Effects of Endocrine Disrupting Compounds in Animal Feed on Reproductive Health in Farm Animals*Euroconference Wageningen, The Netherlands, 20–22nd November 1998

This Euroconference was a follow-up to the Euroconference held in Halle, April 1997. The programme of the conference in Halle had an exploratory character with respect to accumulation of endocrine disrupting compounds (EDCs) in the environment and in animal tissues and their effects on animal physiology and reproduction. Many questions arose from the first Euroconference, such as: What are biologically meaningful levels of environmental contamination? Is there a risk for farm animals’ health and reproduction? What assays are available and which are the most appropriate to be used? These questions formed the basis for the programme of the second Euroconference held in Wageningen in November 1998. Taking these questions into consideration, the programme of the Wageningen Euroconference was divided into four main topics. In the first session an overview was given on sources and levels of EDCs in the environment. The second session addressed chemical nature and metabolism of EDCs including phytoestrogens. In the third session the effects of EDCs on ovarian function and embryo development were discussed and in the last session the advantages and disadvantages of different in vivo as well as in vitro assays were debated.     

环境因素对羊繁殖性能影响的研究

在现代化的养羊业中,环境因素对羊的繁殖等生产性能造成的影响不可忽视,高温对羊性细胞生成、受精卵发育、内分泌和妊娠等方面危害性最大,其他因素也不容小觑。文章从空气温度、湿度对母羊发情受胎和公羊精子品质的影响,光照对母羊发情排卵及其他生殖激素的影响,饲养密度对羊繁殖性能的影响以及空气中有害气体对羊的危害和防治措施等方面进行简要介绍,以期在生产中改善环境条件,提高羊的繁殖效率。     

环境污染对蚕茧生产的影响及其防控措施

本文就影响蚕茧生产的氟化物、硫化物、重金属、环境激素及其他环境污染物的来源及对蚕的生物影响进行了分析,提出了相应的防控措施,为相关部门进行产业规划及生产指导时提供参考。     

Linear-Accelerator-Based Modified Radiosurgical Treatment of Pituitary Tumors in Cats: 11 Cases (1997–2008)

Objective: Determine the efficacy and safety of a linear-accelerator-based single fraction radiosurgical approach to the treatment of pituitary tumors in cats.
Design: Retrospective study.
Animals: Eleven client-owned cats referred for treatment of pituitary tumors causing neurological signs, or poorly controlled diabetes mellitus (DM) secondary either to acromegaly or pituitary-dependent hyperadrenocortism.
Procedures: Cats underwent magnetic resonance imaging (MRI) of the brain to manually plan radiation therapy. After MRI, modified radiosurgery was performed by delivering a single large dose (15 or 20 Gy) of radiation while arcing a linear-accelerator-generated radiation beam around the cat's head with the pituitary mass at the center of the beam. Eight cats were treated once, 2 cats were treated twice, and 1 cat received 3 treatments. Treated cats were evaluated for improvement in endocrine function or resolution of neurological disease by review of medical records or contact with referring veterinarians and owners.
Results: Improvement in clinical signs occurred in 7/11 (63.6%) of treated cats. Five of 9 cats with poorly regulated DM had improved insulin responses, and 2/2 cats with neurological signs had clinical improvement. There were no confirmed acute or late adverse radiation effects. The overall median survival was 25 months (range, 1–60), and 3 cats were still alive.
Conclusions and Clinical Importance: Single fraction modified radiosurgery is a safe and effective approach to the treatment of pituitary tumors in cats.     

The Proportion of Beef Bulls in Sweden with Mature Spermiograms at 11–13 months of Age

Semen samples collected postmortem from 142 yearling beef bulls (11-13 months old) of three different breeds (Charolais, Hereford and Simmental) were examined to evaluate the proportion of bulls with mature spermiograms. Before slaughter, testes and epididymides were clinically examined and scrotal circumferences were measured. Aliquots of the cauda epididymal contents taken postmortem were used for sperm morphology examination. Sperm head morphology was studied in dry smears stained with carbol-fuchsine. For each preparation, 500 spermatozoa were counted in each smear under light microscope (x 1000). The presence of proximal cytoplasmic droplets, abnormal acrosomes, detached heads and abnormalities of the midpiece and tail were recorded in wet preparations of formol-saline-fixed spermatozoa. For each preparation, 200 spermatozoa were counted in each preparation under a phase-contrast microscope (x 1000). The abnormalities were classified according to a classification system developed by Bane (1961). Morphological abnormalities were recorded as a percentage of the total number of counted spermatozoa. Criteria for a spermiogram to be considered mature included <15% abnormal heads and <15% proximal droplets. According to this definition approximately 48% (68 of 142) of the examined bulls were considered mature. The bulls in this study represent approximately one-fifth of the total amount of performance-tested beef bulls in Sweden during 5 years. Our results indicate that only less than half of the Swedish yearling beef bulls at the testing station appear to have a mature spermiogram at the time they are offered for breeding purposes.     

山东省牛主要污染物产生量估算及环境效应研究

[目的]估算了山东省牛粪便的总量及其养分的负荷量和占当年排泄污染物的比例。[方法]根据2010年山东省和各地市牛存栏的行业和统计局两套数据和2012年行业数据,通过计算参数和估算的方法算出了牛粪产生总量。[结果]全省牛粪总共约在7000~9700万 t 之间,占当年所有畜禽粪便产生量的34.07%~37.37%之间,即三分之一以上。德州、济南两市单是牛粪便的土地承载量分别达到了29.7 t/hm2和27.4 t/hm2,接近了欧洲标准30 t/hm2的限量值。[结论]应该引起我们对全省牛业发展方式和发展战略的高度重视。     

瘦素在生殖调节方面的研究进展

瘦素是一种由Leptin(ob)基因编码并主要由脂肪组织合成分泌的蛋白质类激素，广泛存在于各组织、器官中。其在调节机体脂肪和保持体重方面具有重要作用。对它的最初的研究主要集中在肥胖的作用，但以后的研究结果发现其缺乏不是造成单纯肥胖的原因。有研究表明，瘦素亦可作为一种代谢信号对下丘脑－垂体－性腺轴发挥功能。     

MicroRNA及其对哺乳动物繁殖的影响

卵巢功能的正常维持有赖于卵巢生殖细胞和体细胞之间的相互作用及若干卵巢自分泌和旁分泌的调节.这些调节物质调控卵巢内不同的细胞活动,包括细胞生长、分化和凋亡,从而对卵泡的发育起着至关重要的作用.Micro-RNAs(miRNAs)是一种小的、非编码、21～25 nt长的单链小分子RNA,近年来科学家们发现其在基因表达转录后水平的调控发挥了重要作用.鼠上的研究显示,miRNAs在卵母细胞成熟和卵巢卵泡发育过程中有调控功能.人上的研究也表明,miRNAs影响颗粒细胞中特定的基因表达,并参与卵巢癌的形成和发展.本文将对miRNAs的生物合成,及其在哺乳动物繁殖系统中的表达,正常和病理情况下miRNAs在繁殖系统中可能的调控作用作一综述.