Susceptibility of Rhipicephalus (Boophilus) microplus to ivermectin (200, 500 and 630 μg/kg) in field studies in Brazil

The present study aimed to determine the susceptibility of 17 Rhipicephalus (Boophilus) microplus populations, originating in the Southeast and Southern regions of Brazil, to different ivermectin concentrations (200, 500 and 630 μg/kg), administered through subcutaneous or topical (pour-on) routes. R. (B.) microplus populations from the states of Minas Gerais (seven populations), São Paulo (seven populations) and Paraná (three populations) were chosen for the tests. The selected cattle were allocated to treatment groups on day 0, and block formation was based on the arithmetic mean of female ticks (4.5–8.0 mm long) counted on three consecutive days (−3, −2 and −1). To evaluate the therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0 mm long) were performed on days 3, 7 and 14 post-treatment, and continued on a weekly basis thereafter until the end of each experiment. The results obtained throughout this study, utilizing field efficacy studies, allowed us to conclude that the resistance of R. (B.) microplus against 200 and 500 μg/kg ivermectin is widely disseminated because all tick populations that had contact with these specific concentrations were diagnosed as resistant. However, it is possible to infer that R. (B.) microplus resistance against 630 μg/kg ivermectin was also widespread, diagnosed at six of ten analyzed properties. Resistance of these ectoparasites to 630 μg/kg ivermectin is most likely emerging in three other populations of R. (B.) microplus. Strategies of resistance management need to be quickly determined to keep the selection pressure at a minimum level in Brazil.     

《水产养殖概论》课程建设的探索与实践

按照精品课程建设的内容和要求,以培养高素质人才为目标,对《水产养殖概论》课程在教学内容、教学方法与手段、实验教学、课程考核等4个方面进行了探索与实践,并取得了较好的教学效果。     

肉鸽大肠杆菌的分离鉴定与耐药性的研究

以南京市郊某肉鸽场病鸽为样本进行细菌分离鉴定,研究肉鸽大肠杆菌的耐药性。从病死鸽体内分离到14株大肠杆菌,鉴定出4种血清型,分别是O2、O18、O78、O101,其中O2型8株,为主要血清型,占血清型总数的66.67%。将分离到的菌株接种20～25日龄雏鸽进行动物回归试验,死亡率达85.17%,说明该分离菌株对雏鸽具有较强的致病性。对分离菌株进行药敏试验,结果表明,14株大肠杆菌对庆大霉素、卡那霉素、头孢拉定3种药物敏感率达100%,对环丙沙星、阿米卡星等13种药物均产生不同程度的耐药,对强力霉素和新霉素2种药物完全耐药。     

50～75日龄番鸭日粮限制性氨基酸水平研究

本试验旨在研究日粮不同赖氨酸粗蛋白质比例和蛋氨酸(含硫氨基酸)赖氨酸比例对50~75日龄番鸭生产性能、血清生化指标和肌肉品质的影响。试验选用1440只健康50日龄番鸭,随机分为9组,每组4个重复,每重复40只鸭,饲喂9种不同赖氨酸粗蛋白质比例(Lys/CP)(分别为5%、5.5%、6%)和蛋氨酸(含硫氨基酸)赖氨酸比例(Me(SAA)t/Lys)(分别为35%(75%)、40%(80%)、45%(85%))的玉米-豆粕型日粮。试验结束时,进行称重,每个重复挑选2只接近平均体重的番鸭进行采血和屠宰。结果显示:①Lys/CP对日均采食量(ADFI)、日均增重(ADG)影响显著,5%和5.5%组显著高于6%组(P<0.05);Me(tSAA)/Lys为40%(80%)的组ADFI显著高于45%(85%)组,40%(80%)组ADG显著高于其他两组,而料肉比显著低于其他两组;②Lys/CP为5%的组血清尿酸和甘油三酯含量显著高于(P<0.05)其他两组;Me(SAA)t/Lys对血清尿酸和甘油三酯含量影响不显著(P>0.05);日粮Lys/CP和Me(tSAA)/Lys对血清甘油三酯含量存在交互作用;③日粮Lys/CP为5.5%的组胸肌干物质(DM)含量显著高于其他两组,粗蛋白质(CP)含量显著高于6%组;Me(tSAA)/Lys为35%(75%)和40%(80%)的组胸肌CP含量显著高于45%(85%)组;日粮Lys/CP和Me(tSAA)/Lys对胸肌DM和CP含量存在交互作用;④日粮Lys/CP为5.5%和6%的组腿肌DM含量显著高于5%组,5.5%组腿肌CP含量显著高于其他两组;Me(tSAA)/Lys为40%(80%)和45%(85%)的组腿肌DM含量显著高于35%(75%)组;日粮Lys/CP和Me(tSAA)/Lys对腿肌DM和CP含量存在交互作用。     

温室授粉蜂群蜂子比值与工蜂出勤率相关性的研究

蜜蜂是设施农业的重要授粉昆虫,授粉蜂群的状况可能影响授粉效率的高低。通过意大利蜂(Apismellifera)对温室草莓、油桃的6次授粉重复试验,采集授粉蜂群的蜂子比值与出勤率的数据,分析蜂子比值与出勤率的相关性。结果表明,蜂子比值与工蜂出勤率之间呈显著的负相关(P<0.05),其相关系数分别为-0.8470、-0.6543、-0.7616、-0.6969、-0.6740和-0.8477,说明在正常范围内,温室授粉蜂群的出勤率随蜂子比值的减小而提高,也就是说,授粉蜂群内的子脾越好,蜜蜂出勤采集的积极性越高。     

Privatization of Veterinary Services in Developing Countries: A Review

Increasing fiscal constraints on the government, a lackadaisical performance by public sector animal health and breeding services and pressure from donor partners have prompted the governments of various developing countries to rethink the role of the public sector in the provision of veterinary services. Various countries have started to implement, or have already implemented, privatization of some veterinary services. The results are mixed. It is established that private provision alone is not optimal, and a blend of private and public sector veterinary services is required to utilize the virtues of both.The privatization process has also begun in India. Certain state governments in India are pursuing a cost recovery approach and are encouraging private practitioners to cope with the financial constraints and to deliver broad and effective animal health and breeding services. This paper considers the global aspects of the privatization of veterinary services as well as the scenario in India, so as to gain an insight into the very complex and debatable issue of privatization of veterinary services.     

退化草原围栏封育后地上生物量干鲜比值的研究

对处于退化恢复演替过程中的羊草草原群落,通过样方法获得其地上部分干、鲜生物量,研究羊草草原的围封动态并对围栏封育效果进行评价.结果表明,羊草群落干鲜比值呈现在波动中略有上升的趋势,波动主要有两个原因:一是降水量的变化;二是演替不同阶段物种组成的差异.各主要科的干鲜比值以禾本科最高,其次为菊科和豆科,各主要科干鲜比值的排序可以解释群落干鲜比值的变化趋势.各物种干鲜比值的变幅较大(锦鸡儿最高,瓦松最低,变幅为0.45),但起主要作用的是羊草、冰草和冷蒿.计算物种的相对干重可以确定草原恢复过程中的最佳放牧时期.     

藜麦种质资源对霜霉病的抗性鉴定与评价

为探究藜麦(Chenopodium quinoa)种质资源在本土环境条件下对霜霉病的抗性,采用田间自然感病和室内离体叶片接菌鉴定方法对50份国内外藜麦种质资源进行了霜霉病抗性鉴定和评价。结果表明：霜霉菌Preonos variabilis对藜麦的侵染程度存在较大变异(发病率变化13.30%～100.00%;病情指数1.00～100.00),藜麦种质对霜霉病的抗性存在明显差异;筛选到1份高抗材料‘台湾红藜’,占参试材料的2.00%1份抗病材料‘QA064’,占比2.00%,2份中抗材料‘陇藜2号’和‘HL-Q5’,占比4.00%,3份感病材料‘QA045’‘QA050-2’和‘青海-02’,占比6.00%;其余43份材料均表现高感,占比86.00%。本研究首次发现‘台湾红藜’能够被P.variabilis侵染,表现为高抗,还进一步证实田间藜麦霜霉病抗性鉴定采用“三叶法”在藜麦盛花期进行效果较好,相比而言,室内离体叶片接菌鉴定技术更具优势,应作为抗性鉴定的首选。     

乳化剂在肉鸡饲料中的效果研究

乳化剂是一种亲油又亲水的物质,能显著降低脂肪的粘度,弥补动物胆盐分泌不足,从而提高脂肪消化率,防止脂肪肝发生和畜禽因脂肪消化不良引起的下痢,且利于脂溶性营养物质（VA、VD、VE、色素等）的吸收。因此,可通过乳化剂调低配方的代谢能水平,降低成本,提高经济效益。本试验研究了乳化剂对白羽肉鸡生产性能的影响。结果显示：减少油脂后添加乳化剂对肉鸡平均日采食量和平均日增重的影响均不显著,从试验全期看,日粮减少油脂5 kg/t 或降低代谢能30 kcal/kg （1 kcal=4.187 kJ,下同）后添加乳化剂,可以使肉鸡平均日增重和料重比保持正常的水平。     

感染高原鼠兔的皮蝇蛆16SrRNA基因序列研究

利用分子生物学技术对高原鼠兔感染皮蝇蛆16SrRNA基因进行了研究,扩增出长度为551 bp的序列,克隆测序,将其序列与GenBank中的皮蝇科、胃蝇科的序列进行了聚类分析,并构建分子进化树.结果显示,感染高原鼠兔的皮蝇蛆与皮蝇科的皮蝇蛆遗传距离更近,在一个大的进化树分支上,基因片段同源性84.6％～88.4％之间,与胃蝇科的红尾胃蝇基因片段同源性60.1％ ～64.4％之间.几株感染高原鼠兔的皮蝇蛆之间的基因片段同源性94.4％～99.6％之间.