Effects of dietary supplementation of citrus by‐products fermented with a probiotic microbe on growth performance,innate immunity and disease resistance against Edwardsiella tarda in juvenile olive flounder,Paralichthys olivaceus (Temminck & Schlegel)

Two consecutive studies were conducted to evaluate the dietary supplementation of citrus by‐products (CB) fermented with probiotic bacteria on growth performance, feed utilization, innate immune responses and disease resistance of juvenile olive flounder. In Experiment I, five diets were formulated to contain 0% (control) or 3% four different CB fermented with Bacillus subtilis (BS), Enterococcus faecium (EF), Lactobacillus rhamnosus (LR) and L. plantarum (LP) (designated as CON, CBF‐BS, CBF‐EF, CBF‐LR and CBF‐LP, respectively). During 10 weeks of a feeding trial, growth performance and feed efficiency were not significantly different among all the fish groups. However, fish fed CBF containing diets had significantly higher survivals than the CON group. Disease resistance of fish against Edwardsiella tarda was increased by the fermentation of CB. In Experiment II, we chose the BS as a promising probiotic and formulated five diets to contain 0%, 2%, 4%, 6% and 8% CBF‐BS. Growth performance was not significantly affected by the CBF‐BS supplementation during 6 weeks of a feeding trial. Innate immunity of fish was significantly enhanced by CBF‐BS supplementation. Myeloperoxidase and lysozyme activities were increased in a dose‐dependent manner by dietary CBF‐BS inclusions. In a consecutive challenge test against E. tarda, an increased disease resistance was found by CBF‐BS supplementation. These studies indicate that the fermentation process of CB with probiotic has beneficial effects on innate immunity and thereby increases disease resistance of olive flounder against E. tarda. Bacillus subtilis can be used as a promising probiotic microbe for by‐product fermentation in fish feeds.     

生物农药对温室秋番茄病毒病的防治效果

[目的]筛选温室秋番茄病毒病的生物农药。[方法]采用测报调查、随机区组设计和统计分析等方法,研究生物农药香菇多糖+赤·吲乙·芸苔(碧护)和宁南霉素+赤·吲乙·芸苔防治番茄病毒病的效果。[结果]在温室大棚秋季番茄病毒病发生较重情况下,施用0.5%香菇多糖水剂3 000 m L/hm~2+碧护可湿性粉剂600 g/hm~2、8%宁南霉素水剂900 m L/hm~2+碧护可湿性粉剂600 g/hm~2,7 d施药1次,连续施用4次,药后10、17、26、35 d防治效果均在88%、87%、78%和67%以上,且两药剂防治效果差异不显著,香菇多糖+碧护极显著高于盐酸吗啉胍(对照药剂)+碧护,宁南霉素+碧护显著高于盐酸吗啉胍+碧护。[结论]香菇多糖+碧护和宁南霉素+碧护不仅可以作为防治病毒病的理想药剂,而且可以作为现代农业示范区、无公害农产品、绿色农产品和有机农产品防治病毒病的理想药剂。     

Reconstitution of a lost forest tree population: A case study of Norway spruce (Picea abies [L.] Karst.)

A population of Norway spruce (Picea abies (L.) Karst.) from southern Poland, named Kolonowskie 0293, exhibited a very high breeding value among 1100 European populations tested in the IUFRO 1964/1968 provenance experiment. However, the original mother stand of that population no longer exists. Owing to international cooperative efforts, a reconstituted clonal seed orchard of that population was successfully established to protect the gene pool of the Kolonowskie 0293 population.     

Accounting for Data Architecture on Structural Equation Modeling of Feedlot Cattle Performance

Structural equation models (SEM) are a type of multi-trait model increasingly being used for inferring functional relationships between multiple outcomes using operational data from livestock production systems. These data often present a hierarchical architecture given by clustering of observations at multiple levels including animals, cohorts and farms. A hierarchical data architecture introduces correlation patterns that, if ignored, can have detrimental effects on parameter estimation and inference. Here, we evaluate the inferential implications of accounting for, or conversely, misspecifying data architecture in the context of SEM. Motivated by beef cattle feedlot data, we designed simulation scenarios consisting of multiple responses in a clustered architecture. Competing fitted SEMs differed in their model specification so that data architecture was explicitly accounted for (M1; true model) or misspecified due to disregarding either the cluster-level correlation between responses (M2) or the correlation between observations of a response within a cluster (M3), or ignored all together (M4). Model fit was increasingly impaired when data architecture was misspecified or ignored. Both accuracy and precision of estimation were also negatively affected when data architecture was disregarded. Our findings are further illustrated using data from feedlot operations from the US Great Plains. Standing statistical recommendations that call for proper model specification capturing relevant hierarchical levels in data structure extend to the multivariate context of structural equation modeling.Supplementary materials accompanying this paper appear on-line.     

我国肉牛产业链价格非线性波动及传递特征分析

为探讨我国肉牛产业链主要环节价格非线性波动及其传递特征,基于2012年1月—2015年10月我国肉牛产业链主要环节价格数据,采用马尔可夫转换向量自回归(MS-VAR)模型进行实证分析。结果表明:肉牛产业链主要环节价格存在2种不同的运行状态,且呈现出明显的阶段性;第1个阶段为2012年初—2013年上半年,第2个阶段为2013年下半年—2015年;肉牛产业链在常规状态运行概率更高,持续时间更长,但两状态相互转换概率均较低,说明价格波动存在平滑性。肉牛产业链价格传递作用明显,架子牛价格在产业链价格传递过程中起主导作用;产业链价格传递在不同状态下作用存在差异,非常规状态下传递作用更为明显;价格传递作用持续时间一般在半年以上。     

我国肉牛养殖效率及影响因素分析

肉牛产业作为我国畜牧业发展的重要组成部分,在提高农牧民收入水平、改善居民膳食结构等方面做出重大贡献。受诸多因素影响,我国肉牛产业和牛肉市场面临巨大压力,提升肉牛养殖技术效率,把握影响技术效率的关键因素,对政府调控肉牛产业、推进产业稳定健康发展具有重要参考意义。利用1998-2014年投入产出非平衡面板数据,借助随机前沿分析方法对河南、黑龙江、宁夏、陕西和新疆五省区肉牛养殖技术效率进行测算,分析其时空分布特征,探究影响肉牛养殖技术效率的关键因素。研究结果表明:1我国肉牛养殖技术效率呈现出逐年上升的趋势,1999-2014年平均技术效率为0.813 7;不同地区肉牛养殖的技术效率存在着显著差异,新疆肉牛养殖技术效率最高,其次为河南,再次为黑龙江,宁夏和陕西排在最后。2养殖密度、产业优势、资本装备和农业机械化对肉牛养殖技术效率具有显著正影响,疫病风险和饲料结构则对其具有显著负影响。     

Antifungal activity of polyacetylenes isolated from Cirsium japonicum roots against various phytopathogenic fungi

Antifungal substances from a methanol extract of Cirsium japonicum roots were purified and characterized, and their antifungal activities against various plant pathogens were evaluated. Three polyacetylene substances were isolated from roots of C. japonicum using repeated column chromatography; these were identified as ciryneol A, ciryneol C and 1-heptadecene-11,13-diyne-8,9,10-triol by mass and nuclear magnetic resonance spectral analyses. In vitro antifungal activity of the three substances varied according to compound and target species. Magnaporthe oryzae, Colletotrichum coccodes, Colletotrichum acutatum, Pythium ultimum and Botrytis cinerea were relatively sensitive to the three polyacetylenes, with IC₅₀ values below 50 μg mL⁻¹. In vivo, they all showed similar and broad antifungal spectra against the seven plant diseases tested. At 500 μg mL⁻¹, all three compounds effectively suppressed the development of rice blast, rice sheath blight, tomato late blight, wheat leaf rust and red pepper anthracnose, with control values over 90%. They were highly active especially against wheat leaf rust; they controlled the development of this disease more than 88% even at a concentration of 125 μg mL⁻¹. In addition, ciryneol C effectively suppressed barley powdery mildew. This is the first report on the antifungal activities of the three polyacetylenes from roots of C. japonicum against plant pathogenic fungi. Polyacetylenes from roots of C. japonicum may contribute to the development of environmentally safer alternatives to protect crops from various phytopathogenic fungi.     

Surface modification of polyester fibers by thermal reduction with silver carbamate complexes

In this study, the surface of polyester fiber was modified by means of thermal treatment with a silver carbamate complex. We used scanning electron microscopy (SEM), an X-ray diffraction technique (XRD), and X-ray photoelectron spectroscopy (XPS) to allow a detailed characterization of the silver-coated polyethylene terephthalate (PET) fibers. The results revealed remarkable changes in the surface morphology and microstructure of the silver film after thermal reduction. On SEM, the silver nanoparticles (AgNPs) were seen to be uniformly and densely deposited on the fiber surface. The XRD pattern of the silver-coated fiber indicated that the film has a crystalline structure. A continuous layer of AgNPs, between 30 and 100 nm in size, was assembled on the PET fibers. The PET/Ag composite was found to impart high conductivity to the fibers, with an electrical resistivity as low as 0.12 kΩ·cm.     

用单克隆抗体鉴定猪繁殖与呼吸综合征病毒分离株

应用ＰＲＲＳＶ单克隆抗体,采用直接与间接免疫荧光抗体试验对分离获得的ＰＲＲＳＶ６个毒株进行了鉴定,结果所有分离毒株均能被单克隆抗体（ＳＤＯＷ１７、Ａ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆ）所识别,呈现特异荧光,６个分离毒株均能与仅识别美洲型ＰＲＲＳＶ的单克隆抗体Ｆ反应,结果表明６个分离毒株均属于美洲型ＰＲＲＳＶ。利用微量细胞培养对分离毒株ＴＣＩＤ５０测定结果表明,６个分离毒株的ＴＣＩＤ５０分别为１０－７．５／０．１ｍｌ、１０－７．５／０．１ｍｌ、１０－７．５／０．１ｍｌ、１０－７．７５／０．１ｍｌ、１０－７．２５／０．１ｍｌ、１０－６．２５／０．１ｍｌ。病毒感染细胞的超薄切片电镜观察表明,在感染细胞浆内可见典型的ＰＲＲＳＶ病毒粒子,呈球形或椭圆形,直径约为６０ｎｍ左右,可见囊膜。