规模化猪场仔猪早期断奶应激研究进展

断奶日龄与断奶后仔猪生长发育和母猪生产性能发挥密切相关。该文回顾了国内外有关不同断奶日龄对仔猪生长发育、行为习性、消化生理与免疫机能以及母猪繁殖性能等方面的研究进展，分析了早期断奶技术在规模化养猪生产中，对改善母猪生产能力和设备利用率，降低饲料消耗，提高养猪生产效益所起的作用，断奶应激可能对仔猪生产的不良影响，以及目前有关技术研究与应用中存在的主要问题，探讨了我国在规模化养猪生产中应用早期断奶技术需解决的问题及今后的研究方向。     

不同断奶日龄对梵净山特种野猪仔猪生产性能的影响

为研究不同断奶日龄对梵净山特种野猪仔猪生产性能的影响,本试验将日龄相同、体重相近的梵净山特种野猪仔猪90头,随机分成3组,分别在14日龄、21日龄、28日龄断奶,单独饲养,比较60日龄体重、饲料转化率、断奶后腹泻率和育成率。结果表明,不同断奶日龄组60日龄体重、饲料转化率、育成率统计学差异显著,断奶日龄越早断奶后腹泻越严重。     

冬季饮水温度对断奶仔猪生长性能与行为的影响

饮水是猪只健康生长的基本条件,但饮水温度是养猪生产中常被忽略的重要因素。饮水温度不适宜将导致猪饮水不足和各种肠道性疾病的发生,严重影响其健康。有关不同饮水温度对断奶仔猪生长性能和行为影响的研究较少,同时现有恒温饮水装置主要用于奶牛饮水,并不适用于规模化猪场,也未在养猪产业内应用推广。为确定适宜断奶仔猪的饮水温度并实现冬季精准恒温饮水,该研究设计了一套利用温度传感器、温控仪等实现自动加热保温的恒温饮水装置,并分析饮水管路的热特性,确定了舍内空气温度、保温桶容积与饮水管路进水温度设定值之间的关系;基于该恒温饮水装置,对比研究了饮水温度分别为13、25、30 ℃时对断奶仔猪饮水量、生长性能、健康指标和行为的影响。结果表明：25 ℃的饮水能显著提高仔猪的日饮水量（P<0.05）、饮水行为比例和活动行为比例（P<0.05）、频次（P<0.05）,能提高仔猪的日增质量,降低料重比（P<0.05）,降低断奶仔猪的发病率和腹泻率（P<0.05）。该研究结果以期为动物福利化养殖模式的改进提供理论参考。     

哺乳母猪自动饲喂机电控制系统的优化设计及试验

随着中国规模化、集约化种猪场数字化智能饲喂需求的快速增加,为解决哺乳母猪少吃多餐且随哺乳日龄变化采食量动态增加的饲喂控制需求,该研究以哺乳母猪为试验对象,将机电系统、无线网络技术、Android技术、SQL Lite网络数据库、电子数据交换与哺乳母猪的营养供给模型集成起来,设计了一种哺乳母猪自动饲喂控制智能系统。研究结果表明,组成一个哺乳母猪智能系统的主要部件包括供料线、缓冲料仓、料位控制筒、料位调控杆、下料控制线管、螺旋输送机、中央控制箱、下料触发器、料槽及下料管道等,而且通过在系统的微处理器内存预设的采食量模型与雨刷电机精确旋转的电子控制技术相结合,实现了对预设饲喂量的准确投料;还通过储料仓的料位控制机构及设置的人工观察孔,可控制缓冲料仓的合理贮料量,尤其对泌乳早期(0~10 d)母猪的存贮料量最佳为大约10 d单头母猪的理论采食量,以保持日粮的新鲜度及减少结拱;预设的采食量的动态投料控制量基本符合哺乳母猪实际采食变化规律,且实际采食量的变化轨迹收敛于对数曲线。基于智能自动饲喂系统中采食量模型计算出不同泌乳日期的预测采食量,按4次/d的饲喂频率及变化的投料比例(30%,25%,25%及20%)进行定时与定量投喂,与人工饲喂对比,能显著促进哺乳仔猪采食量的增加(P0.05),以及极显著提高哺乳仔猪的平均体质量日增加量(P0.01)。此外,考虑安装、清理料槽及母猪采食的方便性,建议母猪饲喂器的触发器安装高度大约为10 cm。总之,该文设计的哺乳母猪电子自动饲喂系统无需传感器及电子标识技术的应用,适合在中国中、小型的种猪繁育场的哺乳舍推广应用,且系统设备及相应的软件系统的部署方便。进一步指出,母猪自动饲喂器除需要验证哺乳母猪的采食特性及哺乳的仔猪的断奶性能外,在未来还需要观察母猪的返情率甚至断奶商品猪的成活率等指标,从整个母猪的利用年限评价智能饲喂设备的优劣。     

断奶前后仔猪小肠Proglucagon mRNA的时空特异性表达

摘要：目的：胰高血糖素样肽-2（GLP-2）与小肠上皮生长关系密切。研究断奶前后仔猪十二指肠、空肠和回肠GLP-2 mRNA 表达丰度的变化规律，探讨断奶前后仔猪小肠上皮更新缓慢，是否与编码GLP-2的基因 — 胰高血糖素原（Proglucagon）的时空特异性表达有关。方法：本实验随机选取新生仔猪9窝，于35日龄（d）断奶。分别于断奶前1周（28d）、断奶当天（35d）、断奶后72h（38d）、断奶后1周（42d）、断奶后10天（45d）随机选取仔猪6头，屠宰，迅速采取十二指肠、空肠（后段）和回肠粘膜，用RT-PCR检测样品中胰高血糖素原 mRNA表达量。结果：胰高血糖素原基因在小肠中的表达呈现明显的空间（肠段）特异性，空肠和回肠表达丰度较高，而在十二指肠表达很少。胰高血糖素原 mRNA在仔猪空肠和回肠的表达显示截然不同的时间（日龄）特异性模式：空肠胰高血糖素原 mRNA表达在42日龄之前保持较高水平，而在断奶后1周和断奶后10天显著下降；而回肠中胰高血糖素原 mRNA表达水平在本实验观察期内保持稳定，未检测到日龄相关的变化。结论：断奶仔猪小肠GLP-2 mRNA表达呈现时空特异性规律。     

黄芪多糖对断奶仔猪生长性能及抗氧化能力的影响

为研究日粮中添加黄芪多糖对断奶仔猪生长性能和抗氧化能力的影响,选用28日龄、公母各半、体重接近的杜长大三元杂交断奶仔猪72头,随机平均分成2组,每组3个重复,每个重复12头。试验1组为对照组,饲喂基础日粮;试验2组饲喂基础日粮+1 000 mg/kg黄芪多糖,试验期为37 d。试验结束后,计算出日增重、日采食量、料重比以及腹泻率等生产性能指标;测定血清中总抗氧化能力(T-AOC)、总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)和丙二醛(MDA)含量。结果表明,黄芪多糖能改善断奶仔猪生产性能以及抗氧化能力。     

电刺激对产后母猪行为及生产性能的影响

解救被压哺乳仔猪是提高规模化养殖场生产效益的重要手段,其中电刺激是最新技术之一,为优化目前电刺激技术研究参数单一,母猪过度反应等问题,该研究基于反应有效性和惊吓指数两类参数分析了产后母猪不同身体部位在不同刺激电压下的反应,确定了电刺激技术参数适宜值,并验证了该参数对母猪生产性能的影响。结果表明：电刺激装置通电0.5 s后,母猪在刺激电压2 000和2 400 V下的有效反应率皆为75%以上,且这2种刺激电压下发生有效反应的概率极显著高于1 200 V(P<0.01)。母猪腰部的有效反应率为70.8%,该部位发生有效反应的概率比侧腹部和大腿根部高将近3倍左右。当刺激部位为腰部,刺激电压为2 400 V时,母猪惊吓指数上限高于60%;当刺激部位为腰部,刺激电压2 000 V时,惊吓指数上限低于60%,综合有效反应和惊吓指数结果,建议电刺激适宜参数为：电压2 000 V,刺激部位为腰部。生产试验结果表明：在整个哺乳期,执行电刺激适宜参数的试验组母猪的平均日采食量（5.50 kg）和断奶窝质量（58.91 kg）略高于对照组的日采食量（5.45 kg）和断奶窝质量（58.42 kg）,但...     

断奶前后仔猪十二指肠、空肠和回肠SGLT1 mRNA表达的变化及半胱胺的影响

研究断奶前后仔猪十二指肠、空肠和回肠SGLT1mRNA表达丰度的变化,并同时观察半胱胺对其表达的影响,从分子水平探讨半胱胺对断奶仔猪葡萄糖吸收的影响与可能的机制。新生仔猪随机分为对照组和实验组,12日龄(D12)起对照组饲喂基础乳猪料,实验组在基础乳猪料中添加120mg/kg半胱胺,两组仔猪均于35日龄断奶,每组分别于断奶前1周、断奶当天、断奶后3d、1周以及断奶后10d随机选取仔猪各6头,宰杀后采集十二指肠、空肠和回肠粘膜,采用RT-PCR方法测定钠-葡萄糖共转运载体1(sodium-glucosecotransporter1,SGLT1)mRNA表达的相对丰度。结果表明,回肠SGLT1mRNA的表达量最高,空肠其次,十二指肠最低;SGLT1mRNA在不同肠段的表达呈现截然不同的发育模式,十二指肠SGLT1mRNA表达量在45d显著上升(P<0.05),而空肠则在42和45d时显著下降(P<0.01),回肠SGLT1mRNA表达在整个实验期间无显著变化;此外,日粮添加半胱胺显著提高38d十二指肠以及42和45d空肠SGLT1mRNA表达,而对回肠SGLT1mRNA表达无显著影响。小肠SGLT1mRNA表达以及日粮添加半胱胺促进SGLT1mRNA表达的作用均呈现时空特异性规律。     

规模化养殖技术在养猪生产中的应用

自野猪被驯化以来,养猪就成了我国养殖业的重要组成部分。随着动物医学和养殖业相关技术的发展,使规模化养猪成为可能。规模化养殖技术的推广及在养猪生产中的应用,推动了养猪水平的提升,且对农民增收有巨大帮助。主要介绍规模化养殖技术在养猪中的应用及应当注意的事项。     

我国养猪产业生产现状及其发展方向

20世纪70年代以来,中国的养猪业有了长足发展,生猪饲养量居世界第一,但养猪业总体水平还较低,特别是在世界猪肉进出口贸易中几乎没有任何地位.本文针对我国农村养猪和规模化养猪的现状,对制约我国养猪生产水平的主要问题进行了详细分析.指出发展农村养猪生产,应注重提高农村仔猪质量、改良生猪精料、建立养猪小区、实施生态养猪等,以规范农村肉猪生产方式,提高生猪生产水平;对规模化养猪场,应改进现有饲养工艺、环境调控及粪污处理技术等,逐步向舍饲散养、清洁生产等方向转变,并且通过加大生产过程中的科技投入,规范生产过程,以提高生猪产品的质量,增强在国际市场中的竞争力;采用"公司+农户+公司"形式,进一步完善我国生猪产业化体系,使我国养猪业步入更加良性的发展轨道.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Collection and preliminary evaluation of native turfgrass accessions in Italy

Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Leaf position and genotype differences for mineral element concentrations in sorghum grown on tropical acid soil 1

Mineral element deficiencies and toxicities are common problems associated with sorghum [Sorghum bicolor (L.) Moench] production on acid soils. To better understand some of the mineral element problems and the analysis of plant tissue of sorghum plants grown on acid soils, four sorghum genotypes were grown on an acid Oxisol at Carimagua, Colombia limed with dolomite at 2 and 6 Mg ha^‐1.

Samples for mineral element analyses were obtained from leaves at different positions on the four genotypes. Concentrations of P and Mg were highest in the flag leaf (Leaf No. 1) and decreased as the position on the plant declined from the top of the plant for plants grown at 2 Mg lime ha^‐1. Similar decreases in P, Mg, K, and Zn concentrations occurred in plants grown with 6 Mg lime ha^‐1. Concentrations of Ca, S, Si, Mn, Fe, Cu, and Al increased as leaf position declined from the flag leaf for plants grown at 2 and 6 Mg lime ha^‐1. The higher lime supply enhanced Ca and reduced Mn and Fe concentrations in leaves. Differences in mineral element concentrations for the four genotypes used were fairly extensive. The elements to show the greatest range among genotypes were Al and Si and the elements to show the least range among genotypes were P, K, and S. Care should be used in collecting leaf samples for plant analysis and genotypic differences for accumulation of mineral elements should be considered in interpretation of results.