新型NIH稀毛小鼠行为学特性的研究报告

目的:针对建立的新型NIH稀毛小鼠种群,研究其遗传学规律,确定其生物学特性。方法:取NIH稀毛小鼠进行葡萄糖耐量实验、胰岛素耐量实验以及Morris水迷宫实验,进一步分析与对照组小鼠糖代谢、胰岛功能和神经系统发育之间的差异。结果:与对照组小鼠相比,NIH稀毛小鼠糖耐量增高,腹腔注射葡萄糖后15 min血糖值显著低于(p0.001)正常小鼠,而胰岛素耐量变化无统计学意义(p0.05)。与对照组小鼠相比,NIH稀毛小鼠游动距离明显缩短(p0.05),进入目标象限次数高于对照组小鼠(p0.05)。结论:NIH稀毛小鼠糖代谢异常,但胰岛功能未受损害,并且其学习记忆能力提高。     

KM小鼠的繁殖性能及季节对其影响的观察

对KM小鼠的繁殖性能按月份和胎次进行了统计·结果表明:KM小鼠平均窝产仔数为12.01(n=7005),胎间隔为28.11d(n=6613).窝产仔数随胎次的增加而增多,到第5胎时最多,以后则减少;胎间隔则随胎次的增加而显著地下降.两者皆明显地受季节(温度)的影响,窝产仔数与各月份平均温度成负相关r=-0.798(P<0.01),胎间隔则与其成正相关r=0.915(P<0.01).KM小鼠繁殖的适宜环境温度为22～25℃.     

NIH稀毛小鼠认知情绪等行为学相关特性的测定

实验小鼠是最常使用的一种模式动物,在生命科学和医学研究中发挥着巨大的作用.NIH稀毛小鼠是被毛异常的自发突变鼠,其背景品系是封闭群NIH小鼠,为常染色体隐性遗传.毛囊的生长发育包括形态发生和周期循环两个阶段,目前研究发现的多种被毛突变小鼠模型主要表现为周期循环阶段的异常,例如典型的Hr基因突变小鼠表现为渐进性脱毛,而N...     

不同的配比对SPF级NIH小鼠繁殖性能的影响

目的：探讨不同的配比对SPF级NIH小鼠繁殖性能的影响。方法：从种鼠中随机抽取雄性30只，雌性60只，分别按1公：1母、1公：2母、1公：3母的方式进行配种。结果1公：2母的配种方式比1公：3母的产仔时间极显著缩短（p〈0．01）、窝产：仔数、离乳率和生长速度极显著的高（p〈0．01）：与1公：1母比较产仔数极显著增加（p〈0.01）。结论1公：2母的配种方式为NIH小鼠的最佳繁殖方式。     

被毛突变无毛小鼠皮肤及毛结构观察

对国内首次发现并培育成群的ＢＡＬＢ／ｃ突变小鼠的３种表型（无毛、全毛、中间态）的皮肤组织及毛结构进行了观察。结果表明，无毛小鼠仅具有非常短（１～２ｍｍ）、细且弯曲的绒毛，其毛于中心为空泡状，缺乏髓质。无毛小鼠表皮、真皮、皮下组织结构基本与全毛、中间态小鼠相同，但其毛生长周期不健全；毛球位置浅表，数目少，排列不规则；皮脂腺异常增生。推测其被毛结构异常是由毛自身结构异常所致。该小鼠外观似裸鼠，能在普通条件下生长繁殖，可望成为某些皮肤病等研究的动物模型。     

被毛突变小鼠解剖及繁殖学特性观察

对一种新的具有个毛、无毛、稀毛３种表型的被毛突变小鼠的大体解剖学特性研究结果表明,其心肝、脾、肺、肾、肾上腺等脏器的位置、形态及组织学结构无表型间差异,但无毛小鼠被毛和皮肤结构异常,大多数脏器的重量和脏器系数表现出表型差异和性别差异（Ｐ〈０．０５或Ｐ〈０．０１）。繁殖学特性研究结果表明,虽然无毛小鼠雌雄生殖系统的器官组成、发情周期与其他２种表型之间无明显差异,但其雄性的初情期明显滞后（约２周左右）     

长大母猪胎盘效率与繁殖性能关系的研究

本文研究了长大二元杂母猪的胎盘效率与产仔性能的关系,测定了长大二元母猪的胎盘面积、胎盘厚度与窝产仔数之间的关系。结果表明:低胎盘效率(5.0)母猪的窝产仔数和窝产活仔数,低于中等(5.3)和高胎盘效率(6.7)的母猪;胎盘面积为1712cm2和1995cm2的母猪,其窝产仔数高于胎盘面积为2176cm2的母猪;胎盘厚度为1.10～1.13mm的母猪,其窝产仔数高于胎盘厚度为0.97mm的母猪。     

深县母猪乳头数对其繁殖性能的影响研究

为研究深县猪母猪乳头数与繁殖性能之间的关系,收集河北正农牧业有限公司2013年1月-2016年3月的深县猪的母猪正常分娩记录,随机选取83头深县母猪。结果表明:母猪乳头数达到18个时其窝产仔数和窝产活仔数达到最高,且显著高于乳头数为15个的母猪;乳头数与其每窝产仔数和窝产活仔数呈现正相关;母猪乳头数为16个和18个时极显著高于母猪乳头数为15个和17个的仔猪初生个体重(P0.01),且显著高其断奶个体重(P0.05);母猪乳头数为16个其仔猪初生窝重和断奶窝重极显著高于母猪乳头数为15个的母猪(P0.01);即母猪乳头的对称性对仔猪的初生个体重、初生窝重、断奶个体重和断奶窝重有一定的影响。说明适当增加母猪的乳头数有可能使母猪的繁殖性状得到相应的提高。。     

营养调控对母猪繁殖性能的影响

为了探讨母猪妊娠早期日粮中添加一定量的甲基吡啶铬、叶酸、维生素E和维生素A对母猪窝产仔数、初生重、仔猪成活率的影响,选用日龄、体况基本一致的长大二元母猪共计56头进行试验。结果表明,在母猪妊娠早期的日粮中添加甲基吡啶铬、叶酸、维生素E、维生素A可显著提高母猪窝产仔数,提高比例平均为29.2%,其中对后备母猪提高比例更大。     

乌腺金丝桃对小鼠生长性能及器官发育的影响

为研究乌腺金丝桃对小鼠生长性能及器官发育的影响,试验选择60只生长发育良好、体重为27~31 g的昆明小鼠随机分成2组,即正常组和乌腺金丝桃组,每组30只,公母各15只,正常组饮用自来水,乌腺金丝桃组饮用乌腺金丝桃水提液。试验结果表明:(1)小鼠饮用乌腺金丝桃水提液后,其末重略有升高,平均日增重呈降低的趋势,平均日采食量也稍有降低,但与正常组相比无显著差异(P>0.05);乌腺金丝桃组的料重比有降低的趋势,但与正常组相比未达到差异显著水平(P>0.05);(2)乌腺金丝桃组心脏指数呈上升趋势,与正常组相比未达到差异显著水平(P>0.05);肝脏指数比正常组降低8.86%,差异显著(P<0.05);脾脏指数稍有降低,与正常组相比无显著差异(P>0.05);肾脏指数呈上升的趋势,比正常组增加26.54%,差异显著(P<0.05)。综上,乌腺金丝桃有益肾、强心的作用,但长期服用能够降低肝脏指数。     

Polymorphisms of the melatonin receptor 1A gene that affects the reproductive seasonality and litter size in Small Tail Han sheep

Previous researches have shown that MTNR1A plays an essential role in sheep reproduction. However, most researches focused more on the reproductive seasonality of sheep, and few scientists had studied the association of polymorphisms of the MTNR1A gene with ovine litter size and reproductive seasonality. Therefore, we chose MTNR1A gene to detect its novel sequence polymorphisms and population genetics and analyse their association with seasonal reproduction and litter size in ewes. The mRNA expression level in hypothalamus, pituitary and ovary was also detected. In this study, five polymorphisms (g.15118664G > T, g.15118683C > T, g.15118756C > T, g.15118774C > T and g.15118951G > A) were identified in exon 2. Most importantly, the g.15118683C > T and g.15118951G > A were significant difference between year‐round oestrous sheep and seasonal oestrous sheep (p < .01), and g.15118756C > T had a great effect on litter size of Small Tail Han sheep (p < .05). In addition, the mRNA expression level of MTNR1A in the hypothalamus of polytocous Small Tail Han sheep was significantly higher than that in monotocous Small Tail Han sheep (p < .01) and the expression of MTNR1A in the hypothalamus of year‐round oestrous sheep was significantly higher than that in seasonal oestrous sheep (p < .01). Polymorphisms in exon 2 may regulate the reproductive seasonality and litter size of ewes by influencing gene expression to regulate the reproductive seasonality and litter size of ewes. Our studies provided useful guidance in marker‐assisted selection of the litter size in Small Tail Han sheep.     

Components of heterosis for growth traits and litter size in line crosses of mice after long-term selection

Strains selected for 54 generations for large 8-week weight (N8, S8), for small weight (N6, S6), for high 3–5-week gain and low 8-week weight (N1) as well as unselected randomly mated control strains (N9, S9) were crossed, and F ₁, F ₂ and both back crosses created. N strains are derived from a NMRI base, S strains from a synthetic four-way cross among inbred lines. Heterosis for 8-week weight (8-ww) was some 6%, but 30% for 3–5-week gain and it was on average negative (22%) for 5–8-week gain. When epistatic effects were taken into account, it appeared that heterosis for 8-ww was largely due to beneficial effects of non-parental gene combinations, i.e. additive × additive epistatic effects were negative. These non-parental combinations neutralized the mostly negative dominance effects. The latter were mostly positive for early gain but in all 9 line crosses negative for late gain. The digenic effects of the non-parental origin were not large enough to balance the negative dominance effects for late gain, so that heterosis was negative. It appears therefore that early and late gain are affected by different sets of genes. Maternal additive effects on 8-ww and early gain are smaller than direct additive effects but mostly of similar sign. For late gain there appears to be no connection with direct additive effects. Direct litter heterosis was almost 50% but much of this was due to positively acting recombinational gene combinations, while direct litter dominance was mostly negative. Maternal additive effects on litter size differed depending on whether they were estimated from dams with crossbred or with purebred litter. Heterosis was small in crosses between control strains. Heterosis caused by recombinant gene pairs should be amenable to improvement by selection.     

副猪嗜血杆菌血清5型岳阳株对昆明小鼠淋巴器官损伤的研究

为探讨副猪嗜血杆菌(HPS)对免疫器官的损伤,本实验将HPS血清5型岳阳株及其茵体裂解物分别接种昆明小鼠,结果显示:HPS血清5型岳阳株及其菌体裂解物,均能够引起昆明小鼠颈淋巴结细胞凋亡和坏死.组织病理学检测可见脾脏红髓扩张、白髓萎缩、淋巴细胞衰减;胸腺病变较轻,皮质部局灶性淋巴细胞坏死和散在性细胞凋亡.此外,免疫器官损伤与剂量相关,随菌量的增大病变更为明显.HPS血清5型岳阳株及其菌体裂解物对昆明小鼠淋巴器官有明显的损伤作用.     

Evaluation of genetic trends and determination of the optimal number of cumulative records of parity required in reproductive traits in a Large White pig population

Genetic improvement of the reproductive performance of pigs is important for pig breeding despite their low heritabilities. The objectives of this study were to investigate the effectiveness of selection concerning reproductive traits and to determine the optimal number of parity records required for accurate estimation of breeding values (BVs) in the open population of a commercial pig breeding company. The study used records of 2220 purebred Large White pigs (9845 litters) farrowed between 1998 and 2009 in the two herds of the Pacific Ocean Breeding Co. Ltd. The traits studied included farrowing interval (FI), total number of piglets at birth (TNB), average weaning weight per litter (AWW), and raising rate (RR). A statistical model was applied to the 4‐trait repeatability animal model. The heritabilities of FI, TNB, AWW and RR were low. The genetic trends in TNB (h² = 0.09) showed approximately 1.0 increase in 6 years from 2003 to 2008. The predicted error variances indicated that up to fourth parity records are necessary for accurate genetic evaluation. The present study results indicated that even reproductive traits with low heritability can be improved.     

Feed and reproductive efficiency differences between divergently selected lines for birthweight environmental variability in mice

Sustainability has come to play an important role in agricultural production. A way to combine efficiency with sustainability might be by searching for robust animals that can be selected for the homogeneity of certain traits. Furthermore, the optimization of feed efficiency is one of the challenges to improve livestock genetics programmes, but this might compromise reproductive efficiency. Animals from two divergent mouse lines, regarding variability of birthweight, were used to check whether homogeneity was also related to both feed and reproductive efficiency. The objective of this study was to use these divergent lines of mice to compare them with their feed efficiency and the reproductive capacity. Animal weight, weight gain, feed intake, relative intake and cumulated transformation index were considered as feed efficiency traits. Animals from the low line had both lower weight and feed intake from 21 to 56 days. They had a worse transforming index in the three last weeks when litter size was fitted as an effect of the model, but the lines become similar if the higher litter size of the low line was not included. Reproductively, the low line performed better considering the number of females having parturitions, the number of parturitions, and with higher litter size and survival in both parturitions. Hence, the low variability line was preferred because of reproductive efficiency without seriously affecting its feed efficiency. Homogeneity seemed to be related to robustness with similar feed efficiency but higher reproductive efficiency.     

Effects of in utero and lactational exposure to the no-observed-adverse-effect level (NOAEL) dose of the neonicotinoid clothianidin on the reproductive organs of female mice

Recently, developmental exposure to clothianidin (CLO) has been shown to cause reproductive toxicity in male mice, but the effects in female mice remain to be clarified. Pregnant C57BL/6N mice were given a no-observed-adverse-effect-level (NOAEL) dose of CLO until weaning. We then examined ovaries of 3- or 10-week-old female offspring. In the CLO-administered group, morphological changes, a decrease in the immunoreactivity of the antioxidant enzyme glutathione peroxidase 4 (GPx4), and activation of genes in the steroid hormone biosynthesis pathway were observed in 3-week-old mice, and decreases of GPx4 immunoreactivity, 17OH-progesterone and corticosterone levels were observed in 10-week-old mice, along with high rates of infanticide and severe neglect, providing new evidence that developmental exposure to CLO affects juvenile and adult mice differently.     

催乳素受体基因对大白、长白猪产仔数的影响

采用PCR—RFLP法对大白、长白猪进行催乳素受体（PRLR）基因多态性检测，结果表明，两个品种的PRLR等位基因B频率略高于等位基因A频率，大白母猪PRLR基因型为AA的各胎平均产仔数比AB型高1．62头（P〈0．05），比BB型高2．41头（P〈0．05）；长白母猪AA型比AB型和BB型相应高1.32和3．33头（P〈0．05）。     

桦褐孔菌多糖对弓形虫感染孕鼠生殖器官及其胎鼠发育的影响

为探讨桦褐孔菌多糖对弓形虫感染孕鼠生殖器官及其胎鼠发育的影响,采用弓形虫RH株感染雌性性成熟小鼠,以蒿甲醚为阳性对照组,桦褐孔菌多糖为试验组,并设立阴性组和模型组.观察孕鼠胎儿的死胎散、体重、体长等发育指标,同时记录剖检前各组孕鼠死亡数和受孕数,并对孕鼠的生殖器官进行病理组织观察.经统计分析,桦褐孔菌多糖组与模型组在孕鼠死亡率和受孕率方面差异极显著(P＜0.01);在死胎率、活胎鼠平均体重、活胎鼠平均体长方面差异也极显著(P＜0.01);而两药物组仅在受孕率方面显著差异(P＜0.05),其孕鼠生殖器官的病理组织仅呈轻微的炎症变化.表明桦褐孔菌多糖对弓形虫感染孕鼠的胎鼠发育具有保护作用;并可明显缓解弓形虫感染对孕鼠生殖机能的损害.