同期排卵处理母牛体温和活动量变化规律及效果分析

为探究同期排卵处理母牛体温和活动量变化规律及不同同期排卵技术处理效果，指导同期排卵技术优化。本研究自动监测了18头20月龄左右同期排卵（GnRH-PG-GnRH）处理荷斯坦母牛和17头产后40~60 d预同期排卵（PG-PG-GnRH-PG-GnRH）处理荷斯坦母牛的体温和活动量，应用自动检测系统进行母牛发情监测。结果发现，同期排卵处理母牛发情时阴道温度平均升高（0.43±0.20）℃，持续（12.37±2.73）h；活动量平均升高（18.28±18.61）倍，持续（11.00±1.68）h；排卵时阴道温度平均下降（0.20±0.10）℃，持续（11.00±1.68）h。自动化发情监测显示，同期排卵处理母牛7头发情并排卵；预同期排卵母牛GnRH处理前全部发情排卵。两种同期排卵处理，虽可改变母牛性周期进程，促进母牛性周期同步化，但均难以使母牛性周期完全同步。因此，将同期排卵-定时输精和发情鉴定技术科学结合才能取得更好的繁殖效果。     

Ovulation and spawning induction in Caspian kutum Rutilus frisii kutum by administration of GnRHa and catecholaminergic pharmaceutical compounds with Ovaprim

The acceleration of final oocyte maturation and ovulation is recognized as a principal process in Caspian kutum Rutilus frisii kutum, a commercial and valuable species in Caspian Sea. The aim of this study was to evaluate the effects of catecholaminergic pharmaceutics which include Salbutamol (β₂‐adrenergic receptor agonist), Metoprolol (β₁‐adrenergic receptor antagonist), Clozapine and Olanzapine (the third generation of D₄ and D₂ dopamine receptor antagonists) which can be more efficient than the first and second generations, in combination with Buserelin ([D‐Ser(tBu)⁶,Pro⁹‐NEt]‐GnRHa) and Ovaprim (D‐Ala⁶,Pro⁹‐Net)‐sGnRH+Domperidone on ovulation and spawning induction in Caspian kutum. One hundred eight adult females were injected once with Buserelin Acetate (BUS) 5 μg kg^?1 BW, Ovaprim 0.5 mL kg^?1 BW, Salbutamol Sulphate (SLB) 4 mg kg^?1 BW, Olanzapine (OLZ) 5 mg kg^?1 BW, Clozapine (CZ) 12 mg kg^?1 BW and Metoprolol Tartrate (MTP) 5 mg kg^?1 BW, being divided into 12 groups: group 1, intact (negative control); group 2, Ovaprim (positive control); group 3, OLZ+SLB; group 4, OLZ+MTP; group 5, OLZ+BUS; group 6, CZ+SLB; group 7, CZ+MTP; group 8, CZ+BUS; group 9, OLZ+BUS+SLB; group 10, OLZ+BUS+MTP; group 11, CZ+BUS+SLB and group 12, CZ+BUS+MTP (N = 9). The results showed that the highest mean value in ovulation success, ovulation index, fertilization success, relative fecundity and the number of eggs belonged to Ovaprim treatment. On the other hand, spawning was successful in OLZ+BUS+SLB and CZ+BUS treatments (P < 0.05), whereas it was lower in CZ+MTP, CZ+BUS+MTP and OLZ+BUS than the other treatments. Therefore, it could be concluded that Clozapine and Olanzapine potentiated the effect of Buserelin treatment in ovulation and spawning induction, while Metoprolol blocked the stimulatory effects of GnRHa, Clozapine and Olanzapine. Salbutamol also can amplify stimulatory effect of all mentioned pharmaceutics.     

Na?ve-like conversion enhances the difference in innate in vitro differentiation capacity between rabbit ES cells and iPS cells

Quality evaluation of pluripotent stem cells using appropriate animal models needs to be improved for human regenerative medicine. Previously, we demonstrated that although the in vitro neural differentiating capacity of rabbit induced pluripotent stem cells (iPSCs) can be mitigated by improving their baseline level of pluripotency, i.e., by converting them into the so-called “naïve-like” state, the effect after such conversion of rabbit embryonic stem cells (ESCs) remains to be elucidated. Here we found that naïve-like conversion enhanced the differences in innate in vitro differentiation capacity between ESCs and iPSCs. Naïve-like rabbit ESCs exhibited several features indicating pluripotency, including the capacity for teratoma formation. They differentiated into mature oligodendrocytes much more effectively (3.3–7.2 times) than naïve-like iPSCs. This suggests an inherent variation in differentiation potential in vitro among PSC lines. When naïve-like ESCs were injected into preimplantation rabbit embryos, although they contributed efficiently to forming the inner cell mass of blastocysts, no chimeric pups were obtained. Thus, in vitro neural differentiation following naïve-like conversion is a promising option for determining the quality of PSCs without the need to demonstrate chimeric contribution. These results provide an opportunity to evaluate which pluripotent stem cells or treatments are best suited for therapeutic use.     

The post-ovulatory rise in progesterone is lower and the persistence of oestrous behaviour longer during the first compared with the second cycle of the breeding season in mares

Mares are seasonally polyoestrous breeders. Therefore, the first ovulation of the season, following winter anoestrus, is the only cycle in which mares ovulate without the presence of an old CL from the previous cycle. The objective of this study was to compare the length of oestrous behaviour, and plasma progesterone concentrations during the early post-ovulatory period between mares after the first and second ovulation of the breeding season. Overall, 38 mares and 167 oestrous periods were used in the study. From those, 11 mares were used during the first and subsequent oestrous period to measure and compare the post-ovulatory rise in progesterone concentration, whereas all the mares were used to compare the length of the post-ovulatory oestrous behaviour between the first and subsequent cycles of the breeding season. The persistence of the post-ovulatory oestrus was longer (p < .001) following the first ovulation of the year (median of 52 h) compared with the subsequent ovulations (median of 36 h for second and later ovulations groups; n = 38 mares). The progesterone concentration at any of the four 8 h-intervals analysed (28, 36, 76 and 84 h post-ovulation) was lower (p < .01) following the first versus the second ovulation of the year. By 36 h post-ovulation the progesterone concentration of mares at the second ovulation of the year had passed the threshold of 2 ng/ml (2.1 ± 0.33 ng/ml), whereas in the first cycle it was 1.2 ± 0.13 ng/ml. In conclusion, mares had lower progesterone concentrations in their peripheral circulation and longer persistence of oestrous behaviour following the first ovulation of the year compared with the second and subsequent ovulatory periods of the breeding season.     

三种化学物质诱导白三叶草叶斑病抗性的研究

为了探明硅酸钾、硅酸钠、水杨酸对白三叶草(Trifolium repens)抗叶斑病的诱导效果,采用离体、活体试验及生物化学方法测定了3种化学物质对白三叶草叶斑病的室内抑菌活性、诱导抗病效果、防御酶活性及田间诱导防病效果。结果表明:浓度为25μg·mL~(-1)时3种化学物质的抑菌率较低,最高仅为4.59%,但诱导抗病效果较高,均在45.00%以上;叶片中多酚氧化酶(PPO),过氧化物酶(POD),苯丙氨酸解氨酶(PAL)活性均有明显增加,除硅酸钾、硅酸钠诱导处理的PPO在第3d达到峰值外,其他化学物质诱导处理的酶活性均在第5d达到最大值;田间处理7d后3种化学物质诱导防病效果均达到了72.00%以上;处理14d后有所降低,最低为23.08%。综上所述,浓度为25μg·mL~(-1)的3种化学物质能够激发白三叶草叶片中与抗病性相关的PPO,POD和PAL活性,对白三叶草抗叶斑病均有较好的诱导防病作用。     

农业技术模式转换与对策探讨——以河南省欠发达平原农业区为例

面对当前农村劳动力转移给农业发展带来的挑战和机遇,转换农业技术模式尤为重要.采用理论分析和调查访谈相结合的方法,得出河南欠发达平原农业区农业技术模式转换必须结合本地实际,遵循诱致性轨迹,注重转换过渡模式,即以农民社会资本为纽带进行土地流转,形成土地适度渐进规模经营,以村集体、宗族等为核心发展种子、生物科技、中小型机械设...     

两个单倍体诱导系对玉米不同材料诱导效果的研究

利用两个单倍体诱导系高诱一号和MT诱导系-2对不同基础材料进行单倍体诱导。结果表明,高诱一号和MT诱导系对不同基础材料均可诱导产生单倍体,平均诱导率分别为2.25%和4.44%,这两个诱导系对所选定的基础材料间诱导率都没有显著的差异。通过浸种法加倍,有助于提高单倍体的鉴别效率。     

外源壳聚糖诱导番茄抗灰霉病的作用

[目的]为了明确壳聚糖对番番茄茄幼苗抗灰霉病的诱导作用。[方法]采用叶面喷施的方法,测定了壳聚糖对番茄灰霉病诱抗效果以及番茄叶片中叶绿素含量、可溶性蛋白质、可溶性糖、愈创木酚过氧化物酶（POD）、丙二醛（MDA）、脯氨酸的影响。[结果]壳聚糖对番茄灰霉病的诱抗效果14d时达到58.26%;与灰霉病菌处理组相比,壳聚糖处理组番茄幼苗叶片中叶绿素含量最高增加34.63%、可溶性蛋白含量增加5.30%、可溶性糖含量增加10.83%、游离脯氨酸含量增加16.21%、POD含量增加16.88%、MDA含量降低16.54%。[结论]外源壳聚糖可以提高番茄幼苗光合利用率和保护酶活性从而提高番茄幼苗对灰霉病的抗性。     

采后UV-C处理对葡萄抗病性和品质的影响

[目的]研究低辐能流短波紫外线（UV-C）处理对甬优1号葡萄腐烂的影响及作用机理,为UV-C应用于葡萄保鲜提供科学依据。[方法]葡萄贮藏前进行0、0.5、1.0、1.5、2.0 kJ/m2 UV-C照射处理,然后在（0±1）℃、相对湿度90%环境下贮藏84 d。贮藏期间取样测定腐烂率、苯丙氨酸解氨酶（PAL）活性、多酚氧化酶（PPO）活性、几丁质酶（Chitinase）活性、β-1,3-葡聚糖酶（β-1,3-Glucanase）活性以及总酚和总类黄酮含量。[结果]UV-C处理有效控制了葡萄果实腐烂,显著提高了PAL、PPO、几丁质酶和β-1,3-葡聚糖酶活性,诱导总酚和总类黄酮含量的迅速增加。[结论]UV-C处理抑制葡萄果实的腐烂与抗病相关酶活性和总酚、总类黄酮含量的升高密切相关。     

人绒毛膜促性腺激素对母驴促排卵效果的研究

[目的]研究人绒毛膜促性腺激素（human chorionic gonadotropin,hCG）对母驴卵泡发育、排卵率、受胎率以及血清生殖激素水平的影响。[方法]选择优势卵泡直径在30~35 mm以及大于35 mm的母驴各30头,不同优势卵泡直径的母驴群体分别设置1个500 IU/头hCG处理组（n=10）、1个1 000 IU/头hCG处理组（n=10）、1个不接受hCG处理的对照组（n=10）。采用肌肉注射方法对各组母驴进行hCG处理。每隔24 h进行1次B超检查,观察各组母驴卵泡发育情况,测量卵泡直径;记录各组发生排卵的母驴数量,计算排卵率。对各组母驴进行人工输精,输精后第18天进行孕检,记录各组受胎母驴头数,计算各组受胎率。于hCG处理后0、24、48、72 h分别测定各组母驴血清中雌二醇（estradiol,E₂）和孕酮（progesterone,PROG）水平。[结果]2个群体母驴的卵泡直径随hCG注射剂量的增加而增大;优势卵泡直径大于35 mm的母驴群体中,肌肉注射hCG的2个组在处理后24 h内均出现排卵,而对照组母驴没有排卵;优势卵泡直径不同的2个母驴群体,在hCG处理48 h后排卵母驴数和排卵率与对照组相比均有所提高,其中,hCG处理后72 h,优势卵泡直径大于35 mm的母驴群体中,1 000 IU/头 hCG处理组的排卵率达到100%。2个母驴群体中,接受hCG处理的母驴,受胎率均高于对照,并且随hCG剂量的增加,受胎率有所提高;优势卵泡直径大于35 mm的母驴群体中,1 000 IU/头 hCG处理组的受胎率达到50%。2个母驴群体中,1 000 IU/头处理组在hCG处理后24 h的血清E₂浓度均较0 h时有较大幅度的提升,在0~72 h内血清PROG浓度的总体提升幅度较大。[结论]hCG处理可提高母驴的排卵率、受胎率以及血清中E₂和PROG水平,1 000 IU/头剂量的效果更好。