生殖激素产品的应用和发展趋势

生殖激素是调控动物体内复杂生殖过程并影响繁殖性能的一系列的重要激素。近年来，利用生殖激素的批次化生产繁殖技术被广泛使用，提高了母猪的繁殖效率，促进了养猪业向集约化和规模化方向的发展。目前在批次化生产过程中主要采用孕马血清促性腺激素（PMSG）和人绒毛膜促性腺激素（HCG）以及化学类激素进行繁殖调控。但是这些产品的应用仍存在一些问题，因此需要开发出成本低、活性好的高品质蛋白类生殖激素产品，应用于猪场批次化生产中，提高生猪养殖效率和降低生产成本，为提升我国乃至全球畜牧业的动物繁殖效率做出贡献，为动物和人类的健康提供重要保证。     

一种改进的CRLP最大许用操作压力设计方法

与传统管线钢管相比,复合材料增强管线钢管(CompositeReinforcedLinePipe,CRLP)具有承压能力高和质量轻等优势,但对其压力设计的研究尚不充分。CSAZ662-2015《油气管道系统》和GB/T35185—2017《石油天然气工业用复合材料增强管线钢管》中最大许用操作压力的设计思路不同,且设计结果差别较大。针对此问题,基于组合薄壁圆筒模型对承压CRLP进行分析,对最大许用操作压力下材料的名义许用应力和真实许用应力进行了区分,进而导出真实许用应力的显式表达形式,并以此作为设计安全裕度的评价指标。分析表明:现有规范和标准中的设计公式均无法保证管线钢和复合材料的真实许用应力为常量,对应两种设计方法,各组分材料的真实许用应力均随CRLP规格差异而发生变化,并且随着试压/预应力处理的历程而改变。基于上述分析和CRLP极限状态下的承载特征,提出一种改进的压力设计方法。新方法优先保证复合材料的真实许用应力为常量,并可由设计系数直接确定;在最大许用操作压力的计算中,考虑了加载历程的影响,物理意义明确。算例表明,其设计安全裕度较现有方法更为合理,对于CRLP压力设计的改进有参考价值。     

基于径向基网络的含缺陷管道安全系数修正

安全系数是管道完整性评价方法的重要参数之一,传统评价方法仅考虑了管道所处地区等级对其影响,未能全面评价管道的真实安全状态。提取管道相关风险因素,比较各因素间相对重要程度并建立表征不同风险状态的分值体系,根据所得风险分值对安全系数进行修正,使得修正后的安全系数能够反映含缺陷管段实际风险状态;结合径向基网络方法的自学习特点,将各风险因素作为输入,修正后的安全系数作为输出,建立基于径向基网络的管道安全系数计算模型。由模型训练得出的修正安全系数与测试样本吻合度较好,验证了模型的准确性。结果表明:修正安全系数在考虑地区等级的基础上同时引入了其他重要风险因素的影响,为管道完整性评价中的安全系数取值提供了新的思路。     

白茶寿眉预防小鼠肥胖作用研究及安全性评价

取1、3、7年寿眉(白茶)制备白茶提取物(White tea extracts,WTEs)。在对雄性C57BL/6J小鼠喂饲高脂饲料的同时给予WTEs干预,诱导建立预肥胖模型。观察小鼠体质量增量、摄食量、脂肪和肝脏组织病理学变化,统计脂肪湿重,测定血脂及血转氨酶水平。q PCR测定小鼠肝脏中脂代谢相关基因表达。综合评价WTEs预防小鼠肥胖功效及其安全性,并对其机制进行探究。结果显示,WTEs在无肝毒性和生长抑制作用条件下,能抑制脂肪细胞分化和脂肪的过度积累,还能下调SREBP-1c、FAS和ACC1的转录水平,抑制肝脏脂肪酸合成和脂肪过度积累,有效预防肥胖和脂肪肝的发生。高剂量下,WTEs预防肥胖功效随白茶年份的增加而显著降低。     

Retracted: Study of testis histology and sperm morphology in the Bunnei,Barbus sharpeyi (Gunther, 1874) induced by luteinizing hormone‐releasing hormone analogue and carp pituitary extract

This study was conducted to determine the effects of hormone treatment on testis structure in Barbus sharpeyi, as well as the morphology of sperm examined by scanning electronic microscopy (SEM). Male B. sharpeyi were divided into three groups (three fish per group) and injected with luteinizing hormone – releasing hormone analogue (LHRH–A₂) or carp pituitary extract (CPE). The first and second groups were treated with 10 μg kg^?1 LHRH–A₂ and metoclopramide (MET), and their testis were sampled pre‐ and Poststripping respectively. The third group received 2 mg kg^?1 CPE and were killed pre‐stripping. Based on the histological results obtained, the testicular connective tissue of the lumen was thicker, and seminal vesicles were of a lower volume, in fish injected with CPE in comparison to the other groups. After treatment with LHRH–A₂ and MET, not all spermatozoa within the testis were ejaculated, and only a small amount of sperm was obtained by abdominal stripping. The highest and lowest diameters of connective tissue within lobules were observed in fish receiving CPE and LHRH–A₂ treatments respectively. There was a significant difference (P < 0.05) in lobule space between the fish injected with the CPE and the fish injected with the LHRH–A₂ and MET. The SEM results revealed that the spermatozoa of B. sharpeyi were composed of a spherical to elliptical head, a cylindrical midpiece, and a lengthy flagellum. In conclusion, it was found that injection with LHRH–A₂ and MET improved the spermatogenic process in comparison to injection with CPE.     

Single nucleotide polymorphisms in the growth hormone gene of Oreochromis niloticus and their association with growth performance

Polymorphisms in the growth hormone (GH) gene that is associated with the growth rate of farmed fish have been the target of many breeding programmes. The present study aimed to identify single nucleotide polymorphisms (SNPs) in GH gene regions to evaluate the association of SNP variations with the growth rate of two Nile tilapia: Oreochromis niloticus (Linnaeus, 1758) strains. The targeted regions were amplified, sequenced, aligned and screened for the presence of SNPs; thereafter, performance tests were used to check for the association between SNPs and weight. Allele and genotype frequencies were estimated for each SNP and genotype. Genotype blocks or sets of SNP genotypes and frequencies were also estimated. Association between SNPs and growth rate was statistically evaluated using a univariate linear mixed model that included both fixed and random effects. A total of 10 SNPs were identified, nine in the proximal promoter and one located in the 5′ UTR, forming 10 genotype blocks. In all weight recordings, five genotype blocks were significantly associated with the highest weights. Single nucleotide polymorphisms 6‐10 were also found to be significantly associated with growth (p‐value < .05). Genotypes with higher additive genetic values for weight were identified in the Chitralada strain, suggesting a possible impact of these additive effects of the GH SNP genotype on the growth rate of Nile tilapia. These findings may be used as part of marker‐assisted selection in tilapia breeding programmes.     

12种杀虫剂对日本通草蛉不同虫态的毒力及安全性评价

为明确常见杀虫剂对日本通草蛉各虫态的影响,在室内分别采用浸渍法和喷雾法测定了12种(8类)杀虫剂对日本通草蛉卵、幼虫、蛹和成虫的毒性,并评价了杀虫剂对日本通草蛉的毒性风险。结果表明,高效氯氰菊酯对日本通草蛉为极高风险,毒死蜱、吡虫啉、烯啶虫胺和阿维菌素为高风险,溴氰虫酰胺、啶虫脒和氯虫苯甲酰胺为中等风险,噻嗪酮、吡蚜酮、螺虫乙酯和甲氧虫酰肼为低风险;与其他虫态相比,12种杀虫剂对日本通草蛉蛹的毒性均为最低。在害虫生物防治及综合治理中应尽量选用对日本通草蛉毒性低的杀虫剂,以起到保护天敌的作用。     

道路草花景观对驾驶人员红灯敏感度的影响

近年来,随着对城市道路景观构建的重视,道路绿化、彩化景观愈发优美和引人注目。该文基于152份有效问卷,研究对比分析了3种道路灌-草层的绿化形式(绿篱式、50%草花覆盖式及100%草花覆盖式)对有驾驶经验的受访者红灯敏感度的影响。结果显示,相对于绿篱式道路绿化,草花式道路绿化会造成受访者红灯敏感度降低;女性比男性的红灯敏感度高,但更易受草花干扰;25—45岁年龄段受访者对红灯的敏感度和抗草花干扰能力比18—25岁及45岁以上受访者高;相对于偏好草花式绿化的受访者,偏好绿篱式绿化的受访者有更高的红灯敏感度和抗草花干扰能力。建议应尽量避免在事故易发地段大面积应用颜色艳丽的草花进行道路绿化。     

油菜素内酯浸根对水稻水卷苗机插植伤的修复效应

目的 探究油菜素内酯(Brassinolide, BR)浸根对机插水卷苗栽后本田生长及产量的影响。方法 以宁粳8号为试验材料,分析不同浓度BR(T1、T10、T20,分别表示水培营养液中BR浓度为1 mg/L、10 mg/L、20 mg/L)浸根对水卷苗机插本田后返青活棵及产量的影响,以正常水培营养液处理为对照(CK)。结果 BR浸根(T1、T10、T20)能够促进水稻地上部生长,栽插本田21d后株高较CK分别增加11.68%、8.12%和7.61%;BR浸根对水卷苗栽后根系的促生作用更为明显,不同浓度BR浸根对水卷苗栽后根长、根表面积、根尖数、根体积、根直径、根质量和根冠比均产生了显著影响,其中根尖数以低浓度BR处理效果更优,而其他根系指标均以高浓度BR处理效果更优。与CK相比,不同浓度BR浸根降低了叶片过氧化氢浓度(至移栽后12 d,分别降低12.50%、23.25%和22.25%),增强了叶片抗氧化酶活性;与移栽当天相比,移栽后第2天BR浸根处理叶片中玉米素(ZT)浓度迅速增加(分别为197.27%、153.11%和243.78%),而CK增加缓慢(2.94%),根系表现一致,且根系中生长素(IAA)浓度显著高于CK;同时BR处理在栽后一周内赤霉素(GA₃)浓度均明显高于对照。与CK相比,T10处理显著提高了每穗粒数和结实率(分别为15.04%和6.62%),T20处理显著提高了结实率(6.17%),但BR处理千粒重均显著下降,最终产量T10和T20处理较CK分别提高5.11%和7.99%。结论 适当浓度的BR(T10~T20)浸根能减轻水卷苗机插植伤,提高抗氧化酶活性,降低H₂O₂含量,提高ZT、GA₃和IAA浓度,高效地促进根系生长,提高了每穗粒数和结实率。本研究可为减轻机插植伤,促进机插水稻高产稳产提供理论依据和技术参考。