砷污染区黄牛和水牛姐妹染色单体交换和细胞周期动力学的研究

本文以外周血淋巴细胞姐妹染色单体互换(SCE)频率和细胞周期动力学为指标,以较长期(4～13年)生活在砷污染区的黄牛和水牛为对象,对砷在动物体内慢性蓄积所诱发细胞遗传学效应进行了研究。其结果表明,砷污染区黄牛和水牛SCE频率均显著高于对照组,参照有关评价标准,可判为弱阳性,提示在当地污染水平下,黄牛和水牛都诱发了一定程度的细胞遗传学效应。对细胞周期动力学的观察结果表明,砷对黄牛和水牛没有明显的细胞毒性。本试验还报告了正常黄牛和水牛外周血液淋巴细胞SCE的自发频率以及培养72小时各期细胞的正常比率。     

3-甲基喹噁啉-2-羧酸的制备及其细胞毒性

通过贝鲁特反应和还原、脱羧反应在体外合成制备3-甲基喹噁啉-2-羧酸,并进行理化鉴定和抗菌活性测试;通过MTT方法研究3-甲基喹噁啉-2-羧酸对多种细胞的生长抑制作用,利用单细胞电泳研究其对细胞DNA的损伤作用,利用流式细胞术研究其对细胞周期的改变。结果显示,体外成功合成制备出3-甲基喹噁啉-2-羧酸,而3-甲基喹噁啉-2-羧酸几乎没有抗菌效果,对多种细胞的生长抑制作用较弱,在剂量检测范围内细胞抑制率不到30%,但在一定剂量下能导致细胞DNA损伤,主要表现为尾长和尾部DNA含量显著升高;并且3-甲基喹噁啉-2-羧酸也能改变Chang细胞的细胞周期,表现为S期阻滞。结果表明,3-甲基喹噁啉-2-羧酸具有一定的细胞毒性。     

CIDR PMSG FSH联合处理不同品种绵羊效果的研究

CIDR、PMSG、FSH联合使用对初产供体羊Borderdale(波德代)3♂15♀、Poll Dorset(无角陶赛特)5♂18♀和Ger-man Mutton Merino(德国肉毛兼用美利奴—德美)3♂15♀进行同期发情和超数排卵。同期化发情波德代、无角陶赛特和德美分别为100.00%、88.89%和93.33%,羊只同期化发情时间经历和各时间点分布3个品种各有特点。超数排卵效果品种间存在差异,波德代、无角陶赛特、德美分别为6.60±2.97(枚)、3.63±2.25(枚)、5.50±3.32(枚),波德代极显著地高于无角陶赛特(P<0.01)。超排有效率波德代、无角陶赛特、德美分别为100.00%、87.50%、92.86%。未受精卵波德代极显著地高于德美羊和无角陶赛特羊(P<0.01)。胚胎总数德美羊极显著地高于波德代(P<0.01)。有效胚胎波德代羊、无角陶赛特羊、德美羊分别为2.40±2.31、2.75±2.05、4.07±3.79,德美极显著地高于波德代(P<0.01)。同一方法进行同期化发情,羊只经历时间和各时间点均衡分布能否有效控制是同期发情的焦点问题,是有效胚胎数目差异的主导因素之一。     

Life cycle of Eimeria procera in experimentally infected grey partridges (Perdix perdix)

We examined exogenous and endogenous development of Eimeria procera in experimentally infected grey partridges (Perdix perdix). Our examination included data on morphology, localization, duration of schizogony and gametogony and morphology of sporulated oocysts. The endogenous stages of E. procera developed in large numbers within the epithelial cells of caecal crypts. The asexual development comprised three generations of schizonts. The first fully developed macrogametes and microgamonts were observed on Day 5 post-infection (p.i.) in histologic section. The patent period began on Day 6 p.i. and ended on Day 11 p.i. with peak production of oocysts on Days 7 and 8. Long oval oocysts of E. procera measured 25.78–28.13 μm in length and 14.06–15.24 μm in width, sporulation time ranged from 18 to 24 h at 25°C and from 36 to 48 h at 20°C.     

Embryo collection from pigs post‐pseudopregnancy induced by estradiol dipropionate

We aimed to define whether embryo collection carried out after pseudopregnancy was of similar outcome and quality as after artificial abortion. To induce pseudopregnancy, 30 gilts or sows were given 20 mg intramuscular estradiol dipropionate (EDP) 10–11 days after the onset of estrus. Ten additional pigs were inseminated artificially at natural estrus as a control group. Prostaglandin F_2α (PGF_2α) was administered twice with a 24 hr interval beginning 15, 20, or 25 days after EDP‐treatment (n = 10 per group) or between 23 and 39 days after artificial insemination in control pigs. Following this, all pigs were given 1,000 IU equine chorionic gonadotropin and 500 IU human chorionic gonadotropin (hCG) and then inseminated. Embryos were recovered 6 or 7 days after hCG treatment and outcome was recorded. There was no significant difference in the number of normal embryos collected from the pigs with PGF_2α initiated at different time points or from the control group. Embryonic developmental stages 7 days after hCG treatment also did not differ among groups. These results indicate that the use of EDP to induce pseudopregnancy, followed by PGF_2α administration to synchronize estrus for subsequent embryo harvest, is a suitable alternative to the artificial abortion method.     

从江香猪生精上皮周期及睾丸发育的形态学分析

试验旨在探究初情期前后生精上皮周期差异及睾丸发育过程中的形态学变化。通过测定15、30、60和90 d睾丸相关指数,结合睾丸组织形态学特征,判断香猪初情期,划分从江香猪生精上皮周期。结果显示,30 d的睾丸指数较15 d极显著升高（P<0.01）,睾丸重、长轴及短轴的增长率分别为298.05%、66.42%和65.45%,60和90 d两个阶段睾丸重增长率相对稳定。形态学观察表明,从江香猪30 d时生精小管出现游离精子,完成第一次生精并进入初情期;与15 d相比,30 d生精小管面积和生精上皮厚度极显著增加（P<0.01）,增长率分别为136.12%和40.19%,在60和90 d均处于稳定增长状态。睾丸细胞数统计显示,日龄增加不影响支持细胞（setoli cells,SC）数量（P>0.05）,而30 d生殖细胞数（germ cells,GC）较15 d极显著增加（P<0.01）。相关分析结果发现,生殖细胞数量增加与生精小管面积增大、生精上皮厚度变化之间呈明显正相关（r=0.994;0.96）。根据生殖细胞组合形式差异,将初情期前后生精上皮分为3和8个阶段。初情期前生殖细胞以第一次减数分裂前期为主,A、B型精原细胞、SC、初级精母细胞（primary spermatocyte,Ps）、前细线期（preleptotene,PI）、细线期（leptotene,L）等生殖细胞在初情期前后生精上皮中均存在,而圆形精子（round spermatids,R）、延伸精子（elongating spermatid,E）、精子细胞（spermatozoa,S）仅存在于初情期后的生精上皮。本研究结果表明,从江香猪30 d初情,睾丸发育以生殖细胞和生精小管面积的迅速增加为主,该结果对从江香猪早熟性状挖掘、种猪选育及开发利用等有重要的指导意义。     

肉牛场生命周期估计及环境影响评价

试验采用生命周期估计(life cycle assessment,LCA)方法对江西高安某存栏1 800头的肉牛育肥场在整个育肥期间(7个月)的污染物排放量,以及污染物在全球变暖、环境酸化、富营养化、光化学臭氧合成方面对环境的影响进行了评估。系统边界包括化肥生产、农作物种植、饲料运输、肉牛生产和粪便处理。结果表明:温室气体排放量为(以CO2当量计)为11 908t,环境酸化气体排放量(以SO2当量计)为84.6t,富营养化气体排放量为(以PO43-当量计)为14.4t,光化学臭氧合成问题气体排放量为(以C2H4当量计)为1.68t。其中饲料运输主要影响全球变暖(占总排放量的49.8%)和光化学臭氧合成问题(占总排放量的54.1%),而粪便处理主要影响环境酸化(占总排放量的70.1%)和富营养化(占总排放量的76.4%),肉牛生产对环境的影响主要是全球变暖(占总排放量的18.1%)和光化学臭氧合成问题(占总排放量的30.9%)。因此,可考虑通过降低运输距离,改善饲料配方、粪便处理方式等降低污染物排放量。     

不同品种受体对绵羊胚胎移植效果及羔羊早期生长性能的影响

旨在探讨以小尾寒羊和蒙古羊作为受体时,二者的胚胎移植效果及所产羔羊的早期生长性能之间的差异。选用南非肉用美利奴羊(n=11)和澳洲白绵羊(n=110)作为供体,以小尾寒羊(n=196)和蒙古羊(n=504)作为受体;对供体母羊进行超数排卵以及人工授精处理,记录供体母羊的收集胚胎总数和可用胚胎数,计算平均每只羊收集的可用胚胎数以及胚胎合格率;对小尾寒羊和蒙古羊进行同期发情及胚胎移植处理,记录受体母羊的产羔数,计算繁殖率;计算并比较不同受体母羊所产羔羊的平均初生重、成活率以及70日龄断奶羔羊数、70日龄断奶重、平均日增重、平均每只母羊提供的断奶羔羊数。结果表明,从供体母羊中共获得可用胚胎549枚,平均每只羊收集可用胚胎4.54枚,胚胎合格率为82.56%;利用胚胎移植技术,移植受体母羊529只,所产羔羊240只,平均繁殖率为45.37%;小尾寒羊的发情率和繁殖率明显高于蒙古羊;共获得70日龄断奶羔羊211只,羔羊成活率为87.92%,平均日增重为280.00g;小尾寒羊和蒙古羊所产的羔羊初生重没有显著差异(P>0.05),小尾寒羊所产羔羊的70日龄断奶重和平均日增重分别极显著(P<0.01)和显著(P<0.05)高于蒙古羊,而蒙古羊所产羔羊的成活率显著高于小尾寒羊(P<0.05);平均每只小尾寒羊母羊可提供的断奶羔羊数(0.42只)略高于蒙古羊(0.39只),小尾寒羊作为胚胎移植受体略具有优势。综合分析表明,在内蒙古兴安盟地区小尾寒羊和蒙古羊均可以作为胚胎移植的受体来使用。     

巴美肉羊发情期外周血E2和P4浓度变化规律与排卵数关系研究

绵羊在发情周期中各生殖激素浓度变化与卵泡发育、成熟和排卵有着密切的关系。为了研究巴美肉羊血清生殖激素的动态变化及其与排卵数关系,试验采用电化学法,测定了12只成年母羊发情期血清中2种类固醇激素(E₂和P₄)的浓度水平,分析其动态变化规律,并用SAS 9.0的方差分析程序分析激素浓度与排卵数的关系。结果表明,两种激素在排单卵组和排双卵组绵羊间变化规律不同,E₂在排单卵组表现为先下降后升高的变化趋势,在排双卵组表现为持续下降趋势;P₄在排单卵组表现为持续上升的趋势,在排双卵组为先上升后下降的变化趋势。排单卵和排双卵组绵羊在各时间点的E₂和P₄激素浓度差异均不显著(P＞0.05)。     

Relation of reproductive performances and rectal palpation for luteum function of heifers 7 days after estrus

Diagnosis of corpus luteum (CL) function by rectal palpation (RP) has been widely used for recipient selection of embryo transfer (ET), a technology essential for genetic improvements in cattle. To examine the accuracy of RP diagnosis method, the relationship between RP‐based CL function and reproductive performance was compared in this study. In Experiment 1, CL of Holstein heifers on day 7 after estrus was classified into functional or hypoplastic by RP, and the results were compared with ultrasonographic (US) images and plasma progesterone (P4) levels. As a result, heifers with functional CL judged by RP had a mean maximum CL diameter of 20.1 ± 3.1 mm on US and a mean P4 concentration of 8.1 ± 2.3 ng/mL. These values were significantly greater than those of heifers with hypoplastic CL (12.4 ± 5.4 mm, 4.0 ± 2.8 ng/mL) (P < 0.001). In Experiment 2, the length of the estrus cycle was examined between functional CL and hypoplastic CL. The rate of heifers with a normal estrus cycle length with 18–25 days was significantly lower with hypoplastic CL than with functional CL (16/24 vs. 43/46, P < 0.01). In Experiment 3, 543 inseminated heifers were similarly classified by CL function by RP 7 days after estrus. The heifers with functional CL showed higher pregnancy rate compared with the heifers with hypoplastic CL (75.2 vs. 47.9%, P < 0.0001). Finally, the CL function of 66 heifers was examined by RP on day 7 post‐estrus, and ET was performed in 49 (74.2%) heifers with functional CL. As a result, 27 (55.1%) of them became pregnant. Taken together, these results reconfirm that RP on day 7 after estrus is useful for selection of heifers with functional CL.