微量元素硒的研究进展

1　硒的生物化学功能硒作为一种化学元素,一直被认为是一种对人畜有毒的物质。直到1957年,Ｓｃｈｗａｒｚ等发现从酿酒酵母中分离出的生物活性因子Ⅲ(即硒),能预防老鼠因ＶＥ缺乏而引起的肝坏死,才使人们认识到硒是动物体的必需微量元素之一。硒的生化功能是多方面的,其中最重要的是硒具有抗氧化作用,抗氧化作用的实现主要通过酶和非酶两个途径。谷胱甘肽过氧化物酶(ＧＳＨ—ＰＸ)是哺乳动物体内第一个被公认的含硒酶,于1957年由Ｍｉｌｌｓ和Ｒａｎｄａｌｌ首先发现,但直到1971年才由Ｒｏｔｒｕｃｋ的研究证明了硒是ＧＳＨ—ＰＸ的组成物质…     

低硒日粮对雏鸡血液中淋巴细胞含硒量和谷胱甘肽过氧化物酶活性的影响

研究低硒日粮对雏鸡血液中淋已细胞含硒量和谷胱甘肽过氧化物酶活性的影响,选用星布罗雏鸡６０只,分２组,第１组喂低硒基础日粮,第２组喂基础日粮补加０．１５μｇ／ｇ硒。结果,低硒日粮组雏鸡血液中淋巴细胞平均含硒量为（０．０６７１５±０．０１５０）μｇ／ｇ,与对照组含硒量（０．２３７２±０．０４５８）μｇ／ｇ差异显著（Ｐ＜０．０５）;低硒日粮组鸡血液中淋巴细胞的ＧＳＨ－ＰＸ活性（１．１９５２±０．３９７７）单位,活性显著低于对照组（５．３４７８±１．６２７９）单位,差异显著（Ｐ＜０．０５）。     

含硫氨基酸对黄曲霉毒素B1的解毒机理

口服黄曲霉毒素Ｂ１（２ｍｇ／ｋｇ）能引起雏鸡肝细胞明显损伤，表现肝脏谷胱甘肽（ＧＳＨ）含量降低，肝糖原减少，谷丙转氨酶活性升高。口服蛋氨酸、Ｎ－乙酰半光氨酸能够提高肝脏细胞ＧＳＨ水平。ＧＳＨ能与ＡＦＢ１结合而解毒。其作用机理是通过谷胱甘肽－硫－转移酶的作用。口服亚硒酸钠能提高谷胱甘肽过氧化物酶的活性，也能对抗ＡＦＢ１的毒性。     

硒对动物免疫功能的影响

硒是机体不能缺少的一种微量元素。硒的生物学功能是多方面的,其中最重要的是它的抗氧化功能,特别是作为谷胱甘肽过氧化物酶(GSH-Px)重要组分,在对抗体内有氧代谢过程中所产生过氧化氢对细胞的破坏作用时必不可少。谷胱甘肽过氧化物酶(GSH-Px)是抗过氧化物的重要酶,其主要功能是阻止过氧化物和自由基的形成。硒正是通过抗过氧化物和清除自由基,减少或延迟脂褐素的形成,从而达到抗细胞衰老和死亡的目的。同样,硒对增强动物的免疫功能也起着十分重要的作用。本文就硒对非特异性免疫、细胞免疫及体液免疫的影响及其硒影响免疫的机制进行综…     

vMDV感染雏鸡的Se-GSH-PX活性和LPO含量

以马立克氏病强毒（ｖＭＤＶ）人工感染１日龄ＡＡ肉用雏鸡,于感染后７,１４,２８,４２和５６日龄分别检测雏鸡中枢、外周淋巴器官及主要内脏器官的含硒谷胱甘肽过氧化物酶（Ｓｅ－ＧＳＨ－ＰＸ）活性和脂质过氧化物（ＬＰＯ）含量的变化。结果表明,ｖＭＤＶ感染雏鸡各器官Ｓｅ－ＧＳＨ－ＰＸ活性在检测各时期多显著低于健康对照雏鸡（Ｐ＜０．０５,Ｐ＜０．０１）,而各器官ＬＰＯ含量则多显著高于健康对照雏鸡（Ｐ＜０．０５,Ｐ＜０．０１）,提示马立克氏病（ＭＤ）及其肿瘤的发生和发展与Ｓｅ－ＧＳＨ－ＰＸ抗氧化活性降低和ＬＰＯ及其降解物对雏鸡的广泛病理损伤有关。     

雏鸡HVT疫苗免疫后Se—GSHPx的活性变化

火鸡疱疹病毒（ＨＶＴ）疫苗免疫雏鸡，地２８、４２和５６日龄脾脏、胸腺、法氏囊以及肝脏、肾脏和性腺含硒谷胱甘肽过氧化物酶（Ｓｅ－ＧＳＨＰｘ）活性比健康对照雏鸡显著和极显著增强（Ｐ〈０．０５，Ｐ〈０．０１），可有产防止马立工病强毒（ｖＭＤＶ）感当导致的脂质过经作用和细胞是性损作，避免马立克氏病（ＭＤ）肿瘤的发生     

有机硒的营养研究与应用

由于硒的毒性以及亚硒酸钠的低利用率 ,在饲料中添加过量的亚硒酸钠可能造成环境的污染 ,从而限制了无机硒在饲料中的应用。１９８４年ＦＤＡ已把硒添加量上限降低到０ １ｐｐｍ。而有机硒可能是一类安全高效的硒添加剂。１硒的生物学功能研究人员已经发现硒在谷胱甘肽过氧化物酶（ｇｌｕｔａｔｈｉｏｎｅｐｅｒｏｘｉｄａｓｅ）方面的作用。谷胱甘肽过氧化物酶是一种可以淬灭或破坏动物体内过氧化物的酶。过氧化物是细胞正常代谢过程中形成的有毒化合物。当过氧化物在细胞中活跃时 ,将会损坏细胞膜 ,结果造成细胞功能失调甚至死亡。至少有…     

饮用天然高钼水诱发的钼中毒耕牛主要生物酶测定

本研究对高钼饮水诱导钼中毒的耕牛及对照牛的血浆及组织（肝脏、肺脏、肾脏、脾脏、心脏、肌肉）中超氧化物歧化酶（ＳＯＤ）、黄嘌呤氧化酶（ＸＯＤ）及谷胱甘肽过氧化物酶（ＧＳＨ－ＰＸ）等３种生物酶活性进行了对比分析测定。结果表明,血浆和组织中ＳＯＤ、ＸＯＤ及ＧＳＨ－ＰＸ均随着钼中毒的加重其活性显著下降。这３种生物酶是钼中毒比较灵敏且相关较大的生化指标,对钼中毒具有一定诊断价值;测定ＳＯＤ。ＸＯＤ、ＧＳＨ－ＰＸ可作为钼中毒监测的重要手段。     

亚硒酸钠对雌鼠生殖系统毒性作用的研究

为探讨高硒亚急性中毒对雌鼠生殖系统的毒性作用。将40只6周龄雌性小鼠随机分为对照组(0.00mg/kg体重.d)、低剂量组(0.135mg/kg体重)、中剂量组(0.54mg/kg体重)、高剂量组(2.16mg/kg体重),连续灌胃30d,研究亚硒酸钠对雌性小鼠的生长发育、生殖系统脏器指数、生殖系统超微结构、组织硒含量、谷胱甘肽过氧化物酶的影响。结果显示,第30天时染硒组小鼠体重极显著小于对照组(P<0.01),体重增幅随染硒剂量增加而降低;对照组的卵巢指数与高剂量组差异极显著(P<0.01),对照组子宫指数与中剂量组差异极显著(P<0.01),与其他两组差异显著(P<0.05),随着染毒剂量增加,卵巢指数下降,而子宫指数先升高后降低;对照组卵巢、子宫细胞发育良好,染硒组卵巢、子宫细胞均有不同程度的变性坏死,呈现凋亡细胞的典型特征;染硒组卵巢、子宫硒含量和对照组卵巢、子宫硒含量差异显著(P<0.05),其硒含量随染硒剂量增加而增加,表现出弱蓄积性;染硒组小鼠血清谷胱甘肽过氧化物酶活性极显著高于对照组(P<0.01),与给硒剂量有明显负相关趋势。表明亚硒酸钠染毒可阻碍小鼠的生长发育,作用于生殖系统且有一定毒性作用,呈剂量效应关系。高硒状态下谷胱甘肽过氧化物酶活性与给硒剂量有明显负相关趋势。     

氟、硒相互作用对绵羊全血及组织中抗氧化酶活性的影响

为了研究氟、硒相互作用对绵羊全血及组织中抗氧化酶活性的影响,试验采用单因子设计,选择蒙古公羊16只,随机分为4组,分别为对照组、高氟组、高氟低硒组、高氟高硒组,试验期为45 d,在第7,14,21天时,测定全血、肝脏、肾脏及肌肉中谷胱甘肽过氧化物酶、超氧化物歧化酶活性。结果表明:高氟组全血、组织中的谷胱甘肽过氧化物酶、超氧化物歧化酶活性显著降低(P<0.05),高氟低硒组、高氟高硒组全血、组织中的谷胱甘肽过氧化物酶、超氧化物歧化酶活性显著提高(P<0.05)。说明日粮中添加0.05,0.1 mg/kg硒能提高谷胱甘肽过氧化物酶、超氧化物歧化酶活性,并且硒在一定浓度范围内通过降低机体内的抗氧化酶活性来颉颃氟的毒性作用。     

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.