光周期和高脂食物对高山姬鼠消化道形态的影响

为探讨光周期和高脂食物对栖息于横断山地区高山姬鼠Apodemus chevrieri消化道形态的影响,将成年雌性高山姬鼠分别驯化于长光照低脂、高脂食物和短光照低脂、高脂食物条件下,7周后测定动物的体重、总消化道、胃、小肠、大肠、盲肠的长度及其含内容物重、去内容物重、干重。结果表明:短光低脂组总消化道长显著大于其他组,短光组的小肠长度显著大于长光组。总消化道含内容物重、去内容物重,胃去内容物重、干重以及大肠和盲肠的各项指标均是低脂食物组显著大于高脂食物组。而小肠干重则是高脂食物组显著大于低脂食物组。以上结果表明,高山姬鼠在光周期和食物质量不同的条件下,可能通过调节消化道形态来维持正常的能量代谢和生理机能。高山姬鼠的消化道在不同光周期和食物质量条件下表现出的变化模式,可能与其光照和食物资源季节性波动的野外生存环境有关,从一方面反映了该物种在不同环境下的生存机制和适应对策。     

光周期和高脂食物对布氏田鼠能量代谢和产热的影响

为了研究光周期和高脂食物对小型哺乳动物能量代谢和产热的影响,将成年雌性布氏田鼠(Lasiopodomys brandtii)分别驯化于长光照低脂、高脂食物和短光照低脂、高脂食物,7周后测定动物的体重、能量摄入、产热、血清瘦素浓度以及褐色脂肪组织解偶联蛋白1(BAT-UCP1)含量等参数.结果发现:1)短光照抑制体重增长、降低体脂重量和血清瘦素水平,增加非颤抖性产热(NST)和UCP1含量;2)高脂食物使摄入能减少和消化率提高,但未显著影响体重、基础代谢率、NST、UCP1含量和血清瘦素;3)血清瘦素与摄入能不相关,但与体脂含量正相关.结果暗示:短光照下瘦素作用敏感性增加和产热能力增强,可能介导了抵抗高脂食物诱导的肥胖.在野外条件下草食性的布氏田鼠能通过能量代谢和产热的适应性调节避免体重的过度增长,有利于降低捕食风险,增强生存能力.同时布氏田鼠是研究食物诱导肥胖机理的一个好模型     

食物限制对高山姬鼠能量代谢和内脏器官形态的影响

为探讨栖息于横断山区高山姬鼠对食物匮乏的适应策略,在实验室条件下,以每日能量需求为标准,测定了饲喂食量为130%每日能量需求(DER)和70%DER两组高山姬鼠的体重、体温、基础代谢率(BMR)、非颤抖性产热(NST)等的变化,并在限食28d后,测定了肝脏鲜重和消化道形态的变化。结果显示:限食组高山姬鼠的体温、体重、BMR、NST显著降低,比0d分别下降了4.4%、23.6%、38.6%、20.3%。肝脏鲜重显著下降,小肠长度和小肠含内容物重显著增加。在限食条件下,高山姬鼠主要通过降低体重、体温、减少肝脏重量和能量代谢水平及消化器官适应性变化来减少能量支出,以适应食物资源短缺的外部环境。     

高山姬鼠幼仔的生长发育和产热特征

根据高山姬鼠幼仔56 d 的生长资料初步分析了其生长发育规律;用电子天平测量了体重的增长过程; 用开放式呼吸仪测定了静止代谢率(Resting metabolic rate,RMR)、非颤抖性产热(Nonshivering thermogenesis, NST)以及肺皮蒸发失水(Evaporative water loss,EWL)。依据逻辑斯蒂曲线的拐点,高山姬鼠的体重生长可划分为加速生长相和减速生长相。幼仔的体温在17 日龄前逐渐升高,35 日龄时接近成体水平;静止代谢率和非颤抖性产热在17 日龄前随日龄逐渐增大,17 日龄后与体重成异速增长关系,RMR 在49 日龄时接近成体水平,NST 在6 日龄内即被激活;蒸发失水在断乳前较断乳后为高。高山姬鼠为典型的晚成性发育动物。高山姬鼠较短的妊娠期、较大的胎仔数、较长的哺乳期与其食物资源较丰富有关。     

大绒鼠和高山姬鼠的体温调节和产热特征

大绒鼠和高山姬鼠为横断山地区小型哺乳动物的代表。为探讨它们在该地区的生理生态适应特征,对其体温调节和产热特征进行了测定。代谢率采用封闭式流体压力呼吸计进行测定。结果表明:大绒鼠和高山姬鼠热中性区分别为25～32.5℃ 和25～30℃;平均体温分别为35.92 ±0.37℃和36.01±0.83℃,前者体温在20～27.5℃ 范围内维持恒定,后者体温在15～27.5℃范围内维持恒定;大绒鼠和高山姬鼠基础代谢率(BMR)分别为3.76±0.07 ml O₂/g.h和4.58±0.09 ml O₂/g.h;大绒鼠和高山姬鼠平均最小热传导(Cm) 分别为0.28±0.005 ml O₂/g.h ℃ 和0.32±0.009 ml O₂/g.h℃;热中性区内,大绒鼠和高山姬鼠的F值(RMR/ Kleiber 期望RMR)/(C/Bradley 期望C) 分别为0.88±0.05 和1.10±0.05。它们的产热特征和体温调节模式很可能反映了横断山地区小型啮齿动物的特征,即体温较低、维持体温稳定的环境温度范围较窄、BMR水平较高、热传导率高。高山姬鼠的体温、C值和BMR 都比大绒鼠的高,并且高山姬鼠维持体温稳定的环境温度范围比大绒鼠的宽,它们产热特征和体温调节模式的这些差异与其分类地位、生活习性和栖息生境等因素密切相关。     

温度和高脂食物对黑线仓鼠代谢产热和体脂累积的影响

能量代谢的适应性调节是小型哺乳动物应对环境季节性变化的主要策略之一。为探讨不同温度下动物在代谢产热能量支出与脂肪累积之间的权衡策略,以成年雄性黑线仓鼠为研究对象开展了3 个实验:实验1 将动物驯化于高脂和低脂食物;实验2 将动物暴露于低温(5℃)和暖温(30℃);实验3 将饲喂高脂食物的动物暴露于低温。以食物平衡法测定摄食量、摄入能和消化率,以开放式氧气分析仪测定代谢产热,以索氏抽提法测定脂肪含量。结果发现,取食高脂食物的黑线仓鼠摄食量显著减少,但脂肪累积显著增加;暖温下摄食量显著减少,但体脂含量显著增加,低温下摄食量显著升高,但体脂含量显著减少;饲喂高脂食物的黑线仓鼠在低温下摄入能显著增加,非颤抖性产热增强,但体脂含量显著降低。结果表明高脂食物对黑线仓鼠体脂累积的影响与环境温度有关,低温诱导脂肪动员,暖温促进脂肪贮存;低温下黑线仓鼠增加能量摄入不能完全补偿用于产热的能量支出,导致脂肪动员增加;暖温下代谢产热降低是脂肪累积的主要因素;与能量摄入相比代谢产热的能量支出在体脂累积的适应性变化中发挥更重要的作用。     

食物限制对黑线仓鼠能量代谢和产热的影响

为阐明动物应对食物短缺的能量学对策与其自身的代谢水平的关系,测定了不同限食程度下黑线仓鼠的体重、基础代谢率和非颤抖性产热。结果发现,限食使基础代谢率、非颤抖性产热、褐色脂肪组织细胞色素c氧化酶活性降低。90% 限食驯化4 周后,存活率为80% ,60% 限食驯化4 周后,存活率为30% 。低温驯化使黑线仓鼠基础代谢率和非颤抖性产热显著增加,使80% 限食动物的体重和存活率显著降低。高基础代谢率组的摄食量比低基础代谢率组多23.8% ,80% 限食后两组体重降低的幅度和存活率差异不显著。结果表明:高水平的代谢率使黑线仓鼠对食物资源短缺的敏感性增加;支持“代谢率转换假说”,符合“具有储食习性的动物对食物短缺的生理耐受性较低” 的预测。     

光周期和温度对布氏田鼠产热的影响

布氏田鼠（Ｍｉｃｒｏｔｕｓ ｂｒａｎｄｔｉ）分组驯化在：（１）长光照温暖环境（ＬＷ，１６Ｌ：８Ｄ，２５℃）；（２）长光照 低温环境（ＬＣ，１６Ｌ：８Ｄ，５℃）；（３）短光照温暖环境（ＳＷ，８Ｌ：１６Ｄ，２５℃）；（４）短光照低温环境（ＳＣ， ８Ｌ：１６Ｄ，５℃）。驯化四周后，长光照动物的体重比短光动物的体重有增加的趋势；四组动物的体温 没有明显差异；低温和短光照均促使静止代谢率（ＲＭＲ）增加；ＳＣ组动物的非颤抖性产热（ＮＳＴ）高 于ＬＷ组。低温诱导肝和褐色脂肪组织（ＢＡＴ）细胞线粒体蛋白增加，短光照再度地增强此作用。短 光照诱导肝细胞线粒体状态－４及状态－３呼吸活力增加，低温没有明显作用。低温和短光照均刺激肝 和ＢＡＴ线粒体细胞色素Ｃ氧化酶活力提高，但后者作用强度大于前者。低温明显激活ＢＡＴ线粒体 的ａ－磷酸甘油氧化酶的活力，短光照无明显影响、结果表明：低温和短光照均能提高布氏田鼠的产 热能力，短光照与低温因子两者的协同作用增强了对布氏四鼠热能代谢的调节。     

光周期和温度对中缅树Qu产热能力的影响

低温短光照诱导中缅树Ｑｕ体重增加、体温降低、产热能力增强,静止代谢率增另的速度和比例高于非颤抖性产热,低温短光照刺激肝脏一体蛋白质量、线粒体氧化能力和细胞色素Ｃ氧化酶活性显著增加;短光照也刺激褐色脂肪组织总蛋白和线粒体蛋白量、线粒体状态ＩＶ呼吸、细胞色素Ｃ氧化酶、α－磷酸甘油氧化酶及Ｔ４５－脱碘酶活性显著提高。低温和短光照促使血清Ｔ３浓度增加、Ｔ４浓度不变。结果表明,中缅树Ｑｕ的适应性产热特征不仅     

光周期和温度对中缅树()产热能力的影响

低温短光照诱导中缅树()体重增加、体温降低、产热能力增强,静止代谢率增加的速度和比例高于非颤抖性产热;低温短光照刺激肝脏线粒体蛋白质量、线粒体氧化能力和细胞色素C氧化酶活性显著增加;短光照也刺激褐色脂肪组织总蛋白和线粒体蛋白量、线粒体状态IV呼吸、细胞色素C氧化酶、α-磷酸甘油氧化酶及T45'-脱碘酶活性显著提高.低温和短光照促使血清T3浓度增加、T4浓度不变.结果表明,中缅树()的适应性产热特征不仅受到低温的显著影响,而且光周期也参与了适应性产热的调节.     

Thermogenesis, energy intake and serum leptin in Apodemus chevrieri in Hengduan Mountains region during cold acclimation

Environmental factors play an important role in the seasonal adaptation of body mass and thermogenesis in small, wild mammals. The purpose of the present study was to test the hypothesis that ambient temperature was a cue to trigger the adjustments in body mass, energy intake, and serum leptin level in Apodemus chevrieri during 42 days of cold exposure. Our data demonstrated that cold acclimation induced a decrease in body mass and a significant increase in energy intake in A. chevrieri. Serum leptin levels were positively correlated with body mass and fat mass. These data suggest that A. chevrieri reduced the body mass and increased energy intake and thermogenic capacity under cold acclimation. Further, serum leptin appears to be involved in the energy intake regulation and thermoregulation.     

唐家河自然保护区高山姬鼠和中华姬鼠夏季生境选择的比较

为揭示影响高山姬鼠和中华姬鼠夏季空间分布的生态因素,采用样线法和样方取样法,于2009年6—8月在四川省唐家河国家级自然保护区内对两种姬鼠的生境选择进行了比较研究。结果表明:两种姬鼠主要利用坡度平缓,郁闭度、落叶层盖度、乔木胸径和高度较小,灌木、竹子和草本密度适中而草本盖度较大的生境;高山姬鼠频繁出现在海拔较低(1400 m左右)、草本植物较大(平均高度为16—30 cm)的生境中,而中华姬鼠频繁出现在海拔较高(1900 m左右)、草本植物较小(平均高度<15 cm)的生境中。此外,高山姬鼠频繁出现在竹林较矮(平均高度<1 m)、水源距离较近(<50 m)、植被演替阶段较低(小树林)的常绿-落叶阔叶混交林中,而中华姬鼠对这4种生态因子无明显的选择性。两种姬鼠在对生境的利用上虽具一定重叠性,但对诸多生境变量选择上的差异表明各自具有不同的生境利用模式。海拔、植被演替阶段、郁闭度和草本高度4个生境变量判别函数系数的绝对值明显大于其他变量,表明高山姬鼠和中华姬鼠在生境上的分割可能主要与这4个变量有关。生境利用模式的不同有助于两种姬鼠同域共存。     

Evaporative water loss and energy metabolic in two small mammals,voles (Eothenomys miletus) and mice (Apodemus chevrieri), in Hengduan mountains region

Evaporative water loss (EWL) and energy metabolism were measured at different temperatures in Eothenomys miletus and Apodemus chevrieri in dry air. The thermal neutral zone (TNZ) of E. miletus was 22.5–30 °C and that of A. chevrieri was 20–27.5 °C. Mean body temperatures of the two species were 35.75±0.5 and 36.54±0.61 °C. Basal metabolic rates (BMR) were 1.92±0.17 and 2.7±0.5 ml O₂/g h, respectively. Average minimum thermal conductance (C_m) were 0.23±0.08 and 0.25±0.06 ml O₂/g h °C. EWL in E. miletus and A. chevrieri increased with the increase in temperature; the maximal EWL at 35 °C was 4.78±0.6 mg H₂O/g h in E. miletus, and 5.92±0.43 mg H₂O/g h in A. chevrieri. Percentage of evaporative heat loss to total heat production (EHL/HP) increased with the increase in temperature; the maximal EHL/HP was 22.45% at 30 °C in E. miletus, and in A. chevrieri it was 19.96% at 27.5 °C. The results may reflect features of small rodents in the Hengduan mountains region: both E. miletus and A. chevrieri have high levels of BMR and high levels of total thermal conductance, compared with the predicted values based on their body masses, while their body temperatures are relatively low. EWL plays an important role in temperature regulation.     

光周期对白头鹎（Pycnonotus sinensis）体重、器官重量和能量代谢的影响

光周期是四季环境变化的最直接表现因素之一,并影响动物的生理变化特征。为探讨光周期驯化对白头鹎(Pycnonotus sinensis)体重、器官重量及能量代谢的影响,以室温28℃、不同光周期 (16L ∶ 8D,LD组和8L ∶ 16D,SD组)对两组白头鹎进行为期4周的光周期驯化,测定其体重、各器官鲜重和干重、基础代谢率(BMR)和食物摄入能、排泄能及同化能并计算同化率。结果发现,SD组个体体重、内部器官(肝、小肠)重量、BMR及同化率相应显著高于LD组个体;短光照刺激白头鹎显著降低摄入能、排泄能及同化能。这些结果表明:光周期对白头鹎的体重、器官重量、BMR及能量收支有着一定影响,并且短光照较长光照更能引起白头鹎体重、器官重量及能量代谢的明显变化,同时验证了"中心限制假说",即白头鹎BMR与中心器官代谢(肝、小肠等)具有相关性,中心器官是改变白头鹎BMR的主要原因之一。     

The effect of cold-acclimation on energy strategies of Apodemus draco in Hengduan Mountain region

Environmental factors play an important role in the seasonal adaptation of body mass and thermogenesis in small mammals. The purpose of the present study was to test the hypothesis that ambient temperature triggers adjustments in body mass, body temperature, energy intake, digestible energy intake, metabolic energy intake, and the length and weight of the digestive tract, in Apodemus draco during 42 days of cold exposure. Body mass and body temperature of the cold-acclimated group decreased during the first 28 days and then stabilized at the lower levels. After 14 days of cold acclimation, the body mass of the cold-exposed group was significantly lower and the energy intake, digestible energy intake, and metabolic energy intake were significantly elevated relative to control animals. The differences were maximal after 21 days. The length and weight of the digestive tract (both wet and dry mass of the stomach, small intestine, large intestine, and cecum) changed significantly in response to decreasing temperature. During cold exposure, A. draco was able to maintain physiological functions and reduce its absolute energy demands by reducing the body mass, increasing energy intake, and adjusting the length of the digestive tract.     

Effects of photoperiod on energy budgets and thermogenesis in Mongolian gerbils (Meriones unguiculatus)

(1)

To investigate the role of photoperiod on the regulation of energy budgets and thermogenesis in Mongolian gerbils, body mass (BM), body fat mass (BFM), basal metabolic rate (BMR), nonshivering thermogenesis (NST), gross energy intake (GEI), mitochondrial cytochrome c oxidase (COX) activity and uncoupling protein1 (UCP1) content of brown adipose tissue (BAT), and serum tri-iodothyronine (T₃), thyroxine (T₄) and leptin levels were measured.     

洞庭湖区黑线姬鼠食性调查

于2009年4月至2011年6月,在洞庭湖区湖滩、滨湖农田、防洪堤坝3种生境中捕捉黑线姬鼠(Apodemus agrarius)223只,观察胃内容物,分析了洞庭湖区黑线姬鼠的食性。结果表明:洞庭湖区3种生境中黑线姬鼠的食物组成都以植物种子为主,总计达(66.55±2.37)%,其次为植物茎、叶,其比例为(19.01±2.13)%,植物根所占比例为(8.27±1.05)%,动物性食物为(6.05±0.97)%。但黑线姬鼠的食物组成会随着不同生境、季节而有一定的变化。种子资源相对较少的季节和生境,相应的黑线姬鼠的食物组成中的种子所占比例就会较低。同一生境中,幼年鼠和亚成年鼠的食物组成与成年鼠、老年鼠区别较大,孕期雌鼠与同季节、同生境的非孕期雌鼠相比也有较大差异。说明尽管黑线姬鼠以取食植物种子为主,但其食性会随着生境可获得资源的不同而有所调整。     

Effects of photoperiod on energy intake, thermogenesis and body mass in Eothenomys miletus in Hengduan Mountain region

The present study was designed to examine whether photoperiod alone was effective to induce seasonal changes in physiology in voles (Eothenomys.) from the Hengduan Mountain region. Eothenomys miletus were randomly assigned into either long photoperiod (LD; 16L: 8D) or short photoperiod (SD; 8L: 16D) for 4 weeks at constant temperature (25 °C). At the end of acclimation, SD voles showed lower body mass and body fat coupled with higher energy intake than LD voles. SD greatly enhanced the thermogenic capacity of E. miletus, as indicated by an elevated nonshivering thermogenesis (NST), mitochondrial protein in brown adipose tissue (BAT); basal metabolic rate (BMR) was also raised. Although no variations in serum leptin levels were found between SD and LD voles, serum leptin levels were positively correlated with body mass and body fat mass, and negatively correlated with energy intake and UCP1 content in BAT, respectively. To summarize, SD alone is effective in inducing higher thermogenic capacities and energy intake coupled with lower body mass and body fat mass in root voles. Leptin is potentially involved in the photoperiod induced body mass regulation and thermogenesis in E. miletus. Our study shows that SD alone is effective.