Tsetse control in cattle from pyrethroid footbaths

In Burkina Faso, we assessed the efficacy of treating cattle with a footbath containing aqueous formulations of pyrethroids to control two tsetse-fly species, Glossina tachinoides Westwood, 1850 (Diptera, Glossinidae) and Glossina palpalis gambiensis Vanderplank 1949. Legs were the most targeted parts of the body for tsetse-fly blood meals: 81% (95% CI: 73, 89) for G. tachinoides and 88% (81, 95) for G. palpalis.

The in-stable efficacy of footbath treatments was compared with manual full spraying with a 0.005% alphacypermethrin (Dominex, FMC, Philadelphia, USA) formulation (250 mL versus 2 L). The proportions of knocked-down flies were the same with footbath and full spray but the latter was more protective against fly bites. In field use, the efficacy of both methods should be similar given the recommended treatment frequency: 3 days for footbath versus 7 days for full spray.

Among 96 cattle drinking at the same water point in Dafinso (Burkina Faso), 68 (71%) were treated with a footbath containing a 0.005% deltamethrin formulation (Vectocid, CEVA SA, Libourne, France). We observed the effect of this live-bait technique on the one hand on released cohorts of reared, irradiated flies, and on the other hand on wild tsetse flies. In both cases, the footbath treatment was associated with a reduction of the apparent fly density probably related to an increased mortality.     

Quantification of stress sensitive markers in single fecal samples do not accurately predict excretion of these in the pig

All feces produced during 24 h were collected from five pigs and cortisol and immunoreactive cortisol metabolites (CICM), and IgA were quantified. Within pigs, the concentrations of CICM and IgA varied extensively between random samples obtained from a single fecal dropping, and deviated in most cases significantly from the true concentration measured in total fecal output (CV 6.7-130%). The CICM and IgA contents varied considerably (CV 8.1-114%) within and between individual fecal droppings from the same pig compared to the total fecal excretion. In conclusion, single random samples could not be used to reliably quantify the total fecal concentration or excretion of CICM or IgA in pigs. Analyses of all feces collected during shorter periods than 24 h did not provide an accurate estimate of the daily excretion of CICM. Thus, the concentration of stress sensitive molecules in random single fecal samples as an indicator of animal welfare should be interpreted with prudence.     

竞争效应对红色型豌豆蚜繁殖的影响

为明确种间竞争和种内竞争效应对红色型豌豆蚜生长和繁殖产生的影响,本研究以红色豌豆蚜克隆、绿色型豌豆蚜克隆及豌豆修尾蚜克隆作为试验材料,选用琼脂法,首先制备4种竞争试验区(1头区,2头区,种内竞争区和种间竞争区),观察各试验区蚜虫的种群动态,另准备3个(红色型、绿色型及豌豆修尾蚜)高密度种群处理,分别往里放入1头4龄红色克隆若虫,统计其3日总产蚜数。结果发现,种内竞争区和种间竞争区,二者的竞争效应都非常明显,竞争区混合种群的增殖率高于2头区,种间竞争区红色克隆胜利组单头红色克隆第10天新生蚜数高于其他处理。此外,高密度的绿色克隆和豌豆修尾蚜种群均能抑制红色克隆的繁殖。因此,红色型豌豆蚜能通过评估竞争种和同伴的相对密度来控制繁殖,无论是种间竞争还是种内竞争均能影响其繁殖,且种间竞争可能加速它的繁殖速率。     

大豆异黄酮在畜牧业生产中的应用及研究进展

近年来,研究者对大异异黄酮在畜禽生产上的应用效果进行了广泛研究,发现其生物利用率高,可调控动物机体养分代谢,改善饲料利用率,并具有抗氧化作用,可改善动物产品品质,提高动物免疫机能和生产性能等作用,因此,有必要对大豆异黄酮对家畜生产的作用及研究进展作以综述.     

基于动物福利视角的规模化奶牛养殖场经济效应分析

本研究遵循动物福利"5F"原则,结合150家规模化奶牛养殖场实地调研数据,构建奶牛场动物福利评价体系,测度动物福利水平,并进一步建立嵌入动物福利水平测度值的规模化奶牛养殖场收入函数,验证关联效应.结果表明:生理福利和环境福利是影响我国规模化奶牛养殖场动物福利的最重要的2个维度,受访的规模化奶牛养殖场生理福利和环境福利的...     

鼠尾藻有性繁育及人工育苗技术的初步研究

对鼠尾藻有性繁育规律进行观察、研究。鼠尾藻雌、雄异株,在黄海北部其生殖季节是7月上中旬,高光照和升温可促进精卵成熟,鼠尾藻在海区和室内都可正常完成受精。干露1~2h能促进幼孢子体生长,幼孢子体在实验范围的光照强度(1000~4000lx)下,光照越强生长越快;在试验盐度(21~40)范围内均可正常生长。在此基础上建立起了鼠尾藻人工苗种繁育技术,并对鼠尾藻有性繁育技术中存在的问题及今后研究的方向进行了分析。     

黄颡鱼人工繁殖的几个关键问题

近年来,随着黄颡鱼养殖的不断发展,黄颡鱼苗种的供应日趋紧张.为了解决和突破这一制约黄颡鱼养殖的"瓶颈"问题,生产更多更优质的黄颡鱼苗种,保证黄颡鱼养殖稳步而快速的发展,对黄颡鱼的人工催产繁殖各地都做了大量的研究工作.     

不同近交程度对三疣梭子蟹(Portunus trituberculatus)繁殖性能的影响

以本实验室建立的三疣梭子蟹(Portunus trituberculatus)全同胞家系为研究对象,通过连续观测6代三疣梭子蟹近交家系的抱卵量、排幼量、孵化率、单位体重抱卵量、单位体重排幼量及幼体发育各阶段的变态率6个指标来评价近交对三疣梭子蟹繁殖性能的影响.方差分析显示,在实验亲蟹的规格大小对测量数据无影响的条件下,近交系数每增加10％,各近交代与非近交代F1m在单位体重抱卵量与单位体重排幼量的差异不显著(P＞0.05),这2个指标的近交衰退系数分别为-2.789％～-6.620％和-1.188％～-5.938％;孵化率的差异也不显著(P＞0.05),衰退系数为-1.859％～-7.222％,表明没有明显的近交衰退;由溞状幼体(Z)阶段、大眼幼体(M)阶段到Ⅱ期幼蟹阶段的变态率变化趋势可知,随着近交代数的增加,各阶段的变态率呈下降趋势.     

动物源性食品中尼卡巴嗪残留量的测定

动物产品中的尼卡巴嗪药物残留已被我国及美国、日本、欧盟等国家和地区列为重点检测内容,其最大残留量为0．01mg／kg-0．2mg／kg不等。为探讨合适的检测方法,本文对国内外相关尼卡巴嗪的分析检测方法的优缺点做了分析和比较,并重点介绍了动物源性食品中尼卡巴嗪残留量检测的高效液相色谱法（HPLC）和高效液相色谱-质谱联用（HPLC-MS）法。运用这两种方法进行检测,其最低检测限可达到10μg／kg甚至0．5μg／kg,基本上符合现有相关标准的限量要求。