猪饲料有效能值预测模型的构建

为探索饲料常规成分及碳水化合物组分与饲料有效能值之间的关系方程,本研究以NRC第11版《猪营养需要量》中发布的122套饲料营养成分表为基础,将饲料中11种基础成分[6项常规成分:干物质、粗蛋白质(CP)、粗纤维(CF)、粗脂肪(EE)、酸性醚提取物、粗灰分(ash);5项碳水化合物组分:淀粉(ST)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、半纤维素、酸性洗涤木质素]作为自变量,将饲料中的消化能(DE)、代谢能(ME)及净能(NE)作为因变量,采用SAS软件中的REG过程,分别建立不同性质饲料、自变量的不同组合与DE、ME及NE之间的回归关系方程,并以相关系数(R2)及变异系数(CV)作为评价回归模型的优劣。研究表明,有效能值与CP、ST及纤维类指标显著或极显著相关(P0.05或P0.01)。将所有饲料作为研究对象时,饲料的DE、ME及NE与上述11种基础成分之间建立的普适性回归模型预测效果较差。当将14种玉米及其加工产品形成子集时,建立饲料基础营养成分与DE、ME及NE的关系方程分别为7、6和7套(P0.05),且3组回归模型R2分别为0.632 8~0.772 3、0.646 9~0.684 9和0.670 5~0.822 1,CV分别为6.61%~8.40%、6.58%~7.34%和6.21%~8.27%;当将13种大豆及其加工产品形成子集时,共建立饲料基础成分与DE、ME关系方程分别有3和4套,回归模型R2分别为0.907 1~0.926 9、0.890 7~0.922 3,CV分别为5.40%~6.09%、5.79%~6.78%,NE与基础营养成分指标之间无法建立具有营养学意义的有效回归方程。对于同类饲料中具有相同自变量组合的DE及ME预测模型而言,两者之间的差异主要是自变量CP的系数上,且CP部分对ME的正效应低于DE,这保证模型预测的ME低于DE。同时选用本研究构建的适宜模型,补充了NRC第11版成分表中第97(去皮大豆粕,低寡糖,浸提)、101(全脂大豆,高蛋白质)及102号(全脂大豆,低寡糖)饲料的DE值分别为15.99、17.35、17.27 MJ/kg,ME值分别为14.53、16.15和16.14 MJ/kg。综上,以NRC(2012)饲料营养成分表为基础,建立的普适性有效能值回归模型预测效果较差。按照玉米类和大豆类进行分类,可建立DE、ME和NE与饲料化学成分之间的多元回归方程,其中最优的预测因子为CP、EE、ST、ash、NDF、ADF。具有相同自变量的同类饲料DE和ME预测模型之间的差异是CP系数,CP影响DE转化为ME的效率。     

Life Histories of Frogs in the Namib Desert

Four anuran taxa inhabit the central Namib: Xenopus laevis, Tomopterna delalandei cryptotis, Phrynomerus annectens and Bufo vertebrate hoeschi. Xenopus is confined to permanent pools in the Kuiseb river canyon. Tomopterna extends further into the Namib, but is restricted to the Kuiseb river bed. The Kuiseb is normally dry, receiving water only briefly (as floods) during the rainy season. These floods are responsible for moving adults and larvae. Phrynomerus and Bufo occur on granite inselbergs. The inselbergs provide shelter mainly in the form of cracks under granite exfoliations. Large runoff surfaces collect the low rainfall (25 mm per year) in depressions in which the frogs breed. Phrynomerus is only active at night; males are aggressive towards one another; oviposition takes place in deep pools and development takes at least eight weeks. Bufo is active during the heat of the day; oviposition takes place in warm shallow pools; development takes about three weeks.     

饲料添加剂L-赖氨酸硫酸盐中L-赖氨酸含量近红外速测方法研究

为了探讨利用近红外漫反射光谱技术(NIDRS)快速定量分析饲料添加剂L-赖氨酸硫酸盐中L-赖氨酸含量的可行性,本试验在全国范围内收集了具有代表性的L-赖氨酸硫酸盐添加剂76个,采用国家标准方法对样品中的L-赖氨酸含量进行化学赋值;用光栅型近红外光谱仪扫描L-赖氨酸硫酸盐样品,获取了不同物理状态下样品的近红外光谱图。依据L-赖氨酸含量将样品分为定标集和验证集,运用适当的光谱预处理方法,采用竞争性自适应重加权(CARS)算法结合偏最小二乘法(PLS)建立了L-赖氨酸硫酸盐的近红外定标分析模型,并将该模型与全波长模型进行了比较。结果表明:用烘干、60目粉碎后的样品结合CARS算法建立的定标模型最优,定标集校正决定系数(R2C)为0.954,校正集标准偏差(SEC)为0.510,交互验证标准偏差(SECV)为0.659;验证集预测决定系数(R2P)为0.952,预测标准偏差(SEP)为0.554,相对分析误差(RPD)值为3.83。由此可见,NIDRS定量分析L-赖氨酸硫酸盐具有一定可行性,对于丰富我国氨基酸盐及其他氨基酸制品的快速检测方法具有实际的应用意义。     

Body weight growth Model of Datong Yak in Qinghai

Summary:This study was conducted to develop a suitable model for describing the growth pattern of the yak. The data used consisted of body weight records of 76 growing yak aged between 5 to 37 months. Three mathematical models were applied to describe the growth curves during this development period:①Y1=20.105 + 11. 250x-0. 526x2 ;used for describing the growth curve of yak aged 5 to 13 months;②Y2 = -359.687 + 49. 977x - 1. 249x2 ;used for animals aged 13 to 25 months;and ③Y3 = -833. 339 + 63. 772x - 1. 019x2 ;used for animals aged 25 to 37 months.     

类胡萝卜素吸收研究进展

关于类胡萝卜素的吸收机制说法不一,目前体外培养的细胞模型被广泛用于类胡萝卜素的吸收研究。本文主要从细胞水平上讨论了类胡萝卜素的吸收研究进展,并详细讨论了类胡萝卜素吸收机制方面研究较多的选择性吸收及吸收过程中的相互影响。细胞对β-胡萝卜素的摄入和分泌表现出浓度依赖性、时间依赖性和饱和性;对不同类胡萝卜素的吸收表现出选择性;类胡萝卜素在吸收过程中表现出相互影响。上述研究结果表明,类胡萝卜素的吸收可能是一个有载体参与的易化运输过程。     

河西半荒漠驴驴蒿草原土壤水盐动态及其对牧草生长的影响

对驴驴蒿草原三个草地型(驴驴蒿型,驴驴蒿—红砂型,驴驴蒿+珍珠型)的土壤水盐动态及其与牧草产量的关系进行了研究。结果表明:土壤水分变化受雨量的影响具有阶段性。随着土壤深度的增加,土壤含水量随时间的变化而变小。土壤各层内,春季含水量相近,并呈下降趋势,夏季变化大,秋冬则随土壤深度增加而增加,趋向稳定。盐分随水分而移动,其含量基本上随土壤深度的增加而增加。牧草产量的变化与土壤水分的变化具有“一致性”。在驴驴蒿型和驴驴蒿—红砂型中,驴驴蒿的绝对生长量与0～40cm内各土层的含水量呈显著的正相关,并建立了产量预测模型。     

An animal model for interface tissue formation in cemented hip replacements

OBJECTIVE: To create a model in sheep for investigation of early changes related to the formation of an interface membrane in hip prosthesis. STUDY DESIGN: Experimental study. ANIMALS: Twenty-four female adult Swiss Alpine sheep. METHODS: Sheep were divided into 2 groups of 12 for unilateral cemented total hip arthroplasty. In Group I, the prosthesis was fixed with retrograde cement gun injection to achieve a complete cement mantle, whereas in Group II a primary cement mantle defect was produced. Groups I and II were further divided into 2 sub-groups with study end points of 2 and 8.5 months after surgery. Radiographs were evaluated postoperatively and at euthanasia for migration of the femoral component and bone resorption. Histologic sections were evaluated semiquantitatively for changes in cell types and numbers, and bone reactions; and quantitatively for size of interface membrane and new bone formation. RESULTS: Radiographically, there tended to be an increase in bone resorption and periosteal bone formation throughout the femoral shaft in Group II compared with Group I, but this was only statistically significant at the region of the femoral neck (R5) at both time periods (P<.05). Semiquantitative histologic evaluation revealed significant increases (P<.05) in cellularity, numbers of fibroblasts, giant cells, macrophages, and mononuclear cells, in Group II primarily at 2 months after surgery. This was also true for interface membrane formation and bone remodeling. Quantitative data showed an increased in the size of the interface membrane and area of bone formation at 8.5 months in Group II. CONCLUSIONS: The cement defect model offered controlled and repeatable production of an interface membrane. The results suggest that a primary cement mantle defect could be a possible trigger for implant instability, eliciting a cascade of biomechanical and molecular events in bone tissue leading to aseptic loosening. CLINICAL RELEVANCE: The results show the effect of defects in the cement mantle in promoting interface membrane formation. Long-term and biochemical studies are required to evaluate the relevance of this interface membrane formation.     

庆阳站持久高效草地农业优化模式

根据多年的技术资料和生产实际，采用线性规划法作为系统优化的基本方法，拟定了庆阳黄土高原试验站草地农业结构的优化模式。     

不同生长模型估计籽鹅早期体重发育规律及遗传参数

运用Logistic,Gompertz,VonBertalanfy和Cubic4种非线性生长模型对籽鹅1～1周龄的平均体重进行拟合,并分析生长发育规律及遗传参数。结果表明:虽然4个模型都能描述籽鹅的生长过程,拟合度均超过额0.99;但Logistic模型更符合实际饲养情况,能更好地预测体重,为最佳模型,其相应的体重极限参数A为2267.63g,调节参数B为16.27,瞬时相对生长率C为0.47,生长的拐点时间为6.48周龄,拐点体重为1136.81g。     

广西巴马小型猪动脉粥样硬化模型的制作

本试验旨在制作广西巴马小型猪动脉粥样硬化模型,初步判断猪发生动脉粥样硬化时的指数值,以期为今后建立相关模型提供依据。试验选取广西巴马小型猪试验组和对照组各10头,通过饲喂高脂高胆固醇饲料建立动脉粥样硬化模型,检测建模过程中血液生化指标,将动脉粥样硬化指数与血管切片作关联分析,初步拟定发生动脉粥样硬化时的指数值。屠宰后血管切片结果显示,试验组有2头广西巴马小型猪发生动脉粥样硬化,对照组均正常。2头广西巴马小型猪的血管切片结果与动脉粥样硬化指数进行关联分析后,初步拟定的动脉粥样硬化指数值在3.8以上,并持续3个月以上。