effects of blends of high-moisture harvested sorghum grain (HMS) and dry-rolled corn (DRC) on site and extent of digestion, high-grain diets were fed to Angus-Hereford heifers (315 kg) in a 5 x 5 latin square. The grain portion consisted of ratios (HMS:DRC) of 0:100, 25:75, 50:50, 75:25 and 100:0. Heifers were equipped with ruminal, duodenal and ileal T-type cannulas. Digestibilities of OM (P less than .05) and non-ammonia nitrogen (NAN; P less than .01) in the total tract declined linearly as HMS replaced DRC. Chyme flow (liters/d) through the duodenum increased linearly (P less than .01), and true ruminal OM disappearance tended to decline linearly (P less than .10) as HMS replaced DRC. A quadratic response (P less than .05) in extent of starch disappearance (g/d) in the rumen was noted; blends were lower than either individual grain. Ruminal escape of feed N tended to be quadratic (P less than .10); values for individual grain types were greater than blends. Microbial efficiency increased linearly (P less than .05) as HMS replaced DRC. Extent of starch digestion in the rumen averaged 82.7% compared to only 2.9% in the small intestine and 5.7% in the large intestine. Altering the ratio of HMS to DRC appeared to have more effect on ruminal fermentation than on digestion in the small intestine; most starch and nitrogen responses were quadratic. Increases in ruminal pH and chyme flow, potentially caused by increased salivary flow, may cause non-linear changes in the solubility of proteins in HMS and DRC, when fed as blends, altering the digestibility of protein and starch from values predicted from the individual grains.     

Absorption of magnesium and other macrominerals in sheep infused with potassium in different parts of the digestive tract

Two metabolism trials were conducted with 12 crossbred wether lambs, each surgically equipped with a ruminal catheter and abomasal and ileal cannulae, to study the effect of K infusion in different sites of the digestive tract on site of absorption and flow of minerals. The treatments consisted of the infusion of 33.6, 12.0 or 12.0 g K/d as bicarbonate into either the rumen, abomasum or ileum, respectively. Each trial consisted of a minimum 5-d preliminary period, five 3-d collection periods to determine mineral balance and a 6-d sampling period to determine mineral flow and site of absorption. Chromic oxide was incorporated into the diet for use as a marker. Magnesium was absorbed primarily from the preintestinal region. Ruminal infusion of K tended to decrease preintestinal Mg absorption. Absorption of Mg in the entire tract was decreased (P less than .05) 43% when K was infused into the rumen. There was a slight absorption of Mg in the small intestine, followed by a net secretion into the large intestine. Serum Mg levels tended to be depressed in lambs infused with K intraruminally. Calcium flow from the preintestinal region was decreased (P less than .05) by infusion of K into the rumen. Only lambs infused with K in the rumen had a net secretion of Na into the small intestine. The large intestine was the primary site of net Na absorption for ruminal-infused lambs. Phosphorus flow from the preintestinal region was decreased (P less than .05) by infusion of K into the rumen. Potassium flow from both the preintestine and small intestine was increased (P less than .05) by ruminal K infusion. The infusion of K into the rumen, abomasum or ileum increased (P less than .05) the total absorption of K, with the small intestine being the major absorptive site. The infusion of potassium bicarbonate into the rumen of sheep raised (P less than .05) the pH of the ruminal contents 15%. Ruminal infusion of K depresses Mg absorption, while the infusion of K into the abomasum or ileum does not affect Mg absorption. Therefore, the role of K in grass tetany may be via this depression of Mg absorption.