Methyl donors dietary supplementation to gestating sows diet improves the growth rate of offspring and is associating with changes in expression and DNA methylation of insulin‐like growth factor‐1 gene

The study aimed to investigate the effects of maternal dietary methyl donors on the performance of sows and their offspring, and the associated hepatic insulin‐like growth factor‐1 (IGF‐1) expression of the offspring. A total of 24 multiparous sows were randomly fed the control (CON) or the CON diet supplemented with methyl donors (MD) at 3 g/kg betaine, 15 mg/kg folic acid, 400 mg/kg choline and 150 μg/kg VB₁₂, from mating until delivery. After farrowing, sows were fed a common lactation diet through a 28‐days lactation period and six litters per treatment were selected to be fed until at approximately 110 kg BW. Maternal MD supplementation resulted in greater birthweight (p < 0.05) and increased the piglet weights (p < 0.01) and litter weights (p < 0.05) at the age of day 28, compared with that in CON group. The offspring pigs in the MD group had greater ADG (p < 0.05) and tended to lower F:G ratio (p = 0.07) compared with that of CON group from day 28 to 180 of age. The offspring pigs from MD group had greater serum IGF‐1 concentrations and expressions of hepatic IGF‐1 gene and muscular IGF‐1 receptor (IGF‐1r) protein at birth (p < 0.05), and greater hepatic IGF‐1 protein (p = 0.03) and muscular IGF‐1r gene expressions (p < 0.05) at slaughter, than that from the CON group. Moreover, the methylation at the promoter of IGF‐1 gene in the liver of newborn piglets and finishing pigs was greater in the MD group than that of the CON group (p < 0.05). In conclusion, maternal MD supplementation throughout gestation could enhance the birthweight and postnatal growth rate of offspring, associated with an increased expression of the IGF‐1 gene and IGF‐1r, as well as the altered DNA methylation of IGF‐1 gene promotor.     

发酵酸羊乳冻干粉的生产方法

介绍了发酵酸羊乳冻干粉的生产方法,主要有羊乳预处理、羊乳发酵、冻干制粉和包装质检四个生产工序。应用此法生产的酸羊乳冻干粉保留了酸羊乳原有的色、香、味和营养物质,还具有较高的乳酸菌生物活性。     

发酵豆粕在犊牛饲料中的应用进展

豆粕是一种优质的植物性蛋白来源,含有丰富的氨基酸,但也含有胰蛋白酶抑制因子、抗原蛋白以及大豆凝集素等抗营养因子,容易引起犊牛消化功能紊乱,造成营养性腹泻,限制了其在犊牛上的使用量。微生物发酵可以改善豆粕的营养价值,使抗营养因子得到充分的降解,生成的小肽和有机酸有利于犊牛消化吸收和肠道健康,进而提高犊牛断奶日增重和免疫能力,降低犊牛的腹泻率和断奶应激。本文综述了豆粕经过发酵后带来营养价值的变化,并就发酵豆粕在犊牛上的应用进行概述,为其今后在犊牛中的应用提供参考。     

Design method and homogeneity control of bridge fair-faced concrete

According to the structural characteristics of bridge engineering, the mix optimization design method of bridge fair-faced concrete was presented, and C30~C50 concrete with high cohesion and package, outstanding fluidity and excellent mechanical properties were prepared. Through the test of air content of fresh concrete, micro hardness and micro structure in different parts of hardened concrete specimens, effects of viscosity-modifying admixtures on homogeneity of concrete were discussed. The results showed that the composition of bridge fair-faced concrete were relatively homogeneous, and the microstructure were relatively dense. When C30 concrete mixed with 5 × 10 -5 cellulose ether or 6% silica fume (mass fraction of cementitious material), air content of fresh concrete were less than 2%, and slurry viscosity values were between 1 900 and 2 000 MPa·s. Also, the micro hardness values in different parts of hardened concrete specimens were closed. The results were applied in practical bridge engineering, which generally meets the apparent quality requirements of bridge fair faced concrete.     

实用型荔枝虫害诊断专家系统设计方法研究 实用型荔枝虫害诊断专家系统设计方法研究

针对大型检索表为表示的专家知识体系，研究提出了一套可重用的、实用性强的系统设计方法，建立了荔枝虫害诊断专家系统（LDS）。经生产示范应用表明：实现了人机操作界面直观、明了，降低了客户端的专业要求，提高了系统的实用性。还对系统所构造的人机界面、知识存储结构设计和控制策略给出实践示例。     

早籼型水稻温敏核不育系M103S的选育与光温反应特性

以温敏核不育水稻安农S—1为母本，以常规高产早籼稻品系92153为父本进行杂交，通过低温选择和人工气候箱鉴定，育成了育性转换临界温度23—24℃的早籼型温敏核不育系M103S。光周期长于12．5h，日平均温度高于24℃，可以用于制种，日平均温度低于23℃，可以用于繁殖。光周期长于13．5h，日平均温度高于23℃，可以用于制种。自然条件下不育起点温度为日均温23—24℃，耐低温期为3—4d。敏感期为抽穗前的7—14d。播始历期为53—79d，主茎叶片数10．0—12．6片。从播种到始穗的活动积温和有效积温，分别为1493．8—1766．3℃和733．4—1058．3℃。不育期的株高63．6—77．5cm，平均72．0cm，单株有效穗6．4—12．0个，平均9．3个，穗长20．9—22．7cm，平均21．2cm，每穗颖花数112．1—137．3朵，平均122．3朵。可育期株高65．7cm，单株有效穗7．2个，穗长17．2cm，每穗总粒数114．1粒，结实率47．23％，千粒重31．34g。以M103S为母本，与100多个早籼品种进行测配，杂种表现生育期早、穗大、粒多、千粒重高。     

速生人工林桉树木材材色处理初步研究

试验用漂白剂、酸性染料和其他化学药剂,采用单纯漂白、单纯染色、先漂白再染色和化学着色等4种不同的方案对人工林桉树木材进行材色改良处理研究.结果发现:单纯漂白可获得一定的材色改良效果;硫化物类、过硫酸铵类的药剂配方漂白效果不明显;硼氢化钠类的药剂配方可得到一定的漂白效果;双氧水类、次氯酸钠类的药剂配方可得到很好的漂白效果.单纯染色比较难获得好的材色处理效果.采用先漂白后染色的方法,获得的材色过于鲜艳.采用化学着色的方法,可获得较理想的材色改良效果;草酸类药剂配方着色效果明显,可消除材色缺陷,根据不同的配方和处理工艺可获得从浅粉红色到红棕色的色调;用双氧水做活性剂,引入带发色团的化学药剂,材色改良效果明显,通过调整配方药品的浓度和处理工艺可获得从浅黄色到橙黄色的不同色调和较佳的材质.     

逆向云在垩白识别中的应

在云理论的基础上提出了一种无需人工干预的垩白识别方法.在此方法中,把垩白与非垩白定义为两个定性概念,以一个不对称云和一个对称云来表达垩白与非垩白,以两组数字特征分别描述垩白云与非垩白云.首先,利用动态阈值算法获得训练样本,然后设计逆向云发生器实现定量到定性的转换,最后根据两个云的隶属度函数,用极大值判定法来实现垩白区与非垩白区的分离.试验结果表明,云分类法分类精度高于传统的硬分类法.     

基于GIS与GPS的中国农村精准施肥的方法研究

在利用GIS和GPS研究土壤养分空间变异的基础上,以农户作为精准施肥的单元,探讨在中国农村进行精准施肥的途径。结果表明,不同农户地块养分存在一定空间变异性,由此导致相邻农户施肥量存在差异性,而采用农户为单元的施肥推荐既可以避免土壤养分空间变异造成的推荐施肥偏差,又可考虑中国农村分散经营的实际的状况,从而使土壤养分管理更加精细化。     

甘蔗叶鞘剥离过程弹性齿运动分析与试验

通过对弹性齿运动状态的分析阐述了弹性齿在叶鞘撕裂和剥离过程中的作用机理,采用ADAMS软件对弹性齿与甘蔗茎秆的接触过程进行仿真分析,确定剥叶滚筒中心距及弹性齿与甘蔗茎秆之间的相对速度变化对叶鞘撕裂和剥离产生的影响。利用物理样机进行剥叶滚筒中心距单因素试验和剥叶滚筒转速单因素试验对运动分析结果进行验证,并通过高速摄影对仿真的结果进行验证。结果表明,剥叶滚筒中心距为310 mm,弹性齿与甘蔗茎秆接触时刻,y轴方向的线速度差为3.91~5.87 m/s时,弹性齿可沿茎秆表面向下滑动,有利于叶鞘沿着纤维方向撕裂,x轴方向的线速度差为4.61~7.54 m/s时,弹性齿在甘蔗轴线方向可以持续滑动,有利于对叶鞘造成刮擦脱离,综合剥叶效果为含杂率低于7%、茎秆折断率低于15%。弹性齿与茎秆分离时刻,由于弹性恢复产生线速度突变,相对速度差增大4~5倍,有利于将叶鞘从茎秆上撕扯脱落。