Green tea polyphenols supplementation alters immunometabolism and oxidative stress in dairy cows with hyperketonemia

Peripartal cows often experience negative energy balance, and are therefore prone to suffering from metabolic diseases such as hyperketonemia, which causes financial losses in dairy farms. This study aimed to investigate the effect of green tea polyphenol (GTP) supplementation during the periparturient period on production performance, oxidative stress and immunometabolism in dairy cows with hyperketonemia. One hundred Holstein cows were assigned to GTP (0.2 g/kg DM; n = 50) or control (without GTP; n = 50) group based on body weight, previous milk yield, and parity on d 15 before expected parturition. Subsequently, 10 cows with hyperketonemia were selected from each group, according to blood β-hydroxybutyric acid (BHBA) concentration between 1.2 and 2.9 mmol/L from 2 to 3 d postpartum. All cows were fed a close-up diet and a lactation diet with or without GTP supply from 15 d prepartum until 30 d postpartum. Milk and blood samples were obtained from 20 cows selected with hyperketonemia on 10, 20, and 30 d postpartum. Compared with control cows, greater milk yield and lower somatic cell count were observed in GTP cows. The GTP group had lower concentrations of BHBA, free fatty acids, cholesterol, triglyceride, reactive oxygen species, malondialdehyde, and hydrogen peroxide, greater concentrations of glucose, lower activities of aspartate aminotransferase, alanine aminotransferase, and glutamyl transpeptidase, alongside greater activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity. Additionally, GTP supplementation up-regulated concentrations of interleukin-6 and interleukin-10, but down-regulated concentrations of tumor necrosis factor-α, interleukin-1β, interleukin-2, interleukin-8, and interferon-γ in plasma. Greater concentrations of plasma immunoglobulin G were also detected in the GTP group. Overall, the data suggested that GTP supplementation from 15 d prepartum to 30 d postpartum improved the milk yield and health status in cows with hyperketonemia during early lactation.     

离心泵叶轮出口宽度对泵腔内压力脉动分布的影响

在试验和数值模拟相互验证的基础上,开展叶轮出口宽度对离心泵泵腔内压力脉动分布影响的研究．通过试验和数值计算获得离心泵的外特性、泵腔内静压分布、泵腔内压力脉动分布及泵体表面的压力脉动幅值分布,并进行对比分析,结果表明：前泵腔内静压和压力脉动幅值随出口宽度的增大而增大,随半径的减小而增大;后泵腔内静压和压力脉动随出口宽度和半径的变化不十分明显．综合考虑外特性和压力脉动,在比转数 ns ＝97时叶轮出口宽度与叶轮出口直径之比应小于0.06;为了使压力脉动在泵腔内有效地衰减,出口宽度与前腔间隙的比值在1.81附近时最佳．研究结果可用于指导离心泵叶轮的优化设计．     

农田平地机激光发射平台调平控制系统设计

为使农田平地机双源激光定位系统的激光发射平台检测数据更精确、调平实时性更好,设计了激光发射平台自动调平控制系统。该系统采用三脚支撑的平台支撑方式,利用倾角传感器检测平台的倾斜度,通过步进电机驱动平台3条支腿伸缩从而实现平台调平。通过加入倾角传感器数据处理算法和基于RBF神经网络的智能PID控制算法,激光发射平台检测的数据更精确,能满足双激光源定位系统的要求,使农田平地机平地作业更精确。     

The effect of lactic acid bacterial starter culture and chemical additives on wilted rice straw silage

Lactic acid bacteria (LAB) are suitable for rice straw silage fermentation, but have been studied rarely, and rice straw as raw material for ensiling is difficult because of its disadvantages, such as low nutrition for microbial activities and low abundances of natural populations of LAB. So we investigated the effect of application of LAB and chemical additives on the fermentation quality and microbial community of wilted rice straw silage. Treatment with chemical additives increased the concentrations of crude protein (CP), water soluble carbohydrate (WSC), acetic acid and lactic acid, reduced the concentrations of acid detergent fiber (ADF) and neutral detergent fiber (NDF), but did not effectively inhibit the growth of spoilage organisms. Inoculation with LABs did not improve the nutritional value of the silage because of poor growth of LABs in wilted rice straw. Inoculation with LAB and addition of chemical materials improved the quality of silage similar to the effects of addition of chemical materials alone. Growth of aerobic and facultatively anaerobic bacteria was inhibited by this mixed treatment and the LAB gradually dominated the microbial community. In summary, the fermentation quality of wilted rice straw silage had improved by addition of LAB and chemical materials.     

发展乡村旅游推进新农村建设

本文通过对合肥市乡村"农家乐"旅游发展现状的解析,提出了推进其发展的建设性意见.     

云南高原粳稻抗白叶枯病新品系云资抗21号的选育

以高产优质的云南高原粳稻品种滇系4号为轮回亲本，以IRBB21为白叶枯病抗性基因Xa21的供体亲本，通过杂交和3次回交以及5次自交形成BC3F，代材料，并结合后代材料的白叶枯病抗性鉴定及农艺性状的评价选择，选育出高原粳稻新品系云资抗21号，对云资抗21号的21个单株采用与Xa21连锁标记RM21和RM229、以及22个独立分离的SSR标记进行检测，结果表明这21个单株在RM21位点上均为IRBB21的纯合基因型，在RM229位点上有1个单株显示为轮回亲本的纯合基因型，其余的20个单株均为IRBB21的纯合基因型，而在其余22个SSR标记位点上均显示为轮回亲本的纯合基因型。该新品系白叶枯病抗性与IRBB21相近，农艺性状与轮回亲本相似，具有很好的应用前景。     

凉山州高原粳稻开花习性研究

凉山州高原粳稻在自然环境中抽穗后3～4d开始开花，5～8d进入开花盛期，10～12d相继结束；1日内的开花时间主要集中在12：00～16：00；每朵颍花开花历时60～110min不等；闭花授粉粒和停止发育粒教因品种而异；水稻开花与颖壳内湿度、田间温度和生态区关系密切。     

果蔬产品变色原因分析及其控制

分析了果蔬产品在加工贮存中变色的原因,综述了目前生产中常用的行之有效的护色措施,包括生物、化学和物理等方面的处理方法。