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41.
The robustness of Pacific oyster, Crassostrea gigas (Thunberg), sperm cryopreservation in the context of selective breeding based on family lines was investigated. Irrespective of egg density, high fertilization success was achieved with cryopreserved sperm when sperm:egg ratios of 1000:1 to 10 000:1 were used. Variation among replicate runs on the same oyster batches was minimal, indicating that cryopreservation and larval rearing procedures were repeatable. Twenty independent single male–female crosses were made to assess the utility of cryopreserved sperm in selective breeding. The fertility of unfrozen sperm was generally a poor predictor of cryopreserved sperm fertility. Based on D‐larval yields, 17 of the 20 crosses were likely to yield adequate spat for selective breeding (>105 D‐larvae from 1 million eggs), two were marginal (5 × 104 D‐larvae) and one was inadequate (4 × 103 D‐larvae). An alternative fertilization strategy to improve D‐yield from a given number of sperm was then tested. Fertilizing 10 million eggs at a sperm:egg ratio of 200:1 increased the total D‐yield when compared with fertilizing 1 million eggs at a sperm:egg ratio of 2000:1 for the same male–female pair. We conclude that, despite wide variation in fertility, cryopreserved sperm is useful for family production.  相似文献   
42.
基于芯样的沥青路面抗剪性能评价指标   总被引:1,自引:0,他引:1  
以沥青路面的取芯芯样为研究对象,采用动载单轴贯入试验方法,通过有限元理论分析和对比试验确定了试验条件和参数,确定以一定作用次数下的贯入深度作为指标,能够较好地评价沥青路面的抗剪切性能.  相似文献   
43.
In this research, the mineral and organic composition of the seminal plasma, physical spermatological parameters and their physiological relationships were investigated in grass carp (Ctenopharyngodon idella). The seminal plasma contained 98.14±5.23 mM L?1 (Na+), 380.85±25.95 mM L?1 (K+), 30.25±4.96 mg dL?1 (Ca2+), 19.16±1.70 mEq L?1 (Mg2+), 1.36±0.11 mg dL?1 glucose, 0.37±0.08 g dL?1 total protein, 12.02±1.18 mg dL?1 cholesterol, 14.85±1.50 mg dL?1 triglyceride and 43.5±9.56 mg dL?1 urea. The following spermatological parameters were found: sperm volume 14.44±1.16 mL, sperm motility 80.60±1.55%, movement duration 67.68±4.32 s, density 15.43±0.72 × 109 mL?1, total density 337.43+45.86 × 109 and pH 7.24±0.17. The Na+ and Ca2+ ions correlated negatively with spermatozoa motility (r=?0.453, P>0.05 and r=?0.192, P>0.05) respectively. The K+ ion correlated positively with spermatozoa motility (r=0.545, P>0.05). But a statistically significant correlation was not observed between sperm motility and seminal plasma parameters. The following correlations were observed between mineral and organic components. The Mg2+ was positively correlated with glucose and cholesterol (r=0.692, P<0.05 and r=0.680, P<0.05) respectively. A highly significant positive relationship was also found between Mg2+ and total protein (r=0.837, P<0.01). On the other hand, a significantly negative relationship was found between Ca2+ and triglyceride (r=?0.639, P<0.05). These parameters should be considered when developing procedures for either artificial fertilization or for cryopreservation of grass carp sperm.  相似文献   
44.
为比较杭白菊主栽品种早、晚小洋菊对菊小长管蚜Macrosiphoniella sanborni、棉蚜Aphis gossypii、桃蚜Myzus persicae的抗性,通过刺吸电位技术(electrical penetration graph,EPG)研究菊蚜在菊顶叶上刺吸行为,并检测了菊顶叶主要化合物。结果表明:在晚小洋菊上,菊小长管蚜的E1、E2波平均持续时间4.31、3.47 min,分别短于在早小洋菊上的4.63、3.75 min;棉蚜、桃蚜的E1、E2波平均持续时间分别为4.32、4.72 min和4.92、4.64 min;3种蚜虫的平均刺探次数均大于在早小洋菊上的平均刺探次数。聚类分析结果显示,2个主栽品种之间抗性存在差异。早小洋菊顶叶平均可溶性糖和可溶性蛋白含量分别为2.71 mg/g和25.36 mg/g,均高于晚小洋菊;早小洋菊顶叶总酚含量为0.24 mg/g,显著低于晚小洋菊;早、晚小洋菊总黄酮含量分别为3.46 mg/g和3.37 mg/g。早小洋菊顶叶可溶性糖、可溶性蛋白含量基本上与每种菊蚜的E1、E2波持续时间显著正相关,总酚含量、总黄酮含量与每种菊蚜的E1或E2波持续时间显著负相关。推测早小洋菊对于菊长管蚜的抗性稍弱于晚小洋菊,2种杭白菊对棉蚜或桃蚜的抗性相当,且菊叶中的这4种物质含量与抗蚜性相关。  相似文献   
45.
46.
肝素或钙离子载体诱导牛、羊冻精体外获能的研究   总被引:3,自引:0,他引:3  
本文采用肝素或钙离子载体(I-A)诱导牛、羊冻精体外获能,根据对去透明带仓鼠卵的穿透情况评定获能效果,并用台盼蓝·姬姆萨(TG)染色观察了精子的死活及顶体状态.结果发现,牛、羊冻精经肝素或I-A处理后与卵子一起培养,2 h穿透仓鼠卵,4 h开始形成雄原核,6 h形成发育良好的雄原核.牛冻精用50μg/mL肝素及0.1μmol/L I-A处理效果最好,穿透率分别为72.8%和92.3%;羊则以20μg/mL肝素及0.3μmol/L I-A为宜,穿透率分别为73.1%和68.O%.咖啡因与I-A或肝素并用均有协同作用,能提高精子的穿透能力,并能促进卵内原核的发育.肝素和I-A均能在体外诱导牛、羊冻精的顶体反应,有顶体反应活精子百分率与穿透率呈强正相关,羊冻精比较脆弱,获能处理后活力较低.  相似文献   
47.
用1500μW/cm2的紫外线照射长牡蛎(Crassostrea gigas)精子60 s以进行灭活处理,并使之与栉孔扇贝(Chlamys farreri)卵子受精,在卵子受精后排出第一极体前用6-DMAP(50 mg/L)处理受精卵,持续处理35 min,抑制第一极体和第二极体的排放,诱导异精雌核发育四倍体。采用二脒基苯基吲哚(DAPI)荧光染色显微观察法,对灭活的长牡蛎精子诱导的栉孔扇贝雌核发育四倍体早期胚胎发育过程进行细胞学观察。结果表明:经紫外线灭活过的长牡蛎精子进入栉孔扇贝卵子后发生轻微膨胀;在第一次卵裂中期,精核形成一致密的染色质小体(DCB),位于两组分开的母本染色体之间,不参与核分裂;第一次卵裂结束时DCB滞留于两卵裂球的分裂沟上或进入其中一分裂球中;第二次卵裂过程中,DCB的去向与第一次卵裂时基本一致。6-DMAP处理有效地抑制了第一极体和第二极体的排出,从而使雌核四倍化。对担轮幼虫染色体倍性分析结果表明,通过本方法可以获得6.25%的四倍体幼虫。本研究还对灭活的异源长牡蛎精子诱导栉孔扇贝雌核发育四倍体过程中产生的复杂倍性、核物质分离紊乱及多精附卵现象进行了观察和分析。  相似文献   
48.
Abstract – In most species, males have a higher reproductive potential than females, leading to skewed reproductive success, particularly in mating systems where pre‐ or postcopulatory sexual selection reinforces inequality in male mating success. We investigated multiple paternity, reproductive skew and correlates of male reproductive success in a wild population of the Trinidadian guppy (Poecilia reticulata). We used nine microsatellite loci to assess the frequency of multiple paternity, number of sires per brood and reproductive skew. Across broods, the frequency of multiple paternity was high with 94% of broods having multiple sires (range: 1–5), resulting in a reproductive skew of 0.14. Variation in male reproductive success was high (range: 0–14 offspring per male), suggesting that there is considerable opportunity for sexual selection. Next, we examined correlations between male reproductive success and sexual coloration, sperm velocity and gonopodium length. Relative area of orange, black, iridescent and total coloration, and sperm velocity were not correlated with reproductive success. However, gonopodium length explained 14% of the variation in reproductive success, suggesting that gonopodium length is likely a sexually selected trait. We discuss these findings in the light of other studies that genetically dissect joint‐sex parentage and examine correlates of male reproductive success in wild populations.  相似文献   
49.
ABSTRACT:   Experimental insemination was performed using artificially produced low-motility sperm. A mathematical model was applied to the results of the insemination in order to clarify the relationship between sperm motility, the density of sperm and the fertilization rate of eggs. In the model, the probability of fertilization by individual spermatozoa was a function of sperm density in the insemination solution. The results showed that the probability of fertilization clearly decreased with increased sperm density, and the maximum possible fertilizing rate by increasing the sperm density was constrained by the proportion of motile sperm (% motility). The model was also applied to the results of insemination tests of cryopreserved sperm in order to evaluate the fertilizing capacity of cryopreserved sperm. It was proven that cryopreserved sperm needed a higher density to obtain the maximum fertilization rate compared with fresh sperm, and it was anticipated that the ratio of the motile inseminated cryopreserved sperm should be more than 5.0% to achieve an egg fertilization rate greater than 90%.  相似文献   
50.
目的 精液冷冻保存作为人工授精不可或缺的一个技术环节,对优质畜禽种群的繁衍和保存有着至关重要的意义。目前,因精液冻存时冻存液成分、冷冻方法和外部氧化应激等因素影响,导致冻存精液品质不一。蜂王浆(RJ)已被证明能提高动物精液品质,蜂王浆主蛋白(MRJPs)作为RJ主要生物活性成分物质,具有多种生物活性和抗氧化能力。方法 为提高冻存精子品质,本研究开展了在公牛精液冻存液中添加不同浓度(0 g/25 mL、0.01 g/25 mL、0.02 g/25 mL、0.03 g/25 mL、0.04 g/25 mL)的MRJPs冻干粉,对冻存48 h后解冻精子的总活力、前进性活力、畸形率等相关参数进行了观察评估。结果 添加MRJPs呈浓度依赖性方式显著降低精子总活力、快速前进性活力、缓慢前进性活力和直行性活力(P<0.05),而且精子畸形率和精子原地移动活力与对照组相比无显著差异(P> 0.05)。结论 精液冻存液中添加MRJPs会抑制冻存精子活力,因此,对MRJPs能以何种方式提高精液品质的研究还需要进一步开展。  相似文献   
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