浊度法测定维生素C注射液细菌内毒素含量

应用BET-32型细菌内毒素测定仪定量测定维生素C注射液的细菌内毒素含量，干扰试验表明，维生素C注射液在400倍稀释时，测定内毒素的干扰最小。7个不同批号的维生素C注射液测定结果显示，7批的回收率均符合测定要求，其中4个批号的人用维生素C注射液内毒素含量符合药典标准，兽用3个批号产品的内毒素含量偏高。     

配合饲料中维生素C含量的测定

维生素C(抗坏血酸．ascorbic acid)是维持人和动物生理功能的重要维生素，对维生素C含量比较高的样品通常采用碘量法和2，4二硝基苯肼法测定含量。配合饲料中维生素C的含量比较低．干扰因素(如金属离子、蛋白质、还原性物质、色素)较多，要分析其中还原性维生素C含量，多采用HPLC法、电化学法等分析方法，然而一般中小型饲料企业往往不具备这些分析仪器。这给控制产品质量、观测维生素C在饲料     

酶解法测定饲料中维生素A、E的含量

维生素A和维生素E为营养元素,是一切畜禽生长所必不可少的。《中国农业标准汇编·饲料卷》中其含量测定采用的是皂化法,本试验探讨采用酶解法同时测定饲料中维生素A、E的含量,并与皂化法测定结果进行比较。1仪器和材料1.1仪器510高效液相色谱工作站,美国W A TE R S公司;W A TE R S2690高效液相色谱仪,美国W A TE R S公司;A gilent1100series高效液相色谱仪,美国安捷伦公司;万分之一分析天平,M ettler A E240;超声波清洗器;超纯水装置。1.2试药维生素A醋酸酯对照品,含量389000IU/g,批号87H0692,SIG M A公司;维生素E(dl-α-生…     

不同热处理加工方式对牛奶中维生素C含量的影响

采用高效液相色谱法测定牛奶中维生素C含量。普遍采用的牛奶杀菌方式是巴氏杀菌法以及超高温瞬时灭菌（UHT）法。测定了不同热处理前后牛奶中维生素C含量。结果表明：巴氏杀菌奶与UHT灭菌奶中维生素C均有不同程度的损失,且UHT奶损失率最多达14.32 %。     

HPLC法同时测定饲料预混料中维生素C(VC)和VC磷酸酯的含量

本文建立了高效液相色谱法(HPLC)同时测定饲料预混料中维生素C(VC)和VC磷酸酯含量的分析方法。采用Lichrospher-NH2分析柱(250mm×4.0mmi.d.,5μm),以乙腈-磷酸缓冲液(30:70,V/V)为流动相,流速为1.0mL/min,检测波长为254nm,柱温为25℃,在此色谱条件下,VC和VC磷酸酯在5.0～200.0mg/L浓度范围内线性关系良好,相关系数为0.9996～0.9999,在100.0～5000.0mg/kg加标浓度范围内,样品平均回收率为95.6%～99.1%,日内相对标准偏差为0.97%～1.76%,日间相对标准偏差为1.98%～3.84%,方法的检出限分别为0.05mg/L和0.1mg/L。     

在养鸡生产中维生素C、小苏打、鱼肝油的功效与应用

在养鸡生产中,经常会在饮水或饲料中添加维生素C、小苏打和鱼肝油等添加剂,来预防鸡群发生各种应激反应,起到辅助治疗疾病的作用,帮助鸡群维持健康状况,有利于鸡群的健康生长和发育.     

高效液相色谱法测定饲料中维生素A含量的测量不确定度评定

对饲料中维生素A含量的测量不确定度进行评定,分析测量不确定度的来源,建立数学模型,经计算得到维生素A的含量测定结果的扩展不确定度为46 IU/g.在维生素A的含量测定过程中,标准溶液浓度是影响含量测量不确定度的主要因素.     

高效液相色谱法同时测定预混合饲料中维生素C、维生素B2及其磷酸盐

本研究建立了高效液相色谱(HPLC)同时测定预混合饲料中维生素C、维生素B2及其磷酸盐形式维生素C-2-磷酸酯(VCP)、维生素B2-5-磷酸钠(VB2P)的方法。预混合饲料用1.5 mmol/L四丁基硫酸氢铵缓冲溶液提取后,进行HPLC检测。采用Zorbax Eclipse Plus C18色谱柱(250 mm×4.6 mm,5μm),以1.5 mmol/L四丁基硫酸氢铵缓冲溶液(p H=3.0)与甲醇作为流动相,梯度淋洗。在此色谱条件下,维生素C、维生素B2、VCP和VB2P的线性关系良好,检出浓度分别为3、1、1、3 mg/kg,定量限为10、5、5、10 mg/kg。应用该法测定了预混合饲料中维生素C、维生素B2、VCP和VB2P,平均回收率为81.5%~106%,相对标准偏差(RSD)均小于10%。     

断奶仔猪日粮中适宜的维生素C和β-胡萝卜素含量

本文通过两个试验评估了在商业化养猪场和试验性养猪场条件下向日粮内添加维生素C和β-胡萝卜素后对猪生产性能的影响。试验1共选用220头22±1.7日龄断奶、体重为6±1.2kg的断奶仔猪;试验2则选用64头20±0.9日龄断奶、体重为6±1.1kg的断奶仔猪。试验1采用随机化完全区组设计,每个处理设11个重复,每个猪圈为一个重复,每圈饲养5头试验猪。试验2采用完全随机设计,每个处理设4个重复,每个猪圈即为一个重复,每圈饲养4头试验猪。菜籽油和动物脂肪分别作为第一个试验和第二个试验的能量添加剂;这些日粮配料储存在断奶猪舍中（温度27～32℃,相对湿度87%～100%）,前后共计49d以促进氧化。两个试验的日粮处理组设置如下：（1）对照组（CON）;（2）维生素C添加组（VC组）：添加维生素C150mg/kg,不添加β-胡萝卜素;（3）β-胡萝卜素添加组（βC组）：添加β-胡萝卜素350mg/kg,不添加维生素C;（4）维生素C和β-胡萝卜素3添加组（VCβC组）：添加维生素C150mg/kg、β-胡萝卜素350mg/kg。对菜籽油、动物脂肪和日粮进行过氧化物含量检测,而维生素C和β-胡萝卜素的检测只在成品日粮中进行。两个试验都进行生产性能测定,试验1的测定日期为24d,试验2为20d。在试验1中,每个猪圈取两头试猪采集血液样本,以测定硫代巴比妥酸活性反应组分（Reactive Species Reactive Species,TBARS）和谷胱甘肽过氧化物酶（Glutathione Peroxidase,GSH-Px）活性。试验1,CON、VC、βC和VCβC组在平均日采食量（分别为395、369、384和400g/d）、平均日增重（分别为301、278、301和304g/d）和饲料转化率（分别为769、758、783和760g/d）上没有差异（P〉0.130）,在血浆谷胱甘肽过氧化物酶活性（P〉0.390）和硫代巴比妥酸活性反应组分（P〉0.179）上无显著差异。试验2,VC和βC组试验猪的平均日采食量显著减少（交互作用,P〈0.05）,试     

肉鸡腹水综合征的病因与防治

肉鸡腹水综合征是由多种因素造成肉鸡机体缺氧,导致其发生肺水肿,心包、胸腹腔大量积液为特征的营养代谢性疾病。近年来本病的发病率和死亡率呈上升趋势,对肉鸡养殖业的危害日益严重。1病因分析肉鸡腹水综合征的发生不是单一因素所致,引发该病的原因大致包括遗传因素、饲养环境、营养因素等。遗传因素,肉鸡的品种常只注重快速生长性能方面的选育,而没有相应地改善其心肺功能,致使其快速生长而不能很好地适应机体本身的代谢要求。     

Serum and milk concentrations of apramycin in lactating cows, ewes and goats

A 20% solution of apramycin was administered intravenously (j.v.) and intramuscularly (i.m.) to lactating cows with clinically normal and acutely inflamed udders, to lactating ewes with normal or subclinically infected, inflamed udders and i.v. to lactating goats with normal udders. The i.v. disposition kinetics of apramycin was very similar in cows, ewes and goats. The elimination half-life was approximately 2 h and the steady-state volume of distribution was 1.26–1.45 L/kg. The absorption rate of the drug from the i.m. injection site was rapid, the i.m. bioavailability was 60–70% and the mean elimination half-life was 265 min in cows and 145.5 min in ewes. The binding percentage of apramycin to serum protein was low (< 22.5%). Concentrations of apramycin in milk produced by clinically normal mammary glands of cows, ewes and goats were consistently lower than in serum; the kinetic value AUC _milk/ AUC _serum was < 0.32. Drug penetration into the milk from the acutely inflamed quarters of cows was extensive; mastitis milk C _max values were more than tenfold greater than the C _max in normal milk. On the other hand, the drug had limited access to the milk produced by subclinically infected inflamed half-udders of ewes.     

万例奶山羊难产的治疗体会

我县地处关中平原 ,是闻名全国的奶山羊之乡。每到产羔季节 ,难产病例虽相对不高 ,但绝对数量相当大。笔者 30余年来共治疗万余例奶山羊难产 ,对奶山羊难产的矫正、治疗方法等有几点体会 ,介绍如下。1　临床症状及检查　轻症 :羊都可站立 ,有腹痛不安的表现 ,努责 ,频频排粪排尿 ,鸣叫 ,多数仍有食欲。心率正常或稍快 ,肺泡音多数粗厉。体温大多正常 ,少数略有升高。外阴轻度肿胀 ,产道湿润 ,手入阴道并无困难 ,胎儿存活或死亡不久 ,无腐败现象。重症 :患羊精神沉郁 ,食欲废绝 ,瘤胃蠕动消失 ,皮温增高或下降 ,有的有呻吟声 ,个别的还有后躯…     

不同胎次和产奶量的奶牛鲜奶脂肪酸含量比较

用气相色谱测定了不同胎次及不同产奶量奶牛鲜奶的脂肪酸含量。一胎４２个、二胎４８个、三胎２０个鲜奶样品。２０００～３０００千克１５个、３００１～４０００千克４１个、４００１～５０００千克３５个、５００１～６０００千克７个鲜奶样品。结果发现，１８：１脂肪酸含量为３３．４８％～３４．８６％；１８：２为８．５１％～１０．０８％；１４：０为７．９４％～１０．１４％；１６：０为２４．０４％～２６．２４％；１８     

气相色谱法测定骆驼奶中的胆固醇

胆固醇的分析方法主要有比色法、薄层法和酶催化法，在应用于食品的测定中，它们具有操作繁琐、选择性低等缺点，而高效液相色谱法用于分析胆固醇时，除了麦角固醇等具有共扼体系的一部分化合物之外。在紫外区都不具有最大吸收，因而没有可供使用的高灵敏度检测器，此外，它对胆固醇和豆固醇分离效果差。为此，笔者等采用气相色谱法对骆驼奶中的胆固醇进行了测定。     

高效液相色谱法测定白牦牛乳中VC的含量

白牦牛（whiteyak）是我国甘肃省天祝县特有的畜种资源。白牦牛乳洁白浓香,营养丰富,具有较高的营养价值,对白牦牛乳中维生素含量的研究具有重要的营养学意义和价值。有关维生素的分析方法较多,包括药典中的标准方法——碘量法、比色法、电位滴定法、化学法、气相色谱法、高效液相色谱法和微生物法等,     

鲜乳及发酵乳中SOD和T-AOC的活性变化

对10份鲜牛乳以98℃煮沸5 min消毒后用乳酸杆菌发酵制作酸乳,测定了发酵前后乳中SOD的活性和T-AOC的变化.结果发酵前SOD活性和T-AOC分别为54.44 U/mL±10.37 U/mL,4.86 U/mL±2.06 U/mL;发酵后SOD活性和T-AOC分别为:66.96 U/mL±6.45 U/mL,7.97 U/mL±3.51 U/mL.发酵乳SOD活性升高了23%,T-AOC升高了64%(均P《0.01).     

Effects of vitamin E and different energy sources on vitamin E status, milk quality and reproduction in transition cows

We investigated whether vitamin E supplementation and supplemental energy sources (fat or starch) influenced plasma and milk levels of vitamin E, and reproductive and other parameters in 28 Italian Friesian multiparous dry cows. From 14 days before expected calving to 7 days after, the animals were assigned to either basal diet (containing 1000 IU/day of vitamin E) or an extra 1000 IU/day of vitamin E (total 2000 IU). In addition they received either 0.5 kg/day of corn or 0.2 kg/day of calcium soaps. Plasma samples were collected 4 days before expected calving and 4 days after calving and analysed for alpha-tocopherol and cholesterol. Milk yield as well as the composition, somatic cell count (SCC) and alpha-tocopherol of milk were determined 7 and 14 days after calving. Milk yield and composition were unaffected by treatments. SCC was significantly lower in (SCC Log 4.62 versus Log 5.1, P < 0.01) 2000 IU/day animals than in the 1000 IU/day group. Milk alpha-tocopherol was higher (P < 0.001) in animals receiving 2000 IU/day (1.11 vs. 0.65 microgram/ml, P < 0.01). Plasma alpha-tocopherol in animals receiving 2000 IU/day was also higher (P < 0.001) than in cows receiving 1000 IU/day (4.85 vs. 3.25 micrograms/ml), but was not affected by dietary energy source. Number of services and days to conception were lower (P < 0.01) in the 2000 IU vitamin E supplemented cows. To conclude, dietary vitamin E supplementation to periparturient dairy cows increased plasma and milk vitamin E, decreased SCC in milk, and improved fertility but different energy sources had no effect on any measured variable.     

Determination of beta-lactamase production in strains of Staphylococcus aureus isolated from the milk of cows

Determination of sensitivity to penicillin G by a standard disk assay diffusion method was compared with a iodometric method of test papers to determine beta-lactamase production after Jorgensen in Staphylococcus aureus strains isolated from cow's milk from different farms. Out of 179 test strains, 32 strains 17.8%) were found to be well sensitive in the diffusion test; eight of these strains (25.0%) were demonstrated to produce beta-lactamase. 54 strains (30.2%) were sensitive. 27 strains (50%) of this group produced beta-lactamase. 93 strains (51.9%) were resistant to penicillin G in the diffusion test. 86 strains (92.5%) were found to produce beta-lactamase and seven strains were negative in this test. Using the diffusion test of sensitivity in these cultures, 86 strains were sensitive (48.1%) and 93 strains were resistant (51.9%). Beta-lactamase was produced by 121 strains (67.6%) and no beta-lactamase production was recorded in 58 strains (32.4%). Differences in the results of both tests were manifest mainly in the set of strains qualified as sensitive (inhibition zone diameter 24 to 16 mm) and well sensitive (inhibition zone diameter larger than 25 mm). The results indicate that the currently performed diffusion test of sensitivity to penicillin G should be accompanied by an assay of beta-lactamase production. The iodometric method of test papers is simple, rapid and cheap and can be made in any bacteriological laboratory. The high resistance of Staphylococcus aureus strains to penicillin G documents that this antibiotic is little efficient in the treatment of mastitis of this etiology in the given region.     

Heat stress decreases plasma vitamin C concentration in lactating cows

Heat stress causes oxidative stress, which decreases plasma levels of vitamin C, an antioxidative vitamin in pigs and poultry. We investigated the plasma vitamin C concentration in lactating cows exposed to a hot environment temperature. In the first experiment, plasma vitamin C concentrations of 8 lactating cows were measured in summer and autumn. The concentration was found to be significantly lower in summer. The second experiment was performed using 4 lactating cows in a crossover design. The ambient temperature was set at 18 °C in the control treatment and at 28 °C in the heat-stressing treatment. Milk yields and feed intake tended to be lower in the stressing than control treatment. Rectal temperature and respiration rate were significantly (P < 0.05) higher in the heat-stressing treatment. The plasma vitamin C concentration was significantly (P < 0.05) lower in the heat-stressing period. These results indicate that heat stress decreases the plasma vitamin C concentration. Dietary supplementation with vitamin C may be beneficial for lactating cows in hot weather.