乳牛精子细胞核可被精确地分成类似于X,Y精子的两个群体

由于哺乳动物雄性配子(精子)有性染色体的差异,使哺乳动物X、Y精子在质量或密度上存在着微小的差别。因此,长期以来人们试图将两性精子分开,以人的意志控制动物性别,按人类的需要进行畜牧业生产。但是由于精于之间发育上的差异所引起的质量差掩盖了染色质的微弱差异,从而难以达到理想的分离效果。本实验先将两性精子共有的顶体和尾部去掉,以突出X、Y染色质的质量差异,再将精子细胞核在氯化铯密度梯度离心下分成两个核群区带。该实验为X、Y精于分离效果的鉴定提供了一种有效的方法。     

国产精子计数板在长白公猪精液检测上的应用研究

文章以精子计数板为研究对象,应用SPSS 19.0软件的单因素方差分析法对81份精液检测数据进行分析,以探讨国产的精子计数板代替进口的精子计数板的可行性。试验结果显示,进口产品组精子计数板测得的随机3个视野平均精子数、精子密度、精子活力、正常精子比例分别为566.06个、249.56×10^6/ml、92.65%、71.52%;国产产品组的对应值测得为577.02个、252.68×10^6/ml、91.32%、72.65%。两产品的同一指标相比均差异不显著。结果表明:国产的精子计数板替代进口的精子计数板是可行的。     

Sperm Susceptibility to Oxidative Stress in the Retuertas Endangered Horse

In order to determine whether the high level of inbreeding of the Retuertas endangered Horses may increase the vulnerability to oxidative stress of the sperm, the susceptibility to lipid peroxidation (LPO) of sperm membranes was evaluated in cooled extended ejaculates. Extended ejaculates (INRA 96) from four Retuertas horses and nine ejaculates from pure Spanish horses were received within 24 hours of collection at our laboratory. An aliquot was analyzed and served as time 0 control. The rest of the ejaculates were split into two additional aliquots: the first aliquot served as an incubation control and the second aliquot received an oxidative insult (Fe₂SO₄). Membrane LPO, motility parameters, membrane integrity, and mitochondrial membrane potential were evaluated. The oxidative insult induced a significant increase in the percentage of sperm with LPO in the Retuertas horses (P < .05). Total and progressive motility were not affected by the oxidative insult in both groups. However, curvilinear velocity (VCL), average velocity (VAP), straightness index (STR), and amplitude of lateral head displacement (ALH) were significantly affected by the treatment (P < .05) in the Retuertas horse population. The membrane integrity of sperm in this group was also affected: the percentage of sperm with intact membranes decreased (57.31% ± 7.76% vs. 47.52% ± 8.28%); and the percentage of necrotic sperm increased (33.27% ± 7.83% vs. 44.85% ± 9.16%) (P < .05). Finally, the oxidative insult increased the population with low mitochondrial membrane potential in these wild horses. We concluded that the high level of inbreeding of this particular breed apparently leads to a higher susceptibility to lipid peroxidation.     

Effect of Storage Time and Temperature of Equine Epididymis on the Viability,Motion Parameters,and Freezability of Epididymal Sperm

The recovery of sperm from the epididymal cauda may be the last chance to obtain genetic material when sudden death or serious injuries occur in valuable stallions. However, the lack of technical knowledge regarding the storage and transportation of the epididymis often prevents the preservation of the sperm. Therefore, the aim of this study was to compare sperm parameters of sperm obtained immediately after orchiectomy with sperm recovered from epididymal cauda at different times after storage at 5°C and at room temperature (RT). For that, 48 stallions of different breeds were used. In group 1 (control group), eight stallions were used, and the harvest of the epididymal sperm was performed immediately after orchiectomy. In group 2, 40 stallions were used, which were divided into five groups according to the storage time of the epididymis after orchiectomy (6, 12, 18, 24, or 30 hours), making a total of eight stallions per group. One epididymis of each stallion was stored at 5°C, and the contralateral epididymis was stored at RT, both for the same period. The sperm parameters of total motility, progressive motility, progressive linear velocity, curvilinear velocity, percentage of rapid sperm, and plasma membrane integrity were evaluated in all the groups after sperm recovery, resuspension in a sperm freezing diluent, and thawing. In conclusion, the storage of the testis-epididymis complex at 5°C provided better preservation of epididymal sperm than the storage at RT, and regardless of the temperature, the progressive motility is the sperm parameter that is most sensitive to storage time.     

α-硫辛酸抗氧化作用机制及其在动物生殖细胞和早期胚胎中抗氧化作用的研究进展

活性氧(ROS)引起的氧化应激是动物生殖细胞和早期胚胎发生凋亡或永久性发育阻滞的主要原因之一。因此,在体外培养系统中添加抗氧化剂成为降低氧化应激对动物生殖细胞损伤和提高早期胚胎发育能力的方法之一。α-硫辛酸(LA)作为一种强抗氧化剂,可以通过直接清除自由基、螯合金属离子并促进其他抗氧化物质形成从而发挥抗氧化作用。在生殖细胞和早期胚胎中,LA可以通过降低ROS水平、促进抗氧化酶活性和线粒体活性来提高生殖细胞质量和早期胚胎发育能力。本文概述了LA抗氧化作用机制及其在动物生殖细胞和早期胚胎发育过程中抗氧化作用的研究进展,为进一步探究LA抗氧化作用的分子机制提供理论依据和研究思路。     

Sperm motility parameters to evaluate the seminal quality of Boa constrictor occidentalis, a threatened snake species

Semen quality analysis constitutes a powerful tool to evaluate the fertility potential of males in threatened species. The Argentine boa constrictor or lampalagua (Boa constrictor occidentalis) is a threatened snake species and has been included in Appendix I of CITES. The objective of this work is to characterize the sperm of B. c. occidentalis on the bases of dynamic parameters to improve this species conservation. Dynamic parameters were measured in sperm samples using videomicroscopy and image analysis software. The sperm population showed a high degree of heterogeneity in velocity parameter values and 95% of the cells showed a linear pattern of movement. Studies in other species indicate that the number of motile spermatozoa and their movement speed is directly correlated with fertilization success. This work will help to establish basic parameter values for the evaluation of the reproductive potential of populations of B. c. occidentalis and to resolve questions referred to its reproductive strategies.     

The genetic consequences of hatchery-induced sperm competition in a salmonid

Supportive breeding is an important tool in conservation management, but its long-term genetic consequences are not well understood. Among the factors that could affect the genetics of the offspring is sperm competition as a consequence of mixed-milt fertilizations - which is still a common practice in many hatcheries. Here, we measured and combined the relevant factors to predict the genetic consequences of various kinds of hatchery-induced sperm competition. We drew a random sample of male Coregonus zugensis (an Alpine whitefish) from a hatchery program and quantified their in vitro sperm potency by integrating sperm velocity during the first minute after activation, and their in vitro milt potency by multiplying sperm potency with milt volume and sperm cell density. We found that not controlling for sperm density and/or milt volume would, at a constant population size, decrease the variance effective number of male breeders N_em by around 40-50%. This loss would decrease with increasing population growth rates. Partial multi-factorial breeding and the separate rearing of in total 799 batches of eggs revealed that neither sperm nor milt potency was significantly linked to egg survival. Sperm and milt potency was also not significantly correlated to other potential quality measures such as breeding tubercles or condition factor. However, sperm potency was correlated to male age and milt potency to male growth rate. Our findings suggest that hatchery-induced sperm competition not only increases the loss of genetic variation but may also induce artificial selection, depending on the fertilization protocol. By not equalizing milt volume in multi-male fertilization hatchery managers lose relatively more genetic variation and give fast-growing males a reproductive advantage, while equalizing milt volume reduces the loss of genetic variation and favors younger males who may have fast sperm to compensate for their subdominance at the spawning place.     

How Stallion Sperm Age In Vitro? Scenario for Preservation Technologies

Recent findings on the molecular damage occurring in the stallion spermatozoa are reviewed. Mechanisms leading to cell death or survival are briefly overviewed, and recent discoveries on molecular pathways leading to sperm death and sublethal damage are discussed. Increasing the understanding of this particular area may disclose clues to develop new strategies to improve current sperm conservation methods.     

兔子精液冷冻保存综述

精子在冷冻保存过程中会受到不可逆的冷冻损伤或者部分功能改变,因此精子的冷冻保存是一个大挑战。虽然从广义上讲,物种之间的精子冷冻保存是非常相似的,但是每个物种的精子有着各自的特殊性,迫使研究人员不断优化冷冻保护剂和操作程序以更好地适应其特殊性。对家兔精液冷冻保存的概况进行了阐述,讨论了家兔精液冷冻保存的研究概况以及影响冷冻精液和人工授精的因素。     

Distribution and viability of spermatozoa in the canine female genital tract during post-ovulatory oocyte maturation

Background

Unlike other domestic mammals, in which metaphase-II oocytes are ovulated, canine ovulation is characterized by the release of primary oocytes, which may take 12 to up to 36 hours. Further 60 hours are needed for maturation to secondary oocytes which then remain fertile for about 48 hours. Oestrus takes 7 to 10 days on average and may start as early as a week before ovulation. This together with the prolonged process of post-ovulatory oocyte maturation requires an according longevity of spermatozoa in the female genital tract in order to provide a population of fertile sperm when oocytes have matured to fertilizability. Therefore the distribution and viability of spermatozoa in the bitch genital tract was examined during post-ovulatory oocyte maturation.

Methods

Thirteen beagle bitches were inseminated on the day of sonographically verified ovulation with pooled semen of two beagle dogs containing one billion progressively motile spermatozoa. Ovariohysterectomy was performed two days later (group 1, n = 6) and four days later (group 2, n = 7). The oviduct and uterine horn of one side were flushed separately and the flushing’s were checked for the presence of gametes. The oviducts including the utero-tubal junction and the uterine horns, both the flushed and unflushed, were histologically examined for sperm distribution.

Results

The total number of spermatozoa recovered by flushing was low and evaluation of viability was limited. Prophase-I oocytes were collected from oviduct flushing in group 1, whereas unfertilized metaphase-II oocytes were detected in group 2. From day 2 to day 4 after ovulation a significant decrease in the percentage of glands containing sperm (P<0.05) and a marked reduction of the mean sperm number in uterine horn glands were observed. A concomitant diminution of spermatozoa was indicated in the utero-tubal junction accompanied by a slight increase in sperm numbers in the mid oviduct.

Conclusions

Oocyte maturation to metaphase-II stage is accompanied by a continuous sperm detachment and elimination in the uterine horns. Entrance of spermatozoa into the caudal oviduct seems to be steadily controlled by the utero-tubal junction thus providing a selected sperm population to be shifted towards the site of fertilization when oocyte maturation is completed.