达乌尔黄鼠实验室饲养、繁殖及其冬眠阵

为探索实验室条件下达乌尔黄鼠饲养与繁殖的方法及冬眠阵的发生规律,参照野生黄鼠冬眠洞穴的主要生态环境参数,建立人工冬眠屋,采用传统锯末技术记录冬眠阵。结果显示: (1) 处于春季繁殖期的黄鼠应以大鼠饲料为主,辅以少量黄瓜等,夏季活跃期交叉饲喂大鼠饲料与兔饲料,辅以多水的瓜果蔬菜,秋季育肥期以大鼠饲料为主,辅以高脂肪高蛋白的花生、豆类等。(2)雌鼠怀孕期为28 d 左右,哺乳期约一个月,雌鼠每窝产仔4 ～ 8 只,平均5.52 只;初生幼鼠两周内忌换垫料,并避免将异味带入鼠房。(3)黄鼠冬眠期从当年11月下旬至次年3 月上旬,平均93.95 d;冬眠阵睡眠时长平均7. 44 d,阵间激醒时长平均1.36 d,睡眠天数占整个冬眠期的89.9% ;整个冬眠期,黄鼠冬眠阵平均7. 55 个。(4)2009 年秋至2011 年春季,自野外共捕回黄鼠185 只, 存活146 只,存活率78. 9% 。在2006、2009 和2011 年的黄鼠繁殖期,共配对25 对,产仔138 只,成活92 只,成活率为66.7% 。结果表明,野生达乌尔黄鼠可在人工饲养条件下实现繁殖,并可在人工冬眠屋成功冬眠。     

腹腔注射对氯苯丙氨酸对达乌尔黄鼠冬眠的影响

本工作采用腹腔注射5-羟色胺合成抑制剂对氯苯丙氨酸降低脑内5-HT含量的方法,观察了脑内5-HT系统在达乌尔黄鼠自然冬眠和脑室注射6-羟多巴胺促进入眠效应中的作用。结果表明;在自然情况下,达乌尔黄鼠入眠后脑内5-HT含量增加,腹腔注射对氯苯丙氨酸后动物入眠诱导期明显延长;在脑室注射6-羟多巴胺人为地降低脑内NE系统活动的条件下,脑内5-HT含量即使处于较低水平,动物也能很快入眠,但入眠时脑内5-HT含量需要恢复到一定的基础水平。提示脑内NE系统功能活动的降低或/和5-HT系统功能活动加强同是触发动物入眠的重要因素。周期性入眠和觉醒可能依赖于脑内这两个系统功能活动的平衡。     

冬眠对达乌尔黄鼠盲肠菌群的影响

冬眠哺乳动物的肠道微生物会发生季节性变化,同时在冬眠期间动物处于禁食状态,对肠道微生物的多样性和组成也产生影响。本研究通过16S rRNA基因高通量测序分析达乌尔黄鼠育肥阶段 (起始育肥期、快速育肥期、育肥完成期) 和冬眠阶段 (冬眠早期、冬眠晚期、出眠期) 共6个时期盲肠菌群的多样性、组成和功能,并通过冗余分析 (RDA) 探究其生理特征与菌群组成和功能之间的关系,揭示达乌尔黄鼠盲肠菌群的季节性变化。菌群组成的分析显示达乌尔黄鼠盲肠菌群主要由厚壁菌门 (Firmicutes)、拟杆菌门 (Bacteroidetes) 和疣微菌门 (Verrucomicrobia) 组成。与其他时期相比,冬眠早期厚壁菌门的相对丰度减少,拟杆菌门和疣微菌门的相对丰度增加。在Alpha多样性中,起始育肥期、快速育肥期和冬眠早期的Chao1和ACE指数显著低于出眠期,育肥完成期的Simpson指数显著低于快速育肥期 (P < 0.05) 。通过加权和非加权的UniFrac距离矩阵的主坐标分析发现盲肠菌群均显示出了明显的季节性聚类。PICRUSt分析中,丁酸代谢等代谢通路在育肥阶段富集,冬眠阶段集中在氮代谢等相关通路中。RDA分析显示达乌尔黄鼠不同时期的生理特征与其盲肠菌群的组成和功能显著相关。本研究表明,冬眠使达乌尔黄鼠盲肠菌群的多样性和相对丰度发生改变,盲肠菌群组成和功能的变化调节了达乌尔黄鼠的生理代谢,使达乌尔黄鼠适应季节性的环境变化。     

达乌尔黄鼠入眠准备期的体温、代谢率及能量特征

贮脂类动物在冬眠前大量积累脂肪来准备冬眠,并在入眠时迅速降低体温和代谢率。为探究入眠准备期达乌尔黄鼠体温、代谢率、呼吸商及能量代谢的变化,将其入眠准备期分为育肥期、体重高峰期、育肥后期和冬眠前的试降期,使用植入式半导体温度记录元件iButton、开放式代谢仪和改进的代谢笼,监测其体温、代谢率及呼吸商和能量摄入的变化。结果显示:(1)达乌尔黄鼠体温在冬眠前13 - 34 d 开始下降,远早于冬眠但晚于体重高峰期;体重高峰期体温有降低的趋势,持续时间为1 - 3 d;育肥后期体温显著下降,体温日波动幅度增加。(2)体重高峰期的静止代谢率高于育肥期,育肥后期有降低的趋势,试降期最低。(3)呼吸商在体重高峰期先升高,之后迅速衰减;入眠准备期的能量摄入在体重达高峰期前达到最大值。结果表明,达乌尔黄鼠在入眠准备期,其体温和代谢率已开始降低,能源物质已开始转变;体重高峰期可能是达乌尔黄鼠入眠的一个转折点或启动入眠的开关。     

达乌尔黄鼠冬眠阵过程中感觉兴奋性的变化

对冬眠阵中的达乌尔黄鼠施加皮肤电刺激,以心率和体温的变化作指标,发现冬眠黄鼠有3种类型的兴奋反应。本实验还发现诱发兴奋性反应的刺激强度在冬眠阵后期有明显的下降趋势,说明随冬眠阵进行达乌尔黄鼠的感觉兴奋性是逐步升高的,即具有“累进的应激性”现象。     

冬眠和非冬眠状态达乌尔黄鼠肾单位及相关功能因子的比较

冬眠是动物应对冬季低温和食物匮乏的一种生存策略。达乌尔黄鼠(Spermophilus dauricus)是典型的贮脂类冬眠动物。为研究冬眠动物肾脏的适应机制,本实验采用组织学、血液生化分析及酶联免疫方法检测了夏季活动期(7月)、冬眠期(12月)和早春出眠后(3月)达乌尔黄鼠肾单位形态学及血清肌酐、尿素和抗利尿激素(ADH)的变化,并用qPCR方法检测了肾脏水通道蛋白基因(AQP1、AQP2和AQP3)、ADH受体(V2R)及内皮型一氧化氮合酶基因(eNOS)的表达。结果发现,冬眠期和早春出眠期的达乌尔黄鼠肾小球密度、近曲小管和远曲小管的相对管径、皮质部近曲小管数与远曲小管数比值均低于夏季活动期;冬眠期血清肌酐和尿素浓度高于夏季活动期和早春出眠期,ADH浓度及其受体V2R基因表达低于夏季活动期;冬眠期AQP1基因表达高于早春出眠期,AQP3基因表达低于夏季活动期,AQP2基因表达无显著差异;冬眠期eNOS基因表达低于早春出眠期。这些结果表明冬眠的达乌尔黄鼠表现出较低的肾功能;不同时期的水通道蛋白,eNOS及ADH表现出适应性的功能调节。该实验结果丰富了对冬眠动物肾脏适应机制的认识。     

达乌尔黄鼠种群生态的一些资料

本文深入地研究了达乌尔黄鼠性别、年龄、繁殖、存活、死亡及数量种群动态。特別是采用了标志流放法结合洞口系数法科学的研究了达乌尔黄鼠种群的死亡率、存活率以及数量变化。同时分析了种群变动的原因,比较了该地区达乌尔黄鼠两个主要分布生境,得出缓坡丘陵砂质暗棕钙土小叶锦鸡儿+丛生小禾草+冷蒿群丛是最适生境。文章为防治该害鼠提供了科学依据。     

达乌尔黄鼠的田间分布型

达乌尔黄鼠是我国北方地区的主要农田害鼠之一。1986年在山西省山阴县甘庄乡,我们选择鼠口密度中等区域,以一亩土地做一个调查样方,共查样方731个,分别记载其有鼠数量。依据所得资料,分别采用频数分布比较法和四种聚集指标测定法测定,均证实达乌尔黄鼠在黄土高原的旱源坡区的田间分布型为聚集分布型。这一结果为研究其田间生态学特性和行为学及对种群数量消长分析提供了科学依据。     

达乌尔黄鼠种群繁殖特征的研究

本文主要报道山西省汾阳和曲沃地区以及陕西省合阳和延长地区的达乌尔黄鼠(Sperm-ophilus dauricus)种群的繁殖特征。在曲沃和合阳地区,该鼠3月中旬开始交尾;在汾阳和延长地区则始于3月下旬交尾。雌体妊娠的高峰期在4月下旬至5月上旬,雄体比雌体提前10天左右进入繁殖高峰期。平均胎仔数因地区而异,合阳地区最高(5.43±0.15),次为曲沃、汾阳,延长地区最低(4.65±0.24)。     

达乌尔黄鼠产热的季节性变化

达乌尔黄鼠（Ｃｉｔｅｌｌｕｓｄａｕｒｉｃｕｓ）的产热表现出明显的季节性变化。在非冬眠期,静止代谢率（ＲＭＲ）和非颤抖性产热（ＮＳＴ）于春季最高,秋季次之,夏季最低。冬眠期,ＲＭＲ降到极低水平,只为春季的３．０％。肝脏的线粒体蛋白含量、线粒体呼吸和细胞色素Ｃ氧化酶活力在秋季显著高于其它各季。褐色脂肪组织（ＢＡＴ）的重量、线粒体蛋白含量、细胞色素Ｃ氧化酶活力和α－磷酸甘油氧化酶活力,在夏季处于一年中的最低水平,到了冬季这些指标达到一年中的最高水平。在非冬眠季节ＢＡＴ产热能力升高时,ＮＳＴ能力也相应升高,这表明ＢＡＴ产热能力的增强是ＮＳＴ能力提高的部分机制。达乌尔黄鼠血清Ｔ＿４含量在年周期中没有明显改变,冬眠时血清Ｔ＿３含量显著高于其它各季。     

短光照诱导达乌尔黄鼠产热

本文通过测定静止代谢率(RMR)、非颤抖性产热(NST)、线粒体呼吸酶、脂肪代谢酶活力、褐色脂肪 组织(BAT)线粒体GTP 结合能力、下丘脑促甲状腺激素释放激素(TRH)和促肾上腺激素释放激素(CRH)等指标,探讨短光照对达乌尔黄鼠产热的诱导和调节。结果表明,温暖(22℃ ) 短光照(8D∶ 6L)组,达乌尔黄鼠的RMR、NST、肝脏和BAT 线粒体细胞色素C 氧化酶活力以及BAT 线粒体GTP 结合能力均明显高于温暖长光照(16D∶ 8L)组中的动物,而体重、BAT 重量、肝细胞呼吸、BAT α - 磷酸甘油氧化酶活力则没有明显变化。短光照组黄鼠下丘脑TRH 水平显著高于长光照组,而血清中三碘甲腺原氨酸(T₃ )及甲状腺素(T₄ )浓度、T₃ / T₄ 以及BAT 中T₄ - 5’脱碘酶的活性没有明显变化。短光照组黄鼠下丘脑CRH 水平显著高于对照组,而肾上腺皮质酮含量无明显变化。结果表明短光照能够诱导达乌尔黄鼠产热增加,主要是通过激活细胞色素C 氧化酶活性和增加BAT 中解偶联蛋白浓度;短光照可能激活下丘脑TRH 和CRH,但它们没有直接诱导产热增加,推测其增加了黄鼠潜在的产热能力。     

光照黑暗循环条件下达乌尔黄鼠的冬眠模式和能量消耗

为研究冬眠季节的光照条件对贮脂类冬眠动物入眠的影响,在达乌尔黄鼠腹腔埋植体温记录元件iButton,在体重高峰后的下降阶段置于5℃和12L:12D的光照条件下,观察测定其冬眠模式和能量消耗。达乌尔黄鼠冬眠模式出现深冬眠型、少冬眠型和不冬眠型,蛰眠阵包括深冬眠阵、短冬眠阵和日眠阵。不同冬眠阵中最低体温、冬眠阵的持续时间、阵间产热的持续时间、冷却速率和复温速率差异显著;阵间产热的最高体温基本相同。平均每日能量消耗在日眠阵中最高、短冬眠阵中居中、深冬眠阵中最低。入眠时间多集中于黑暗时相,觉醒时间多集中于光照时相。本实验结果提示,在冬眠季节施加光照黑暗循环条件可减少达乌尔黄鼠冬眠的时间,升高阵间最低体温,缩短冬眠阵与阵间产热的持续时间,降低复温速率;增加冬眠期间能量消耗。入眠与觉醒受光照条件影响,具有明显的光暗节律。     

The optimal depot fat composition for hibernation by golden-mantled ground squirrels (Spermophilus lateralis)

Golden-mantled ground squirrels (Spermophilus lateralis) are herbivores that hibernate during winter. Although little is known about the nutritional/physiological constraints on hibernation, numerous studies have demonstrated that increasing the amount of linoleic acid (a polyunsaturated fatty acid) in the diet enhances hibernation. This is probably because high linoleic acid diets reduce the melting points of the depot fats produced for hibernation which makes them more metabolizable at low body temperatures. This suggests that a major limitation on hibernation may be obtaining enough linoleic acid in the diet for proper hibernation. In all previous studies, however, the amount of linoleic acid in the diets of free-ranging animals was either not considered, or the range of dietary linoleic acid contents in the experiments was less than that of natural diets. It is thus not known whether the amount of linoleic acid available to hibernators under natural conditions actually limits their torpor patterns. A series of laboratory feeding and hibernation experiments were conducted with S. lateralis and artificial diets with different linoleic acid contents that were either below or above the linoleic acid content of the natural diet. The results demonstrated that when dietary linoleic acid contents are either below or above natural levels, hibernation ability is greatly reduced. Hibernation ability was reduced when the squirrels were maintained on a high linoleic acid diet probably by the production of toxic lipid peroxides in brown adipose tissues. The results indicate that there is an optimal level of dietary linoleic acid for proper hibernation, and this is equal to that of the natural diet. The amount of linoleic acid available in the diet thus does not limit hibernation under normal natural conditions.Abbreviations BAT brown adipose tissue - bm body mass - FA fatty acid - PUFA polyunsaturated fatty acid - T _a ambient temperature - T _b body temperature - WAT white adipose tissue     

Comparison of surface temperature in 13-lined ground squirrel (Spermophilus tridecimlineatus) and yellow-bellied marmot (Marmota flaviventris) during arousal from hibernation

Surface temperatures (Ts) of eight 13-lined ground squirrels and seven yellow-bellied marmots were measured during arousal from hibernation using infrared thermography (IRT) and recorded on videotape. Animals aroused normally in 5 degrees C cold rooms. Body temperatures were recorded during arousal using both cheek pouch and interscapular temperature probes. Warming rate in arousal was exponential. Mean mass specific warming rates show the squirrels warm faster (69.76 degrees C/h/kg) than the marmots (4.49 degrees C/h/kg). Surface temperatures (Ts) for 11 regions were measured every few minutes during arousal. The smaller ground squirrel shows the ability to perfuse distal regions without compromising rise in deep body temperature (Tb). All squirrel Ts's remained low as Tb rose to 18 degrees C, at which point, eyes opened, squirrels became more active and all Ts's rose parallel to Tb. Marmot Ts remained low as Tb rose initially. Each marmot showed a plateau phase where Tb remained constant (mean Tb 20.3+/-1.0 degrees C, duration 9.4+/-4.1 min) during which time all Ts's rose, and then remained relatively constant as Tb again began to rise. An anterior to posterior Ts gradient was evident in the ground squirrel, both body and feet. This gradient was only evident in the feet of the marmots.     

Ecological factors affecting flight initiation distance in Daurian ground squirrels (Spermophilus dauricus)

More often than not, animals forage under predation risk. Foragers, therefore, face a challenge to balance between two conflicting tasks, namely energy intake and safety. Flight initiation distance (FID, defined as the distance between a prey and a predator when the prey starts to flee) has been widely measured in many taxa to study such economic trade‐offs. However, FID may also be affected by limitations on the prey's ability to detect predators, especially when there is visual obstruction caused by surrounding vegetation. Although both vegetation cover and vegetation height may contribute to such obstruction, the effect of vegetation height on FID has not been well studied. In this study, we explored the effects of vegetation height, vegetation cover and distance to refuge on FID in free‐living Daurian ground squirrels (Spermophilus dauricus) inhabiting a grassland in Inner Mongolia, China. Multiple linear regressions suggested that both vegetation height and distance to refuge significantly affected FID in S. dauricus. Ground squirrels fled earlier when vegetation was low or when foraging farther away from a refuge. No significant effect of vegetation cover on FID was detected. Our results have implications for ecologically based pest control, and FID may be used as an effective and easy‐to‐use behavioral indicator in wildlife management.