一种从马鹿粪便中提取DNA的改进方法(英文)

[目的]介绍一个从马鹿粪便中提取DNA的改进方法。[方法]本实验采用的是,在传统的CTAB裂解法的基础下,根据马鹿粪便的特征摸索出来的改进方法。[结果]采用该方法从天山马鹿粪便中提取了高质量的粪便DNA并扩增了天山马鹿线粒体细胞色素b基因片段,通过测序检测,同时提取马鹿肌肉和皮毛样品的DNA作为对照,进一步证实了提取的可靠性。[结论]该方法提取过程中不需要用蛋白酶K;所提取的DNA不需要用DNA纯化试剂盒纯化,可直接用PCR扩增,因此,费用量很低。     

Comparison of the regression analysis technique and the substitution method for the determination of true phosphorus digestibility and faecal endogenous phosphorus losses associated with feed ingredients for growing pigs

Two digestibility experiments were carried out to comparatively measure true phosphorus (P) digestibility and the faecal endogenous P loss associated with soybean meal (SBM) and wheat middling meal (WM) for growing pigs by the simple linear regression analysis technique and the substitution method. Eight barrows, with an average initial body weight 21 kg, were randomly divided into two groups of four pigs with each group being fed four test diets according to a 4 × 4 Latin square design. Eight maize starch-based diets containing four levels (on dry matter basis) of P (0.20, 0.24, 0.36 and 0.42%) and P (0.181, 0.26, 0.36, and 0.43%) were formulated from SBM and WM as a sole source of P, respectively. Chromic oxide (0.30%) was used as a digestibility marker. Each experimental period comprised 8 d with a 4-d adaptation and a 4-d collection of faecal samples. Levels of the assay ingredient substitutions had no effects (P > 0.05) on true P digestibility and the endogenous P loss associated with SBM and WM measured by the substitution method. There were no differences (P > 0.05) between the regression technique and the substitution method in measuring the true P digestibility (SBM: 49.4 ± 3.51 vs. 50.6 ± 2.4; WM: 63.7 ± 5.0 vs. 63.2 ± 5.4%) as well as the faecal endogenous P loss (SBM: 0.62 ± 0.10 vs. 0.71 ± 0.11; WM: 0.65 ± 0.16 vs. 0.70 ± 0.17 g/kg dry matter intake) for the growing pig. Thus, true P digestibility and the faecal endogenous P loss in feed ingredients for pigs may be measured by using the regression analysis technique and the substitution method.     

Assessing the efficacy of Duddingtonia flagrans chlamydospores per gram of faeces to control Haemonchus contortus larvae

The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 10⁶, (T3) 2.5 × 10⁶ and (T4) 5 × 10⁶. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.     

A survey on anthelmintic resistance in nematode parasites of sheep in the Slovak Republic

The prevalence of anthelmintic resistance on 27 sheep farms in Slovakia was investigated in 2003 and 2004 using the faecal egg count reduction test (FECRT) according to the WAAVP guidelines. Resistance to albendazole was detected on one farm (3.7%) and suspected on two farms (7.4%) out of 27 sheep flocks. Resistance to ivermectin was tested on 26 farms. On six (23.1%) farms, results indicated the presence of ivermectin resistance. Resistance to ivermectin was suspected on eight farms (30.8%). However, it is also possible that generic ivermectin anthelmintics used in survey have a lower efficacy against sheep nematodes.     

一种从马鹿粪便中提取DNA的改进方法

[目的]介绍一种从马鹿粪便中提取DNA的改进方法。[方法]在传统的CTAB裂解法的基础下,根据马鹿粪便的特征进行改进所得的DNA提取方法。[结果]采用该方法从天山马鹿粪便中提取了高质量的粪便DNA并扩增出了天山马鹿线粒体细胞色素b基因片段,通过测序检测,同时以提取的马鹿肌肉和皮毛样品DNA作为对照,进一步证实了提取的可靠性。[结论]该方法提取过程中无需使用蛋白酶K;所提取的DNA无需使用DNA纯化试剂盒纯化,可直接用于PCR扩增,因此,试验费用很低。     

养殖粪水长期贮存过程理化特性变化规律

目前中国中小规模畜禽养殖场主要采用自然贮存后还田的形式处理养殖粪水,受场地制约,养殖粪水贮存时间通常仅有1～2个月,之后便直接还田利用,贮存后的粪水理化特性变化尚不清楚,是否适宜直接还田尚需研究。该研究以猪粪水和牛粪水为研究对象,重点分析粪水在长期贮存中粪大肠菌群、电导率(Electrical Conductance,EC)以及化学需氧量(Chemical Oxygen Demand,COD)的变化,分析粪水最佳贮存期及还田利用方式,以期为粪水资源化及安全还田提供参考。结果表明,粪水经自然贮存6个月,铵态氮损失达68%以上,不仅引起环境污染,且降低了养分;贮存后粪水基本可达到无害化要求,但pH值、EC值以及COD浓度仍然偏高,还田前应制定合理的粪水资源化利用方案;固液分离可以有效降低粪水中的COD浓度和EC值,促进粪水无害化进程。该研究为中国畜禽养殖粪水资源化用探索了新的技术路径。     

生乳的微生物检测

在乳和乳制品的生产过程中消毒是一个重要环节。目前市售鲜乳主要为巴氏杀菌乳和UHT灭菌乳，但也有一部分未经消毒的散装生牛乳。实验采用国家规定的标准办法检验未经消毒的生牛乳中的细菌总数和犬肠菌群数。实验证明，未经消毒的生牛乳中的细菌总数是大大超标的．犬肠菌群虽然为阴性，但其中含有致病性葡萄球菌和链球菌。因此饮用这种乳对人们的身体健康有极大危害。     

Epidemiology of nematodosis in Romney lambs selectively bred for resistance or susceptibility to nematode infection

Field trials were undertaken to compare nematode population dynamics, lamb productivity and levels of breech soiling in experimental flocks of Romney lambs selectively bred for increased resistance or susceptibility to nematode infection. In each year of the 2 year study, spring-born ewe lambs derived from Wallaceville Animal Research Centre's divergent nematode-resistant and nematode-susceptible breeding lines were grazed as separate flocks on matched farmlets from weaning (at 3 months old) until they were approximately 10–11 months old. Allocation of farmlets was reversed between Years 1 and 2 of the study to account for any possible paddock-related effects. Within each year both flocks were subjected to identical management conditions, including anthelmintic treatment (which was administered only when the overall mean faecal worm egg count measured across both genotypes reached 1500 eggs g⁻¹). In both years, by mid-autumn (April) nematode larval infestation levels on pasture were approximately 5–6-fold greater on the farmlet grazed by susceptible (S) genotype lambs than on that grazed by their resistant (R) counterparts (Year 1: 2506 cf. 544 larvae Kg⁻¹ herbage; Year 2: 431 cf. 74 larvae kg⁻¹ herbage). This led to 51-fold and 56-fold differences in faecal egg count between R and S lambs by late autumn (May) and winter (July) in Years 1 and 2, respectively. Although mean growth rates were similar in the R and S lambs over summer (while pasture infestation levels on the farmlets were still in the process of diverging), significantly higher growth rates occurred in the R than in the S lambs over autumn-winter in both years of the study (P < 0.01). In contrast, no significant differences in growth rate occurred in either year between male lambs derived from the nematode-resistant and nematode-susceptible breeding lines which were grazed together on another area of the Wallaceville farm from weaning until late autumn. Despite the substantially lower pasture infestation levels encountered by the R ewe lambs, they nevertheless temporarily suffered more breech soiling (dags) than their S counterparts (P < 0.01) in both years. Yearling fleece-weights of the R and S genotypes did not differ significantly in either year. Although the results of our study confirmed that there are potentially significant epidemiological benefits to be derived from breeding sheep for resistance to nematode infection, these benefits did not appear to be associated with large advantages in animal performance. Further work is needed to establish how these results should be interpreted with respect to anthelmintic drench requirements of genetically resistant animals.     

杭州湾粪大肠杆菌和异养细菌的分布特征及其环境因子

根据１９９９年５月￣６月的杭州湾现场调查资料,对杭州湾粪大肠肝菌及异养细菌的分布特点进行了研究,并分析了其与环境因子的相关关系。结果表明,杭州湾粪大肠肝菌数量分布主要受陆源性物质的支配,呈现西北高东南低的特征;而异养细菌则主要与浮游植物的数量有关,其分布特征为西南低东部高。与环境因子的相关分析表明粪大肠肝菌和异养细菌除均与水温、盐度相关较高外,前者还与无机磷、而后者则与叶绿素ａ呈现数量上的相关性。     

在线酶底物法检测地表水中粪大肠菌群的适用性分析

结合酶底物法检测粪大肠菌群的相关研究,运用酶底物在线监测系统对上海市某河段进行检测,用标准方法-多管发酵法进行同步检测,讨论在线酶底物法在地表水中检测粪大肠菌群的适用性。结果表明,2种方法的测定数据显著相关,没有统计学差异（P＞0.05）。相对于多管发酵法,在线酶底物法特异性强,检测时间短,自动进样,自动检测,二次污染少,可以实现地表水、饮用水等重要水源地的实时监测需求,对地表水的污染程度监控和卫生学质量评价具有重要作用。