甜味剂莱鲍迪苷A的致突变作用试验

为了评价甜菊糖苷中的主要成分之一莱鲍迪苷A的致突变作用,在2 500~4μg/皿范围内,对莱鲍迪苷A(含量≥97%)进行了Ames试验,灭菌水作为阴性对照;以5.0 g/kg体重、2.5 g/kg体重和1.25 g/kg体重剂量进行了小鼠骨髓细胞微核试验和小鼠精子畸形试验,以40 mg/kg环磷酰胺为阳性对照,生理盐水为阴性对照。结果 Ames试验中,莱鲍迪苷A对TA97、TA98、TA100和TA102菌株的回变菌落数均小于阴性对照组的两倍,且未见剂量-反应关系,Ames试验阴性;小鼠骨髓细胞微核试验和小鼠精子畸形试验均为阴性。表明莱鲍迪苷A在试验剂量下无致突变作用。     

原虫净可溶性粉防治鸡球虫病的试验

应用中草药复方制剂原虫净可溶性粉对鸡球虫病进行治疗试验，试验方法包括建立球虫病鸡模型，采用不同剂量组应用原虫净可溶性粉对试验的球虫病鸡进行口服投药，观察症状，剖检变化，检查虫卵，通过抗球虫指数分析该药对鸡球虫病的治疗效果，同时设地克珠利对照组。结果显示，原虫净可溶性粉以0．5g／L的剂量对鸡球虫病的治疗效果较好，治愈率达98％。治愈率不低于地克珠利药物组。原虫净可溶性粉对鸡球虫病有显著的疗效，是抗球虫病的理想药物。     

中药复方免疫增强剂中多糖的提取及毒性试验研究

试验采用超声辅助提取法对中药复方免疫增强剂中的多糖进行了提取，并用分光光度法进行含量测定，然后回归动物试验。结果表明，多糖在试验剂量下无毒副作用，对免疫器官的增重有促进作用。     

强普生Ⅲ号毒性安全试验

采用动物毒性试验方法,对强普生Ⅲ号进行了毒性、安全性评价。结果显示:小鼠的急性毒性反应和死亡率与给药剂量成正比,强普生Ⅲ号的半数致死量(LD50)为44.20±2.96 mL/kg,LD50的95%可信限为47.26~41.35 mL/kg,表现为无急性毒性。亚慢性毒性试验,实验期间小鼠的临床表现、体质量变化、饲料消耗量、血常规检查、血清生化检查等各项指标,试验组与对照组均无显著差异,各组脏器剖检和病理学切片检查也均无病理学变化。吸入毒性试验,试验组鸡整体状况正常,72 h内无中毒反应和死亡,血清生化指标值均在正常范围内,与对照组无显著差异。     

泛达宁亚慢性毒性试验

对泛达宁进行３０天毒性试验，试验用ＳＤ大鼠８０只，设３个剂量组和正常饲喂对照组，每组大鼠２０只，结果表明各剂量级瑟对照组比较红，白细胞，血色素，白细胞分类，肾功能指标，脏器系数和脏器组织病理切片观察均未见显著性差异，高剂量组雌性大鼠出现毒性反应，表现为体重增长停滞，从低剂量组到高剂量组谷丙转氨酶单位呈线性升高，但未超出正常值范围。     

鸭瘟灭活疫苗效力试验和安全试验

将已建立的鸭瘟病毒(DPV)AV1221株基础种毒经鸭胚繁殖、收集胚液病毒、0.2%甲醛溶液灭活后,与矿物油佐剂乳化制备了3批鸭瘟灭活疫苗.成鸭的免疫攻毒测定,疫苗最小免疫剂量为0.12 mL,确定使用剂量为每羽份0.5 mL.单剂量、单剂量重复和超剂量安全试验结果显示,疫苗不引起产蛋鸭的全身不良反应和明显的局部反应.疫苗的免疫攻毒试验结果表明,疫苗在不同品种的成鸭中,使用不同的免疫途径,均能诱导产生80%以上保护;在雏鸭中,经二次免疫也能够诱导产生80%以上保护.疫苗一次免疫鸭后,不同时间诱导产生的中和抗体滴度(GMT)分别是,7 d为1:3.2、10 d为1:4.6、14 d为1:8,21 d、30 d和60 d均为1:7;免后10 d可以产生80%攻毒保护,14 d和21 d可产生完全保护.疫苗的免疫持续期试验结果表明,成鸭经1次免疫后150 d,雏鸭经二次免疫后60 d均可维持80%以上保护.     

白毒注射液对鸡新城疫的临床疗效试验

采用体外抗病毒试验和临床治疗试验对白毒注射液进行了药效学试验，结果表明：白毒注射液以10^-1浓度对抗鸡新城疫病毒具有明显的杀灭作用，高剂量的白毒注射(1mL／kg)对鸡新城疫具有显著治疗效果，其治愈率为72．8％，高于低剂量组(0．5mL/kg)(P＜0．05)，明显高于药物对照组(P＜0．01)。     

表达传染性喉气管炎病毒gB基因重组鸡痘病毒疫苗的安全性试验与最小免疫剂量测定

将表达鸡传染性喉气管炎病毒糖蛋白gB基因的重组鸡痘病毒(rFPV-ILTVgB)通过鸡胚成纤维细胞培养,加入适当的保护剂制成冻干疫苗.取3批冻干疫苗,生理盐水稀释后分别经翅内侧无血管处皮下接种14日龄和50日龄SPF鸡,接种剂量为5 × 106PFU,接种后3天出现局部反应,5天局部肿胀达到最大,接种鸡无其它全身反应,精神、食欲以及发育等均不受影响,说明重组病毒对试验鸡是安全的.取其中的200003批疫苗,用生理盐水作210-2～210-5稀释后,翅内侧无血管处皮下接种40日龄SPF鸡,免疫后4周分别攻击传染性喉气管炎病毒WG株和鸡痘病毒102株,结果表明,重组病毒对试验鸡翅内侧皮下接种能产生良好的免疫力,在接种剂量为210-2～210-40.1ml/鸡的范围内可以使全部试验鸡产生局部反应,当接种剂量为210-50.2ml/鸡时可以使部分试验鸡(5/15)产生局部反应,鸡体对重组疫苗的最小反应剂量为210-40.1ml(相当于1000PFU).攻毒试验结果进一步证明,当接种剂量为210-40.1ml(相当于1000 PFU)时可以使免疫鸡产生可靠免疫力,抵抗传染性喉气管炎病毒WG株强毒和鸡痘病毒102株的攻击,降低鸡群的发病率和病死率.这些结果说明,疫苗接种后的局部反应与重组疫苗的免疫效力之间具有相关性,疫苗对接种鸡的局部作用反应了疫苗的免疫效力,我们研制的重组疫苗的最小免疫剂量为1000 PFU,这就为我们进一步考察疫苗的免疫效力试验奠定了基础.     

喹烯酮对肉用仔鸡的增重试验

在饲料中分别添加２５ｐｐｍ、５０ｐｐｍ及７５ｐｐｍ三个剂量的“喹烯酮”与“喹乙醇”对肉用仔鸡进行了饲喂试验。结果表明，５０ｐｐｍ、７５ｐｐｍ剂量均能明显促进肉用仔鸡生长发育，其中以７５ｐｐｍ剂量最佳。与空白对照组相比“喹烯酮”增重率为１２１．９９％，“喹乙醇”增重率为１１８．１４％，“喹烯酮”的增重率稍高于“喹乙醇”，证明“喹烯酮”确有明显的促生长作用。通过临床扩大试验，选取７５ｐｐｍ添加剂量的“喹烯酮”进行了９批试验，与空白对照组相比，平均增重率为１１７％；减少死亡率５．４２％；提高饲料利用率１２％以上。     

三氯苯咪唑混悬剂对牦牛肝片吸虫的驱虫试验

应用三氯苯咪唑混悬剂,选择自然感染肝片吸虫的牦牛60头进行了驱虫试验。结果表明:①三氯苯咪唑混悬剂5mg/kg体重剂量对肝片吸虫的虫卵转阴率、减少率分别为83.3%、90.0%,对成虫的驱净率和驱虫率分别为91.7%、93.8%,对童虫的驱净率和驱虫率分别为83.3%、90.1%;10、15mg/kg剂量对肝片吸虫虫卵转阴率、减少率及成虫、童虫的驱净率和驱虫率均达100%;②三氯苯咪唑混悬剂10mg/kg剂量与同剂量三氯苯咪唑片剂的驱虫效果无明显差异;③三氯苯咪唑混悬剂3个剂量组试验牛未见异常反应。试验证明三氯苯咪唑混悬剂10、15mg/kg剂量驱除牦牛肝片吸虫高效安全,临床使用以10mg/kg剂量为宜。     

高职动物微生物综合设计性实验教学模式实施与思考

动物微生物综合设计实验是实践性和应用性都很强的课程,是理论与实践相结合的纽带,是实现能力型人才培养目标的重要教学环节。综合设计性试验开设对传统动物微生物学实验教学中存在的问题进行了改革。改革的实施,提高了学生分析和解决实际问题的能力,增加了学生学习的兴趣和主动性。     

全血中DNA的5种不同提取方法比较研究

比较几种从血液中提取DNA方法所需要的时间、样本量、提取的DNA纯度、产量以及成本等。结果表明,几种方法所提取的DNA质量都能达到分子生物学的试验要求,但在DNA的纯度、产量、试验时间和价格等方面存在差别。实验人员可根据自己的实验要求、实验室以及经济条件等选择适当的方法。     

大动物试验生物安全防控要点

为规范和提高我国大动物试验的生物安全,以及建设大动物试验用生物安全动物舍提供借鉴,在分析和比较国内外生物安全重大事件和目前大动物试验条件的基础上,考察和研究美国与加拿大动物实验室的设计理念、硬件设施、软件管理及动物尸体与废弃物处理等程序。大动物试验的生物安全关系到我国畜牧业健康发展和社会稳定,应学习和借鉴欧美国家高科技含量的大动物试验室和人性化设计的理念和管理。我国应根据各地资源和社会环境建设与国际接轨的大动物试验用生物安全动物舍,并探索建立在实践中逐步完善的大动物实验生物安全综合防控体系。     

Dose-response-models and their implications for quantitative risk assessment for Campylobacter infections

For some time now there have been several projects dealing with the assessment of campylobacteriosis risks for consumers. Dose-response relationships form a crucial part of such assessments, as they specify disease probabilities depending on different microbial concentrations in foods. Evaluation of such models, however, is difficult because of problems to find data on which reliable assumptions could be based. Ongoing risk analyses for Campylobacter mainly refer to a single administration study with human volunteers published by Black et al. (1988). However, whether results from this study can be transferred to target populations envisaged in risk assessments remains questionable for several reasons. In this paper some alternative dose-response models, their fit to the data of Black et al., and risk estimates resulting in a fictitious scenario are discussed and compared. Depending on the dose-response model assumed risk estimates can differ remarkably. Therefore it is hardly possible to make reliable quantifications of risks in reality, however, it can be determined how much they may vary assuming different scenarios.     

商品乌骨鸡生长性能测定

目的：为了开发商品乌骨鸡的经济价值和遗传潜能，对商品乌骨鸡进行选育时可以针对公鸡和母鸡的质量特性及屠宰性能进行性状选择，以达到快速提高商品乌骨鸡体重的目的。方法：用单因素试验对公鸡和母鸡性能进行测定并比较。结果：在相同饲养条件下，公鸡生长速度比母鸡快，屠宰性能公鸡总优于母鸡。结论：商品乌骨鸡进行选育时可以侧重于公鸡，从而迅速提高乌骨鸡质量，以满足消费者对乌骨鸡的迫切需要。     

Safety and efficacy of an inactivated vaccine against Lactococcus garvieae in rainbow trout (Oncorhynchus mykiss)

We studied the safety and efficacy of an inactivated vaccine (Ichtiovac-Lg) against Lactococcus garvieae in rainbow trout (Oncorhynchus mykiss). In an initial dose-response experiment to test safety, we injected 50 rainbow trout weighing 30-40 g with a double dose of vaccine (0.2 ml) intraperitoneally. We observed these fish three times a day until day 50 post-vaccination when they were killed to evaluate visceral reactions, adhesions and intraperitoneal absorption. Survival was 100% in both the treatment and control groups and no significant differences were found in percentage of severe adhesions and pigmentation of peritonea and viscera. In a second trial, we injected 50 rainbow trout weighing 30-40 g with 0.1 ml of vaccine and a control group was injected with 0.1 ml of PBS intraperitoneally. On day 29 post-vaccination, both groups were challenged by intraperitoneal injection with 0.1 ml of a virulent heterologous strain of L. garvieae at 3 x 10(6) cfu ml(-1) and fish were observed for a further 21 days. At the end of the experiment, the survivals of the vaccinated fish and control group were 94 and 4%, respectively.     

公共基础化学实验微型化教学改革探讨

将微型实验与常规实验仪器规格和试剂用量进行了对比,并进行了试验。微型化学实验具有减少环境污染、节约实验经费、节省实验时间和实验室空间、培养学生科学创新的能力等优点,微型化化学实验为研究性学习提供了一个崭新的化学实验教学模式,有利于学生综合素质的提高。     

Investigations on iron bioavailability of different sources and supply levels in piglets

Two experiments were conducted to investigate the iron bioavailability of different sources and supply levels in piglets. In experiment 1, the influence of feeding an iron deficient basal diet or the basal diet supplemented with 28 ppm Fe either in form of Fe-chelate, crystalline Fe-glycinate, or Fe-sulphate on apparent iron digestibility and on blood parameters was determined. In experiment 2, a dose-response approach was used to determine the effects of supplementing an iron-deficient basal diet with 30, 60, or 90 ppm of Fe either in form of crystalline Fe-glycinate or Fe-sulphate on digestibility of Fe, growth and blood parameters. In experiment 1, comparison of iron sources revealed a tendency (0.05 < p < 0.1) for a higher Fe digestibility from Fe-glycinate (40.9%) compared with Fe-chelate (30.8%) or Fe-sulphate (30.7%). Fe-balance was higher (p < 0.05) for Fe-glycinate compared with Fe-sulphate but iron balance was similar for iron sulphate and iron chelate. Those results, however, were not reflected in data of blood parameters. In experiment 2, iron digestibility, blood parameters and performance were significantly (p < 0.05) influenced by iron supply. Effects of iron source on digestibility of iron were lower than observed in the first experiment.     

Growth performance and carcass characteristics of male broilers fed diets varying in digestible threonine to lysine ratio from 21 to 49 days of age

Two experiments were conducted to ascertain digestible Thr to Lys ratio of male broilers from 21 to 35 d of age (experiment 1) and 35 to 49 d of age (experiment 2) based on growth performance and processing yields. In both experiments, 2 diets (dilution and summit; 3,108 kcal ME/kg and 18.2% CP in experiment 1; 3,163 kcal ME/kg and 17.2% CP in experiment 2) consisting of corn, soybean meal, poultry by-product meal, and peanut meal formulated to be surfeit in limiting amino acids with exception of digestible Lys and Thr were mixed at various proportions to create 8 titration dose-response diets. Digestible Lys was formulated to contain 95% of the requirements from 21 to 35 and 35 to 49 d of age. In each experiment, gradient treatment structure was arranged in a randomized complete block design. Calculated digestible Thr to Lys ratios ranged from 0.512 to 0.806 in approximately increments of 0.040 (1,600 Hubbard × Cobb 500 broilers; experiment 1) and 0.552 to 0.793 in approximately increments of 0.035 (3,000 Ross × Ross 708 broilers; experiment 2). In experiment 1, digestible Thr to Lys ratio for male Hubbard × Cobb 500 broilers was estimated at 0.68 and 0.67 for BW gain and feed conversion from 21 to 35 d of age. In experiment 2, digestible Thr to Lys ratio of Ross × Ross 708 was determined at 0.68 and 0.63 for feed conversion ratio with quadratic and linear broken-line models, respectively. Meat weights and yields were not affected by the dietary treatments in either experiment. These data indicate that a digestible Thr to Lys ratio of 0.68 can optimize growth performance of broilers from 21 to 35 and 35 to 49 d of age.