提高集约化奶牛场经济效益的有效途径

以河北省农林科学院粮油作物研究所奶牛场为例,介绍了提高奶牛场经济效益的有效措施,并重点提出了加强科学的饲养管理和先进技术(DHI技术、TMRJ技术)的采用.     

基于NIR定量模型快速预测发酵麸皮中还原糖和可溶性蛋白成分的含量

为建立一种能快速预测发酵麦麸还原性糖和可溶性蛋白含量的定量分析模型,本研究以发酵麦麸为样本,采用3,5-二硝基水杨酸比色法（3,5-dinitrosalicylic acid, DNS）和BCA蛋白浓度测定法分别测定样品的还原性糖和可溶性蛋白含量;利用近红外光谱技术（Near infrared spectrum instrument, NIR）结合偏最小二乘法（Partial least squares regression, PLS）,比较预处理方法、最佳波长及主成分因子的决定系数R²,建立发酵麦麸还原性糖和可溶性蛋白含量的NIR快速检测定量模型。结果表明：1）发酵麦麸还原性糖定量模型的预处理方法使用一阶导数 （First derivative, FD）+二阶导数 （Second derivative, SD）+标准正态变换 （Standard normal variate, SNV）,光谱范围为908~1 670 nm ,主因子数为7时,模型效果最优,其决定系数Rc²为0.904 8,校正均方根误差（Square error corrected, SEC）为1.576 1,相对分析误差（Relative percentage difference, RPD）为3.240 8;外部验证集决定系数Rp²为0.954 9且还原糖活性成分的验证集样本的测定值与NIR光谱预测值的P值为0.959 5>0.05。2）发酵麦麸可溶性蛋白定量模型的预处理方法使用一阶导数 （First derivative, FD）+二阶导数 （Second derivative, SD）+标准正态变换 （Standard normal variate, SNV）,光谱范围为908~1 670 nm ,主因子数为10时,模型效果最优,其决定系数Rc²为0.938 2,校正均方根误差（Square error corrected, SEC）为2.003,相对分析误差（Relative percentage difference, RPD）为4.021 9;外部验证集决定系数Rp²为0.994 4,且可溶性蛋白活性成分的验证集样本测定值与NIR光谱预测值的P值为0.901 9>0.05。综上,建立的NIR光谱定量模型稳定性和准确性较好,且预测准确度良好,可用于快速预测发酵麦麸样品的还原性糖和可溶性蛋白含量。     

Effects of different dietary copper sources on the growth and intestinal microbial communities of Pacific white shrimp (Litopenaeus vannamei)

An 8‐week feeding trial was conducted to evaluate the effects of dietary copper sources on growth performance and intestinal microbial communities of juvenile Pacific white shrimp (Litopenaeus vannamei). Four isonitrogenous (420 g/kg crude protein) and isolipidic (70 g/kg crude lipid) experimental diets were formulated to contain different copper sources, Diet NSC (no‐supplemented copper), Diet CS (copper sulphate), Diet Availa (copper amino acid complex from Availa^®Cu100) and Diet M (1:1, copper sulphate + copper amino acid complex). A total of 360 Pacific white shrimp juveniles (initial weight: 1.86 ± 0.03 g) were randomly allocated into four groups, with three replicates per group and 30 shrimps each replicate. An Illumina‐based sequencing method was used to analyse the intestinal bacterial composition of shrimp juveniles. The results revealed that shrimps fed Diet M had significantly higher percent weight gain (PWG) than that fed Diet NSC and Diet CS, while there were no significant differences between Diet M and Diet Availa. Survival was not affected by the dietary copper sources. Proteobacteria and Bacteroidetes were dominant in the intestines of Pacific white shrimp. Shrimps fed Diet M and Diet Availa had higher bacterial richness and diversity than those fed Diet NSC and Diet CS with no significant differences among all treatments. Furthermore, Diet M and Diet Availa which contained copper amino acid complex reduced the relative abundance of Vibrionaceae in shrimp intestinal tract. This study indicated that dietary copper sources could affect the intestinal microbial communities and diets supplemented with Availa^®Cu100 could have a positive impact on the growth performance and decrease the potential risk of disease in Pacific white shrimp.     

云南宝台山国家森林公园森林资源现状分析

为掌握云南宝台山国家森林公园的森林资源特点,并为制定森林公园的森林资源保护与利用规划提供依据,对该公园2019年森林资源监测数据进行了分析.结果 表明:该森林公园林地面积占公园总面积的99.4％,森林覆盖率高达90.50％.林地以有林地为主,面积占比为90.9％.森林起源以天然为主,面积占比为77.8％;人工起源为辅....     

Molecular identification and genetic analysis for 24 turf-type Cynodon cultivars by Sequence-Related Amplified Polymorphism markers

Bermudagrass (Cynodon ssp.) germplasm is genetically diverse and widely distributed in the world. The study was conducted to identify and assess the molecular variation and relationship among 24 cultivars developed in China, Australia and the USA. Sequence-Related Amplified Polymorphism (SRAP) was applied to cultivars identification in this study for the first time. Thirty of the 90 SRAP primer combinations generated a total of 274 clearly bands encompassing 249 (91%) polymorphic. Each bermudagrass cultivar has its unique binary code and can be distinguished from the others. Three distinct clusters were obtained by unweighted pair-group method with arithmetic averages based on the polymorphic markers. Coefficients of genetic distance among the genotypes ranged from 0.57 to 0.97. The results demonstrated that SRAP marker is a stable molecular marker technique for the identification of bermudagrass cultivars and their genetic relationships.     

Generation of insulin-producing cells from PDX1 and NKX6.1 gene-modified bone marrow mesenchymal stem cells

AIM: To differentiate bone marrow mesenchymal stem cells (BMSCs) into functional insulin-producing cells to produce sufficient pancreatic islet cells for transplantation. METHODS: Recombinant adenovirus vectors carrying PDX1 and NKX6.1 genes were constructed and the bone marrow mesenchymal stem cells were infected by the recombinant adenovirus combined with several cytokines for differentiation. The expressions of PDX1, NKX6.1 and insulin and C-peptide in the differentiated bone marrow mesenchymal stem cells were detected by RT-PCR and Western blotting. After the differentiated bone marrow mesenchymal stem cells were transplanted into subrenal capsule of diabetic mice, cell morphology of the grafts as well as their secretion of insulin and C-peptide were detected. Besides, regulating capacities of grafts on the blood glucose level of the diabetic mice were also detected. RESULTS: BMSCs induced by recombinant adenovirus (pAdxsi-CMV-PDX1/CMV-NKX6.1) and several cytokines showed positive dithizone staining and the expressions of β-cell related molecule such as insulin and glucose transporter 2 were detected by RT-PCR, which showed a sustaining and stable expression. The similar results were showed by Western blotting, immunohistochemical staining and indirect immunofluorescence. The insulin secretions in the cells stimulated with glucose at concentrations of 5.5 and 25 mmol/L in the experimental group were (1 240.4±109.3) mU/L and (3 539.8±245.1) mU/L, respectively, and were significantly higher than those in control group. Moreover, transplantation of the cells to STZ mice in treatment group made serum glucose recover to normal level. CONCLUSION: PDX1 and NKX6.1 gene-modified bone marrow mesenchymal stem cells differentiate into insulin-producing cells in vitro. When these cells transplanted into STZ induced diabetic mice, their serum glucose could return to the normal level and they could live well. Thus this is a promising method for diabetes treatment.     

Effects of apolipoprotein (a) on vascular smooth muscle cells proliferation and cell signal transduction pathway

AIM: To investigate the effect and the mechanism of apolipoprotein (a) ［apo (a)］ on proliferation of vascular smooth muscle cells (VSMCs). METHODS: All VSMCs used in experiments were serial subcultured from primary cells and were identified by immunohistochemistry staining of α-actin. Cell growth assay was observed as cell counting and MTT assay. Western blotting was also employed to detect the related mechanism. RESULTS: All cells used in experiments were confirmed as VSMCs. Although apo (a) enhanced VSMCs proliferation, this effect was attenuated by anti-integrin αⅤβ3, LM609. Use these reagents alone had no effect on VSMCs growth. The results of Western blotting demonstrated that focal adhesion kinase (FAK) was activated by apo (a) and the expression of total or phosphorylated transforming growth factor β1 (TGF-β1) was also decreased. However, these effects described above were all blocked by LM609. CONCLUSION: Apolipoprotein (a) enhances VSMCs proliferation and this effect is mediated by integrin αⅤβ3, which activates FAK and attenuates TGF-β1 and phospho-TGF-β1 expression.     

北京市小龙门国家森林公园大型真菌名录

北京市小龙门国家森林公园大型真菌资源丰富。在保护区内共采集标本212号,鉴定出47种,隶属于2个门、7个目、20个科、47个种。     

基于控制局域网的拖拉机液压悬挂电控系统

根据拖拉机悬挂系统机电液一体化的控制方式要求,以单片机C8051F040/1为主控制器,设计了基于CAN总线的拖拉机电控液压悬挂电子控制系统,开发了系统的CAN网络、硬件电路、软件程序,提出了控制系统的CAN传输信息帧的身份码(ID)和数据的编写方式,并实现了通过CAN网络对拖拉机悬挂的操作以及对其工作状态的监测与调控.