单宁酸对根田鼠食物摄入量和蛋白质消化率的效应

在食物中含10 %和20%蛋白质的条件下, 采用食物平衡法测定了单宁酸对根田鼠食物摄入量和蛋白质消化率的作用。食物蛋白质含量为10 %时, 第1～5 天, 单宁酸对根田鼠食物摄入量具有显著的抑制作用, 自第6天, 其作用不明显, 以3 %和6 %单宁酸处理的根田鼠, 其食物蛋白质消化率较对照组分别降低22 %和47.67 %;在食物蛋白质含量为20 %的条件下, 单宁酸对根田鼠的食物摄入量和蛋白质消化率无显著作用。上述结果验证了植物次生化合物能抑制植食性小哺乳动物食物摄入量及蛋白质消化率的假设。     

蛋白质,纤维素和单宁酸对东方田鼠摄食的影响

食物选择性是动物对取食生境中现存的食物种类做出的选择,是一个复杂的生态适应过程,与动物自身生理状及环境中食物的可利用量密切相关。单宁酸、蛋白质和纤维素是影响植食性动物食物选择的重要因素。在控制其它营养因子的条件下,设置10%蛋白质+2.25%纤维素+3%单宁酸(食物1)/6%单宁酸(食物2)和20%蛋白质+4.51%纤维素+3%单宁酸(食物3)/6%单宁酸(食物4)4个处理组,通过自助餐式选择笼内的喂养实验,测定单宁酸、蛋白质和纤维素对东方田鼠食物选择的影响。结果表明,东方田鼠对3%单宁酸处理组食物摄食量显著高于对6%单宁酸处理组(P0.001);但东方田鼠对6%单宁酸食物摄食量依蛋白质浓度变化,在20%蛋白质处理组的摄食量显著高于10%蛋白质处理组(P0.05);在含3%单宁酸处理组中,纤维素成为影响东方田鼠摄食的主要因素,而当单宁酸浓度增加到6%时,纤维素和蛋白质对东方田鼠摄食影响差异不显著;总之,单宁酸、蛋白质和纤维素对东方田鼠的摄食都产生重要影响,单宁酸对东方田鼠食物选择的影响程度最大,纤维素次之,蛋白质对东方田鼠摄食的影响会随单宁酸浓度的升高而增大。     

饥饿和食物单宁酸对东方田鼠(Microtus fortis)食物摄入量和觅食行为的影响

实验室条件下,测定饥饿和食物单宁酸对东方田鼠食物摄入量和觅食行为的影响。结果表明,饥饿使实验个体的食物总摄入量增加,食物摄入率及口量大小随饥饿强度的增大而增加,而觅食频次则无显著改变,实验个体每取食回合的觅食时间呈缓慢增加的趋势,与对照组比较,觅食时间差异不显著。东方田鼠优先选择0%单宁酸食物,次为3%单宁酸食物,而对6%单宁酸食物的摄入量最少。在饥饿条件下,东方田鼠食物摄入率的增加主要源于其口量大小,觅食频次和觅摄食时间对食物摄入量增加的贡献不显著。在饥饿条件下,植食性小哺乳动物并未通过延长觅食时间,降低用于防卫、繁殖活动时间来增加食物摄入量,而是通过增加口量大小,提高其食物摄入率来满足其营养需要。验证了饥饿与植物次生化合物共同作用引起田鼠类动物生理的改变,能影响其食物摄入量及觅食行为的假设。     

饥饿和食物单宁酸对东方田鼠(Microtus fortis)食物摄入量和觅食行为的影响

实验室条件下,测定饥饿和食物单宁酸对东方田鼠食物摄入量和觅食行为的影响。结果表明,饥饿使实验个体的食物总摄入量增加,食物摄入率及口量大小随饥饿强度的增大而增加,而觅食频次则无显著改变,实验个体每取食回合的觅食时间呈缓慢增加的趋势,与对照组比较,觅食时间差异不显著。东方田鼠优先选择0％单宁酸食物,次为3%单宁酸食物,而对6%单宁酸食物的摄入量最少。在饥饿条件下,东方田鼠食物摄入率的增加主要源于其口量大小,觅食频次和觅摄食时间对食物摄入量增加的贡献不显著。在饥饿条件下,植食性小哺乳动物并未通过延长觅食时间,降低用于防卫、繁殖活动时间来增加食物摄入量,而是通过增加口量大小,提高其食物摄入率来满足其营养需要。验证了饥饿与植物次生化合物共同作用引起田鼠类动物生理的改变,能影响其食物摄入量及觅食行为的假设。     

根田鼠对食物单宁酸的解毒代价

在实验室条件下,测定了根田鼠对单宁酸的解毒代价。结果表明,在食物蛋白质为10％的条件下,摄食3％和6％单宁酸食物的根田鼠经尿液分泌的葡萄糖醛酸较对照组分别增加13．77％和38．80％;与对照组比较,在食物蛋白质为20％的条件下,摄食3％和6％单宁酸食物的实验个体尿液分泌的葡萄糖醛酸分别增加6．11％和22．25％。在食物蛋白质为10％时,用3％和6％单宁酸食物处理的个体,其尿液NH4^ —N含量较对照组个体分别增加51．69％和198．44％。在食物中蛋白质为20％时,摄食3％和6％单宁酸食物的试验个体,其尿液中的NH4^ —N含量分别较对照组高1．72％和74．19％。由此说明,单宁酸能显著增加根田鼠尿液葡萄糖醛酸分泌量,根田鼠尿液的NH4^ —N的含量随食物单宁酸增加而增高,从而增加动物机体对单宁酸的代谢价。     

棕色田鼠的配偶选择和相关特征

为了确定野外生态研究中对棕色田鼠婚配制度为单配制的预测,在实验室观察记录了棕色田鼠的配偶选择箱内对配偶鼠（与选择鼠交配刚生过仔,雌鼠产后动情）与陌生鼠、熟悉鼠（雌雄田鼠山居一段时间后,开始进行交配）与陌生鼠的选择,发现棕色田鼠访问、追逐、嗅闻、爬胯配偶鼠和熟悉鼠以及与配偶鼠和熟悉鼠交配和相伴的时间明显地多于对 陌生鼠,而且攻击陌生鼠的时间明显多于配偶鼠和熟悉鼠（Wilcoxon检验,P＜0.05）。结果表明：雌雄棕色田鼠特异性地选择配偶鼠和熟悉鼠,对陌生鼠表现出较多的排斥,从而在配偶选择上呈现单配制特征。通过统计计算棕色田鼠社会组织特征和室内的个体形态、幼仔发育、交配行为、双亲育幼行为、社交倾向等参数,然后把这些参数和婚配制度较明确的草原田鼠、松田鼠、山地田鼠、草甸田鼠的相关数据进行比较,发现它与多配制种类差异较大,而与单配制的田鼠各类相似,通过以上实验分析结果推断棕色田鼠的婚配制度可能呈单配制,和野外生态研究的推测相一致。     

不同音乐环境对小鼠生长发育的影响

目的探讨音乐对小鼠生长发育的影响。方法采用30只ICR小鼠,在50 dB与60 dB的古筝与葫芦丝音乐环境中,饲养27 d,每3天测定体重一次,每9天测定饲料各种营养消化率一次。结果雌鼠体重在不同音乐环境中都有显著提高（P〈0.05）,且50 dB组高于60 dB组（P〈0.05）。雄鼠体重在古筝音乐环境中有显著提高（P〈0.05）;而在葫芦丝音乐环境中有显著降低。在不同音乐环境中,鼠的各种营养物质消化率无显著差异（P〉0.05）。结论不同的音乐环境对小鼠的体重有显著影响,而对小鼠的各种营养物质的消化率无显著影响。     

单宁酸对布氏田鼠能量代谢的影响

为了解单宁酸对成年布氏田鼠(Lasiopodomys bandtii**)能量代谢和产热的影响,本文采用含0、3.3%和6.6%单宁酸浓度的食物饲喂布氏田鼠21 d,对其体重、基础代谢率、非颤抖性产热和能量收支等进行了测定。代谢率采用封闭式流体压力呼吸计测定;非颤抖性产热用皮下注射去甲肾上腺素诱导;能量摄人采用食物平衡法测定。结果发现:(1) 单宁酸食物对布氏田鼠的体重没有明显影响;(2)取食含6.6%单宁酸食物的动物的基础代谢率于第10 d高于对照组。20 d时,3组动物的基础代谢率没有显著差异;(3) 单宁酸食物对非颤抖性产热没有显著影响;(4) 食用含单宁酸食物的动物的摄人能和消化能于第10 d显著低于对照组,但第20 d时则差异不显著。这些结果表明:布氏田鼠的基础代谢率和能量摄入对单宁酸的反应具有时段性,短期内能量消耗增加,随着动物对食物的适应,生理功能恢复到正常水平。     

雌性棕色田鼠和昆明小鼠在慢性间歇性低氧条件下血象变化的比较

本文旨在对雌性棕色田鼠(Lasiopodomys mandarinus)和昆明小鼠(Mus musculus)在慢性间歇性低氧条件下血象的变化进行比较,从而为地下生活鼠种血液系统对慢性间歇性低氧的应答对策的研究提供基础数据。采用实验氧舱对棕色田鼠和昆明小鼠进行每天4h、持续28d的慢性间歇性低氧(氧浓度10.0%)处理,然后对其血象进行了比较分析。结果显示:(1)常氧下棕色田鼠的红细胞计数(red blood cell count,RBC)显著高于昆明小鼠,而红细胞平均体积(mean corpuscular volume,MCV)则显著小于昆明小鼠,慢性间歇性低氧处理后昆明小鼠的MCV和红细胞压积(hematocrit,HCT)显著增加,而棕色田鼠MCV和HCT无明显影响;(2)常氧条件下棕色田鼠的平均血红蛋白含量(mean corpuscular hemoglobin,MCH)显著低于昆明小鼠,而平均血红蛋白浓度(mean corpuscular hemoglobin concentration,MCHC)则显著高于昆明小鼠,慢性低氧处理后昆明小鼠血红蛋白(hemoglobin,HGB)含量和MCH均显著增加,而在棕色田鼠仅出现MCH的明显增加;(3)常氧条件下棕色田鼠的白细胞计数(white blood cell count,WBC)和血小板(platelet,PLT)都显著低于昆明小鼠,慢性低氧处理后棕色田鼠和昆明小鼠的WBC和PLT均未发生显著变化。以上结果表明,棕色田鼠作为地下生活鼠种,对低氧环境具有较好的耐受性,其血液系统对低氧胁迫的应答机制与地面生活鼠种昆明小鼠不同。     

五种鼠的脑和头骨形态及其生态关系

通过测量棕色田鼠（Microtus mandarinus）、沼泽田鼠（Microutus fostis）、甘肃鼢鼠（Myospalax can-sus）、大仓鼠（Cricelulus triton）、黑线姬鼠（Apodomus agraius）的头骨和脑外部形态,计算其长度与体长的比值、脑重与体重的比值及其发头化指数。发现棕色田鼠和甘肃鼢鼠的宽与体长之比、齿列长与体长之比显著大于大仓鼠和黑线姬鼠,这些特征和各自的食物类型紧密相关。棕色田鼠脑颅测量值和体长之比、脑重和体重之比较大,甘肃鼢鼠以上值较小,发头化指数由大到小依次为：棕色田鼠、沼泽田鼠、黑线姬鼠、大仓鼠、甘肃鼢鼠、小白鼠、大白鼠。棕白田鼠脑除嗅球外无性二型,而且大脑测量值相对较大。以上脑特征可能和棕色田鼠单配,制婚配制度有关。而甘肃鼢鼠大脑较小的原因可能和其多配制婚配制及其独居生活有关。甘肃鼢鼠和棕色田鼠的小脑测量值与体长之比小于沼泽田鼠、大仓鼠、黑线姬鼠;甘肃鼢鼠的视神经很细,棕色田鼠视神经较细,而其他3种鼠视神经都较粗;甘肃鼢鼠的嗅球较大;这些特征与它们分别适应于地下和地上生活方式有关。     

光照对棕色田鼠和昆明小鼠活动性的影响

光照对啮齿动物的行为格局和活动节律有着重要的影响。本研究以比较生物学方法,以光照强度和鼠种两个因素,在实验室内利用动物行为监视系统,以焦点动物取样法( Focus animal sampling) ,在＜ 20 Lux、200 Lux、800 Lux 和1 600 Lux 等4 个水平的光照强度下,监测和记录棕色田鼠和昆明小鼠的移动和静止行为,并在实验结束时测定实验动物的体重; 在800 Lux 光照强度下,设置正常( 12L∶ 12D) 和全黑( 0L∶ 24D) 两种光照时间,连续12 h监测并记录实验动物的行为。采用双因素方差分析方法对数据进行统计分析。结果表明:1) 光强与鼠种对静止行为存在显著交互作用,棕色田鼠的静止行为与光强间存在显著的负相关关系,而昆明小鼠的静止行为则与光强无显著的相关; 2) 光强对两种动物移动行为的影响与静止行为表现方式相反; 3) 在12 h的光暴露条件下,棕色田鼠的相对活动显著强于昆明小鼠; 4) 光强对两种动物体重的影响不同,棕色田鼠体重与光强呈正相关关系,昆明小鼠与光强呈负相关关系,但差异不显著。本研究进一步验证了地面鼠与地下鼠对光强适应的差别。     

储草期增加食物对布氏田鼠越冬存活率的影响北大核心CSCD

布氏田鼠(Lasiopodomys brandtii)是内蒙古典型草原区主要鼠种之一。该鼠种在秋季将食物储存在储草仓内,以此来度过植被贫瘠的冬季。为探究储草期增加食物对布氏田鼠越冬存活率的影响,2004年10月,于内蒙古阿巴嘎旗白音图噶苏木的布氏田鼠鼠害草场随机选取两块100 m×200 m的样地,分别设为增食样地和对照样地。增食样地内给每个布氏田鼠洞群补充食物,每天补充500 g小麦,连续补充2 d共计1000 g。对照样地内则不做任何处理。2004年10月,采用标志重捕法调查两块样地内布氏田鼠种群数量,调查显示,增食样地和对照样地内,布氏田鼠数量分别为310只和318只,以该结果作为计算其越冬存活率的基数。2005年5月,返回样地再次进行标志重捕,分别计算两样地布氏田鼠的越冬存活率。卡方检验显示,储草期增加食物能显著提高布氏田鼠越冬存活率。增食样地布氏田鼠越冬存活率为41.3%,显著高于对照样地布氏田鼠越冬存活率(24.2%,P<0.01)。增食样地雌性和雄性布氏田鼠越冬存活率分别为45.4%和37.3%,均显著高于对照样地雌性和雄性布氏田鼠越冬存活率(25.8%和22.6%,P<0.01)。但样地内雌性和雄性越冬存活率均无明显差异(P>0.05)。本研究结果表明,补充食物可大幅度提升布氏田鼠冬季存活率,增加布氏田鼠越冬存活基数,对来年种群增长起重要作用。     

Expression patterns of clock genes in the hypothalamus and eye of two Lasiopodomys species

ABSTRACT

To investigate the relationship between light sensing systems in the eye and circadian oscillators in the hypothalamus of subterranean rodents, we studied subterranean Mandarin voles (Lasiopodomys mandarinus) that spend their entire lives under dark conditions with degenerated eyes, and compared oscillatory expression patterns of clock genes in the hypothalamus and eye between Mandarin voles and their aboveground relatives, Brandt’s voles (L. brandtii). Individuals of both vole species were kept under a 12-h light/12-h dark condition or continuous dark condition for 4 weeks. In both species, the expressions of most genes showed significant cosine rhythmicity in the hypothalamus but relatively weak rhythmicity in the eye. The number of rhythmic genes in the eye of Mandarin voles increased under the dark condition, but the opposite trend was observed in the eye of Brandt’s voles. The expression levels of most clock genes in the hypothalamus of both vole species did not significantly differ between the two conditions, but unlike in Mandarin voles, these expression levels significantly decreased in the eye of Brandt’s voles kept under the dark condition. In both vole species, the peak phase of most clock genes exhibited advanced or invariant change in the hypothalamus under the dark condition, and the peak phase of most clock genes showed consistent changes between the eye and hypothalamus of Mandarin voles. However, most clock genes in the eye showed a delayed phase in Brandt’s voles kept under the dark condition. In conclusion, the hypothalamus plays an important role in both vole species irrespective of the light condition. However, the expression patterns of clock genes in the eye differed between the vole species, indicating that each species adapted differently to their environments.     

Diet specialisation and foraging efficiency under fluctuating vole abundance: a comparison between generalist and specialist avian predators

Specialist species, using a narrow range of resources, are predicted to be more efficient when foraging on their preferred food than generalist species consuming a wider range of foods. We tested whether the foraging efficiency of the pallid harrier Circus macrourus, a vole specialist, and of sympatric Montagu's harriers C. pygargus, a closely related generalist, differed in relation to inter‐annual variations in vole abundance over five years (including two peak‐ one intermediate and two low vole abundance years). We show that the hunting parameters of pallid harriers strongly varied with vole abundance (higher encounter rates, capture rates and proportion of successful strikes in high than intermediate and low vole abundance years, respectively), whereas Montagu's harriers showed stable capture rates and hunting success (proportion of strikes that were successful), irrespective of vole abundance. Encounter rates and capture rates were higher for pallid than for Montagu's harriers when voles were abundant, but lower when voles were scarce. The hunting success of pallid harriers was also lower than that of Montagu's harriers when voles were scarce, and when they had to target alternative preys, in particular birds. Overall, estimated biomass intake rate was 40% higher for pallid harriers than for Montagu's harriers when voles were abundant, but 50% lower when voles were scarce. Our results indicate that specialists predators, like pallid harriers, which evolve specific adaptations or breeding strategies, do better when their preferred prey is abundant, but may face a cost of specialisation, being not efficient enough when their preferred prey is scarce. These results have broader implications for understanding why specialist predators are, in general, more vulnerable than generalists, and for predicting how specialists can cope with rapid environmental changes affecting the abundance or predictability of their preferred resources.     

Limits to food intake and fiber utilization in the prairie vole,Microtus ochrogaster: effects of food quality and energy need

We fed prairie voles (Microtus ochrogaster) rat chow diluted with variable amounts of -cellulose to determine 1) how much fiber the voles could tolerate in their diet; 2) changes in food intake and digestibility of dry matter and of fiber; 3) the extent to which voles utilized fiber as an energy source; and 4) whether any of these variables differed between groups of animals maintained at 5 or 22°C. Fiber content of the diets ranged from 20 to 84%. Animals held at 5°C maintained body mass through a diet containing 69% fiber, while animals held at 22°C maintained body mass through the 84% fiber diet. Dry matter intake increased with fiber level from 9.3 to 15.0 g·day^-1 for animals at 5°C and from 5.6 to 14.0 g·day^-1 for animals at 22°C; intake on the highest fiber diet eaten by either group was not different. Dry matter digestibility decreased significantly as the fiber in the diets increased, but was not affected by temperature treatments. Digestible dry matter intake for each group remained constant regardless of diet quality, but on each diet digestible dry matter intake for animals at 5°C was significantly higher than that of the animals held at 22°C. Digestibility of the fiber portion of the experimental diets remained constant as food quality decreased, so the percent of daily energy need met by fiber utilization increased with higher food intake. On the lowest quality diet each group tolerated, fiber digestion provided approximately 42 and 68% of the energy needs of voles at 5 and 22°C, respectively.Abbreviations BM body mass - BMR basal metabolic rate - DE digestible energy - DM dry matter - DMD dry matter digestibility - DDMI digestible dry matter intake - MR metabolic rate - NDF neutral detergent fiber (=cell walls) - NDS neutral detergent solubles (=cell solubles) - SEM standard error of mean - T _a ambient temperature     

Male short-tailed field voles (Microtus agrestis) build better insulated nests than females

Nest construction is an extremely widespread behaviour. In small endotherms the nest serves primarily to provide insulation, and thereby retard heat loss of the constructor, or its offspring. In arctic and temperate regions many small mammals build nests to protect themselves from low ambient temperatures. We measured the physical properties of nests built by short-tailed field voles Microtus agrestis that were kept in captivity under cold conditions. The most important factor influencing nest insulation was nest wall thickness; however, nests with thick walls also contained more nesting material. Insulative capacity of the nest did not reach an asymptote up to nests containing 20 g of material. Nest insulation was not correlated with resting metabolic rate, body mass or body composition of the vole that constructed the nest. However, nests built by males had greater insulation than those made by females; males also had significantly lower food intake rates when compared to females with nests. No significant difference was observed in either fat mass or whole animal thermal conductance between males and females. Thermal conductance did increase significantly with increasing body mass, although not with resting metabolic rate. Voles with nests for prolonged periods had lower food intakes than voles without nests. The absolute saving averaged 1.9 g and was independent of body mass. This was a 28% saving on intake for a 22-g vole but only an 18% saving for a 40-g individual. When voles had nests for short periods they used the energy they saved to reduce food intake and increase body mass. Accepted: 2 September 1999     

根田鼠母体摄食经历对幼体食物选择的影响

社会学习是动物的一种可塑性行为表型,能使动物个体获得提高其适合度的行为模式。母体对幼体的食性形成具有重要的影响。本文以栖息于青藏高原的根田鼠作为研究对象,在实验室条件下,根田鼠母体怀孕后期及哺乳期分别供给以0.01%糖精或0.1%橘子汁处理的食物,当幼体断乳时,同时供给断乳幼体糖精和橘子汁分别处理的食物,测定其食物选择。结果表明:根田鼠母体在怀孕期和哺乳期摄食经橘子汁处理的食物,断乳幼体在同时供给经橘子汁处理的食物和糖精处理的食物时,断乳幼体喜食经橘子汁处理的食物;而母体在怀孕期和哺乳期摄食经糖精处理的食物,断乳幼体在同时供给根田鼠断乳幼体经橘子汁处理和糖精处理的食物时,断乳幼体喜食经糖精处理的食物。说明根田鼠在断乳后仍喜食母体在怀孕期和哺乳期摄食过的食物种类。根田鼠栖息于季节性变化剧烈的环境中,幼体通过母体尽早学习食物选择是一种可塑性表型方式,利于其获得适应栖息地的行为模式。