单胃动物消化道内源氨基酸排泄量测定方法学研究进展

综述迄今所提出的内源氨基酸排泄量测定方法的基本原理及其优缺点。并将这些方法划分为３类，第１类是非正常生理条件下的测定方法，包括绝食法（ＦＡＳ）、无氮日粮（ＮＦＤ）法、ＮＦＤ＋合成氨基酸（ＡＡＳ）、ＮＦＤ＋静脉注射ＡＡＳ以及回归法（ＲＥＧ）；第２类是接近生理条件下的测定方法，包括同位素标主内源氮法、同位素标记外源法、静脉１次注射小剂量「＾３Ｈ」Ｌｅｕ法、胍基化蛋白法、酶解格蛋白／超滤法、第３类是体外     

筛选家蚕分子标记的有效方法—SADF法

从家蚕品种 Ｃ１０８ 和大造后部丝腺提取的基因组 Ｄ Ｎ Ａ 用 Ｐｓｔ Ⅰ酶解后与自行设计的人工接头相连，并用与人工接头序列相匹配的选择性引物进行选择性 Ｐ Ｃ Ｒ 扩增（ Ｓｅｌｅｃｔｉｖｅ Ａｍ ｐｌｉｆｉｃａｔｉｏｎ） 。扩增产物经琼脂糖凝胶电泳检测显示，用 Ｓ Ａ Ｄ Ｆ 法在两品种中能检测到稳定的 Ｄ Ｎ Ａ 多态性片段，表明此方法可用于分子标记的筛选。经研究发现：当 Ｐ Ｃ Ｒ 反应体系中 Ｍｇ２ ＋ 为１５ ｍ ｍ ｏｌ／ Ｌ，ｄ Ｎ Ｔ Ｐｓ 为２００μｍ ｏｌ／ Ｌ，引物为１μｍ ｏｌ／ Ｌ 时可得到较好的结果；在热循环过程中，以５６ ℃退火为宜；扩增反应对模板 Ｄ Ｎ Ａ 质的要求远胜于量。     

饲喂玉米型日粮的生长绵羊限制性氨基酸研究

本实验采用９ 只安装有瘤胃、十二指肠和回肠瘘管的生长羯羊， 采用随机区组试验设计，研究了饲喂以玉米、玉米蛋白粉和青干草为基础日粮的绵羊消化道不同部位营养物质流通量，以及由十二指肠瘘管按“递减法”灌注不同氨基酸［Ａ：减赖氨酸（Ｌｙｓ） ；Ｂ：减蛋氨酸（ Ｍｅｔ） ；Ｃ１ ：全量；Ｄ：减苏氨酸（Ｔｈｒ） ；Ｅ：减组氨酸（Ｈｉｓ） ；Ｃ２ ：全量；Ｆ：减精氨酸（ Ａｒｇ） ；Ｇ：减色氨酸（Ｔｒｐ） ；Ｃ３ ：全量］ 对绵羊体内氮沉积、血浆尿素氮（ＰＵＮ） 、血浆游离氨基酸（ＦＡＡ） 浓度等指标的影响。结果表明：饲喂玉米型日粮的绵羊瘤胃食糜流通速率（ Ｋｐ） 为５ ．０９ ％ ～６ ．１５ ％ ／ ｈ ， 进入十二指肠中微生物蛋白占总氮的比例为１７ ．７９ ％ ～３０ ．４３ ％ 。绵羊十二指肠中Ｍｅｔ 、Ｌｙｓ 、Ｈｉｓ 和Ａｒｇ 流量偏低，而Ｌｅｕ 的流量较高。与对照组（Ｃ１ 、Ｃ２ 、Ｃ３） 相比，减少Ｌｙｓ 、Ｍｅｔ 、Ｔｈｒ 、Ｈｉｓ 、Ａｒｇ 和Ｔｒｐ 组的绵羊体内沉积氮（ｇ／ ｋｇ Ｗ０ ．７５） 分别下降２３ ．５０ ％ 、４６ ．６７ ％ 、２８ ．６６ ％ 、１５ ．００ ％ 、１７ ．３３ ％ 和１５ ．８９ ％ ；日增重分别下降３７ ．０４ ％ 、５３ ．１７ ％     

同位素标记内源氮法测定回肠内源氨基酸排泄量研究进展

内源氨基酸排泄量(LEAA)是测定饲料氨基酸真消化率的重要指标,而同位素标记内源氮法是直接测定内源氨基酸排泄量的有效方法之一。本文综述了同位素标记内源氮法测定回肠内源氨基酸排泄量的基本原理、假设条件和影响因素。     

允许使用的饲料添加剂品种

中华人民共和国农业部公告（第１０５号）附件总计：１７３种（类）类　　别饲料添加剂名称饲料级氨基酸７种Ｌ赖氨酸盐酸盐；ＤＬ蛋氨酸；ＤＬ羟基蛋氨酸；ＤＬ羟基蛋氨酸钙；Ｎ羟甲基蛋氨酸；Ｌ色氨酸；Ｌ苏氨酸饲料级维生素２６种β胡萝卜素；维生素Ａ；维生素Ａ乙酸酯；维生素Ａ棕榈酸酯；维生素Ｄ３；维生素Ｅ；维生素Ｅ乙酸酯；维生素Ｋ３（亚硫酸氢钠甲萘醌）；二甲基嘧啶醇亚硫酸甲萘醌；维生素Ｂ１（盐酸硫胺）；维生素Ｂ１（硝酸硫胺）；维生素Ｂ２（核黄素）；维生素Ｂ６；烟酸；烟酰胺；Ｄ泛酸钙；ＤＬ泛酸…     

鸡传染性支气管炎病毒S1基因在昆虫细胞中的高效表达

将鸡传染性支气管炎病毒（ Ｉ Ｂ Ｖ） Ｓ１ 基因 ｃ Ｄ Ｎ Ａ 克隆至含有起始密码 Ａ Ｔ Ｇ 的转移载体 ｐ Ｓ Ｘ Ｉ Ｖ Ｖ Ｉ＋ Ｘ３／４,构建成重组转移质粒 ｐ Ｓ Ｘ Ｉ Ｖ Ｖ Ｉ＋ Ｘ３／４ Ｓ１． Ｈｏｌｔｅ,再与粉纹夜蛾核型多角体病毒 Ｔｎ Ｎ Ｐ Ｖ Ｓ Ｖ Ｉ－ Ｇ Ｄ Ｎ Ａ（ Ｏ Ｃ Ｃ－ , ｇａｌ＋ ）共转染 草地夜蛾（ Ｓｆ９） 细胞, 经空斑纯化得 到已插入 Ｓ１ 基 因并能形成多角体 的重组病毒 Ｔｎ Ｎ Ｐ Ｖ（ Ｘ３／４） Ｓ１． Ｈｏｌｔｅ Ｏ Ｃ Ｃ＋ 。以重组毒株感染 Ｔｎ５ Ｂ１ 细胞,在不同时间收取感染了病毒的细胞进行 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ 与 Ｗ ｅｓｔｅｒｎ 印迹检测。 Ｔｎ Ｎ Ｐ Ｖ（ Ｘ３／４） Ｓ１． Ｈｏｌｔｅ Ｏ Ｃ Ｃ＋ 在感染的细胞中高效表达了 Ｓ１ 基因,表达产物为约 １００ ０００ 的融合蛋白,与预计的表达修饰后的产物大小相符,推测此蛋白已糖基化。 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ凝胶薄层色谱分析结果显示,感染病毒后 ４８、７２、９６ ｈ, Ｓ１ 蛋白分别占细胞内总蛋白量的 ２８７％ 、３５８％ 、３７１％ 。     

新城疫病毒弱毒株分子生物学特性的研究

于１９９６年从长春地区一养鸡场分离到一株新城疫病毒（ＮＤＶ长春株）,经过病毒生物学特性的研究表明该ＮＤＶ毒株为弱毒株。将ＮＤＶ长春株纯化培养后,提取病毒ＲＮＡ,经ＲＴ－ＰＣＲ扩增Ｆ基因,并测定出Ｆ基因的全部核苷酸序列为１７５８ｂｐ,编码有５５３个氨基酸残基。与国内外发表的部分ＮＤＶ病毒的强毒株和弱毒株的相同序列进行比较,其核苷酸同源性在８８．２％￣９６．７％之间,氨基酸同源性在９０．１％￣９８．１％之间,并与所有弱毒株Ｆ蛋白裂解位点区（１１２￣１１７）氨基酸序列Ｇｌｙ－Ａｒｇ／Ｌｙｓ－Ｇｌｎ－Ｇｌｙ／Ｓｅｒ－Ａｒｇ－Ｌｅｕ相同,从基因和分子水平上进一步证明ＮＤＶ长春株为ＮＤＶ弱毒株。     

日粮类型和羊草细度对肉牛瘤胃挥发性脂肪酸比例及能量转化效率的影响

用装有瘤胃瘘管和真胃瘘管的肥育阉牛,按完全拉丁方设计,连续定点消化道食糜采样,用ＫＢ－１型自控大型呼吸测热室测定能量平衡和氮平衡。结果表明,４种不同加工细度羊草,在维持饲养水平（１Ｍ）下的ＤＥ／ＧＥ,ＭＥ／ＤＥ,ＨＰ／ＭＥ,Ｋｍ,ＶＦＡ总量,乙酸：丙酸比例等的组间差异均不显著（Ｐ＞０．０５）,代谢能转化为维持净能效率（Ｋｍ）平均为６５．６９％（Ｃ．Ｖ＝０．８８％）;１．３Ｍ饲养水平的各种能量参数,４组间的差异亦均不显著（Ｐ＞０．０５）,代谢能转化为增重净能效率（Ｋｆ）平均３３．９２％（Ｃ．Ｖ＝１．８６％）。４种不同精料：羊草比例的日粮,在维持饲养水平下,ＣＨ４（ＫＪ）／ＤＥ（ＫＪ）＝０．０７３８＋０．０６１５（ＮＤＦ／ＯＭ）,ｒ＝０．８９２８,Ｋｍ＝６０．８６５１＋０．３３０４（丙酸ｍｏｌ／１００ｍｏｌＶＦＡ）,ｒ＝０．９９５５;在１．５Ｍ下,ＨＰ／ＭＥ＝１４．３８３８＋０．７８０５（乙酸ｍｏｌ／１００ｍｏｌＶＦＡ）,ｒ＝０．９９０３,Ｋｆ＝２２．９６９７＋０．６０２２（丙酸ｍｏｌ／１００ｍｏｌＶＦＡ）,ｒ＝０．９９８１,或Ｋｆ＝５７．２２６５－０．３８１７（ＮＤＦ／ＯＭ）,ｒ＝－０．９９８７。     

互助白牦牛血液蛋白质多态性的研究

采用聚丙烯酰胺凝胶电泳法对７１头互助白牦牛４种血液蛋白质的多态性进行研究。结果表明：（１）血红蛋白显现ＨＢＦ￣＋Ｓ￣－，ＨＢＦＳ和ＨＢＦ￣－Ｓ＋三种表型，其表型频率分别为４．３％，９４．３％和１．４％；（２）血清白蛋白、血清运铁蛋白和血清亲血色蛋白均呈单态，显现单一的ＡＬＢＡＡ，ＴＦＤＤ和Ｈｐｌ－１型；（３）互助白牦牛４种血液蛋白质的Ｐｐｏｌｙ为２５．０％，Ｈ为０．０２７３。     

互助白耗牛血液蛋白质多态性的研究

采用聚丙烯酰胺凝胶电泳法对７１头互助白牦牛４种血液蛋白质的多态性进行研究。结果表明：（１）血红蛋白显著ＨＢＦ＾＋Ｓ＾－，ＨＢ ＦＳ和ＨＢＦ＾－＾Ｓ＋三种表型，其表型频率分别为４．３％，９４．３％和１．４％；（２）血清白蛋白、血清运铁蛋白和血清亲血色蛋白均呈单态，显现单一的ＡＬＢＡＡ，ＴＦＤＤ和Ｈｐｌ－１型；（３）互助白牦牛４种血液蛋白质的Ｐｐｏｌｙ为２５．０％，Ｈ为０．０２７３。     

肉仔鸡内源氨基酸基本损失量测定方法的比较研究

通过强饲无氮饲粮(NFD)、NFD +3.39 %平衡氨基酸(AAs)、NFD +6.81 %AAs、NFD +3.20 %酶解酪蛋白(EHC)或NFD +6.40 %EHC饲粮 ,直接测定肉仔鸡48h内源氨基酸基本损失量(EAAEb)。给肉仔鸡强饲以豆粕为唯一氮源的粗蛋白(CP)含量为5 %、10 %、20 %及30 %饲粮 ,利用回归法(REG)间接研究EAAEb。结果表明 ,上述几种方法测定的EAAEb 相似 ,说明肉仔鸡有一相对稳定的EAAEb。     

罗曼公母鸡内源氨基酸排泄量的比较研究

试验选取28周龄健康的罗曼公母鸡各16只,分别分为2个处理,每处理8个重复,每个重复1只鸡,分别饲喂2种试验日粮,即无氮日粮(NFD)和NFD+5%酪蛋白,比较分析2种方法测得的公母鸡内源氨基酸排泄量(EAAL)的差异。结果表明:采用NFD法和NFD+5%酪蛋白所得的公母鸡内源氨基酸和总蛋白质的排泄量有所不同。酪蛋白组能够增加内源氮和内源氨基酸的排泄量,NFD+5%酪蛋白法所测得的内源氮和内源氨基酸排泄量更接近试鸡的真实情况。2种测定方法公鸡内源氮和内源氨基酸的排泄量均高于母鸡的结果。     

无氮日粮法与绝食法测定肉仔鸡内源氨基酸损失量的研究

本试验分别用无氮日粮法和绝食法测定肉仔鸡内源氨基酸损失量,并比较两种方法得到的结果之间的差异.选用49日龄健康的AA肉仔鸡公鸡20只,随机分成2组,每组10只,采用48 h空腹+48 h全收粪法进行试验.结果表明,无氮日粮法和绝食法测定的肉仔鸡内源氨基酸中,精氨酸、苏氨酸、胱氨酸、酪氨酸内源损失量之间无显著性差异(P＞0.05);无氮日粮法测定的其他氨基酸内源损失量极显著(P＜0.01)或显著(P＜0.05)高于绝食法;无氮日粮法测定的总氨基酸内源损失量极显著(P＜0.01)高于绝食法.     

泰和鸡内源氨基酸排泄量的研究

分别选用4只去盲肠泰和公鸡 ,以无氮日粮法和绝食法测定了泰和鸡的内源氨基酸排泄量。结果表明 :除赖氨酸、组氨酸和精氨酸外 ,无氮日粮法其它氨基酸测值极显著(P<0.01)或显著地(P<0.05)高于绝食法 ,无氮日粮法氨基酸总量极显著高于绝食法(P<0.01)。综合前人及本试验结果 ,建议采用无氮日粮法测定鸡内源氨基酸排泄量     

猪内源氨基酸测定技术评述

氨基酸的真消化率是评价饲料蛋白质生物学效价的重要指标,而要测定氨基酸的真消化率,就必须对内源氨基酸排泄量进行估测。本文就目前内源氨基酸的测定方法进行了综述,并对各种方法的优缺点进行了评述。在内源氨基酸的测定方法中,以传统方法(无氮日粮法、回归外延法和完全可消化蛋白源或静脉灌注平衡氨基酸法)最为常用,但存在种种缺陷。为克服传统方法的缺陷,学者们提出了新的估测内源氨基酸的方法,如同位素标记法、高精氨酸法、肽营养超滤技术、氨基糖测定法以及体内体外结合测定法,但这些方法也存在或多或少的缺陷,还有待于改进。     

Variation in precaecal amino acid and energy digestibility between pea (Pisum sativum) cultivars determined using a linear regression approach

An experiment was conducted to study the variation in the precaecal amino acid (AA) and energy digestibility of 4 cultivars of white-flowering peas (Pisum sativum) for broiler chickens. The 4 cultivars were grown and harvested under the same agronomic and environmental conditions. One basal diet and 8 diets including each pea cultivar at inclusion rates of either 150 or 300 g/kg were used. Peas were included at the expense of starch. Hence, the differences in dietary crude protein and AA concentrations resulted only from the inclusion of peas. Titanium dioxide was included as an indigestible marker. Crude protein concentrations in the complete diets ranged from 164 to 244 g/kg. All diets were fed ad libitum to broiler chickens between 14 and 21 d of age. Seven pens of 12 chickens were allocated to each treatment. Digesta were sampled on a pen basis from the section of the gastrointestinal tract between Meckel's diverticulum and 2 cm anterior to the ileo-caeco-colonic junction. The proportions of crude protein and AAs digested responded linearly to increased intake and the relationships between quantitative intake and digested amounts of AAs were described by multiple linear regressions. The slope determined for each pea cultivar was taken as a measure of AA digestibility without the need for consideration of basal endogenous crude protein and AA secretions. Digestibility of AAs in peas ranged from 0.60 to 0.91. One cultivar had significantly lower AA digestibilities than the other three cultivars. This could be explained neither by the trypsin inhibitor activity nor by tannin levels. The AAs with the highest digestibilities in all cultivars were arginine > glutamic acid > lysine > methionine > phenylalanine > leucine. The AAs with the consistently lowest digestibilities were cystine < threonine. The ranking of the remaining AAs varied slightly between cultivars. The multiple linear regression approach is suitable to study differences in AA digestibilities without the need for consideration of basal endogenous AA losses. Diets containing 300 g/kg of peas had significantly lower energy digestibilities than the pea-free basal diet. The pea cultivar with the lowest AA digestibility caused the lowest energy digestibility at both levels of pea inclusion.     

Estimation of endogenous protein and amino acid ileal losses in weaned piglets by regression analysis using diets with graded levels of casein

Background： Many studies have investigated endogenous loss of proteins and amino acids （AAs） at the ileal level in growing pigs. However, only a few studies have researched this subject in piglets. Knowledge regarding AA ileal digestibility in piglets would be helpful during the formulation of diets for weaning piglets, rather than just using coefficients obtained in growing pigs. Therefore, in this study, we sought to estimate endogenous protein and AA ileal losses in piglets. Furthermore, apparent and true ileal digestibility （AID and TID） of protein and AAs from casein were measured. Results： The average flow of protein was 20.8 g/kg of dry matter intake （DMI）. Basal protein loss, as estimated by regression, was 16.9 g/kg DMI. Glutamic acid, arginine, and aspartic acid （2.2, 1.4, and 1.2 g/kg DMI, respectively） were the AAs for which greater losses were seen. The AID of protein and AAs increased as the protein level in the diet increased. A higher increment in AID was observed between diets with 80 and160 g CP/kg of feed; this finding was mainly attributable to increases in glycine and arginine （46.1% and 18%, respectively）. The TID of protein was 97.8, and the TID of AAs varied from 93.9 for histidine to 100.2 for phenylalanine. Conclusions： The basal endogenous protein loss in piglets was 16.9 g/kg DMI. Endogenous protein was rich in glutamic acid, aspartic acid, and arginine, which represented 32.7% of endogenous protein loss in weaning piglets. The TID of casein was high and varied from 93.0 for histidine to 100.2 for phenylalanine.     

单胃动物内源氨基酸损失的测定方法及影响因素研究进展

氨基酸消化率是评定饲料蛋白质生物学效价的重要指标。对内源氨基酸损失进行准确测定可获得精准的氨基酸消化率,不仅可以节约日粮蛋白资源,降低饲料成本,还可减少因氮排放造成的环境污染。目前,内源氨基酸损失测定的方法主要包括无氮日粮法、绝食法、差量法、酶解蛋白日粮法、回归法、高精氨酸法和同位素法等。内源氨基酸损失又与动物、饲养环境、日粮组成(日粮蛋白、纤维、抗营养因子)及测定方法等有关。本文综述了内源氨基酸损失的测定方法及影响因素。     

The effects of phytase and phytic acid on the loss of endogenous amino acids and minerals from broiler chickens

1. The effects of myo-inositol hexaphosphate (IP6) and phytase (EC 3.1.3.26) on the excretion of endogenous compounds were investigated using growing broiler chickens. 2. A total of 32 female Ross broilers were used in a precision feeding assay involving a 2 x 2 factorial arrangement of treatments. The materials administered were glucose, glucose + 1000 units of phytase activity (FTU), glucose + 1 g of IP6 and glucose + 1 g of IP6 + 1000 FTU. Excreta were collected quantitatively over a 48-h period following intubation of the test materials. The excretion of nitrogen, amino acids, minerals, sialic acid and phytate phosphorus was determined. 3. The ingestion of 1 g of IP6 by broilers increased the excretion of endogenous nitrogen, amino acids, iron, sodium, sulphur and sialic acid compared with birds fed on glucose. Supplementation of IP6 with exogenous phytase reduced the excretion of endogenous amino acids, calcium, sodium, phytate phosphorus and sialic acid compared with birds fed IP6. 4. It can be concluded that IP6 increases the excretion of endogenous minerals and amino acids in broiler chickens. Part of the beneficial effects of the addition of exogenous phytases to the diets of poultry appears to be mediated through a reduction in endogenous losses of these nutrients.