三种优良禾本科牧草与本地品种生长性状对比分析

分析了三种引进优良禾本科牧草与一种当地禾本科牧草的生长性状，结果表明：三种引进禾本科牧草的鲜重均比当地禾本科优良牧草垂穗披碱草高，种植第三年引进牧草品种的鲜草产量为无芒雀麦19316kg／hm^2，达乌里披碱草16457kg／hm^2，猫尾草15754kg／hm^2。引进的三种牧草品种表现出较好的抗逆性，推广价值较高，适宜在高寒地区种植。     

重庆市近郊区县鸭传染性浆膜炎病病原分离鉴定及防治

通过对重庆近郊的沙坪坝区、北碚区、九龙坡区、永川市、璧山县、铜梁县的7个养鸭场病死鸭的病原分离,分离到三株细菌,经染色镜检、生化鉴定、动物回归实验,确诊为鸭里氏杆菌。药敏试验结果显示对庆大霉素、青霉素、链霉素、土霉素等高度敏感。在临床上交替使用这些药物,收到较好治疗效果。将分离菌制成灭活苗免疫1周龄的健康鸭,20日龄时用分离菌进行攻毒,平均保护率达83.3%。     

纤维素酶渣替代黄豆饲喂杂交奶牛试验

采用纤维素酶渣替代黄豆对西黄杂奶牛(西门塔尔×本地黄牛)作饲喂对比试验,并对其产奶量及奶品质进行观察。结果表明:试验组比对照组牛日产奶量平均提高1 88kg,其乳蛋白和乳糖含量也有不同程度的提高。     

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.     

Soil phosphorus fractions and their availability over natural succession from clear-cut of a mixed broadleaved and Korean pine forest in northeast ChinaOA

To assess phosphorus(P) status of forest soil under naturally restored vegetation, P fractions in the 10-cm soil layer were quantified at different successional stages on the clear-cut site of mixed broadleaved and Korean pine forest. Four communities of shrub, softwood broad-leaved forest, softwood and hardwood broad-leaved forest, and hardwood broad-leaved forest represented different successional stages. A soil sample from a primary broad-leaved and Korean pine stand was the control. A sequen...     

茶树LOX基因家族的鉴定及其在白茶萎凋过程的表达分析

脂肪族类化合物是植物芳香物质的重要组成部分,对白茶香气的形成具有重要作用.利用生物信息学方法,在染色体级别的茶树基因组数据库中,对LOX基因家族进行鉴定,从中获得12个茶树LOX基因家族成员,命名为CsLOX1～CsLOX12.12个茶树LOX基因序列,主要定位于细胞质或叶绿体中,其编码蛋白具有相同的特征结构域及保守基...     

湖南小溪国家级自然保护区生态旅游资源的SWOT分析

对湖南小溪国家级自然保护区进行了生态旅游资源的SWOT分析,其优势是:良好的原始次森林和高品位的自然资源、森林浴的理想场所、优秀独特的人文资源、丰富的植物基因库存.但是可进入性差、知名度低、接待设施及能力较差.周边存在张家界国家森林公园和栖凤湖风景区的竞争威胁.分析了发展机会.     

云南哀牢山自然保护区南华片区项目建设必要性分析

对哀牢山国家级自然保护区南华片区的生物多样性、经营现状和经营管理进行评价,对项目建设必要性分析结果:项目建设有利于该保护区的整体效应;有利于对珍稀植物物种和生态系统的保护;有利于对候鸟迁徙通道的保护;有利于社会经济的可持续发展;是加强科研和宣教工作的需要。最后阐述了项目建设的主要内容。     

湖北薤山自然保护区两栖爬行动物多样性调查

2005年8月对湖北省薤山自然保护区的两栖动物和爬行动物进行了专项调查.分别记录到两栖动物21种,隶属于2目8科;爬行动物31种,隶属于2目9科.对它们的物种组成、地理区系特点和保护等级进行了研究,并提出了保护建议.     

马尾松胶合板材用材林优良家系生长与物理力学性质的研究

通过对不同家系马尾松的生长和物理力学性质研究,结果表明,采用经过遗传改良的良种造林,能使马尾松人工林生产力大大提高,从而缩短大径材的培育年限,达到良好的增产效果,提高经济效益.结合材性分析结果,培育优质胶合板材的马尾松优良家系主要有建瓯南雅-24、建瓯川石-3、连城-48、龙岩-61、南平-85、南平-86、连城-50、建瓯川石-4家系.