Survival and retention of infectivity of the mitePsoroptes ovis off the host

Psoroptes ovis mites were removed from infected sheep and placed in positions where wool and mites normally accumulate during sheep scab outbreaks. The ambient temperature and humidity were monitored over a 3-week period and the survival and infectivity times were examined. The procedure was carried out during each of the seasons. The hatchability of mite eggs was also examined. It was found that little variation occurred between seasons, with mites regularly retaining viability and infectivity for 15 days during all seasons. Mites that survived for more than 16 days failed to infect sheep. Mite eggs retained hatchability for up to 7 days.     

家蚕一代杂交种实用孵化率质量指标的再评估

依据1999-2006年全国蚕种质量监督抽查的测试成绩,将家蚕一代杂交种实用孵化率的检验情况与行业标准《桑蚕一代杂交种》(NY326-1997)中的质量指标比较发现,现有行业标准中家蚕一代杂交种的实用孵化率≥90%的质量指标偏低,平附种和散卵种的实用孵化率都采用同一个质量指标来衡量而不够合理。分析8年的检验数据认为,平附种和散卵种的实用孵化率应采用不同的质量指标来衡量:散卵种实用孵化率质量指标可提高到≥94%,平附种实用孵化率质量指标可提高到≥92%。     

Effect of mating combination and environmental factors on hatchability of chicken eggs in Tibet

To improve the hatchability of introduced high-yield chickens in Tibet, and ameliorate the egg yield and reproduction traits of the local Tibetan chickens, four mating combinations between the Recessive White and Tibetan chicken were employed to investigate the effect of the mating combination and environmental factors on hatchability in this study. The results showed that the fertility of the eggs with Tibetan chicken as female parent was significantly lower than that with Recessive White as female parent (P < 0.05), while hatchability was the reverse (P < 0.05). The embryonic mortality of Recessive White was significantly higher by 7.95% than the Tibetan chickens, particularly during the last stage of incubation. The hatchability of combination III, whose female parent was Tibetan chicken, was higher by 20.44% than combination II, whose female parent was Recessive White. This provided a theoretical basis for a cross using the Tibetan chicken as female parent. Binary logistic regression analysis results also showed that the mating combination and environmental temperature were of importance to egg hatchability. Translated from Acta Veterinaria et Zootechnica Sinica, 2006, 37(1): 28–33 [译自: 畜牧兽医学报]     

９种交配组合鳢的人工繁殖试验

运用人工催产的方法进行了9种交配组合鳢的人工繁殖试验,9种组合来源于乌鳢(Channa argus)、斑鳢(C.maculate)和杂交鳢(Hybrid snakehead)彼此之间的交配繁殖.结果表明,无论采用何种孵化方式,9种交配组合所产卵的受精率和孵化率高低顺序基本一致,且各组合间都存在显著差异.交配组合斑鳢(♀)×斑鳢(♂)、斑鳢(♀)×杂交鳢(♂)、杂交鳢(♀)×斑鳢(♂)及杂交鳢(♀)×杂交鳢(♂)在繁殖过程中,其受精率和孵化率高于其他组合,具有较强的繁殖优势,但其子代的生产性能优势还有待进一步研究.孵化方式对受精卵的发育与孵化有重大影响,其中以微流水孵化方式时的受精率和孵化率最高、孵化效果最好.雄亲鱼的重复催产次数会影响受精率及孵化率,一般以重复利用2～3次为宜.     

响应面法分析光照强度与盐度对卤虫休眠卵孵化率的联合效应

为了探明光照强度（L）与盐度（S）对卤虫（Artemia）休眠卵孵化率的联合影响,采用中心复合设计试验设计方案进行响应面分析,寻找最适的条件组合,并对预测的条件组合进行验证。结果表明,在该试验条件下,光照强度与盐度的一次效应、二次效应对孵化率均有极显著影响（ P ﹤0.01）,两者的交互效应无显著影响（ P ﹥0.05）,随着光照强度或盐度的上升,孵化率呈先升后降的变化趋势。孵化率对实际自变量 L 和 S 的二次多元回归方程的拟合程度高,可用于预测。光照强度2134.02 lx、盐度31.57 g·L -1为最适组合条件,在此最佳因子组合下卤虫休眠卵的孵化率达到最优,为29.86％,其可靠性达到0.983。对该组合条件进行结果验证,数据表明验证结果与预测值相符。建议该品系卤虫休眠卵在该研究得到最优的光照强度-盐度下进行孵化,以提高孵化效果。     

西兰花茎叶粉对仙居三黄蛋鸡蛋品质、受精率和孵化率的影响

选取384只三黄蛋鸡,随机分成4个处理,即对照组和试验Ⅰ、Ⅱ、Ⅲ组,每个处理3个重复,每个重复32只,分别饲喂添加0、4%、6%和8%西兰花茎叶粉的日粮。结果表明:1)添加西兰花茎叶粉对仙居三黄蛋鸡生产性能无显著影响(P0.05);2)与对照组相比,试验组蛋白高度、蛋黄颜色、哈氏单位、蛋壳厚度和蛋壳强度均显著升高(P0.05);试验Ⅱ和Ⅲ组蛋黄胆固醇含量均显著下降(P0.05);3)与对照组相比,试验Ⅰ组和试验Ⅱ组的受精率显著提高(P0.05),试验Ⅲ组受精率提高不显著(P0.05);试验组孵化率有所下降,其中试验Ⅱ组和试验Ⅲ组显著下降(P0.05)。试验组间受精率和孵化率均差异不显著(P0.05)。添加西兰花茎叶粉可以改善仙居三黄蛋鸡蛋品质,降低蛋黄胆固醇水平;此外可以提高受精率,但随着西兰花茎叶粉添加量的增加,孵化率有降低的趋势。     

2个凡纳滨对虾选育群体亲虾形态特征及其产卵量、孵化率的比较

本研究对A、B两个凡纳滨对虾选育群体的亲虾形态特征及其产卵量和孵化率进行比较,结果表明A、B群体的体型性状存在一定差异,尤其是体重、体长、头胸甲长、第二腹节高和尾节长存在显著差异(P0.05),其他形态性状差异不显著(P0.05)。两个群体亲虾产卵量分别为(0.65±0.20)×104、(0.64±0.18)×104粒/体重(g),差异不显著(P0.05),但无节幼体量和孵化率差异显著(P0.05)。A群体产卵量与体型不显著相关(P0.05),亲虾产卵量(Y,×104粒)与体重(W,g)的回归方程:Y=0.010 3W1.0878(R2=0.410 3);B群体凡纳滨对虾亲虾体重与产卵量显著相关(P0.05),亲虾产卵量(Y,×104粒)与体重(W,g)的回归方程:Y=0.054 5W0.677 8(R2=0.522 8)。     

番鸭蛋壳性状对孵化效果的影响

对番鸭白壳蛋、青壳蛋、砂壳蛋的失重率,蛋壳的矿物成分、厚度和气孔数进行测定,并用扫描电镜观察蛋壳结构,研究它们对孵化效果的影响.结果表明:番鸭白壳蛋的孵化率(89.1%)显著高于青壳蛋(67.4%)(P0.05),极显著高于砂壳蛋(48.7%)(P0.01).青壳蛋孵化率低于白壳蛋的原因不在于壳厚(P0.05),而在于青壳蛋的蛋壳气孔数明显低于白壳蛋(P0.05).砂壳蛋蛋壳结构异常与蛋壳的磷含量显著高于白壳蛋有关.对番鸭蛋壳超微结构的扫描电镜观察发现:番鸭白壳蛋、青壳蛋、砂壳蛋不仅外观有差别,而且在超微结构上也有差别.     

不同去壳部位对鸡种蛋孵化效果的影响

为探讨不同去壳部位对鸡种蛋孵化效果的影响,分别于种蛋钝端、赤道板和钝端侧面钻孔去壳,然后均以保鲜膜封口进行孵化。结果表明：于种蛋钝端、赤道板和钝端侧面钻孔去壳处理的最终孵化率分别为4．5％,8．8％和60．5％,且于种蛋钝端侧面钻孔去壳处理的孵化率明显高于另外2组处理（P〈O．05）;3组去壳处理的孵化率均与对照组（96．9％）存在明显差异（P〈0．05）;于种蛋钝端去壳的种蛋失重量明显高于其他处理,从孵化第12d以后,对照组及于赤道板、钝端侧面钻孔去壳处理的种蛋失重量基本一致。可见,于种蛋钝端侧面去壳可视为一种较理想的开窗方法。     

泛酸对种母鸡繁殖性能的影响

选用２４００羽艾维菌父母代种母鸡分４组,饲喂不同水平的泛酸饲料,添加量分别为０,５０,１００,１５０ｍｇ·ｋｇ－１日粮,在夏季进行为期６０ｄ的饲养试验,研究炎热季节泛酸对种母鸡生产性能和繁殖性能的影响。结果表明,高剂时泛酸提高种母鸡的产蛋量（Ｐ＜００１）、蛋重（Ｐ＜００５）和采食量（Ｐ＜００５）泛酸具有改进蛋品质的作用,提高浓蛋白高度、哈夫单位（Ｐ＜００１）,促进蛋黄的合成（Ｐ＜００５）,降低蛋黄中胆固醇含量（Ｐ＜００１）,增加蛋壳的厚度和强度（Ｐ＜００５）;泛酸提高种蛋的受精率和孵化率（Ｐ＜００５）,对降低胚胎后期死亡率有明显的作用。