β-折叠抗菌肽的研发及应用策略

抗生素的滥用导致全球细菌耐药性问题愈发严重,严重威胁人类、畜禽健康及畜牧业发展,功能多样且不易导致细菌产生耐药性突变的抗菌肽（antimicrobial peptides,AMPs）逐渐发展为抗生素的潜在替代品。β-折叠是抗菌肽一个主要的二级结构分类,该类肽通常由一个或多个二硫键来维系结构的稳定,现已发现许多抗菌肽具有此类结构。相比于目前研究广泛的α-螺旋AMP,它们被认为拥有更强的抗酶解能力和更高的细胞选择性。本篇综述介绍了β-折叠抗菌肽的来源和抗细菌机理,并梳理了一些常见的分子设计方法和应用策略,以期为β-折叠抗菌肽的研发应用提供新思路。     

多重PCR检测猪瘟病毒、猪细小病毒和猪伪狂犬病病毒的研究--猪瘟病毒、猪细小病毒和猪伪狂犬病病毒多重PCR引物设计

在GeneBank中查出CSFV、PPV、PRV的所有已知序列。对病毒各基因区进行同源性分析 ,确定CSFV的E2 基因 ,PPV的VP2 基因和PRV的 gⅡ基因为各病毒扩增的靶序列。利用DNAsis对上述保守区进行引物设计 ,对设计出来的 3种病毒引物利用DNAstar进行引物二聚体分析 ,以避免引物之间形成稳定的引物二聚体。选出扩增序列为CSFV 2 88bp、PPV575bp和PRV 70 0bp的 3对引物 ,并对每对引物扩增序列的同源性或互补性进行分析。避免它们之间有较高的同源性或互补性 ,从而确定了 3种病毒的多重PCR引物     

猪场建设中“水”问题的探讨

给水及排水是在猪场规划建设时就应该统筹考虑的重大问题。从给水工程设计和废水处理两方面探讨了猪场建设中所涉及的"水"问题,介绍了水源、水量、水质、水温控制、施工要点、废水处理方式等诸多细节,以供同行参考。     

Evaluation of ground grain versus pre- and post-pellet whole grain additions to poultry diets via a response surface design

1. The objective of this study was to compare the effects of pre- and post-pellet whole grain wheat additions to diets on growth performance, gizzard and pancreas development, nutrient utilisation and starch and protein (N) digestibility coefficients in broiler chickens via an equilateral triangle response surface design.

2. The three apical treatments of the equilateral triangle comprised (1A) a standard diet containing 600 g/kg ground wheat, (2B) the same diet containing 600 g/kg pre-pellet whole wheat and (3C) the same diet containing 300 g/kg ground wheat and 300 g/kg post-pellet whole wheat. Seven blends of the three apical diets were located within the triangle to complete the design and a total of 360 male Ross 308 chicks were offered the ten experimental diets from 7 to 28 d post-hatch. Model prediction and response surface plots were generated with R 3.0.3 software.

3. The most efficient FCR of 1.466 was observed in birds offered an almost equal mixture of the pre- and post-pellet whole grain apical dietary treatments, which corresponded to 172 g/kg ground grain, 256 g/kg pre-pellet whole grain, 172 g/kg post-pellet whole grain in a diet containing 600 g/kg wheat.

4. The most efficient energy utilisation (ME:GE ratio of 0.766) was observed in birds offered a blend of the ground grain and pre-pellet whole grain apical dietary treatments which corresponded to a mixture of 384 g/kg pre-pellet whole grain and 216 g/kg ground grain.

5. Pre-pellet whole grain feeding generated the most pronounced responses in increased relative gizzard contents, reduced gizzard pH and increased relative pancreas weights. Consideration is given to the likely differences between pre- and post-pellet whole grain feeding.     

氮、磷、钾配施对草原3号苜蓿干草产量的影响

采用“3414”试验设计对草原3号苜蓿进行大田施肥,通过对苜蓿干草产量进行多元回归分析和模拟寻优分析来探索氮、磷、钾肥的肥料效应。结果表明,施肥在不同程度上增加了苜蓿干草产量,增产幅度在7.20%~26.85%之间,增产最高的施肥处理是P2K1N1;在单因子施肥效应中,苜蓿干草产量随着磷肥施入量增加而增加,随着钾肥和氮肥施入量增加而先增加后降低。在两因子互作效应中,氮磷、磷钾互作对苜蓿干草产量具有一定的促进作用,氮钾互作对苜蓿干草产量具有一定抑制作用。通过模拟寻优分析得到最优施肥配比为P2O5 180.22kg/hm^2、K2O 52.82kg/hm^2、N 41.84kg/hm^2,产量达11257.09kg/hm^2。磷、钾、氮以及饲草产量的最优配比区间分别为178.2~182.33kg/hm^2、51.38~54.38kg/hm^2、40.8~42.9kg/hm^2、11247.36~11266.82kg/hm^2。     

超声波法提取黄芩挥发油工艺研究

以黄芩为试验样品,研究超声波法提取黄芩中挥发油的工艺条件。在单因素试验的基础上,采用L（93）3正交试验优化超声提取挥发油的工艺条件。结果表明,影响黄芩挥发油超声提取的主要因素是料液比,其次是超声时间和超声功率,优化工艺条件为：超声时间50 min,料液比1∶20,提取功率70 W。     

基于机器视觉的饲料生产智能包装系统设计与应用研究

为提高饲料生产订单的包装效率、智能化程度、降低包装成本,文章基于机器视觉,从硬件选择与软件设计两个层面设计饲料生产智能包装系统.采用AutoMod软件对饲料生产智能包装系统进行仿真试验,检验整个包装系统效果.结果表明,该智能包装系统包装效率高、关键设备利用率高、系统可靠性、可行性良好.     

H5亚型禽流感疫苗对特禽及水禽的免疫效果观察

用H5N2亚型禽流感疫苗,分别免疫SPF鸡、乌鸡、珍珠鸡、贵妃鸡、火鸡、鸭及鹅,免疫后采血测定其HI抗体,观察我国现有的H5N2亚型禽流感疫苗对特禽及水禽的免疫效力.结果,免疫后3周,SPF鸡、乌鸡、珍珠鸡、贵妃鸡、火鸡、鸭及鹅的平均HI抗体滴度分别为2 7.2、2 7.6、2 4.3、2 4.83、2 4.6、2 6.2及2 5.3,乌鸡两次免疫,其中一次HI抗体为2 9.65.试验证明,SPF鸡、特禽及水禽用H5N2亚型禽流感疫苗免疫后,均能产生一定水平的HI抗体,但不同种类的家禽所产生的HI抗体滴度存在较大差异,以SPF鸡及乌鸡所产生的HI抗体滴度最高,而珍珠鸡、贵妃鸡及火鸡所产生的HI抗体滴度较低,水禽对H5N2亚型禽流感疫苗可产生一定水平的HI抗体.     

鼓浪屿弃屋到民宿----文创的力量

本文基于落实党和国家近年关于支持和推动鼓浪屿文化大经济发展大繁荣的意见和决定, 着眼于与鼓浪屿文化大项目建设相关的旅游文创产品部分的开发和研究,目的为了更好的通过文创 产品的社会力量吸引社会大众保护和弘扬传承鼓浪屿的历史文化和特色。     

蔬菜穴盘苗自动精确移栽组合式取苗机构设计与测试

Precision planting is one key point of precision agriculture.A doorframe type swing seedling pick-up device for the automatic precise field transplanter was designed and tested in a laboratory.The seedling device could automatically extract seedlings from growing trays, transfer them, and release them into the planting unit where they were to be precisely transplanted into the ground.It consisted of a path manipulator and two grippers.The path manipulator for seedling extraction was constructed with creative design of Ⅱ-type mechanism combination in series.It consisted of an oscillating guide linkage mechanism and a grooved globoidal cam mechanism.According to the planned seedling pick-up trajectory, the design of the path manipulator for seedling extraction was finished with a set of the closed loop vector equation.The gripper was a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling extraction.It consisted of multiple pick-up pins, U-type pull rod, shaft, stop block, compression spring and frame.The mechanical dimensions of the gripper were determined by the tray size and plant characteristic with a set of rectangular equations and the boundary constraint conditions.The final gripper was developed on the basis of cultural practice for vegetable seedling in China.A prototype of the seedling pick-up device was constructed to examine whether its working efficacy was satisfactory or not.According to the analysis on the work process, the seedling pick-up device could precisely complete a work cycle of approaching, penetrating, extracting, transferring, erecting and discharging a seedling.Taking pepper seedlings, tomato seedlings and cucumber seedlings as the transplanting objects, the performance tests were conducted to evaluate the practicality and adaptability of the pick-up device.The laboratory evaluation showed that the pick-up device equipped with two grippers could extract 70 seedlings per minute with an average success ratio of 90.49%.The quality of extracting seedlings was satisfactory.