褪黑激素受体基因的多态性及其与繁殖季节性之间关系的研究进展

褪黑激素通过与药理学特异的高亲和性G-蛋白偶联受体相结合来发挥其生物学功能。本文介绍了褪黑激素受体基因的多态性分析及其与繁殖季节性之间的关系,并对牦牛该基因的研究做一展望。     

Histomorphological and immunohistochemical study of angiogenesis and angiogenic factors in the ovary of the mare

Cyclical ovaries of 18 mares were examined histologically and immunohistochemically for vascular endothelial growth factor A and B (VEGF A; VEGF B), angiopoietin1 and 2 (Ang1; Ang2), vascular endothelial growth factor receptor 1 and 2 (VEGF-R1; VEGF-R2), angiopoietin receptor (Tie2) and von Willebrand factor. The most intensive coexpression of the examined factors and receptors was detected in the periovulatory period, when a distinctive ovarian angiogenesis takes place, being essential for tertiary follicle maturation and for the endocrine function of the Corpus luteum. Based on the immunohistochemical results, VEGF A, Ang2, VEGF-R2 and Tie2 in particular seem to play a significant role on angiogenesis during follicular and luteal development in the mare, while Ang1 supports vessel stabilisation. The findings of luteal regression and follicular atresia showed that, in the absence of VEGF A, Ang2 and its receptor Tie2 contribute substantially to vessel regression and therefore to luteolysis and follicular atresia.     

Equine Aging and the Oocyte: A Potential Model for Reproductive Aging in Women

Numerous similarities in reproductive aging have been documented between the mare and woman. Aging is associated with a decline in fertility. In mares and women, oocyte transfer procedures were initially used to establish that oocyte donor age is associated with oocyte quality. Age-associated differences in oocytes include altered morphology, gene expression, and developmental potential. Reactive oxygen species and mitochondrial dysfunction are thought to be important contributors to loss of oocyte quality. In the woman, aneuploidy is a primary consideration with maternal aging. Although misalignment of chromosomes during meiosis has been observed in the mare, less is known in this area. Reproductive aging will be reviewed in the mare and compared with the woman with emphasis on factors that affect oocyte quality and developmental potential. Areas in which the mare could be used as a research model to study reproductive aging in women will be highlighted.     

母牛体内生殖激素变化规律的研究进展

生殖激素是对母牛繁殖活动起直接调节作用的激素,因此对其进行精准测定,掌握生殖激素的变化规律对生产上提高母牛繁殖效率具有重要意义。但在动物体内大部分生殖激素的含量是极其微量的,所以选择准确灵敏的测定方法非常重要。本文论述生殖激素的生物测定法、受体分析法、免疫测定法（放射免疫测定和酶免疫测定）的优缺点,同时对各生殖激素的来源、生理作用和变化规律,及各激素之间的相关性分析做阐述,将对研究母牛的生殖生理,提高母牛繁殖效率,促进高产、高效、优质的牛业生产,加快牛业繁殖改良进程有着极其重要的意义。     

Secretion of luteinizing hormone into pituitary venous effluent of the follicular and luteal phase mare: novel acceleration of episodic release during constant infusion of gonadotropin-releasing hormone

We tested the hypothesis that continuous infusion of native GnRH into mares during the estrous cycle, at a dose of 100 μg/h, would elevate circulating concentrations of LH without disrupting the endogenous, episodic pattern of LH release. Ten cyclic mares were assigned to one of two groups (n = 5/group): (1) Control (saline) and (2) GnRH in saline (100 μg/h). On experimental day 0 (3 to 6 d after ovulation), osmotic pumps containing saline or GnRH were placed subcutaneously and connected to a jugular infusion catheter. Blood samples were collected from jugular catheters daily and at 5-min intervals from catheters placed in the intercavernous sinus (ICS) for 8 h on experimental day 4 (luteal phase; 7 to 10 d after ovulation), followed by an additional 6-h intensive sampling period 36 h after PGF(2α)-induced luteal regression (experimental day 6; follicular phase). Treatment with GnRH increased (P < 0.001) concentrations of LH by 3- to 4-fold in the peripheral circulation and 4- to 5-fold in the ICS. Continuous GnRH treatment accelerated (P < 0.01) the frequency of LH release and decreased the interepisodic interval during both luteal and follicular phases. Treatment with GnRH during the luteal phase eliminated the low-frequency, long-duration pattern of episodic LH release and converted it to a high-frequency, short-duration pattern reminiscent of the follicular phase. These observations appear to be unique to the horse. Further studies that exploit this experimental model are likely to reveal novel mechanisms regulating the control of gonadotrope function in this species.     

Effects of physiologic and pharmacologic agents on serum prolactin concentrations in the nonpregnant mare

Four studies were conducted to evaluate the effects of several physiologic and pharmacologic agents on serum prolactin concentrations in the nonpregnant mare. An increase in prolactin measured in response to administration of thyrotropin-releasing hormone (TRH; 50 micrograms, iv) was found not to vary (P = .20) in mares in estrus compared with mares in diestrus (5 to 10 d post-ovulation). Administration in the dopamine receptor blocker, metoclopramide (25 or 100 mg, im), rapidly increased serum prolactin, and the response was dependent on dose administered (total prolactin measured for 420 min was 3,362.7 +/- 182.1 ng for 25 mg, and 4,485.7 +/- 212.6 ng for 100 mg administered im; P less than .05), but not on route of injection (3,026.3 +/- 492.3 ng prolactin with 25 mg, iv; P less than .05). Similarly, sulpiride, a D-2 dopamine receptor blocker, induced an increase in serum prolactin, which appeared to be maximal at a dose of 25 mg (6,556.3 +/- 636.9 ng prolactin/420 min compared with 6,594.5 +/- 169.3 ng prolactin/420 min with 100 mg sulpiride; P less than .10). Finally, bromocriptine, a dopamine agonist, decreased serum prolactin compared with vehicle-injected controls, but the inhibitory effect was found only when basal levels of serum prolactin were highest (in May). These data suggest that mechanisms controlling prolactin secretion in the mare are similar to those described in other mammalian species, and that the seasonal decline in serum prolactin is not the result of increased sensitivity to the proposed prolactin-inhibiting factor, dopamine.     

Polymorphisms of the melatonin receptor 1A gene that affects the reproductive seasonality and litter size in Small Tail Han sheep

Previous researches have shown that MTNR1A plays an essential role in sheep reproduction. However, most researches focused more on the reproductive seasonality of sheep, and few scientists had studied the association of polymorphisms of the MTNR1A gene with ovine litter size and reproductive seasonality. Therefore, we chose MTNR1A gene to detect its novel sequence polymorphisms and population genetics and analyse their association with seasonal reproduction and litter size in ewes. The mRNA expression level in hypothalamus, pituitary and ovary was also detected. In this study, five polymorphisms (g.15118664G > T, g.15118683C > T, g.15118756C > T, g.15118774C > T and g.15118951G > A) were identified in exon 2. Most importantly, the g.15118683C > T and g.15118951G > A were significant difference between year‐round oestrous sheep and seasonal oestrous sheep (p < .01), and g.15118756C > T had a great effect on litter size of Small Tail Han sheep (p < .05). In addition, the mRNA expression level of MTNR1A in the hypothalamus of polytocous Small Tail Han sheep was significantly higher than that in monotocous Small Tail Han sheep (p < .01) and the expression of MTNR1A in the hypothalamus of year‐round oestrous sheep was significantly higher than that in seasonal oestrous sheep (p < .01). Polymorphisms in exon 2 may regulate the reproductive seasonality and litter size of ewes by influencing gene expression to regulate the reproductive seasonality and litter size of ewes. Our studies provided useful guidance in marker‐assisted selection of the litter size in Small Tail Han sheep.     

青藏高原东缘不同恢复措施对披针叶黄华繁殖构件及资源分配的影响

以青藏高原东缘不同恢复措施草地中典型毒杂草披针叶黄华(Thermopsis lanceolata)为研究对象,通过设置放牧、围封和综合措施(围封+施肥+划破+补播)3种不同处理,比较披针叶黄华形态特征、器官生物量和资源投资状况,以揭示不同恢复措施对披针叶黄华繁殖分配的影响.结果表明:围封和综合措施显著降低了披针叶黄华的生殖枝高、营养枝高、每株分枝数、花和荚果数量(P<0.05).围封比放牧处理显著增加了披针叶黄华的根系生物量和生殖投资,显著降低了茎叶投资(P<0.05);综合措施比围封处理显著降低了披针叶黄华的总生物量、地上部生物量、花和荚果重以及生殖投资(P<0.05).3种处理下披针叶黄华的茎叶生物量与总生物量之间极显著相关(P<0.01).植物可以通过调整繁殖对策来适应环境的变化,围封对严重退化草地上披针叶黄华的防控效果并不理想,需要结合施肥、划破、补播措施才能使其得到有效的防控.     

Calving date and its variability as a potential trait in the breeding objective to account for reproductive seasonality in alpacas

The low fertility and offspring survival indicators in alpacas can be partially due to their particularity seasonal reproduction that reduces the opportunities of the females to become pregnant within a season, with the survival of the offspring concerned by the availability of food and exposure to diseases that depends on the calving date. Optimizing the date of delivery and reducing its variability are shown as eligible criteria that could be used as selection criteria within the genetic improvement programmes in alpacas, the calving date being a much more appropriate trait to measure and optimize fertility unlike of age at first calving and the calving interval, this due to the reproductive seasonality in camelids. For this study, 6,533 birth date records were taken between 2001 and 2018 of Peruvian alpacas, to estimate the genetic parameters. Models assuming heterogeneity in the residuals were fitted besides classical homogeneous models to address, not only the possibility of forwarding or delaying the calving date, but also the trend to have parturitions in similar dates. The heritability and repeatability ranged from 0.07 to 0.20 for a homogeneity model and from 0.08 to 0.23 for a heterogeneity model, and suggest the possibility of advancing or delaying the calving date. It should be taken into account that the gestation length of camelids makes it difficult to adapt many reproductive traits, and trying to centre the calving date could delay it. It was concluded the feasibility to genetically select the calving date, also in the production of camels and dromedaries, which have the same reproductive characteristics as alpacas. This selection can be combined with other traits. The heterogeneity model was shown to provide a better fit.     

几种微量元素对动物生殖毒性的研究进展

随着微量元素饲料添加剂的广泛应用,其对动物的生殖毒性已经引起了人们的关注。文章就微量元素氟、砷?锰?镍、硒对动物生殖的毒性作用作了简要的综述。     

鸭繁殖性状分子遗传研究进展

本文着眼于现代分子数量遗传新技术在鸭遗传育种中的应用前景,对鸭繁殖性状的分子遗传研究进行综述。介绍繁殖相关激素和调节因子的基因研究、与肝脏及卵巢中脂肪酸代谢相关功能基因的研究、与生长发育相关基因的研究等进展情况;同时介绍鸭分子遗传标记的开发和连锁图谱构建等方面的新进展。     

贵阳市奶牛小区奶牛繁殖性能调查

本文就贵阳市具有典型代表性的某奶牛小区奶牛的繁殖性能进行调查,调查结果表明：该奶牛养殖小区2007～2009年的平均年受胎率为83.0%,产犊间隔时间为427.00±3.36d,产后子宫复旧时间为39.94±1.72d;产后瘫痪、胎衣不下、子宫内膜炎及死胎的发病率均有逐年下降的趋势,但乳房炎和肢蹄病的发病率却呈上升的趋势。该奶牛养殖小区的胎衣不下、乳房炎、子宫内膜炎及肢蹄病的发病率仍较高,严重影响了该小区的经济效益。     

环境温湿度对母猪繁殖性能的影响

浙江中白母猪繁殖成绩与地面温湿气象资料相结合进行统计分析的结果表明,母猪在60天哺乳期饲养制度下,产后发情并配种受孕平均需66.57天。其中离仔后配种占75.41％,就这部分母猪而言,离仔次旬平均日最高气温超过30℃或RH78％以上或THI值大于75,离猪后7天内的受孕率显著降低;配种时和配种后20天内受高温剌激,胎几发育数减少,平均气温25℃以上时的窝仔数(11.73头、11.83头)较20—25℃条件下少0.68头和0.37头;产前当旬处于高温的,产仔成活率较高;20日龄仔猪存活率以出生后次旬环境温度在20℃以上或THI值大于65时为高,而35—45日龄时的环境温湿度对20—60日龄仔猪存活率影响不明显。     

猪场常见繁殖系统疾病的临床区别诊断

布氏杆菌病、细小病毒感染、猪繁殖与呼吸障碍综合征(PRRS)、猪瘟、猪伪狂犬病、猪乙型脑炎、猪附红细胞体病、衣原体、猪钩端螺旋体及饲料霉菌毒素中毒都共同出现流产症状,同时也有很多不同点。本文根据临床经验,将其归纳整理,系统地比较各病之间的不同点,为临床兽医正确区别诊断这类疾病提供宝贵的经验。     

大雁生殖系统的解剖学和组织学研究

实验对生殖季节与非生殖季节的大雁生殖系统进行了组织学研究。大雁雌性生殖系统左侧发育，右侧退化。生殖系统由卵巢、输卵管、交际器组成。输卵管包括漏斗部、蛋白分泌部、峡部、子宫与阴道五个部分。卵巢表面无浆膜覆盖，覆以单层生殖上皮，由浅部的皮质和深部髓质组成，皮质内含各级卵泡。雄性生殖系统由精巢、输精管、睾丸旁导管系统和交接器组成。精巢的基本结构单位为曲精细管，外层包被着浆膜，其下是白膜，白膜结缔组织伸入精巢实质部，呈网状分布，繁殖季节的睾丸实质内充满曲细精管。     

热带亚热带BMY牛的繁殖性状研究

为了探索BMY的繁殖性能，通过在全日制放牧管理和季节性配种条件下，把2001年至2005年的BMY牛繁殖率进行了统计分析，在扩繁点年平均繁殖成活率为68．46％，小哨点为78．72％，表现出良好的繁殖性能。     

BVDV对后备牛生长发育状况及繁殖性能的影响

牛病毒性腹泻/黏膜病(BVD/MD)是一种严重危害奶牛健康的病毒性传染病,其病原为牛病毒性腹泻病毒(BVDV)。BVDV感染牛后主要表现两种状态,即一过性感染(TI)和持续性感染(PI)。BVD在牛场的流行,可严重影响奶牛的生产性能、繁殖性能及牛群健康状况,对奶牛的影响可表现为流产、胎儿畸形、腹泻和免疫抑制等。怀孕母牛在特定妊娠阶段感染BVDV后,可娩出PI犊牛,部分PI犊牛能像正常犊牛一样生长发育至成年,但其生长发育状况和繁殖性能较同龄健康牛差异十分明显。为评价BVDV对后备牛生长发育及繁殖状况的影响,笔者采用ELISA方法检出北京地区28个规模化奶牛场141头BVDV-PI牛,并与同龄健康牛生长发育及繁殖数据相比较,结果表明,BVDV-PI后备牛各月龄段的体高、体重均低于健康后备牛,其首次输精日龄、配准日龄、耗精量明显高于健康后备牛,而一次情期受胎率显著低于健康后备牛。数据显示,BVDV严重影响后备牛的生长发育及繁殖状况。     

黄淮杜泊羊繁殖性能和FecB基因多态性研究

为系统评价黄淮杜泊羊的繁殖性能,本实验对2家黄淮杜泊羊核心育种场1年的繁殖数据进行了统计和分析,并随机采集了145只核心群羊只进行FecB基因多态性分析。结果表明:黄淮杜泊羊性成熟为6～7月龄,年繁殖率为252.82%,羔羊断奶成活率为95.79%,每只母羊年提供断奶羔羊数2.39个;黄淮杜泊羊群体FecB基因存在BB、B+和++3种基因型,其中B+型(杂合型)是群体中的优势基因型,基因型频率为0.606 9;基因型与产羔数关联分析表明,BB和B+基因型产羔数极显著高于++基因型。综上,黄淮杜泊羊具有多胎高繁的特性,在繁殖性能方面符合专门化肉用高繁绵羊品种的标准。