玉米青贮与花生秧配比对奶牛瘤胃中花生秧降解特性的影响

本试验旨在研究玉米青贮与花生秧配比对奶牛瘤胃中花生秧降解特性的影响。选择4头体重、生理状态、生产性能相近,装有永久瘤胃瘘管的中国荷斯坦奶牛,分别饲喂含有玉米青贮与花生秧不同配比的全混合日粮(TMR),3种TMR中玉米青贮与花生秧的干物质(DM)配比分别为3.9∶1.0(A组)、1.2∶1.0(B组)、0.4∶1.0(C组)。试验分3期进行,依次进行A、B、C组试验。每期预试15 d,采样期4 d;共57 d。采用尼龙袋瘤胃降解技术测定花生秧在奶牛瘤胃中DM、粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的72 h瘤胃降解率,并求得目标养分的动态降解参数及有效降解率。结果表明:1)花生秧的DM在瘤胃中有效降解率为56.49%~59.62%,CP为40.45%~47.36%,NDF为33.26%~35.20%,ADF为36.31%~37.45%。2)B组DM的有效降解率显著高于C组(P0.05),极显著高于A组(P0.01);B、C组的CP有效降解率显著高于A组(P0.05)。3)B、C组的NDF快速降解部分含量显著高于A组(P0.05);3种TMR对花生秧粗NDF和ADF有效降解率无显著影响(P0.05)。由此可见,花生秧具有较高的饲用价值。本试验条件下,玉米青贮与花生秧DM配比为1.2∶1.0时,可有效提高花生秧DM和CP的瘤胃降解率。     

Estimation of Crown Temperature of Winter Wheat and the Effect on Simulation of Frost Tolerance

Accurate estimation of winter wheat frost kill in cold‐temperate agricultural regions is limited by lack of data on soil temperature at wheat crown depth, which determines winter survival. We compared the ability of four models of differing complexity to predict observed soil temperature at 2 cm depth during two winter seasons (2013‐14 and 2014‐15) at Ultuna, Sweden, and at 1 cm depth at Ilseng and Ås, Norway. Predicted and observed soil temperature at 2 cm depth was then used in FROSTOL model simulations of the frost tolerance of winter wheat at Ultuna. Compared with the observed soil temperature at 2 cm depth, soil temperature was better predicted by detailed models than simpler models for both seasons at Ultuna. The LT50 (temperature at which 50 % of plants die) predictions from FROSTOL model simulations using input from the most detailed soil temperature model agreed better with LT50 FROSTOL outputs from observed soil temperature than what LT50 FROSTOL predictions using temperature from simpler models did. These results highlight the need for simpler temperature prediction tools to be further improved when used to evaluate winter wheat frost kill.     

The influence of progesterone and prostaglandin F2α on decorin and the adhesion of caruncular epithelial cells of bovine placenta at early-mid pregnancy—Part II

One of the most important processes determining the proper course of gestation and its physiological termination in cows is the adhesion of epithelial cells allowing for direct contact of maternal and foetal parts of the placenta. Throughout pregnancy, placental cells are under strict hormonal control, which among others regulates the concentration and activity of specific proteins participating in the extracellular matrix remodelling of foetal membranes. The aim of the study was to evaluate the influence of progesterone and prostaglandin F_2α on the adhesion of epithelial cells at early-mid pregnancy in cows. Additionally, the impact of selected hormones on anti-adhesive properties of decorin was evaluated. Caruncular epithelial cells were isolated from healthy cows during pregnancy, immediately after slaughter. Primary cell cultures derived from the 2nd and 4th month of gestation were used in the experiments. The viability of cells was assessed by MTT assay. The adhesion of cells to fibronectin was measured spectrophotometrically. The activity of metalloproteinases was confirmed by the metalloproteinase assay. Progesterone (10^–5 and 10^–7 mol/L) and prostaglandin F_2α (10^–4_, 10^–5 and 10^–7 mol/L) increased the viability of bovine caruncular epithelial cells in the 2nd month of pregnancy. The treatment with prostaglandin F_2α significantly reduced the number of adherent cells from the 2nd month of gestation at the doses of 10^–4 and 10^–5 mol/L. Both progesterone and prostaglandin F_2α were shown to have an effect of decorin resulting in both a decrease in metalloproteinase activity and an increase in adhesion of cells to fibronectin.     

我国西番莲的研究状况浅析

采用文献计量分析方法,通过对近30年在刊物上发表的有关西番莲研究文献的类型、年限分布、刊物分布等方面进行计量分析研究,以揭示我国西番莲的研究现状。     

土壤处理防治烟草病虫害的效果

在偏酸性土壤中施用石灰及硫酸铜进行土壤消毒处理,结果表明,土壤处理后对烟叶各生育期的农艺性状无明显毒害作用,在产量及产值上无明显不良影响.在抑制花叶病的发生上有较好的减轻作用,对后期赤星病的发生有明显的抑制作用,可作为高山烟区赤星病综合防治的重要措施之一.     

基于图像识别的农产品品质无损检测

农产品外观颜色在一定程度上反映其内在品质,如破损、霉变、成熟度等.从农产品外观颜色的局部区域及全局区域两方面,介绍了根据农产品外观颜色进行无损检测及判断其品质的不同方法.     

6类9种杀虫剂对稻飞虱的田间效果综合评价

水稻稻飞虱是我国和许多亚洲国家当前水稻生产中最主要的害虫,也是湖北省水稻生产上的主要迁飞性害虫之一。近几年来我省连续特大发生。特别是2006年。为了明确防治稻飞虱当家农药品种和不同剂型的田间实际防治效果,选择高效、环保、低毒和安全的农药品种推广应用,我们于2006年     

Nutrient limitations to bacterial and fungal growth during cellulose decomposition in tropical forest soils

Nutrients constrain the soil carbon cycle in tropical forests, but we lack knowledge on how these constraints vary within the soil microbial community. Here, we used in situ fertilization in a montane tropical forest and in two lowland tropical forests on contrasting soil types to test the principal hypothesis that there are different nutrient constraints to different groups of microorganisms during the decomposition of cellulose. We also tested the hypotheses that decomposers shift from nitrogen to phosphorus constraints from montane to lowland forests, respectively, and are further constrained by potassium and sodium deficiency in the western Amazon. Cellulose and nutrients (nitrogen, phosphorus, potassium, sodium, and combined) were added to soils in situ, and microbial growth on cellulose (phospholipid fatty acids and ergosterol) and respiration were measured. Microbial growth on cellulose after single nutrient additions was highest following nitrogen addition for fungi, suggesting nitrogen as the primary limiting nutrient for cellulose decomposition. This was observed at all sites, with no clear shift in nutrient constraints to decomposition between lowland and montane sites. We also observed positive respiration and fungal growth responses to sodium and potassium addition at one of the lowland sites. However, when phosphorus was added, and especially when added in combination with other nutrients, bacterial growth was highest, suggesting that bacteria out-compete fungi for nitrogen where phosphorus is abundant. In summary, nitrogen constrains fungal growth and cellulose decomposition in both lowland and montane tropical forest soils, but additional nutrients may also be of critical importance in determining the balance between fungal and bacterial decomposition of cellulose.     

Diversity and abundance of springtails (Hexapoda: Collembola) in soil under 90-year potato monoculture in relation to crop rotation

The monoculture cropping system causes significant changes within the soil ecosystem, which constitutes a habitat for soil-dwelling springtails. Focusing on the response of soil fauna to 90 years of potato cultivation in monoculture the study investigates the abundance and diversity of soil-dwelling springtails, considering changes in the soil environment in relation to five-crop rotation. Another point was the soil quality evaluation using Collembola as bioindicators (QBS-c index). A long-term monoculture experiment was established in Poland in 1923 and has continued uninterruptedly to the present time. Soil samples were taken over a period of three years (2011–2013) to determine collembolan abundance and composition, as well as physical and chemical soil properties.

The study demonstrated that there were greater numbers of Collembola in the long-term monoculture of potatoes, especially before planting time, compared to numbers in a five-field crop rotation. At the same time apparently greater species diversity was found in potato culture within crop rotation. The biological indicator of soil quality based on the occurrence of springtails (QBS-c) has proved useful in assessing changes in soil caused by agrotechnical activities. This index indicated better biological soil quality in the five-field rotation system compared to monoculture.     

Protein recovery from rainbow trout (Oncorhynchus mykiss) processing byproducts via isoelectric solubilization/precipitation and its gelation properties as affected by functional additives

Solubility of rainbow trout proteins was determined between pH 1.5 and 13.0 and various ionic strengths (IS). Minimum solubility occurred at pH 5.5; however, when IS = 0.2, the minimum solubility shifted toward more acidic pH. Isoelectric solubilization/precipitation was applied to trout processing byproducts (fish meat left over on bones, head, skin, etc.), resulting in protein recovery yields (Kjeldahl, dry basis) between 77.7% and 89.0%, depending of the pH used for solubilization and precipitation. The recovered protein contained 1.4-2.1% ash (dry basis), while the trout processing byproducts (i.e., starting material) 13.9%. Typical boneless and skinless trout fillets contain 5.5% ash, and therefore, the isoelectric solubilization/precipitation effectively removed impurities such as bones, scales, skin, etc., from the trout processing byproducts. The recovered proteins retained gel-forming ability as assessed with dynamic rheology, torsion test, and texture profile analysis (TPA). However, the recovered proteins failed to gel unless beef plasma protein (BPP) was added. Even with BPP, the recovered protein showed some proteolysis between 40 and 55 degrees C. Addition of potato starch, transglutaminase, and phosphate to the recovered proteins resulted in good texture of trout gels as confirmed by torsion test and TPA. Higher ( P < 0.05) shear stress and strain were measured for gels developed from basic pH treatments than the acidic counterparts. However, proteins recovered from acidic treatments had higher ( P < 0.05) lipid content than the basic treatments. This is probably why the gels from acidic treatments were whiter ( L* - 3 b*) ( P < 0.05) than those from the basic ones. Our study demonstrates that functional proteins can be efficiently recovered from low-value fish processing byproducts using isoelectric solubilization/precipitation and subsequently be used in value-added human foods.