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11.
We used egg break‐out and spermatozoa trapped in the perivitelline layer of eggs to test the hypothesis that sperm supply and egg fertilization rate are high in the ostrich. Egg fertilization status was determined at break‐out by the appearance of the germinal disc (GD) and then the perivitelline layer overlying the GD region was collected to count sperm (SpermOPVL) under fluorescence following staining with 4′,6′‐diamidino‐2‐phenyindole (DAPI). The study was carried out on commercial ostrich farms over two laying seasons. In the first year, 229 eggs from nine randomly chosen ostrich pens comprising pairs, trios (two females, one male) and larger groups were collected for 1 week of every month of laying. Eggs contained 253 ± 18 SpermOPVL/mm2 of the GD (mean ± SEM; range 0–1330). Egg fertilization rate averaged 89.4 ± 3.4% and varied from 78.6 to 98.2% between pens. Month had no effect on sperm supply or egg fertilization status. Eggs from paired birds (sex ratio 1 : 1) had less sperm in the GD than the eggs from pens with a higher sex ratio. In the second year, 150 eggs from seven pens, each containing only one male and either one, two or three females, were studied for 2 weeks at the beginning (winter), middle (spring) and end (summer) of laying. Eggs contained 364 ± 45 SpermOPVL/mm2 of the GD (range 0–2880). Season had no effect on sperm supply or egg fertilization. The number of SpermOPVL varied between pens, assumed to be due to variation between individual males. The number of SpermOPVL increased as the sex ratio increased only when very high‐ranking males were excluded from the analysis. Egg fertilization rate was 94.4 ± 3.1% but varied from 64.0 to 100% between pens. Egg fertilization was not affected by season or sex ratio. Low fertilization rates were observed in two pens and appeared related to the lack of synchrony between timing of laying and sperm production in the first, and lack of mating in the second pen. We conclude that ostrich flocks generally have high rates of egg fertilization and any infertility is associated with lack of sperm supply. 相似文献
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In vitro Effect of Zearalenone and α-Zearalenol on Boar Sperm Characteristics and Acrosome Reaction 总被引：2，自引：0，他引：2
IA Tsakmakidis AG Lymberopoulos C Alexopoulos CM Boscos SC Kyriakis 《Reproduction in domestic animals》2006,41(5):394-401
This study was conducted to determine the in vitro effects of three different concentrations (125, 187.5 and 250 microM in diluted semen) of zearalenone (zen) and alpha-zearalenol (alpha-zen) on boar sperm. Semen parameters such as motility, viability and spontaneous acrosome reaction were evaluated. From the results it was shown that both zen and alpha-zen affected the sperm characteristics significantly (p < 0.05), except for alpha-zen at the low concentration which did not decrease the percentage of live reacted spermatozoa significantly. In conclusion, zen and alpha-zen are directly toxic when they affect boar semen in vitro and consequently decrease the fertilization ability of the sperm. The higher the concentration of mycotoxin tested, the greater the decline of sperm parameters noticed. The influence of mycotoxins was found to be time- and dose-dependent. 相似文献
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Biomimetic Pathways for Assembling Inorganic Thin Films 总被引：3，自引：0，他引：3
IA Aksay M Trau S Manne I Honma N Yao L Zhou P Fenter PM Eisenberger SM Gruner 《Science (New York, N.Y.)》1996,273(5277):892-898
Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic surfaces through a two-step mechanism. First, under acidic conditions, surfactant micellar structures are self-assembled at the solid/liquid interface, and second, inorganic precursors condense to form an inorganic-organic nanocomposite. Epitaxial coordination of adsorbed surfactant tubules is observed on mica and graphite substrates, whereas a random arrangement is observed on amorphous silica. The ability to process ceramic-organic nanocomposite films by these methods provides new technological opportunities. 相似文献
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Athina Basioura Georgios Tsousis Constantin Boscos Aristotelis Lymberopoulos Ioannis Tsakmakidis 《Reproduction in domestic animals》2019,54(Z4):41-45
The computer‐assisted sperm analysis (CASA) has become a standard laboratory tool. Although it contributes a lot to the objective sperm motility assessment, its measurements may be affected by many factors. The aim of the study was to evaluate the effect of chamber on boar semen CASA results. Totally, 100 extended (30 × 106 sperm/ml) boar semen samples were analysed by CASA. Each sample was evaluated using Makler, Leja 4 chamber 20 μm and conventional glass slide/coverslip chambers (MC, LC and GSC, respectively). The differences in values between MC and LC and between MC and GSC were significantly positive (higher values for MC compared with LC and GSC) for total motility, progressive, rapid movement, VCL, VSL, VAP, STR and hyperactive, thus indicating a systematic effect. Between LC and GSC, the differences in many parameters (non‐progressive, progressive, slow, LIN, STR, hyperactive) were evenly distributed around zero, while in all other parameters the differences were significantly positive (higher values for LC compared with GSC), except for medium movement. Based on the estimated intraclass correlation coefficients, the method agreement between MC and LC and between LC and GSC was overall moderate to good, depending on the parameter; nonetheless, it was poor between MC and GSC. The limits of agreement between methods can vary considerably depending on the parameter and should be considered when comparisons between CASA measurements of different andrology laboratories or studies have to be performed. 相似文献
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大豆有效营养面积研究进展 总被引：1，自引：0，他引：1
2001～2004年,运用作物有效营养面积理论,对北方垄作区大豆垄幅的合理性问题进行了试验研究。研究表明大豆主产区黑龙江省中部、南部地区大豆有效营养面积为2210～4500 cm2,有效株行距为47.0～67.1 cm。其中中部地区的有效营养面积在2210～4025 cm2,即有效株行距为47.0～63.0 cm,南部地区的有效营养面积在3838～4500 cm2,即有效株行距为61.9～67.1 cm。南部地区品种有效营养面积较大,中部地区品种有效营养面积较小。据此阐明目前生产上广泛采用67～70 cm的垄作,已超过了大豆的有效株行距,造成了土壤资源等的浪费。尤其是中、北部垄作区采用55 cm左右的垄距种植大豆,将会更有利于大豆群体产量的提高。该理论为目前黑龙江省北部地区栽培面积逐渐增大的大豆窄行垄栽培提供了有力的理论根据。 相似文献
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李舟 《信阳农业高等专科学校学报》2007,17(3):6-9,30
"和谐世界"得以构建的前提和基础,是主体和谐利益观的形成。"和谐世界"主张以和谐秩序超越现实主义权力冲突状态,以民主、平等、包容性和普适性的行为体互动关系来规范、超越新自由主义强权依附型的国际机制思想,以理性、唯物的国际政治观超越理想主义和建构主义。我们对"和谐世界"的理解,不能仅仅停留在外交政策或文化层面上。应深入挖掘其理论内涵,构建和完善与之相适应的逻辑体系,使之与国际相关理论尤其是西方理论相接轨,并自然融入到国际政治理论体系中,从而拓展民族性理论的世界影响力。 相似文献
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DC Orfanou HN Ververidis A Pourlis IA Fragkou AN Kokoli CM Boscos IA Taitzoglou A Tzora CM Nerou L Athanasiou GC Fthenakis 《Reproduction in domestic animals》2009,44(S2):152-155
We aimed to study the normal puerperium in the bitch. Ovariohysterectomy was performed in nine bitches, each at a different day after normal whelping; their genital tract was subject to gross anatomical examination, as well as to histological examination and electron microscopy scanning. Corpora albicans were evenly distributed in the left and right ovaries and placental sites were evenly distributed among left and right uterine horns. Placental sites were initially of dark green to grey colour, later becoming dark brown; their length and height progressively decreased. Height of the myometrium and diameter of the uterine glands progressively decreased. Trophoblast-like cells were consistently observed at the placental sites and on the surface of the interplacental areas, at all time points where hysterectomy had been performed. It is suggested that involution of the canine genital tract can last up to 3 months and is slow. Continuous (up to D84 post-partum) presence of prominent placental sites should be considered a normal feature of canine uterine post-partum involution. 相似文献
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Serological response to Actinobacillus pleuropneumoniae serovar 7 infection in a commercial pig herd
IA GARDNER JT BOSSɆ RF SHELDRAKE† S ROSENDAL† RP JOHNSON§ 《Australian veterinary journal》1991,68(11):349-352
Serological responses to Actinobacillus pleuropneumoniae serovar 7 infection were monitored by enzyme-linked immunosorbent assay in a cohort of 66 pigs between weaning and market. Antibody concentrations were high (63/65 seropositive) at 4 weeks of age but declined to low levels from 8 to 12 weeks. Mean antibody concentrations rose significantly (p less than 0.001) between 12 and 23 weeks. Between 8 and 23 weeks of age, 33 (51.5%) of 64 surviving pigs seroconverted to A pleuropneumoniae serovar 7. Peak antibody concentrations in the seroconverting pigs usually (28/33) occurred at 23 weeks. Seroconversion to A pleuropneumoniae during the grower/finisher phase was not significantly associated (p greater than 0.05) with passive antibody concentrations at 4 weeks of age, lack of vaccination against Mycoplasma hyopneumoniae, or weaning weight. Pleuropneumonic lesions were evident at slaughter in 4 (6.3%) of 64 pigs. A pleuropneumoniae serovar 7 was isolated from 2 of 4 lungs with pleuropneumonia and from another lung with lesions considered typical of enzootic pneumonia. 相似文献