甘肃鼢鼠适应地下生活的消化道形态和结构的季节可塑性

甘肃鼢鼠(Myospalax cansus)是终生营地下生活的小型哺乳动物,为研究其在自然环境中的消化对策和调节,探讨地下鼠消化道的可塑性,测定了不同季节消化道各器官长度、重量及各器官的组织结构。结果显示,甘肃鼢鼠总消化道长度、各消化器官长度和含内容物总重量无显著季节差异。总消化道及各器官的鲜重和干重多在春季最高,含内容物重量于秋季较高。组织结构有显著性季节变化,黏膜层和肌层的厚度及肠道绒毛高度春季最高。结果表明,甘肃鼢鼠主要依靠肠道重量的增加和组织结构的可塑性变化来适应相对稳定的地下生活环境,无需增加消化器官长度满足其能量需求。     

饥饿驯化对树麻雀消化道长度和重量的影响

鸟类消化系统的形态结构与能量摄入密切相关.本文以相同环境中进食量充足的树麻雀(Passer montanus)为对照组,与4种处于相同饥饿环境但不同饥饿天数(1D、3D、5D、7D组)树麻雀的各消化器官的长度及重量进行比较.结果显示,饥饿驯化各组树麻雀的体重和体脂含量均低于对照组;1D组树麻雀的消化器官胃、小肠、直肠长度显著增长,重量显著增加;3D、5D、7D组各消化器官的长度和重量表现出波动的变化趋势,摄食量的限制是胃干重没有发生显著变化的原因.结论是,摄能需求的不同引起树麻雀消化器官长度和重量发生显著变化,这种变化可对摄食量及消化吸收率产生直接的影响,同时这种适应性变化应当是快速、可逆和可重复的,是消化器官形态结构与功能能力及器官自身能耗之间能量预算的结果,也是个体与环境及适合度之间能量预算的结果.     

长爪沙鼠脏器重量和肠道长度的季节性变化

小哺乳动物内脏器官的重量和消化道的长度具有可塑性,与其所处的环境密切相关.为进一步了解长爪沙鼠对季节性环境的适应,比较了活捕于内蒙古太仆寺旗的长爪沙鼠的体重、内脏器官的重量及肠道各段长度的性别和季节变化.结果显示:除体重和体长雄鼠高于雌鼠,肝脏的湿重低于雌鼠外,其他指标均未检测到性别差异.雌雄鼠的体重和心脏的湿重都在冬季最高,夏季最低;雄鼠肝脏的湿重夏季最高,春季和冬季最低,雌鼠无季节性变化.睾丸的湿重在春季最高.盲肠和小肠的湿重秋季高于春季,胃和大肠的湿重无季节性差异.小肠的长度冬季最长,夏季最短;盲肠春季最短,大肠春季最长,夏季最短.体重、心脏、消化器官和其他内脏器官的重量,以及消化器官长度的可塑性变化等对于长爪沙鼠适应环境具有重要的意义.     

4种雀形目鸟消化道形态特征

鸟类消化系统的形态结构与其食性密切相关。本文对红点颏(Luscinia calliope)、红喉姬(Ficedula parva)、栗(Emberiza rutila)和普通朱雀(Carpodacus erythrinus)4种雀形目鸟类的消化道形态特征进行了比较研究。实验结果显示,4种鸟的总消化道长度和各消化器官的长度(胃长度除外),消化道总重量和各消化器官的重量均存在明显的种间差异。植食性鸟(普通朱雀)具有相对较长的消化道,而食虫鸟(红点颏和红喉姬)则具有相对较高的消化道重量。实验证明,鸟类不同的食性特征塑造了不同的消化道适应对策。     

七种鼠科啮齿动物消化道长度和重量的比较

测定浙江省金华地区7种鼠科啮齿动物的总消化道及各消化器官的长度和重量,与其食性和生境作比较,旨在检测近缘种之间消化道长度和重量的差异,家栖种类与野栖种类消化道形态的差异,野外捕获动物带回实验室处死,解剖分离消化道为胃,小肠,盲肠和大肠,精密直尺测定各器官的平展长度,纵剖肠道,生理盐水冲净内容物,65℃恒温干燥后称得干重,研究结果表明,消化道长度的种间差异明显大于消化道重量的种间差异;盲肠和大肠长度的种间差异明显大于小肠长度的种间差异,植食性野栖种类的胃,盲肠和大肠大于杂食性家栖种类,而两类动物小肠长度的差异不明显。     

棕色田鼠消化道形态变化与能量需求的关系

为研究能量代谢与消化道形态结构变化及其某些生活史特征之间的关系，采用食物平衡法、耗氧量测定、形态测量和组织学方法，分别测定了雄性、非繁殖雌性及哺乳雌性棕色田鼠(Mirotus mandarinus)的摄食量、每日消化能、静止代谢率和胃肠器官长度、重量以及肠道各段管径和黏膜厚度。结果表明：哺乳雌鼠摄食量、每日消化能、静止代谢率高于非繁殖雌鼠和雄鼠，且消化道各器官有最大的重量、管径和黏膜厚度。由此可见，哺乳雌鼠能量需求增加，促使消化道形态结构进行一些有益的调节。棕色田鼠在哺乳期代谢率增加时，仅有消化道器官重量、黏膜厚度及小肠管径的明显变化，这可能与其哺乳期较长，胎仔数较少，生后生长缓慢等生活史特征有关。同时也说明在未受到十分严峻的能量胁迫的情况下，动物并不需付出昂贵的代价去增加消化器官的长度。     

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。     

社鼠和褐家鼠消化道长度和重量的季节变化

测定了浙江金华的社鼠和褐家鼠消化道长度和重量的季节变化。野生社鼠消化道各器官无论长度不审重量都有明显季差异,在寒冷的冬季具有相对较大的小肠、大肠、盲肠、雄性社鼠的消化道长度在秋季由于食物条件的改善而明显下降,但雌性社鼠由于在秋季仍有繁殖负担,其消化道长度下降不明显,而家栖的褐家鼠只有总消化道、小肠和大肠的长度有季节差异,冬、春季高于夏、秋季。消化道形态季节变化与温度、食物条件和繁殖有关。     

大仓鼠消化道长度和重量变化的初步研究

对华北平原旱作区的主要害鼠大仓鼠消化道各器官的长度和重量进行了测定,结果表明,大仓鼠消化道的长度与重量在性别、年龄及季节中差异明显。说明消化道长度、重量和容量的调节是消化对策中的一个重要方面,大仓鼠有能力满足其高繁殖力的营养需求。     

小鼠肠道组织结构在低温环境下的适应性调整

对长期(3个月)处于低温条件下的小鼠各肠道组织结构的适应性变化进行了比较研究。低温驯化后小鼠的体重(P0.05)、消化道总长度(P0.05)、小肠长度(P0.01)和盲肠长度(P0.05)显著增加,而十二指肠肠腔隙截面积未发生显著变化,提示小鼠的肠腔隙体积在低温环境下明显增加。同时,低温驯化小鼠十二指肠的肠道和肠壁组织截面积均显著降低(P0.05),而其绒毛高则显著增加(P0.001),提示其黏膜层厚度增加,而黏膜下层结构趋于萎缩,表明小鼠肠道组织的形态结构为应对低温条件已经产生了适应性调整,即通过增加消化道的长度和营养物质的吸收面积来增加食物摄取量、食物吸收速率和吸收效率等,进而满足低温条件下小鼠能量需求的增加。相比之下,低温鼠的胃大小、盲肠重量、大肠长度与重量、直肠组织结构均未产生显著变化,暗示这些肠道结构对外界温度变化的敏感性相对较低。研究结果表明,小型哺乳类主要通过增大消化道长度和吸收面积来提高其消化效率,通过改变消化道的形态和结构来提高消化和吸收效率,以便更好地去适应环境温度变化而导致的能量需求变化。     

Age-related changes in blood pressure, hematological values, concentrations of serum biochemical constituents and weights of organs in the SHR/Izm, SHRSP/Izm and WKY/Izm.

Age-related changes in hematological values, serum biochemical constituents, and weights of various organs in both sexes of the Spontaneously Hypertensive (SHR/Izm), Stroke-prone SHR (SHRSP/Izm), and Wistar Kyoto (WKY/Izm) rat strains, bred under SPF conditions, were examined to obtain fundamental data. The body weights from 3-30 weeks and systolic blood pressure from 6-30 weeks in each strain were measured every week. At the ages of 8, 16, and 30 weeks, the hematological values (erythrocyte, hemoglobin, hematocrit, leucocyte, thrombocyte), serum biochemical constituents (total protein, GOT, GPT, ALP, BUN, creatinine, glucose, total Ca and phosphorus, and ionized Ca, Na, K, and Cl were measured. Also, the organs, brain, heart, lung, thymus, liver, spleen, pancreas, bilateral kidneys, adrenal glands, testes/ovaries, digestive tract, and muscle (soleus) were weighed. The age-related changes as well as the strain and sex differences in each measured item were examined. The body weights of each strain increased, but rate of the increase was less in SHR and SHRSP, and was lowest in SHRSP. The blood pressure of SHR and SHRSP elevated with age, and showed higher in SHRSP than SHR, while that of WKY did not change. There were many strain differences in most measured items at each time point, particularly at 30 weeks. In SHRSP, high values of BUN, creatinine, total and ionized Ca, weights of brain, heart, liver, kidney and digestive duct were observed at most time points indicating that this strain's abnormality of calcium metabolism may be related to functions of the kidney and digestive duct as well as hypertension.     

黄羊消化道形态和结构的特征

研究了51副黄羊消化道的形态结构特征。腮腺（g）占体重（kg）的比率为1.035,整个胃组织重占体重的比率为2.74%～2.89% , 瘤胃最大,占整个胃组织重量的72%～76%,其次是网胃（9%～10%）、皱胃（8%～10%）和瓣胃（5%～6%）,除瘤胃与体重呈线性正相关外,其它3个分胃与体重呈线性负相关,瘤胃表面扩张系数（SEF）值为8.52,瘤胃粘膜乳突密度为89,整个肠道长度是体长的17.8倍,肠重占体重的比率为4.96%,从消化道的形态结构特征分析,黄羊属于混饲者。     

Organ growth of selected lines of chickens and their F1 crosses to a common body weight or age

Summary Organ growth of male chickens selected for high and low 56-day body weight and their reciprocal F₁ crosses was compared at a common age (56 days) or at a common body weight (180 g). Organs that differed at a common body weight included weights of proventriculus, small intestine, lungs, feathers and abdominal fat and length of esophagus. Organ weights that differed at a common age included esophagus, gizzard, heart, liver, lungs, breast, legs, feathers and abdominal fat, and lengths of shank, esophagus and small intestine. Heterosis for most organs was less than 15%. Those exhibiting heterosis greater than 30% included weights of fat depots and feathers, plus lengths of the esophagus, small intestine and shank. Heterosis for these traits, however, varied depending on whether comparisons were made at common body weight or age. These results imply that biological functions of organs at specific ages may not reflect the situations at common body weights and suggest differences in resource allocations among populations.     

高纤维食物对海南社鼠能量代谢的影响

自然界中食物质量常存在季节性变化,可影响小型哺乳动物的生理特征及其生存和分布。为研究高纤维(低质量)食物对栖息于贵州遵义的海南社鼠(Niviventer lotipes)能量代谢的影响,通过饲喂标准兔饲料(高纤维)或鼠饲料(低纤维)处理海南社鼠4周,实验期间测定动物的体重和能量摄入,使用开放式代谢仪测定动物的能量消耗,并在实验处理结束后解剖动物进行身体成分分析。研究发现,饲喂兔饲料的海南社鼠实验期间体重持续下降,到实验结束时为饲喂鼠饲料动物(对照组)体重的62.8%。饲喂兔饲料4周后,动物的整体基础代谢率和非颤抖性产热显著下降,分别为对照组的55.1%和63.4%。饲喂兔饲料的海南社鼠干物质摄入、消化能和消化率显著降低,分别为对照组的63.7%、38.8%和71.8%;身体成分分析显示,主要内脏器官重量以及消化道的重量和长度也显著下降。研究结果表明,饲喂高纤维的兔饲料后海南社鼠没有增加食物摄入来补偿消化率的下降,消化道形态尤其是小肠和盲肠的重量和长度没有适应性增加,虽然动物可通过降低基础代谢率和非颤抖性产热节约能量,但动物能量利用效率太低不能维持能量平衡而体重显著下降,海南社鼠对高纤维...     

Quantitative trait loci for body size components in mice

Do body size components, such as weights of internal organs and long bone lengths, with different functions and different developmental histories also have different genetic architectures and pleiotropic patterns? We examine murine quantitative trait loci (QTL) for necropsy weight, four long bone lengths, and four organ weights in the LG/J × SM/J intercross. Differences between trait categories were found in number of QTL, dominance, and pleiotropic patterns. Ninety-seven QTLs for individual traits were identified: 52 for long bone lengths, 30 for organ weights, and 15 for necropsy weight. Results for long bones are typically more highly significant than for organs. Organ weights were more frequently over- or underdominant than long bone lengths or necropsy weight. The single-trait QTLs map to 35 pleiotropic loci. Long bones are much more frequently affected in groups while organs tend to be affected singly or in pairs. Organs and long bones are found at the same locus in only 11 cases, 8 of which also include necropsy weight. Our results suggest mainly separate genetic modules for organ weights and long bone lengths, with a few loci that affect overall body size. Antagonistic pleiotropy, in which a locus has opposite effects on different characteristics, is uncommon.     

Interrelation between size of body and of digestive tract organs in some myomorpha: Isometry or allometry?

Using nonparametric tests, we analyzed the weights of the digestive tract organs of 198 rodent individuals belonging to 11 species of Arvicolinae (family Cricetidae) and Murinae (family Muridae), using both fresh and fixed material, the weight characteristics of which were identical. It has been shown that no unique dependence exists between the body weight and the entire digestive tract one in Arvicolinae rodents weighing 8–73 g. It was also shown that interspecific differences in the relative mass of such a dynamic system of organs as the digestive system cannot always be regarded as a function of the body size alone.     

Thymus, peripheral lymphoid tissues and immunological responsiveness of the pituitary dward mouse (author's transl)]

Snell's pituitary dwarf mice (dw) were used for studies on the relationship between hypophysis and lymphoid organs. The age-dependent changes of thymus or spleen weights of dwarf mice were compared with those of normal littermates. The suppression of growth of the thymus or spleen in dwarf mice was recognized at 5th day of age. Although involution of the thymus varied among animals, a strong positive correlation was demonstrated between relative thymus weight and body weight in 30 approximately 40 days old dwarf mice. Lymphoid organs of dwarf mice were reconstituted by injection of growth hormone and or thyroxin. Relative thymus weight significantly increased in dwarf mice when the treatment with growth hormone started at 7 days of age, but the same treatment at 3 months of age did not show any effect on the increment of relative thymus weight. On the other hand, the antibody-forming capacitiy against sheep erythrocytes of dwarf mice was significantly increased even when the treatment with growth hormone was started at 3 months of age. A marked increase in the number of lymphoid cells in dwarf mice was observed by treatment with thyroxin, even if treatment was started either at 7 days or 3 months of age. Similar changes were also obtained in the antibody-forming capacity.     

Phenotypic flexibility of body composition in relation to migratory state,age, and sex in the western sandpiper (Calidris mauri)

We investigated the flexibility of body composition in relation to seasonally variable demands for endurance flight capacity and hyperphagia in a migratory shorebird. Migrating western sandpipers were sampled in spring and fall while refueling at a north temperate stopover and were compared with nonmigrating birds captured at a tropical wintering area in Panama. Sandpipers weighed 25% more at stopover, and nearly 40% of migratory mass increase consisted of lean body components. Most organs and flight muscles were 10%-100% larger during migration, and the greatest relative size increases occurred in the digestive system (including liver). Birds preparing to initiate spring migration from Panama deposited only fat, suggesting that changes in lean body components take place after migration has begun, possibly through training effects. Sex did not influence body composition. Juveniles making their first southward migration were similar to adults in structural size and body mass but had substantially enlarged alimentary tracts. Sandpipers appeared to deposit lean mass during stopover in fall but not in spring. The dramatic enlargement of the digestive system in this small species that makes short flights and fuels frequently contrasts with the reduction of digestive components in larger species that fuel only once or twice by making one or two very long flights to their destination.     

洞庭湖不同生态类型区黑线姬鼠消化道重量和长度的季节变化

对洞庭湖3种不同生态类型区(农区、林区、农林交错区)不同季节黑线姬鼠消化道各器官长度、鲜重和干重的测量表明,在3种生态类型区中,黑线姬鼠消化道各器官鲜重和干重季节变化显著。农区和林区消化道各器官的鲜重和干重在春季和冬季显著重于夏季和秋季,农林交错区消化道各器官鲜重和干重在春季显著重于夏季和秋季,这可能与春季和冬季黑线姬鼠能量需求增加、食物缺乏和食物质量下降有关。在同一季节,3种生态类型区之间消化道各器官长度、鲜重和干重均无显著性差异。这与3种生态类型区间黑线姬鼠食物变化较小有关。关于消化道各器官长度变化方面,除了农区的大肠长度有显著季节性差异外,其它指标均无显著季节性差异。以上结果表明黑线姬鼠消化道各器官在外界环境因素的影响下能产生不同的反应,消化道形态的变化是黑线姬鼠面临外界胁迫因子时的一种消化对策。