植物乳杆菌P8微囊化的初步研究

试验以海藻酸钠、海藻酸钠/β-环糊精、海藻酸钠/阿拉伯胶为壁材;脱脂奶粉、脱脂奶粉/麦芽糖、脱脂奶粉/乳糖为保护剂,采用乳化法和锐孔-凝固浴法制备植物乳杆菌P8微胶囊。结果表明:制备植物乳杆菌P8微胶囊的最佳工艺条件为海藻酸钠/β-环糊精浓度为2%、脱脂奶粉/麦芽糖浓度为4%、CaCl2浓度为3%,活菌率达到2.27×1011CFU/g。     

O通量特征及排放贡献

：２００３年５月－２００４年４月,利用静态箱－气相色谱法对生长季与非生长季三江平原小叶章湿地N₂O 通量特征及排放贡献进行了研究。结果表明,生长季N₂O 呈脉冲式排放,通量介于０．００５～０．１１１ｍｇ／（ｍ^２·ｈ）,５月较低通量与降水较多有关,６月通量骤然增加与冻层融通有关,７－８月与降水少及蒸发旺盛有关,９月与土壤中较多氮有关。N₂O 通量与５ｃｍ 地温呈显著正相关（P＜０．０１）;非生长季N₂O 表现为“吸收－排放”,通量介于－０．００１５～０．０４９７ｍｇ／（ｍ^２·ｈ）。N₂O 通量与气温、土壤融化时间均呈指数关系（P＜０．０１）,说明在冻结期,温度仍是控制微生物活性的主要因素,而在融化期,温度和冻层融通是导致N₂O 通量迅速增加的重要原因。总之,生长季N₂O 排放量为２０５．５４ｍｇN₂O／ｍ^２,为N₂O 的“源”,非生长季N₂O 排放量为－２６．９７ ｍｇN₂O／ｍ^２,为N₂O 的“汇”,全年N₂O 排放量为１７８．５７ｍｇN₂O／ｍ^２,为N₂O 重要释放“源”。     

生长季与非生长季小叶章湿地N2O通量特征及排放贡献

 ：２００３年５月－２００４年４月,利用静态箱－气相色谱法对生长季与非生长季三江平原小叶章湿地N₂O 通量特征及排放贡献进行了研究。结果表明,生长季N₂O 呈脉冲式排放,通量介于０．００５～０．１１１ｍｇ／（ｍ^２·ｈ）,５月较低通量与降水较多有关,６月通量骤然增加与冻层融通有关,７－８月与降水少及蒸发旺盛有关,９月与土壤中较多氮有关。N₂O 通量与５ｃｍ 地温呈显著正相关（P＜０．０１）;非生长季N₂O 表现为“吸收－排放”,通量介于－０．００１５～０．０４９７ｍｇ／（ｍ^２·ｈ）。N₂O 通量与气温、土壤融化时间均呈指数关系（P＜０．０１）,说明在冻结期,温度仍是控制微生物活性的主要因素,而在融化期,温度和冻层融通是导致N₂O 通量迅速增加的重要原因。总之,生长季N₂O 排放量为２０５．５４ｍｇN₂O／ｍ^２,为N₂O 的“源”,非生长季N₂O 排放量为－２６．９７ ｍｇN₂O／ｍ^２,为N₂O 的“汇”,全年N₂O 排放量为１７８．５７ｍｇN₂O／ｍ^２,为N₂O 重要释放“源”。     

鸡源乳杆菌微胶囊的制备及特性研究

为了提高益生菌对不良环境的抗性,使其以活性状态到达肠胃并发挥相应的功效,采用微胶囊包被与冷冻干燥相结合的技术,以实验室分离的鸡源乳杆菌为对象,设计L9（34）正交试验,筛选制备乳杆菌微胶囊的最佳配方,并检测乳杆菌微胶囊的特性。试验结果证明,海藻酸钠浓度为3%,氯化钙浓度为2%,脱脂奶粉浓度为4%,乳糖浓度为6%时,制备的微胶囊中活菌包埋产率最高,达到92.40%,且产品具有较好的耐酸性与肠溶性,在室温下具有较好的贮存稳定性。     

禽流感病毒CH02株(H9)的鉴定及其NS 基因分子特征分析

从疑似感染H9亚型禽流感病毒的病鸡内脏组织中分离到1株能凝集鸡红细胞的病毒,通过血凝抑制试验、鸡胚中和试验、RT-PCR鉴定,确认其为H9亚型禽流感病毒,并命名为CH02株。该病毒HA效价为2^7.67±0.58;其血凝性可被抗H9亚型禽流感病毒阳性血清完全抑制,HI效价为7log2;鸡胚半数感染量(EID₅₀)为10^-8.68 EID₅₀/0.1 mL;最小致死剂量致鸡胚死亡的平均时间(MDT)为85.6 h;1日龄鸡脑内致病指数(ICPI)为0.625;其NS基因与香港株、南京株、北京株、汕头株、韩国株、巴基斯坦株的核苷酸同源性为88.6%~100%,经进化分析CH02株与香港株(A/duck/Hong Kong/Y280/97)同属一个分支。     

盐酸环丙沙星在患子宫内膜炎奶牛子宫内给药的药物浓度

本研究以反相高效液相色谱为定量分析手段，选用5头患子宫内膜炎的奶牛，通过子宫内灌注盐酸环丙沙星（2.5 g/头），研究了盐酸环丙沙星在患子宫内膜炎奶牛体内的药物动力学规律。以二氟沙星为内标，血浆样品经甲醇沉淀蛋白，离心，经针头式过滤器处理，用反相高效液相法测定其中盐酸环丙沙星的浓度。 色谱条件为：ODS-1C₁₈柱；测定流动相为0.015 mol/L四丁基溴化铵溶液-乙腈（92∶8，V/V），pH为3.0；流速为1.0 ml/min；荧光检测器，激发波长（λex）278 nm，发射波长（λem）465 nm。通过采用MCPKP房室分析程序，分析血中浓度 时间数据，发现有3头奶牛血样药时数据符合无吸收三室开放模型。其血样中主要药动学参数为：T_1/2α为0.916 h、T_1/2β为49.20 h、AUC高达7.6296 mg/L·h、Clβ为1.582 L/kg·h，β为0.642 h^-1。有2头奶牛血样药时数据符合一级吸收二室开放模型。其主要药动学参数为：T_1/2α为1.26 h、T_1/2β为9.2 h、AUC高达28.336 mg/L·h，β为0.3571 h^-1。试验结果表明，盐酸环丙沙星子宫给药吸收快，分布广，消除慢。     

日粮阴阳离子差对奶牛的影响及其在生产实践中的应用研究进展

阴阳离子差(DCAD)是指日粮中每千克或每百克干物质所含的主要阳离子（Na⁺、K⁺、Ca²⁺、Mg²⁺）毫摩尔数与主要阴离子（Cl^-、S^2-、PO^3-₄）毫摩尔数之差。DCAD直接影响奶牛血液的酸碱平衡及酶系统等的功能，可以改善奶牛的健康状况、提高奶牛生产性能。在此，作者综述了国内外关于调节日粮阴阳离子差对奶牛影响的研究结果及现状，探讨了DCAD在奶牛不同阶段生产实践中的应用。     

SA、H2O2 和6-BA预处理对沟叶结缕草耐寒性的影响

 通过对沟叶结缕草进行叶面喷施信号化合物ＳＡ、H₂O₂ 和6-BA,研究了预处理对沟叶结缕草耐寒性的影响。结果表明,ＳＡ、H₂O₂ 和6-BA预处理可以有效控制或者防止结缕草叶片中活性氧的积累和氧化伤害的发生,从而提高其抗寒性;预处理植株中ＰＯＤ、ＣＡＴ 和ＡＰＸ 活性在胁迫过程中显著高于对照,冷胁迫本身可以诱导ＳＯＤ 的活性避免O₂ ^-的积累,ＧＲ 在抗寒胁迫过程中可能起到负反馈的作用,抗氧化酶活性升高与沟叶结缕草耐寒性的获得密切相关;在这３种信号化合物中,ＳＡ 预处理植株中ＳＯＤ,ＣＡＴ 和ＧＲ 活性高于对照和其他化合物预处理植株,并且具有最小的ＭＤＡ 浓度,因此,ＳＡ 对于提高沟叶结缕草的耐寒性最有效。     

猪流感病毒H1、H3、N1、N2亚型分型 RT-PCR方法的建立

根据GenBank中H1N1和H3N2亚型猪流感病毒(SIV)血凝素(hemagglutinin,HA)、神经氨酸酶(neuraminidase,NA)和M基因保守序列,分别设计合成了5对特异性引物,利用RT-PCR技术对SIV的型和亚型进行鉴定。结果表明,该方法的型RT-PCR可以检测出10⁴ EID₅₀病毒量所提取的RNA;H1、H3、N1和N2的亚型RT-PCR均可以检测出10⁴ EID₅₀病毒量所提取的RNA。除每对特异性引物所对应的亚型外,对其他亚型及猪繁殖与呼吸综合征病毒(PRRSV)和猪瘟病毒(CSFV)的检测均为阴性,应用该方法对临床样品进行检测,其结果与病毒分离结果符合率为100%。结果表明,该方法特异性好、敏感性高,有望成为SIV的一种特异、敏感、快速的分型检测方法,为猪流感分子流行病学的调查奠定了良好的基础。     

二氢吡啶对生长阶段猪生长性能的影响研究

为探讨二氢吡啶对生长阶段（20～60 kg）猪生长性能的影响及作用机理，试验选体重25 kg生长猪21头，随机分为3组，日粮中添加不同浓度（0、10、20mg/kg）的二氢吡啶。结果表明：20 mg/kg组在试验前期具有一定促生长作用，后期无促生长作用。血清中T₃、T₄、生长激素、胰岛素在试验前期含量有升高趋势，皮质醇含量呈下降趋势，试验后期相反。10 mg/kg组无促生长作用。     

保健型香蕉酸奶的研制

以香蕉、脱脂奶粉为主要原料,研制了一种新型的凝固型酸奶。结果表明：香蕉最佳护色工艺为100℃,热烫8min后加入0.2%柠檬酸、0.1%半胱氨酸及0.1%维生素C混合打浆;凝固型香蕉酸奶的最佳配方为：乳酸菌用量5%,脱脂奶粉用量12%,香蕉浆用量6%,蔗糖用量6%。产品清香爽口、凝乳均匀、酸甜适当、营养丰富、风味独特,在4℃下可储存9d。通过果蝇生存试验证实,该酸奶具备延缓衰老的功效。     

铁皮石斛多糖发酵乳饮料工艺优化

以铁皮石斛多糖提取液、脱脂乳粉为主要原料,发酵制备铁皮石斛多糖酸乳饮料.铁皮石斛多糖乳饮料的最佳工艺参数(以质量分数计):50％铁皮石斛多糖溶液添加量10％、蔗糖添加量7％、发酵剂(保加利亚乳杆菌:嗜热链球菌=1:1)接种量0.10％,在发酵温度42℃条件下发酵6h,所得铁皮石斛多糖酸乳饮料风味最佳.     

Enhancement of viability of a probiotic Lactobacillus strain for poultry during freeze‐drying and storage using the response surface methodology

A rotatable central composite design (CCD) was used to study the effect of cryoprotectants (skim milk, sucrose and lactose) on the survival rate of a probiotic Lactobacillus strain, L. reuteri C10, for poultry, during freeze‐drying and storage. Using response surface methodology, a quadratic polynomial equation was obtained for response value by multiple regression analyses: Y = 8.59546 ? 0.01038 X₁ ? 0.09382 X₂ ? 0.07771 X₃ ? 0.054861 X₁² ? 0.04603X₃² ? 0.10938 X₁X₂. Based on the model predicted, sucrose exerted the strongest effect on the survival rate. At various combinations of cryoprotectants, the viability loss of the cells after freeze‐drying was reduced from 1.65 log colony forming units (CFU)/mL to 0.26–0.66 log CFU/mL. The estimated optimum combination for enhancing the survival rate of L. reuteri C10 was 19.5% skim milk, 1% sucrose and 9% lactose. Verification experiments confirmed the validity of the predicted model. The storage life of freeze‐dried L. reuteri C10 was markedly improved when cryoprotectants were used. At optimum combination of the cryoprotectants, the survival rates of freeze‐dried L. reuteri C10 stored at 4°C and 30°C for 6 months were 96.4% and 73.8%, respectively. Total viability loss of cells which were not protected by cryoprotectants occurred after 12 and 8 weeks of storage at 4°C and 30°C, respectively.     

猕猴桃奶豆腐加工工艺及配方研究

开发一种新型的适合大众口味的高营养奶制品。以山羊奶为主要原料,以适量的猕猴桃汁和白砂糖等作为辅料,通过工艺改进和配方优化,加工一种新型山羊奶制品。得出猕猴桃奶豆腐的加工工艺为:原料乳(制作奶皮子后的脱脂乳)→杀菌→添加发酵剂→自然凝乳→切割→排乳清→升温搅拌→保温搅拌→静置→排乳清→切碎→压榨→成形→冷藏。配方为:鲜羊奶75%,猕猴桃汁17%,白砂糖8%,再加入少量的甜味剂和调味剂。研制的猕猴桃奶豆腐既有羊奶的乳香、猕猴桃的酸甜,同时更富于其更全面的营养物质。     

乳清蛋白对羊、牛混合乳粉发酵乳品质的影响

本试验研究了不同比例羊奶粉、脱脂牛乳粉及浓缩乳清蛋白WPC-34代替部分混合奶粉生产酸乳,对酸乳发酵品质特性的影响,测定了pH值、滴定酸度、黏度和持水性,并做了感官评价。结果表明,用脱脂牛乳粉和羊奶粉按不同比例制作酸乳时（乳固形物恒定为13％）,随着羊奶粉比例的增加,凝块变软,黏度降低,NpH值和滴定酸度变化不明显,在羊奶粉比例小于70％时感官评价分数降低不明显,然而当大于70％时感官评价有明显的下降趋势。当使用WPC-34替代混合乳粉（固形物含量为13％）发酵酸乳时,在替代率为10％-40％时滴定酸度、黏度、持水性均出现了先上升后下降的趋势,各项指标均在替代率为20％时达到最好。     

Motility and fertility of boar semen after liquid preservation at 5°C for more than 2 weeks

This study investigated the effects of skim milk on the quality and fertility of boar spermatozoa under long‐term chilled preservation. Semen samples were stored in Modena solution supplemented with 0 (control) to 50 mg/mL skim milk at 5°C for 4 weeks; spermatozoa stored with 7.5 and 15 mg/mL of skim milk (7.5‐SM and 15‐SM groups, respectively) exhibited significantly higher motility indices than those of the control group up to 3 weeks (P < 0.05), and the 7.5‐SM group showed improved motility indices even after 4 weeks (P < 0.05). In vitro fertilization using spermatozoa in the 7.5‐SM and 15‐SM groups stored at 5°C for 2 weeks showed significantly higher fertilization rates of spermatozoa and the development rates to blastocyst than the control group (P < 0.05), and the 7.5‐SM group showed similar rates of fertilization and blastocyst formation in the fresh non‐stored spermatozoa group. After artificial insemination using spermatozoa stored for 2 weeks in the 7.5‐SM group, healthy piglets were obtained. Boar spermatozoa can be stored at 5°C in a Modena solution containing skim milk. Supplementation of 7.5 mg/mL skim milk improves boar spermatozoa motility and fertility even after liquid preservation at 5°C for 2 weeks.     

褐色乳酸菌饮料加工工艺优化

以脱脂乳粉与葡萄糖为原料,经热处理发生美拉德反应,再通过干酪乳杆菌长时间发酵,添加白砂糖、稳定剂、酸味剂等辅料制得褐色乳酸菌饮料.通过对热处理条件、稳定剂、糖酸比等参数的优化,开发出一种风味浓郁稳定性较好的褐色乳酸菌饮料工艺.结果表明:杀菌条件115℃、15 min;稳定剂最优组合为羧甲基纤维素添加量0.10％、海藻酸丙二醇酯添加量0.05％、果胶添加量0.15％;糖酸比为蔗糖添加量9％,pH 4.0.     

Comparison of 2 enzyme immunoassays and a radioimmunoassay for measurement of progesterone concentrations in bovine plasma, skim milk, and whole milk

The objective of this study was to compare 2 enzyme immunoassays (EIAs) with a radioimmunoassay (RIA) as to sensitivity and accuracy in the measurement of the progesterone (P4) concentration in bovine plasma, skim milk, and whole milk. The 72 samples from 24 lactating dairy cows expected to have either a high P4 concentration (cows in diestrus or pregnant) or a low P4 concentration (cows in estrus or anestrus) were analyzed by RIA, solid-phase EIA (SPEIA), which included a solvent extraction step, or direct EIA (DEIA) without solvent extraction. The overall mean concentrations of P4 did not differ (P < 0.4) among the assays. However, for the cows that were in diestrus or pregnant, the mean P4 concentrations (and standard error) were higher (P < 0.03), regardless of sample type, with RIA than with SPEIA, at 7.3 (0.7) and 6.1 (0.6) ng/mL, respectively. When only the high-P4 samples analyzed by RIA were compared, the mean P4 concentration was higher (P < 0.001) in whole milk than in skim milk, at 9.8 (1.0) and 4.1 (0.7) ng/mL, respectively. Although the mean P4 concentrations in the low-P4 samples did not differ (P < 0.80) among assays, the proportions of cows with a P4 concentration > or = 1 ng/mL were 3%, 14%, and 44% for RIA, SPEIA, and DEIA, respectively (P < 0.01; DEIA > SPEIA > RIA).     

体外转录法制备新城疫病毒荧光定量RT-PCR标准阳性模板

本研究针对新城疫病毒M基因设计了1对荧光定量RT-PCR引物和Taqman探针,在上游引物的5′端引入T7启动子,采用RT-PCR方法获得了体外转录模板,并对转录产物RNA的浓度及D值进行了测定。线性试验和特异性试验结果表明,该模板具有良好的线性范围和特异性,模板稀释度为2.95×104～2.95×108拷贝/L时,相关系数为0.998。该模板稳定性好,-80℃保存30 d后无显著变化。浓度为2.95×104～2.95×108拷贝/μL的标准品的变异系数分别为0.20%、0.28%、1.00%、0.54%、0.52%,表明以此模板进行荧光定量PCR具有较好的重复性。     

Freezability of Tushin Ram Semen Extended with Goat or Cow Milk Based Extenders

Cow milk is used as an extender for ram semen cryopreservation. Caseins, the major proteins of milk, appear to provide some protective effect to sperm during cryopreservation. Goat milk has unique casein structure. The aim of this study was to investigate effect of goat milk, as a main semen extender, on freezability of Tushin Ram semen. For this aim, ejaculates from four Tushin rams were collected with artificial vagina and pooled. Pooled semen was separately extended with four different extenders: TRIS based (TRIS), cow skim milk based (CSM) (10 g/100 ml), cow semi‐skim milk based (CSSM) and goat semi‐skim milk based (GSSM) extenders, containing egg yolk and glycerol. The semen was cryopreserved and stored in liquid nitrogen until examination date. After thawing (at 37°C for 1 min), sperm motility, viability, morphology, acrosome and membrane integrity (HOST) were evaluated. Although, there was not any significant differences between extenders in post‐thaw percentage of viable spermatozoa (p > 0.05), Tushin ram semen extended with GSSM or CSM extenders had significantly higher post‐thaw percentage of progressive motility (25.0% and 30.8% respectively), compared with CSSM and TRIS (7.5% and 14.1% respectively, p < 0.001). Moreover, lowest abnormality percentage of post‐thaw spermatozoa were detected in ram semen extended with GSSM (49.5%) and CSM (51.5%), compared with CSSM (65.7%) and TRIS (60.7%) (p < 0.05). Whilst the results were considered, it was concluded that goat milk based extenders may be effectively and trustfully used in cryopreservation of Tushin ram semen, instead of cow milk and Tris based extenders, as a main extender.