烟草抗CMV细胞突变系筛选系统的研究

在单倍体烟草6叶期接种CMV,接种前3d适当增施氮肥,接种后置28±2℃和自然光照条件下最适合CMV侵染和发病,发病后烟苗仅9或10位叶全部畸型褪绿,这是用绿岛法筛选抗CMV细胞突变系的临界选择压。用0.3％EMS(硫酸二乙酯)诱变烟苗心叶,接种CMV后置临界选择条件下从普通烟草良种Burley18的928个病株中选到每叶仅1～2个绿岛的畸型褪绿叶78片。截取绿岛进行组织培养得到146株无病试管苗,移栽盆钵后再接种CMV鉴定,选到抗CMV突变系R_2和R_8,其当代无性系在夏季网室条件下病情指数较亲本低40.1～45.3,并能通过有性过程传递。     

新疆淡水藻类研究：乌鲁木齐南山八一林场绿藻初报

本文首镒报道乌鲁木齐南山八一林场山区的绿藻１１属，１２种，其中１０属，１０种为新疆新记录。这些结果是对１９９１年７月采集的２０号标本经鉴定后获得的。     

农村肉狗绿色养殖模式刍议

近年来，农村肉狗养殖成为农民增收致富新的亮点，但也存在着一些误区。本文就农村肉狗养殖现状，分析了存在的主要问题，并提出绿色养殖肉狗的建议与对策。     

利用体外培养法建立饲料营养成分与瘤胃丙酸产量的回归模型

根据美国康乃尔净碳水化合物和蛋白质体系 (CNCPS) ,分析测定了 4类 2 4种饲料的营养成分 ,利用体外批次培养技术测定了它们在体外培养一定时间后的丙酸产量 ,并由此建立了饲料中产丙酸的营养成分和瘤胃丙酸产量的回归方程     

芽孢杆菌绿色荧光蛋白标记及其在小麦体表定殖的初探

 将来自质粒pAD4412的启动子和绿色荧光蛋白基因gfpmut3a插入大肠杆菌-枯草芽孢杆菌穿梭载体pBE2,构建成芽孢杆菌表达载体pGF P4412,用其转化野生型生防芽孢杆菌83-6和A-47等8个菌株,均得到良好的发光表型。质粒稳定性实验表明重组质粒pG FP4412稳定性为92%。借助荧光显微镜对gfp标记的菌株A-47-gfp在小麦体表的定殖进行初步的研究。结果表明:A-47-gfp能够在小麦根际及小麦体表定殖(包括根表和茎叶表面);相对于在茎叶表面定殖的A-47-gf p在根表定殖的菌体与根的结合更为牢固;从根基到根尖A-47-gfp的定殖量有明显的减少趋势。     

几种绿色饲料添加剂在肉鸡生产上的应用效果

选1日龄AA肉鸡390只,分成13组,分别添加不同种类和不同种类组合的绿色饲料添加剂。试验结果表明,益生素能显著(p<0.05)提高肉鸡的生产性能,改善肉品质。     

尿素水平对青山羊血液生化指标的影响

应用饲养试验与氮平衡试验,研究了不同尿素水平的日粮对青山羊血清总蛋白(STP)、血清清蛋白(ALB)、血清球蛋白(GLB)、血清清球蛋白比值(A/G)、血清尿素氮(SUN)及血清谷丙转氨酶的含量变化的影响。试验采用4×4拉丁方试验设计,试验分4个阶段,在基础日粮一致的情况下,采用4、9、14、0(对照)g/kg·DM4种不同的处理,试验结果表明:不同尿素水平极显著影响ALB、SUN浓度和GPT活性浓度(P<0.01),对血清清球比(A/G)无显著差异(P>0.05),尿素水平与STP、GLB浓度存在负相关;血清含氮生化指标STP、ALB、GLB、A/G、GPT、SUN随时间呈动态变化,出现高峰的时间比瘤胃氨浓度出现的时间平均推迟1～2h。进食尿素后,血液生化指标由平稳逐渐缓慢升高到高峰,随后又下降并趋于平衡。     

现代集约化肉羊业主要关键技术研究与应用

专门化肉用种羊选定、引进后，通过适应性研究，在较大规模养羊业生产实践中。对现代集约化肉羊业的主要关键技术进行研究、完善和创新，组装集成并应用于生产。技术研究应用结果既为市场提供了大批专门化肉用种羊和优质安全的杂种肉羊，取得了高水平的研究成果及显著的经济效益和社会效益．又为我国目前正在迅速发展的集约化肉羊业提供了可靠的技术支持和理想的生产模式：从适宜的专门化肉羊品种到运用高效母羊快速扩繁技术．建立和完善有效的肉羊杂交利用体系，普遍应用种羊鲜、冻精生产大批肉用杂种羔羊，种植高产优质饲草及其科学加工调制和利用．建立严格兽医防疫制度．实行放牧 补饲或全舍饲的精细管理和集约化育肥，至生产优质、安全、标准肉羊，获得显著的经济效益和社会效益。     

The evolution and application of enzymes in the animal feed industry: the role of data interpretation

ABSTRACT

1. Enzymes have been used commercially for nearly 40 years and save significant costs through sparing of expensive nutrients but the mechanism by which this is achieved is still debated.

2. The research focused on non-starch polysaccharidase (NSPase) enzymes is used as an example of where greater progress could have been made if the details of the work had been described more fully and the analysis of the data generated had been broader in scope and more critical.

3. Lack of standardisation of the details presented in the materials and methods has been identified as a significant barrier to meaningful retrospective analysis and thus limits advances in the understanding of the mode of action of these enzymes.

4. The identity of the enzyme employed and its activity is often lacking, and more importantly the purity is rarely disclosed. Contaminant activities which are neither listed nor assayed could play a significant role in the responses observed.

5. The dose optimum of most enzymes is often considerably higher than that employed in most studies. Thus studies claiming synergy between two ‘activities’ should ensure that the response is not related to each enzyme simply augmenting the dose of just one activity in the finished feed. This is a common problem, and coupled with the lack of factorial experiments to justify the presence of each enzyme in a multi-enzyme product, it is not surprising that there is still debate as to whether single or multi-enzymes are best suited poultry rations.

6. The three proposed mechanisms for NSPases (viscosity, cell wall and prebiotic) are discussed, and along with their strengths and weaknesses it is suggested that a re-evaluation of each is needed. Viscosity may have to be re-evaluated as being a function not only of the cereal being fed, but of the age of the animal as well. The cell wall theory as described is poorly modelled in vitro and hence the validity of these data is questioned. The prebiotic theory may need significant modification as it appears that the quantities of oligomers produced are insufficient to generate the additional volatile fatty acids (VFA)’s reported. It is likely that all three mechanisms play a role in the responses observed, but the prebiotic mechanism probably plays by far the most important part in low viscosity diets.

7. Future research would be improved if it considered all potential mechanisms when designing a trial. Significant failings are apparent as a result of adherence to tenets in explanation of the results. Most importantly, it should be emphasised that a hypothesis is there to be tested, not defended.     

Changes in technical efficiency of the broiler production in Poland, 1994–2013

1. The effects of changes in technical efficiency on the increase of broiler production are presented for the period 1994–2013 based on the panel data from seven farms located in southern and central Poland. A total of 766 cycles were analysed.

2. The Cobb–Douglas production function was used to assess the changes of output elasticities as well as technical changes in broiler production, for 5-year sub-periods separately.

3. Technical indices of broiler production significantly improved between years 1994–2013: feed conversion ratio decreased from 2.50 kg/kg to 1.78 kg/kg, mortality rate from 8.8% to 4.0% and daily weight gain increased from 37.1 g/d to 58.7 g/d, respectively.

4. Before accession to the EU, there was a substantial increase of fixed capital connected with modernisation of buildings and equipment. In the period 1994–2013, inputs of fixed capital per kilogram of livestock increased by 72% and at the same time the input of labour decreased by 56%.

5. Technical changes in years 1994–1998 contributed to a rapid production increase at a rate of 4.6% annually and only by up to 0.7% annually during 2009–2013. The slowdown of production rate increase after 2009 was partially caused by decreasing the stocking density.