蛋白质摄入量对牛奶尿素氮影响的评价

本文分析了奶牛瘤胃降解蛋白(RDP)、瘤胃非降解蛋白(RUP)日摄入量和泌乳净能(NEL)日摄入量对牛奶尿素氮(Milk Urea Nitrogen,MUN)值直接影响的程度大小,结果是RUP摄入量的影响程度最大(P<0.001),RDP摄入量次之(P=0.001),NEL摄入量的影响最小(P=0.414)。NEL摄入量对MUN的影响主要是通过RDP和RUP的摄入量来对MUN产生间接影响。用RDP摄入量(X1)和RUP摄入量(X2)估测MUN(Y)的多元回归方程:Y=0.50×X1+0.65×X2-14.82(R2=0.92,P<0.001)     

反刍动物蛋白质代谢研究进展

综述了近年来有关瘤胃降解蛋白(RDP)、过瘤胃蛋白(RUP)以及限制性氨基酸(LAA)、理想氨基酸模式(Ideal Amino Acid Pattern)、小肽(Small Peptide)的吸收机制和特点等在反刍动物营养中的研究应用,以及反刍动物蛋白质代谢与能量的关系.     

日粮营养因素对牛奶尿素氮含量的影响

本研究收集了21个(92个处理组,551头奶牛)有关中国荷斯坦牛牛奶尿素氮(MUN)的试验资料分析日粮因素对MUN值的影响。结果为,在单因素回归分析中日粮粗蛋白(CP)含量、产奶净能(NEL)、瘤胃降解蛋白(RDP)含量、能蛋比(NEL与CP的比值,N∶P)和瘤胃未降解蛋白(RUP)含量与MUN值有极显著的回归关系(P0.01),CP含量的决定系数最高,然后依次是NEL、RDP含量、N∶P、RUP含量、酸性洗涤纤维(ADF)含量、RDP∶RUP、干物质采食量(DMI)和中性洗涤纤维(NDF)含量。在多因素回归分析中,每种日粮因素组合都与MUN值有极显著的回归关系(P0.01),同时含有CP含量和RDP∶RUP指标的公式的决定系数最高。结果表明,日粮CP水平是影响MUN值的最主要因素。     

过瘤胃蛋白和氨基酸对奶牛、绵羊干物质采食量、消化率和生长性能的影响

数量充足和配比合理的营养对家畜生产性能起着决定性作用,其中蛋白质是动物生长发育、繁殖性能的主要限制因素之一。蛋白质的种类和水平决定着动物机体组成及日粮中必需氨基酸的供应。对反刍动物来说,蛋白质的作用是双方面,既要满足瘤胃厌氧微生物发酵的需要,又要满足动物成长的营养需要。然而,由于瘤胃的发酵作用,日粮中绝大多数蛋白质在瘤胃内被降解(称为瘤胃降解蛋白,RDP),只有小部分能通过瘤胃在小肠内吸收(称为非瘤胃降解蛋白,RUP),因此用于厌氧合成微生物蛋白的RDP以及RUP的种类决定了反刍动物日粮和机体必需氨基酸的利用率。微生物蛋白和过瘤胃蛋白决定了高产动物日粮中必需氨基酸的供应。因此,饲喂过瘤胃蛋白和氨基酸被认为是满足反刍动物生理以及生产需要的有效方法。文章综述了过瘤胃蛋白、过瘤胃赖氨酸和过瘤胃蛋氨酸在反刍动物上的应用,以及对奶牛、绵羊干物质采食量、消化率、生产性能影响的研究。蛋白质是反刍动物重要的限制性营养,由RDP和RUP组成。瘤胃微生物通过将RDP降解成小肽、氨基酸和氨等来合成微生物蛋白,其数量主要受日粮中瘤胃发酵率的制约。因此,RDP和RUP或氨基酸的供应对于满足反刍动物营养需要非常重要,尤其是对于饲喂低水平日粮的反刍动物。添加瘤胃保护蛋白和瘤胃保护氨基酸(特别是赖氨酸和蛋氨酸)能提高奶牛、绵羊的干物质采食量和消化率。同时,还能够提高生长性能、繁殖效率和产奶量。不管是单独添加,还是与赖氨酸同时添加,如果蛋氨酸的添加量大于肠道的可消化吸收量时,则有可能会产生负面影响。在奶牛泌乳早期的低蛋白水平日粮中添加蛋氨酸,能避免奶牛长期的不良反应。总而言之,反刍动物在低营养水平下添加瘤胃保护蛋白质和氨基酸,能提高饲料采食量、消化率以及生长性能。     

奶牛代谢蛋白及氨基酸饲喂状况调查研究

为探明南方奶牛养殖的限制因素,选择浙江嘉兴地区5个典型奶牛场,调查高产奶牛日粮中代谢蛋白（MP）的供应量及典型日粮中RDP（瘤胃降解蛋白）、RUP（瘤胃非降解蛋白）及MP的供给量,并探讨南方奶牛场典型日粮中的限制性氨基酸。结果表明,南方地区奶牛日粮中代谢蛋白含量偏高,并对繁殖造成一定影响,而日粮提供的代谢蛋白中氨基酸含量不平衡,普遍缺乏蛋氨酸和赖氨酸。     

核桃饼干物质和粗蛋白质瘤胃降解规律研究

本研究采用单因子随机设计,选择4头健康的、安装有永久性瘤胃瘘管的荷斯坦奶牛,进行核桃饼干物质和粗蛋白质瘤胃降解规律研究。结果表明,核桃饼干物质和粗蛋白质瘤胃降解率分别为46.78%和51.78%;核桃饼RUP为48.22%CP。经分析认为,核桃饼作为精饲料原料饲喂反刍动物时,应进行保护处理或搭配不同品种蛋白质原料,以获取日粮蛋白质RDP和RUP比例的平衡。     

可降解蛋白及非蛋白氮对模拟瘤胃体外发酵、营养物质降解率的影响

以11.85%和8.38%两个水平的可降解蛋白(RDP)及非蛋白氮(NRN)作为试验因子,进行2×2试验设计。应用体外短期发酵技术,研究了RDP及RDP与非蛋白氮组合对模拟瘤胃发酵及营养物质降解率的影响。结果表明:添加NPN处理组的pH、NH3-N浓度显著(P<0.05)高于未添加NPN处理组。高RDP水平pH值、NH3-N浓度、细菌N与低RDP水平的相比,高RDP处理组显著(P<0.05)高于低RDP处理组,说明日粮中RDP水平显著提高瘤胃内pH值、NH3-N浓度和细菌N的产量。同时发现,RDP与NPN互作对瘤胃发酵影响不显著。对瘤胃发酵营养物质降解率的研究发现,反刍动物日粮中添加适量的NPN,有利于优化瘤胃内环境,提高物质成分在瘤胃中的降解率。RDP水平对模拟瘤胃发酵时干物质(DM)、酸性洗涤纤维(ADF)降解没有显著影响,但显著提高了中性洗涤纤维(NDF)的降解率。     

以农副产品为基础日粮过瘤胃蛋白的作用

DCP(可消化粗蛋白)的测定在评估日粮蛋白质价值方面显得很不完善和不尽人意,因为蛋白质在前胃和小肠中的消化有很大差异。 饲料中的蛋白质应分为瘤胃可降解蛋白质(RDP)和瘤胃不可降解蛋白质(UDP)。通常,人们都愿意将易得的含高UDP或过瘤胃率高的蛋白质饲料加入生长和泌乳的反刍动物日粮中。然而,一旦这些资源缺乏或者昂贵,就要谨慎考虑将降解率高的蛋白质经过热处理或甲醛处理来获得理想的过瘤胃率。世界各国的种种研究表明,在以农副产品为基础日粮,用过瘤胃蛋白质饲料饲喂反刍动物可以提高其生长及泌乳期间的饲料转化率。     

过瘤胃氨基酸的研究

蛋白质是反刍动物日粮中主要限制性营养成分之一，在反刍动物营养中，日粮蛋白在瘤胃中降解是一种低效的营养过程。在有些条件下仅靠饲喂高蛋白日粮也不一定能提高反刍动物生产性能。为了减少瘤胃内蛋白质的降解损失，人们采取各种措施以提高日粮中蛋白质的过瘤胃值（斯钦，1996）。研究发现，单靠增大过瘤胃蛋白的量，并不一定能保证家畜增产，蛋白质对反刍动物的。     

日粮粗蛋白水平及降解率对泌乳奶牛瘤胃发酵和氮利用的影响

俄罗斯的研究人员近来研究了2种含有相似瘤胃非降解蛋白(RUP)和可代谢蛋白(MP)浓度，但瘤胃可降解蛋白(RDP)浓度不同的日粮对奶牛瘤胃发酵、消化率、瘤胃氨氮转化成乳蛋白的影响。他们把4头装有瘤胃和十二指肠瘘管的荷斯坦奶牛分为2组，并按交换设计进行试验。结果发现，可降解蛋白组瘤胃氨的浓度比适宜可降解蛋白组高(P=0．06)。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.