溴隐亭和克罗米芬对乌鸡醒抱及醒抱后蛋品质量的影响

研究溴隐亭和克罗米芬对就巢鸡就巢时间和产蛋性能的影响以及恢复产蛋后对蛋品质量的影响,试验将36只抱窝的丝羽乌鸡随机分成3组,Ⅰ组为对照组,Ⅱ组第1～2天每只鸡每天口服溴隐亭1.25mg,第3～7天每只鸡每天口服克罗米芬12.5mg;Ⅲ组第1～2天每只鸡每天口服溴隐亭0.625mg,第3～4天每只鸡每天口服溴隐亭1.25mg,第5～6天每只鸡每天口服克罗米芬25mg,第7天每只鸡口服克罗米芬12.5mg。研究。试验结果表明,Ⅰ组鸡只平均抱窝时间最长为8.58d,Ⅱ组为6.67d,Ⅲ组为6.83d;处理后一个月内的平均产蛋率分别为37.72%、59.65%和53.51%,Ⅱ组和Ⅲ组的产蛋率显著高于对照组(P<0.05);3个组的平均蛋重分别为43.86g、44.65g和44.16g,蛋形指数分别为1.306、1.312和1.323,蛋壳厚度分别为0.327mm、0.338mm和0.332mm,溴隐亭和克罗米芬对后3项指标的作用效果差异不显著(P>0.05)。     

Life history traits and food supplementation affect productivity in a translocated population of the endangered Hihi (Stitchbird, Notiomystis cincta)

We studied the effect of food supplementation, female age and clutch order on productivity in a translocated species. Food supplementation increased clutch size from 3.9 to 4.4 (average) eggs per nesting attempt, and more than doubled fledging and recruitment success. Supplemented females started a second clutch 9 days sooner after fledging first clutch chicks than unfed females. During second clutches, supplemented females incubated the eggs for a shorter period of time (15.2 days vs. 16.8). Older females laid larger clutches (4.6 vs. 3.7 eggs) than yearlings and incubated second clutch eggs for a shorter period (15.4 vs. 16.6 days). Females laid more eggs in first clutches (4.2 vs. 3.8 eggs), and those eggs took approximately 30% longer to lay than eggs in second clutches. The successful maintenance of hihi populations on the available islands may be dependent on the permanent provision of supplemental food at nest sites.     

Nitrogen Dynamic in Soils Amended with Legislated and Extremely High Doses of Pig Slurry

The application of pig slurry as soil amendment is a common agronomic practice, but to avoid environmental hazards the doses are regulated. This article evaluates the N dynamic in two calcareous soils amended with legislated (170 kg N, D1) and high doses (1700 kg N, D2) of pig slurry and incubated for 300 days. Nitrification increased at the end of incubation (39–45 and 154–285 mg kg^?1 in control, D1, and D2). Net N mineralization was similar in all soils (24–36 mg kg–1), but negative in D2 in soil 1 (–72 mg N kg^?1). Soil type was an important factor for nitrification processes, with greater rates in the soil with high calcium carbonate content and with no effects on ammonification. Thus, legislated doses compared to control could be considered a wise practice. Conversely, overdoses displayed potential N processes influenced by the carbonate content and the salinity of the amended soil.     

Monitoring the development of thermoregulation in poultry embryos and its influence by incubation temperature

The general purpose of this review is to show the stage of the development of peripheral and central nervous thermoregulatory mechanisms in poultry embryos at the end of incubation, and the impact of long-term changes in incubation temperature. Methods are described which (a) allow continuous measurement of peripheral thermoregulatory mechanisms simultaneously with the body temperature of the embryo, and (b) can be used for identification of changes in the sensitivity of the central controller of body temperature during the development as well as after prenatal temperature experiences. Further, a method for characterisation of ‘critical periods’ in the development of the respective body function is introduced.The results of our investigations were discussed in relation to the following general rules:(a) The development of peripheral and central nervous thermoregulatory mechanisms begins in the course of the prenatal ontogeny. At the end of incubation poultry embryos have all the prerequisites to react to changes in incubation temperature. Regarding the peripheral thermoregulatory mechanisms the most sensitive parameter for characterization of the developmental level of embryonic thermoregulation is the deep body temperature.(b) Functional systems of the organism develop from open loop system without feedback control into closed system controlled by feedback mechanism. Acute changes in the environmental conditions (e.g. incubation temperature) induce as a rule, initially uncoordinated and immediately non-adaptive reactions. Later the uncoordinated (immediately non-adaptive) reactions change into coordinated (adaptive) reactions, probably with closing of the regulatory system (‘critical period’). Environmental manipulation of immature physiological mechanisms could be used for characterization of ‘critical periods’ of the respective system. Monitoring of changes in the reactions of thermoregulatory mechanisms on the applied changes in incubation temperature during different perinatal time windows could help to limit ‘critical periods’ in the development of the thermoregulatory system.(c) During this ‘critical periods’, the actual environment modulates the development of the respective physiological control systems for the entire life period. Perinatal epigenetic temperature adaptation could be a tool to adapt poultry embryos or hatchlings to later climatic conditions. For detection of immediate and long-term effects of perinatal epigenetic temperature adaptation (‘imprinting’ of the thermoregulatory system) recordings of changes in neuronal hypothalamic thermosensitivity as well as in neuronal response on temperature stress are useful and have to be verified by identification of the respective effector genes and epigenetic changes in its expression.     

Changes in recovery of native and applied phosphorus with time as affected by soil properties in some calcareous soils

In an attempt to investigate variations in availability of native and applied phosphorus (P) with time, twenty five calcareous soil samples were treated with 0, 50 and 500 mg P kg^?1 soil and incubated at 80–90% of field capacity moisture content in an open door glasshouse for a period of one year. Soil samples were taken out at certain intervals for P extraction with Olsen extractant under moist condition. Results indicated that following wetting the mean value of native Olsen-P decreased initially and then increased gradually with time of incubation. Generally, the short term (24 h) recoveries were not correlated with long term ones. The recovery of added P with time was described properly by the following new proposed model: R = 100/(1 + kt^b), where R is percent recovery at time t, and k and b are empirical parameters. The values of k constant at 50 and 500 mg P kg^?1 were in the ranges of 0.40 to 1.22 (0.84 ± 0.25, on average) and 0.04 to 0.52 (0.23 ± 0.14, on average), respectively. The corresponding respective values of b constant also ranged from 0.05 to 0.32 (0.15 ± 0.06, on average) and 0.12 to 0.92 (0.46 ± 0.23, on average).     

施磷和培养时间对两种石灰性土壤无机磷形态转化的影响

采用培养试验研究了施磷和培养时间对两种石灰性土壤无机磷形态转化及其有效性的影响。结果表明:不施磷肥时,随着培养时间的延长,两种土壤各种无机磷均略有增加;施入不同数量磷肥后,两种土壤中各种无机形态磷均有不同程度的增加,但Ca2-P和Ca8-P在培养初期均急剧增加,而后Ca2-P逐渐下降,Ca8-P则为有增有减,Al-P、Fe-P、Ca10-P和O-P含量随培养时间呈持续增加趋势。     

Effects of a cadmium-contaminated sewage sludge compost on dynamics of organic matter and microbial activity in an arid soil

 An incubation experiment lasting 120 days was carried out to ascertain the effect on the soil microbial activity and organic matter mineralization of adding a sewage sludge compost contaminated with two different levels of Cd to an arid soil. Two composts, with a low (2 mg kg^–1) and high (815 mg kg^–1) Cd content, respectively, were used in this experiment. Both composts increased the total organic C, humic substance and water-soluble C contents, the beneficial effects still being noticeable after 120 days of incubation. The most labile C fraction (water-soluble C) was the most sensitive to the high Cd content. The high Cd concentration decreased soil microbial biomass C and stimulated the metabolic activity of the microbial biomass, the metabolic quotient (qCO₂) revealing itself to be a very sensitive index of the stress that the incorporation of a Cd-contaminated sewage sludge compost causes in a soil. The effect of Cd contamination on enzyme activities (urease, protease that hydrolyse N-α-benzoil-l-arginamide, phosphatase, and β-glucosidase) depended on the enzyme studied. Received: 10 September 1997     

Reproduction of the African earthworm,Eudrilus eugeniae (Oligochaeta) — cocoons

Summary Although various authors have contributed to our knowledge of the biology of Eudrilus eugeniae some basic facts about the life cycle and reproduction are still not fully documented. Quantitative observations were made of the cocoons at 25 °C in different substrates. The incubation period for 166 cocoons was 16.89 days, based on cocoons produced by worms between the ages of 70 and 100 days. These cocoons produced a mean 2.12 hatchlings per cocoon after incubation in cattle manure, moist filter paper and distilled water. A smaller batch of cocoons incubated in cattle manure produced a mean of 2.7 hatchlings per cocoon. The hatching success of the cocoons was 84% in cattle manure, 50% in distilled water, and 48% on moist filter paper. The reproductive capabilities of E. eugeniae and Eisenia fetida were compared.     

电脑孵化机多变量模糊专家控制

基于现代家禽孵化工艺要求,将复杂的多变量耦合孵化过程控制系统分解成风门控制子系统、加热控制子系统和加湿控制子系统,提出一种多变量模糊专家控制器及其解耦设计方法,成功地应用于家禽孵化设备,实现了孵化机模糊专家计算机控制系统,提高了孵化机的控制性能和自动化水平,从而提高了孵化率,减少了弱雏数量,并减轻了工人的劳动强度。     

榆叶梅花粉贮藏及生活力的测定

对不同品种的榆叶梅新鲜花粉及贮藏后花粉的生活力进行测定的结果表明：品种不同，花粉生活力及耐贮力均不相同，其中单辨品种的生活力和耐贮力最强。榆叶梅花粉最适萌发培养基成分为15％蔗糖 2％琼脂。花粉的适宜贮藏条件为0-4℃低温黑暗条件。