动物种群性比失调及其影响因素

为了了解动物种群性比失调现象及其影响因素,从生态环境、资源竞争、动物自身适应性、人为干预、营养因素及现代生物技术手段等方面对动物种群出生性别比例的影响因素进行了阐述,旨在为壮大野生动物种群及保护野生动物资源指出努力方向。     

影响猪第二性比若干因素的研究

本文分析研究了２３８１窝共３４８２５头二花脸仔猪第二性比与若干因素的关系，发现产仔年份季节，胎次及产仔数等四个因素对仔猪第二性比有明显的影响，调控某些因素可望在一定程度上控制猪的第二性比。     

蛋形指数对孵化率及性比例的影响

用单因子试验设计，探讨了罗曼父母代种蛋蛋形指数与孵化率，性比例的关系，结果表明，蛋形指数为72％－77％时孵化率最高，蛋形指数与性比例无直接关系，符合遗传规律1：1的性比例关系。     

旱养模式下饲养密度和公母配比对肉种鸭生产性能的影响

本研究旨在探讨旱养模式下不同饲养密度、不同公母配比对SM3樱桃谷种鸭生产性能的影响。选择24周龄产蛋期父母代SM3樱桃谷种鸭21600只。将试验鸭随机分为饲养密度调整为2、3、4、5、6只/m25组,每组3个重复,每个重复1200只,公母配比均为1:4.5,试验至48周龄结束。对存活率、产蛋率、种蛋合格率及42周龄种蛋受精率指标进行测定和分析,结果表明:在旱养条件下肉种鸭饲养密度以4只/m2最适宜。选择24周龄产蛋期父母代SM3樱桃谷种鸭14400只。将试验鸭随机公母配比为1:4、1:5、1:6、1:74组,每组3个重复,每个重复1200只,各组密度均为4.2只/m2,试验至65周龄结束。通过测定产蛋率、种蛋合格率和受精率,用与密度试验相同的分析方法,结果表明:1:5的公母性别比例为最佳配比。     

蜜蜂性比的分子调控机制研究

蜜蜂性比是指蜂群中雌性蜜蜂与雄性蜜蜂的比例。按亲属选择理论和性比原理预测 ,工蜂则可能对雌性性别更多地投资 ,这样蜂王和工蜂在决定性比问题上存在矛盾。本试验通过RAPD技术测定蜂王交配次数 ,并利用亲属选择和性比理论 ,研究了蜂群中的性比冲突问题。研究结果支持了工蜂调控蜜蜂性比的观点。     

体外培养体系对牛体外受精胚胎性比的影响

研究了不同体外培养体系对牛体外受精胚胎性比的影响。结果表明，添加血清的2组培养系统中所得雄性囊胚与雌性囊胚的性比虽偏离了1：1，但差异不显著（P〉0．05），而总的体外胚胎的性比则显著偏离了1：1（P〈0．05）。这说明在体外培养系统中雄性胚胎比雌性胚胎发育能力更强，并且血清的存在对于雄性胚胎的发育有明显的促进作用。     

过冷却处理家蚕卵对四倍体诱发率及后代性比的影响

探讨了家蚕盛产卵后不同时间的卵过冷却处理对四倍体诱发率和后代三倍体性比发生的影响。不同杂交组合材料盛产卵后不同时间卵所处的分裂期不同 ,影响到四倍体雌蚕的诱发率 ,处于第一分裂期的卵数越多 ,诱发率越高 ;诱发的四倍体与正常二倍体交配产生的三倍体蚕雌雄比例由 3∶1变为 5∶1是由于四倍体减数分裂中性染色体的行为 ,性比 3∶1时 ,仅是Z与Z、W与W之间的联会 ,其后随着这种联会增加 ,Z与W之间的联会也逐渐开始 ,从而使雌雄比例接近 5∶1。     

蜜蜂性比的生理生化调控机制研究

试验研究了不同季节不同蜂群子脾间温度、湿度和CO2体积分数等巢内环境因素变化规律,同时测定不同状况不同蜂群中不同日龄工蜂保幼激素酯酶的活性及血淋巴中K+/Na+变化。结果表明,巢内CO2体积分数和湿度环境因素改变,引起群内15—20日龄工蜂保幼激素含量提高和血淋巴中K+/Na+降低,从而使蜂群表现出调控蜜蜂性比行为。     

Effects of Hyaluronan Supplementation on Cryopreserved Equine Spermatozoa Hyaluronan and Cryopreserved Equine Spermatozoa

Addition of hyaluronan, a nonsulfated glycosaminoglycan, to fresh and frozen thawed human semen results in substantial retention of motility over time. Hyaluronan also has been reported to preserve postthaw viability and maintain membrane stability of boar spermatozoa. Therefore, experiments were designed to investigate the use of a commercially available hyaluronan (Map-5, Bioniche Animal Health, Inc., Athens, GA) in freezing extender for cryopreservation of equine spermatozoa. In experiment 1, aliquots from ejaculates were supplemented before freezing with one of four levels of hyaluronan: 100 μg/mL, 200 μg/mL, 400 μg/mL, and 1000 μg/mL along with an untreated control. No differences in sperm motility, assessed by computer-assisted sperm motility analysis (CASA), were found for any treatment at times 0, 30, or 60 minutes postthaw. Decreases in motility were noted in the highest hyaluronan group (1,000 μg/mL) after 90 and 120 minutes of incubation. Sperm viability, as assessed using SYBR-14/propidium iodide staining, was decreased (P < .05) when treated with 1,000 μg/mL compared with the control (37.1% and 46.1%, respectively). Motility parameters tended to remain elevated in those ejaculates treated with 200 μg/mL at various time points. Experiment 2, therefore, further investigated the effects of hyaluronan at 200 μg/mL on motility parameters and acrosome integrity and zona pellucida binding. Total (TM) and progressive (PM) motility of treated sperm immediately after thawing and at 60 minutes post-thaw were higher compared with control (P < .05). A tendency (P < .1) to maintain TM at 90 and 120 minutes post-thaw also was noted. No differences were noted for the mean number of spermatozoa bound to bovine oocytes for control or treated sperm (22 ± 14 vs 25 ± 17, respectively). Acrosome integrity also was unchanged between the two groups based on fluorescein isothiocyanate (FITC)−peanut agglutinin (PNA)/propidium iodide staining. All samples contained <1% live acrosome-damaged spermatozoa. In the final experiment, the effects of hyaluronan supplementation post-thaw was investigated using hyaluronan concentrations of 100, 200, and 400 μg/mL. Motility parameters studied over an 8-hour period at 37°C yielded no consistent differences. In conclusion, addition of hyaluronan at a concentration of 200 μg/mL before freezing increased spermatozoal post-thaw motility. High concentration of hyaluronan (1,000 μg/mL) appeared to be detrimental to post-thaw motility. Effects of hyaluronan on fertility are beyond the scope of this study and have yet to be determined.     

样本量和性比对微卫星分析中群体遗传多样性指标的影响

以4个中国地方鸡品种遗传多样性的微卫星分析数据为例,分析样本量和性比对微卫星分析中群体遗传多样性指标的影响。结果表明:当样本量超过20后,期望杂合度值趋于稳定,样本量与期望杂合度无显著相关,而与平均等位基因数呈正相关,在微卫星分析中性比对群体遗传多样性指标不表现出显著影响;微卫星位点多态性的高低直接影响到检测所需的样本量,在使用平均等位基因数分析群体遗传多样性时,应该充分考虑样本量对检测结果的影响;期望杂合度受样本量变动的影响较小,可作为度量群体遗传多样性的一个最适参数,而且样本量以20～25较为适宜。     

两性异型红隼的子代性比研究

Fisher经典的性比分配理论预测:如果双亲繁殖雄性和雌性子代的代价相同,那么子代的性比应趋于平衡.然而,性比组成是长期进化的结果,常因不同因素的影响而出现偏离.文献报道猛禽由于存在不同形式的两性异型现象而导致子代性比常出现偏离,但子代性比偏离方向因种而异.本研究中我们对红隼(Falco tinnunculus)子代的性比组成进行了调查,目的是检验红隼子代性比是否受产卵日期、产卵顺序、卵重、出雏顺序或窝卵数影响.在窝水平上,红隼(雄性)的初级性比为47.0%,没有偏离0.5,但次级性比为40.8%,显著偏离0.5(p=0.029).在种群水平上,初级性比和次级性比都没有出现偏离.窝卵数和卵重影响红隼的次级性比组成,窝卵数越大,雄性后代数量越多,且发育为雄性后代的卵重较发育为雌性后代的重.初级性比和次级性比都受到产卵日期的影响,产卵越早,雄性后代比例越高.     

用 Percoll 不连续密度梯度分离奶牛精液对控制性别比率的研究

利用Ｐｅｒｃｏｌｌ不连续密度梯度分离的定性精液,经在兰州、西安两市１１个大中型奶牛场的验证试验,结果表明本项目配制的奶牛定性精液对后代性别比例的影响较大,其中利用富含Ｙ－精子的１号２号定性精液所生产的后代雌雄比例分别为３６：６４和４６．３：５３．７;利用富含Ｘ－精子的３号和４号定性精液所生产的后代雌雄比例分析为６０．５：３９．５和６５．４：３４．６。     

品种,性别和日龄对肉兔饲料转化率的影响

试验选用大耳白，加里福尼亚兔和比利时兔，通过对试验兔７５－１５０日龄生长阶段饲料转化率的测定，结果表明：日龄是影响试兔饲料转化率的主要限制性因素（Ｐ＜０．０１）。由此得出：要提高商品兔的生产效率，必须注重兔的早期饲养管理，使之在较短的时间同进入生长高峰，加快周转，而饲养“长寿兔”将使商品兔生产的经济效益显著降低。     

Effects of Pentoxifylline on Equine Epididymal Sperm

This study evaluated whether pentoxifylline (PTX) present in the flushing extender influenced the function of equine epididymal spermatozoa after recovery and after thawing. For this experiment, 58 testicles from 29 Brazilian Jumping Horses were used. Cauda epididymides of each stallion were separated and flushed with a skim milk extender, with or without 7.18 mM PTX and then subjected to the freezing process. Samples flushed with the extender containing PTX showed a significant increase in total motility, progressive motility, straight line velocity, curvilinear velocity, and percentage of rapid sperm immediately after the recovery of epididymal sperm and after 15 minutes of incubation at 37°C (P < .05). However, the presence of PTX in the flushing extender did not affect the post-thaw motility parameters or plasma membrane integrity (P > .05). The results of this study showed that the PTX present in the flushing extender improved motility parameters of recently recovered epididymal sperm and had no deleterious effects on plasma membrane integrity and freezability of equine epididymal sperm.     

控制sch单养雄蚕品种雌雄蚕孵出比例的催青处理因素研究

研究结果表明 :在RH 6 0 %状态下 ,控制性比的温度和下限时间负相关达到显著水平 ;控制性比的高温处理适于干燥状态下进行 ;处理后雌蚕孵化整齐度明显低于雄蚕孵化整齐度 ,雌雄蚕孵化整齐度均随处理温度的升高而下降 ,尤以雌蚕更为明显。由此提出了在RH 6 0 %状态下sch单养雄蚕品种控制性比的起点温度及温度、时间范围。认为高温催青用下限温度配合 1日收蚁法效果好 ,高温处理以后的胚胎适于在RH 80 %～ 85 %的湿度中保护     

Risk Factors for Equine Postoperative Ileus and Effectiveness of Prophylactic Lidocaine

Background: Postoperative ileus (POI) is a frequent and often fatal complication of colic surgery. Reliably effective treatments are not available.
Objectives: To determine risk factors and protective factors associated with POI, and to assess the effect of lidocaine IV on short-term survival.
Animals: One hundred and twenty-six horses that underwent small intestinal colic surgery and that survived for at least 24 hours postoperatively.
Methods: Retrospective cross-sectional study. The association of 31 pre-, intra-, and postoperative variables with POI and the association of lidocaine treatment with short-term survival were investigated. Associations were evaluated with univariable logistic regression models, followed by multivariable analysis.
Results: Significant associations of high heart rate (odds ratio [OR] = 1.05, 95% confidence interval [CI] 1.03–1.08), the presence of more than 8 L of reflux at admission (OR = 3.02, 95% CI 1.13–8.02) and the performance of a small intestinal resection (OR = 2.46, 95% CI 1.15–5.27) with an increased probability of POI were demonstrated. Prophylactic lidocaine treatment was significantly associated with a reduced incidence of POI (OR = 0.25, 95% CI 0.11–0.56). Lidocaine treatment was also significantly associated with enhanced short-term survival (OR = 0.30, 95% CI 0.09–0.98).
Conclusions and Clinical Importance: The variables associated with an increased risk of POI can be useful in identifying horses at risk of POI and in providing a more accurate prognosis. The results are supportive for lidocaine IV as an effective prokinetic treatment after small intestinal colic surgery.     

分离Y精子在茸鹿性别控制中的应用研究

为研究一种新的茸鹿繁殖方法,2007～2008年对469头马鹿,79头梅花鹿进行性别控制技术研究。结果表明：性别控制冻精情期受胎率马鹿为87．21％,梅花鹿为60．76％,两者之间差异极显著（P〈0．01）,性比率（指产公仔率）马鹿为90．95％,梅花鹿为93．75％,两者之间无显著差异（P〉0．05）;性别控制冻精与普通冻精输精比较,马鹿情期受胎率之间、性比率之间和梅花鹿性比率之间都存在极显著差异（P〈0．01）,梅花鹿情期受胎率之间则无显著差异（P〉0．05）。普通冻精受胎率马鹿为94．89％、梅花鹿为61．63％,性比率马鹿为50．22％、梅花鹿为49．06％,性别控制冻精受胎率整体接近普通冻精,性比率则提高40％以上,比较分析认为对茸鹿X、Y精子分离进行性别控制试验是成功的。     

应用分子粪便学方法调查太阳岛地区灰松鼠性别比例

采用已优化的硫氰酸胍-硅藻土法提取乙醇保存的灰松鼠粪便DNA,PCR检测sry基因,从而确定灰松鼠的性别比例。结果表明,应用该法提取DNA方法简单易行,价格低廉,PCR检测太阳岛地区灰松鼠雌雄比例为59∶27。     

The Effect of Cholesterol Addition,Buffer, and pH on Equine Sperm Stored at 5°C

Cooled stallion semen has a short viable life, which ranges with acceptable motility and viability from 24 up to 48 hours. The purpose of this study was to compare the effects of storage pH, the ability of three different zwitterionic buffers, and cholesterol-loaded cyclodextrins (CLC) to preserve the motility and integrity of stallion sperm cooled to 5°C for 48 hours. Fourteen ejaculates were collected and split to receive CLC or not (control group). After incubation, each sample was split into six subsamples and diluted in KMT extender containing 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), or 2-(N-morpholino)ethanesulfonic acid (MES) buffers, and the final pH was adjusted to either 7.0 or 6.6, totalizing 12 experimental groups as a function of CLC, buffer, and pH variables (2 × 3 × 2 factorial). The motility parameters and integrity of plasma and acrosome membranes (live cell index) were determined using computer-automated semen analysis and epifluorescence microscopy at 3, 6, 24, and 48 hours of cooling period. According to results, pH was not a significant source of variation for motility and live sperm over different cooling periods. However, samples diluted in BES exhibited higher progressive motility within 3 hours and higher percentages of total motile cells after 48 hours of incubation at 5°C (P < .05). After 24 hours of storage, CLC-treated sperm samples presented higher motility than control group (P < .05), and after 48 hours of incubation, CLC-treated sperm exhibited higher percentages of live, motile, and progressively motile sperms (P < .05). We inferred that equine semen diluted in KMT containing BES as buffer and CLC treatment improve the equine sperm survival during storage at 5°C for 48 hours.     

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.