Effect of dietary energy on digestibilities,rumen fermentation,urinary purine derivatives and serum metabolites in Tibetan and small‐tailed Han sheep

Tibetan sheep are indigenous to the Qinghai–Tibetan Plateau, graze the grassland all year round without supplementation and are well‐adapted to the harsh conditions. Small‐tailed Han sheep were introduced to the plateau and are raised mainly in feedlots. Based on their different backgrounds, we hypothesized that the ability to cope with poor diets would be better in Tibetan than in Han sheep. To test our prediction, we examined the effect of dietary energy on apparent digestibilities, rumen fermentation, urinary purine derivatives and serum metabolites by using a 4 × 4 Latin square design in each sheep breed. Four diets were formulated to be low in crude protein (~7%) but to differ in metabolizable energy concentration. Average daily gain was greater in Tibetan than in Han sheep (p < 0.01) and increased linearly with an increase in energy intake (p < 0.001). The digestibilities of dry matter, organic matter, gross energy, and neutral and acid detergent fibres were greater in Tibetan than in Han sheep (p < 0.05). Ruminal pH was lower (p < 0.05), while volatile fatty acids (VFAs), urea‐N, ammonia‐N and soluble protein‐N concentrations were higher (p < 0.05) in Tibetan than in Han sheep. As a molar proportion of total VFA, acetate decreased (p < 0.001) with an increase in dietary energy whereas propionate and butyrate increased (p < 0.05). Urinary purine derivative excretion was greater in Tibetan than in Han sheep (p < 0.01), as was microbial nitrogen production; both parameters increased with dietary energy (p < 0.01). Serum concentrations of glucose, insulin and insulin‐like growth factor‐1 increased (p < 0.05) as energy level increased, while non‐esterified fatty acids and growth hormone decreased (p < 0.05). It was concluded that Tibetan sheep were better able to cope with low‐protein, low‐energy diets and, consequently, our prediction was supported.     

外源调节物质对干旱胁迫红椿苗木形态及光合生理的影响

【目的】探明褪黑素（MT）、水杨酸（SA）和茉莉酸甲酯（MeJA）3种外源调节物质对干旱胁迫红椿苗木表观形态及光合生理的影响,筛选对红椿干旱损伤缓解效果最好的外源物质。【方法】以2年生红椿幼苗作为试验材料,通过盆栽控水试验,设置土壤湿度为45%,对红椿进行中度干旱胁迫（MD）处理,在此基础上分别外源施加0.1 mmol/L MT（MD+MT）、0.5 mmol/L SA（MD+SA）和0.4 mmol/L MeJA（MD+MeJA）进行3个缓解试验处理,同时设土壤湿度为70%的正常供水对照（CK）,比较各处理红椿幼苗生长指标、表观形态、气孔和叶肉细胞形态、叶绿素含量、气体交换参数和叶绿素荧光参数的变化情况,运用隶属函数法综合评价3种外源物质的干旱缓解效果。【结果】①中度干旱胁迫(MD)会抑制红椿幼苗地径、株高和叶长等的生长,MD+SA处理可显著缓解干旱对地径和株高的抑制,但MD+MeJA处理对地径生长有抑制作用,MD+MT处理对株高生长有抑制作用。②中度干旱胁迫会损害红椿叶片的表观形态、气孔及叶肉细胞形态,MD+SA处理对红椿叶片脱落、叶色、气孔开闭程度及叶肉细胞形态有明显恢复效果,MD+MeJA处理对红椿叶片萎蔫情况和气孔开闭程度的恢复具有明显缓解效果。③中度干旱胁迫会显著抑制红椿的光合作用,MD+SA处理对干旱胁迫下红椿叶绿素含量、气孔参数和叶绿素荧光参数的抑制有缓解作用,MD+MeJA处理对气孔参数和叶绿素荧光参数有一定缓解作用,MD+MT处理仅对叶绿素荧光参数有缓解效果。④抗旱性综合评价结果显示,MD+SA、MD+MeJA和MD+MT处理抗旱性指标的隶属函数均值分别为0.55,0.52和0.45,表明MD+SA处理对红椿干旱损伤的缓解效果最好。【结论】干旱胁迫条件下,红椿表观形态受损,叶绿素含量下降,气体交换参数和PSⅡ反应中心等光合机构受损;MT、SA和MeJA 3种外源调节物质均可以缓解干旱胁迫下红椿的受损情况,且SA的调节效果最好。     

山东近海星康吉鳗体长-体质量关系及其时空异质性

为了解山东近海星康吉鳗(Conger myriaster)体长和体质量等生物学特征,基于2016年10月和2017年1月、5月、8月山东近海4个航次底拖网调查采集的星康吉鳗样本,研究了星康吉鳗体长、体质量组成以及肥满度的时空差异,并利用线性混合效应模型分析了其体长-体质量关系的时空异质性。结果表明,山东近海星康吉鳗的体长、体质量、体长-体质量关系参数以及肥满度在时空上均有较大波动。冬季航次星康吉鳗的平均体长、体质量显著小于其他3个航次(P<0.05)。肥满度季节间差异显著,夏季肥满度显著大于其他季节。线性混合效应模型表明,季节和水域对星康吉鳗的体长-体质量关系参数a具有显著的影响。最优模型中,参数b的估计值为3.27,参数a在不同季节和海区的变动范围为4.78×10^-4～5.68×10^-4,其中夏季的a值最大,秋季和冬季次之,在春季最小;Ⅲ区(水深>50m)最大,Ⅰ区(水深<30m)次之,Ⅱ区(30m≤水深≤50m)最小。星康吉鳗体长-体质量分布特征及其相关关系的季节和水域变化可能与其洄游习性、摄食强度以及饵料丰度等有关。未...     

Thermal Properties of Starch in Corn Variants Isolated After Chemical Mutagenesis of Inbred Line B73

The starch from eight ethyl methanesulfonate (EMS) treated M4 families of the corn (Zea mays L.) inbred line B73 was analyzed using differential scanning calorimetry (DSC), a Rapid Visco Analyser (RVA), a texture analyzer (TA), and scanning electron microscopy (SEM) coupled with image analysis. The eight families were chosen from 144 families previously selected for having starch with unusual DSC parameters. Apparent amylose contents of the starch from the eight families generally were lower than that of the control. According to DSC, starches from mutagenized families tended to have lower onset temperature (T₀) of gelatinization, enthalpy (ΔH) of gelatinization, and peak height index (PHI), but broader gelatinization range (R) than the B73 control. Their values for ΔH and percentage of retrograzdation (%R) were clustered around that of the control. Pasting properties from the RVA of the starches from the M4 families also were clustered around those of the control B73 starch, except for the setback values which were lower than B73 for M4 starches. Gel firmness values, as measured by TA, of all the M4 starches were generally lower than that of the B73 starch at storage treatments of one day at 25°C or seven days at 4°C. The stickiness of the gels of the M4 starches tended to be greater than that of B73 after seven days of storage at 4°C. These observations were consistent with the lower apparent amylose values for the M4 starches. SEM and image analysis data revealed no differences among the treatments in granule size and shape. Possibly, EMS treatment altered the genes, affecting internal structure of the starch granules. Starch from the mutagenized families likely had lower bonding forces among molecules and fewer long chains in the amylopectin molecules than did B73.     

基于试验和分子动力学模拟的海藻多糖热解机理

该文选取海藻内2种主要的多糖分子:条浒苔硫酸多糖和羊栖菜褐藻糖胶,采用Py-GC/MS、TG-MS宏观试验和微观分子动力学模拟的方法研究海藻多糖热解过程及其热解主要产物的形成机理,Py-GC/MS试验表明条浒苔多糖的热解产物以呋喃类物质为主,典型产物为5-甲基-糠醛,而羊栖菜多糖的热解产物以酸酯类物质为主。对海藻多糖模型化合物的热解过程进行分子动力学模拟发现热解过程主要发生在中温阶段,温度升高到420 K时,开始有羟基断裂;温度升高到500 K时,糖苷键开始断裂,环状单体内部化学键相继分解成各种分子碎片,由于其成分差异,热解产物也不尽相同,模拟分析的热解规律与试验结果基本一致。该文还结合TG-MS试验结果推导其热解过程中主要气体产物H2O、CO2、SO2的形成机理。     

奶牛体征参数监测系统设计

根据奶牛发情期和发病时活动量异常和体温波动的特点,设计了奶牛体征参数检测系统采集奶牛的活动量和体温,对于奶牛的发病诊断和生活环境分析具有重要意义。该系统以16位超低功耗混合信号处理器MSP430F133、数字温度传感器DS18B20和ND专用传感器为硬件核心,实现了奶牛体征参数的实时监测,并进行了系统硬件和软件设计。该系统结构简单、易于实现、可靠性较高,且功能易于扩展,能够对奶牛的体征参数进行定时、连续、无损伤、精确地测量和记录。     

卷曲乳杆菌对生长猪生长性能、粪便菌群和短链脂肪酸组成以及血清长链脂肪酸组成的影响

本试验旨在研究猪源卷曲乳杆菌对生长猪生长性能、粪便菌群和短链脂肪酸组成以及血清长链脂肪酸组成的影响。选取体重(20.35±0.53) kg的二元杂交(长×大)生长猪120头,随机分成2组,每组4个重复,每个重复15头。对照组饲喂基础饲粮,试验组在基础饲粮中添加卷曲乳杆菌冻干制剂(卷曲乳杆菌添加量为5.5×109CFU/kg),饲喂期为30 d。饲养试验结束当天采集新鲜粪便用于16S rRNA V3～V4区菌群和短链脂肪酸组成的测定,采集血清用于长链脂肪酸组成的测定。结果显示:1)与对照组相比,试验组生长猪平均日增重提高了7. 32%(P <0.05),料重比降低了5.68%(P<0. 05); 2)饲粮中添加卷曲乳杆菌能够提高生长猪粪便菌群物种丰富度,增加厚壁菌门及乳酸杆菌属和光岗菌属的比例; 3)与对照组相比,试验组生长猪粪便中丁酸含量增加了6.20%(P<0.05),乙酸含量减少了9.88%(P<0.05); 4)试验组猪群血清中亚油酸和花生四烯酸含量分别比对照组提高了11.12%(P<0.05)和6.28%(P<0.05)。上述结果表明,在饲粮中添加5.5×109CFU/kg卷曲乳杆菌能够影响生长猪的粪便菌群组成,增加粪便中丁酸的含量,并改善血清中不饱和脂肪酸的组成,从而对生长猪的肠道健康及生长起到促进作用。     

白菜型油菜冬油2号选育报告

冬油2号是以郑杂1号为母本,宁油1号为父本通过杂交选育而成的白菜型油菜品种。在2010—2012年的甘肃省油菜品种区域试验,2 a平均折合产量2 349.45 kg/hm²,比对照品种天油4号增产2.56%;2011—2012年度参加生产试验,平均折合产量2 882.55 kg/hm²,比对照品种天油4号增产8.49%。该品种株高114.9 cm,单株有效角果数179.9个,角粒数22.9粒,千粒重3.2 g。芥酸含量187 g/kg,硫苷73.41μmoL/g,含油量417.2 g/kg。适宜在甘肃省中东部天水、平凉、陇西、宁县等地种植。     

应用Logistic模型研究糯玉米果穗的生长动态

为了提高糯玉米栽培技术和品种选育效果,应用Origin软件对糯玉米品种‘垦粘1号’,‘吉糯3号’和‘京科糯2000’的果穗的生长动态进行Logistic曲线拟合,并对拟合结果进行分析。结果表明,各糯玉米品种的单穗重与果穗发育时间可用Logistic曲线方程拟合且各糯玉米品种单穗重的Logistic曲线方程相关系数均大于0.99,达极显著水平;各测量值与曲线拟合值间的残差相对较小,且残差随时间变化具周期性;通过所求曲线参数求得的糯玉米单穗重发育的关键点和关键时期,能更好的说明糯玉米单穗重的发育过程,实验结果表明Logistic曲线能较好地反映糯玉米单穗重的生长动态。     

纳米蛹虫草活性肽靶向型微囊降血糖活性研究

为探究纳米蛹虫草活性肽靶向型微囊的降血糖活性,通过复相乳液法制得蛹虫草肽聚乳酸微囊,进行了蛹虫草肽聚乳酸微囊对小鼠降血糖指标的影响试验.结果表明,经STZ干预后,连续灌胃4W,模型对照组以及M CP组小鼠体重明显低于正常对照组(P<0.01),MCP中剂量组降血糖浓度效果最佳可达38.12％,与模型对照组比较,阳性对照组与MCP组小鼠的血糖水平和AUC均显著降低(P<0.05),除心/体比各组间无明显差异,其它脏/体比呈现显著性差异(P<0.05);考察TG、CHO、BUN指标影响,MCP各剂量组、阳性对照组均显现明显的下降现象(P<0.05),且中剂量组效果最佳.可见,纳米蛹虫草活性肽靶向型微囊对小鼠血糖调节具有明显的改善作用.