从水貂生殖器官特征探讨其授精过程

水貂(Mustla visen)的人工饲养,在我国虽有20多年的历史,但对其生理学特征及生殖规律,尚缺乏系统研究。水貂的繁殖力是评定水貂经济意义的重要指标之一,如何提高水貂的受胎率及产仔数,对水貂生产关系很大。据国外文献报道,母水貂的产仔数仅占排卵数的50％左右,且个体间差异很大,多则17只,少则1     

双酚A对啮齿动物生殖毒性的研究进展

双酚A(BPA)是一种新型环境污染物,具有内分泌干扰作用,对动物的健康产生严重的威胁。该文从BPA暴露对啮齿动物生殖器官的损伤和神经行为毒性方面的研究文献进行总结和展望,为进一步研究BPA这种新型污染物的生殖毒性提供理论依据。     

影响水貂繁殖力的因素及提高措施

繁殖力是指动物在正常生殖机能条件下生育繁殖后代的能力.繁殖力受生态环境、营养、饲养管理方法、生理状况等多种因素的影响.对水貂养殖来说,繁殖力就是生产力,它直接影响生产水平的高低和经济效益,提高水貂繁殖力在生产实践中具有重要意义.笔者对影响水貂繁殖性能的主要因素进行了分析,并提出提高其繁殖力的具体技术措施.     

二噁英免疫毒性研究进展

机体免疫系统功能紊乱可引起多种疾病,这些疾病中很大一部分是由于机体长期暴露于环境中的各种污染物所引起的。二噁英是非人为生产,没有任何用途,存在于各种环境介质的一类环境持续污染物,具有致畸性、致癌性、免疫毒性、神经和行为毒性及生殖和发育毒性等,不仅对畜牧业造成巨大的经济损失,对人类的健康也构成严重威胁。该文主要介绍了二噁英对哺乳动物及人类免疫系统在细胞免疫、体液免疫和非特异性免疫等方面的影响。     

氟的生殖毒理学研究进展

生殖毒理学是在毒理学的基础上发展起来的一门学科,它主要研究外来化学物质或其它环境因素对人和动物生殖系统的不良影响及其机理。随着环境污染越来越严重,很多污染物都会引起机体生殖系统产生一定的变化。因此,研究外来刺激物对生殖系统的影响,一方面可对它们的毒性做出全面评价,并对其引起损害的病理过程及机理有进一步的了解;另一方面可以为制定防治措施提供依据。氟是机体必需的一种微量元素,缺乏或过剩均可引起疾病。人们对氟的生殖毒性研究已取得了一些研究成果,认为氟可作用于生殖过程的不同方面和不同阶段而表现出生殖毒性。1氟对…     

略谈日照与水貂的生殖

<正> 水貂原产北美洲北纬45度以北地区,是一种季节性繁殖的珍贵毛皮兽。水貂季节性繁殖是长期受自然环境条件的影响,在自然选择的基础上形成的遗传特点。水貂一年一度的生殖活动,与日照周期性变化有着密切的关系。水貂从北方移至低纬度的南方饲养,生殖机能发生紊乱,繁殖     

水貂的生殖和生育力(一)

原文作者于1988年秋,检索出世界上有关水貂的研究论文4650篇,其中涉及水貂生殖方面的占16％。作者参考了358篇文章,对水貂的生殖问题进行了全面、详细地综述,具有一定的参考价值。现由山西大学生物系吕恩余等同志译出,由于译文篇幅较长,本刊将按专题分两期发表。     

玉米赤霉烯酮的毒害作用及对种猪繁殖性能的影响

玉米赤霉烯酮是一种非甾体雌激素样作用的霉菌毒素。大量研究表明,玉米赤霉烯酮具有生殖发育毒性、免疫毒性,对肿瘤发生也有一定影响。本文综述了玉米赤霉烯酮的毒性毒害作用及对种猪繁殖性能的影响,以引起养殖者的高度重视。     

略谈水貂的某些生物学特性

野生水貂居栖在中纬和北纬地区,至今被人们驯养仅有60—70年历史。目前,人工繁殖的笼养水貂,尽管毛色和体型等都发生了很大变异,但生活习性、新陈代谢、生殖生理及大体解剖等,与其野生的祖先相比,几乎没有差异。因而,人们在饲养水貂过程中,往往采用仿野生生态的方法。一、水貂生命活动的季节性变化     

维生素E对水貂的营养作用

维生素E作为一种脂溶性维生素,在水貂正常生长发育和繁殖的过程中起着非常重要的作用。水貂作为一种肉食性动物,其自身合成维生素E的能力极低,应在水貂的日粮中添加适量维生素E以保证水貂的营养需要。研究维生素E对水貂的营养生理及消化吸收作用进行综述;提出水貂对维生素E的需要量及不同的维生素E含量对水貂各项性能的影响。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.