饥饿对鱼类生理生态学影响的研究进展

为了考察不同禁食时间对两栖动物身体参数和餐后代谢反应的影响, 选取40尾大鲵(Andrias davidianus)幼体[(5.44±0.08) g, (10.87±0.06) cm]为研究对象, 将其平均分为对照组(F0)、1周禁食组(F1)、2周禁食组(F2)和4周禁食组(F4)进行不同禁食时间处理, 随后测量其体质量、体长、静止代谢率和餐后代谢相关参数。研究发现F1、F2和F4组的终末体长和终末体质量分别显著低于各自初始体长和初始体质量(P<0.05); F4组终末肥满度显著低于其初始肥满度(P<0.05); F1、F2和F4组之间的终末体长无显著性差异; F4组终末体质量和终末肥满度都显著低于F1和F2组(P<0.05); F1、F2和F4组之间的体长变化比率无显著性差异(分别为–3.51%、–2.72%和–2.76%); F4组体质量变化比率(–18.54%)和肥满度变化比率(–11.30±1.50)显著低于F1(分别为–11.48%和–1.26±3.07)和F2 (分别为–11.81%和–3.89±2.60)组(P<0.05)。F2和F4组的静止代谢率无显著差异, 但均显著低于F0和F1组(P<0.05); 各个处理组之间的代谢峰值、峰值时间、SDA时间都无显著性差异; F4组峰值比率显著高于F0、F1和F2组(P<0.05); F4组SDA耗能和SDA系数显著高于F0和F1组(P<0.05)。研究表明: (1)禁食过程中大鲵幼体体质量下降得比体长更加显著; (2)大鲵幼体在2—4周禁食期间显著下调了其基本维持能量消耗; (3)大鲵幼体最大摄食代谢能力和消化时间在禁食过程中维持稳定, 但长期禁食(4周)导致大鲵幼体餐后代谢耗能显著增加, 这可能与其再次摄食后消化系统结构和功能恢复所需额外的耗能增加有关。总体而言, 禁食对大鲵幼体身体参数、维持代谢耗能和摄食代谢耗能具有显著的影响, 但其影响程度与禁食时间长短有关。

     

Individual variation and repeatability of the aerobic performance in Brandt's voles (Lasiopodomys brandtii)

Metabolism is thought to play an important role in shaping behaviour, ecology and physiology in animals. To study the changes of metabolism among different ages or generations as well as the repeatability during the ontogeny, we carried out the research in Brandt's voles (Lasiopodomys brandtii), which covered two generations’ life. Meanwhile, we estimated the among-family variations to facilitate the heritability evaluation. Resting metabolic rate within the thermoneutral zone, resting metabolic rate at 5 °C, non-shivering thermogenesis and maximal metabolic rate during thermogenesis in both juveniles and adults were simultaneously measured. Population-average values of aerobic traits were generally consistent among different ages or generations; however, there was no repeatability at the level of individual variation during the ontogeny, which indicated that the aerobic traits of the young were not good indicators for that of later life. At the same time, the coefficient of intraclass correlation for full sibs failed to reach statistical significance, suggesting that heritability of aerobic traits in Brandt's voles was not high.     

Postprandial gastrointestinal blood flow, oxygen consumption and heart rate in rainbow trout (Oncorhynchus mykiss)

The present study is the first to simultaneously and continuously measure oxygen consumption (MO₂) and gastrointestinal blood flow (q_gi) in fish. In addition, while it is the first to compare the effects of three isoenergetic diets on q_gi in fish, no significant differences among diets were found for postprandial MO₂, q_gi or heart rate (f_H) in rainbow trout, Oncorhynchus mykiss. Postprandial q_gi, f_H and MO₂ were significantly elevated above baseline levels by 4 h. Postprandial q_gi peaked at 136% above baseline after 11 h, f_H peaked at 110% above baseline after 14 h and MO₂ peaked at 96% above baseline after 27 h. Moreover, postprandial MO₂ remained significantly elevated above baseline longer than q_gi (for 41 h and 30 h, respectively), perhaps because most of the increase in MO₂ associated with feeding is due to protein handling, a process that continues following the absorption of nutrients which is thought to be the primary reason for the elevation of q_gi. In addition to the positive relationships found between postprandial MO₂ and q_gi and between postprandial MO₂ and f_H, we discovered a novel relationship between postprandial q_gi and f_H.     

Hibernation and non-shivering thermogenesis in the Hottentot golden mole (<Emphasis Type="Italic">Amblysomus hottentottus longiceps</Emphasis>)

Although heterothermy (hibernation and torpor) is a common feature among mammals, there is debate over whether it is a derived or ancestral trait relative to endothermic homeothermy. Determination of the physiological characteristics of primitive mammals is central to understanding the evolution of endothermy. Moreover, evaluation of physiological mechanisms responsible for endothermic heat production [e.g. non-shivering thermogenesis (NST)] is key to understanding how early mammals responded to historical climate changes and colonised different geographical regions. Here we investigated the capacity for NST and heterothermy in the Hottentot golden mole, a basal eutherian mammal. NST was measured as the metabolic response to injections of noradrenalin and heterothermy by recording body temperature in free-ranging animals. We found that hibernation and torpor occurred and that the seasonal phenotypic adjustment of NST capacity was similar to that found in other placental mammals. Using phylogenetically independent contrasts, we compared measured values of NST with those obtained from the literature. This showed that all variation in NST was accounted for by differences in phylogeny and not zoogeography. These findings lend support to the observation that NST and heterothermy occur in the Afrotheria, the basal placental mammalian clade. Furthermore, this work suggests that heterothermy, rather than homeothermy is a plesiomorphic trait in mammals and supports the notion that NST mechanisms are phylogenetically ancient.     

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     

The allometry of metabolism in southern African millipedes (Myriapoda: Diplopoda)

Abstract. We determined standard metabolic rate at 25°C in forty-eight species of millipede from southern Africa and compared these data with confident measures of standard metabolic rate previously published for other arthropod groups.Metabolic rate in millipedes was not significantly different from that in beetles, ants or spiders once body mass effects had been accounted for, but was significantly higher than that in ticks.The exponent for the mass scaling of metabolic rate did not vary significantly between the five arthropod orders.Our best estimate for the relationship between standard metabolic rate (μl O₂ h^-1) and body mass (mg) in non-tick arthropods was 0.86 mass^0.73.     

南方鲇的日总代谢和特殊动力作用的能量消耗

采用封闭式呼吸仪,在15、20、25、30℃条件下测定了91尾南方鲇(Silurus meridionalisChen)幼鱼(8.49—151.0g)的日总代谢率。日总代谢率与静止代谢率之比随温度的升高而降低,随日粮水平的增加而上升,变幅为1.076—3.066倍。代谢率与生长率之间存在的线性关系表明,每增长1g体重,生长过程的代谢耗能量增加2288.2J。温度和体重对特殊动力作用(SDA)无明显的影响,SDA的耗能量占摄入能量的百分比相对恒定,为20.18％。     

Thermoregulation in three species of Afrotropical subterranean mole-rats (Rodentia: Bathyergidae) from Zambia and Angola and scaling within the genus Cryptomys

The thermoregulatory characteristics of three species of Cryptomys from Zambia and Angola are examined and, together with published data on four other species of Cryptomys from southern Africa, used to determine whether scaling occurs in this genus of subterranean rodents. The thermoregulatory properties of acclimated giant Zambian mole-rats, Cryptomys mechowi ( =267 g), Angolan mole-rats, Cryptomys bocagei ( =94 g) and Zambian common mole-rats Cryptomys hottentotus amatus ( =77 g) are as follows. Mean resting metabolic rates (RMRs) within the respective thermoneutral zones were 0.60±0.08 cm³ O₂ g^-1 h^-1 (n=12) for C. mechowi; 0.74±0.06 cm³ O₂ g^-1 h^-1 (n=8) for C. bocagei and 0.63±0.06 cm³O₂ g^-1 h^-1 (n=21) for C. h. amatus. The thermoneutral zones (TNZs) of all three species are narrow: 29–30°C for C. mechowi; 31.5–32.5°C for C. bocagei and 28–32° C for C. h. amatus. The increase in mean RMR at the lowest temperatures tested (15° C for C. mechowi, 18° C for C. bocagei and C. h. amatus) was 2.35, 2.2 and 3.82 times their RMR in the TNZ respectively. Body temperatures are low, 34±0.53° C (n=24) for C. mechowi, 33.7±0.32° C (n=20) for C. bocagei and 33.8±0.43° C (n=40) for C. h amatus. At the lower limit of thermoneutrality, conductances are 0.09±0.01 cm³ O₂ g^-1 h^-1 °C^-1 (n=30) in C. mechowi; 0.12±0.01 cm³ O₂ g^-1 h^-1 °C^-1 (n=20) in C. bocagei and 0.12±0.03 cm³ O₂ g^-1 h^-1 °C^-1 (n=32) in C. h. amatus. The range in mean body mass among the seven species of Cryptomys examined for scaling was 60 g (C. darlingi) to 267 g (C. mechowi). There is no clear relationship between RMR within the TNZ and body mass. The resultant relationship is represented by the power curve RMR=2.45 mass^-0.259.     

鲤幼鱼标准代谢率的个体差异与运动性能和摄食代谢的关系

为考察鲤科鱼类种内个体标准代谢率的差异及其与运动性能和摄食性能的内在关联,本研究以我国广泛分布的鲤(Cyprinids cardio)幼鱼[体重(4.79±0.08)g,n=36]为实验对象,在(25.0±1.0)℃下分别测量实验鱼的标准代谢率(SMR),随后测定单尾鱼的特殊动力作用(SDA)、自发运动、临界游泳速度以及活跃代谢率(MO2active)。实验鱼标准代谢率(SMR)的变幅为76.7~317.6 mg/(kg·h),其变异系数(CV)达24.4%;实验鱼在10 min内的尾鳍摆动次数(P0.05)和摄食代谢峰值(P0.05)均与标准代谢率(SMR)呈正相关;活跃代谢率(MO2active)(P0.05)与摄食代谢峰值以及活跃代谢范围与摄食代谢范围(P0.05)均呈正相关。然而,鲤幼鱼的标准代谢率(SMR)与相对临界游泳速度、活跃代谢率(MO2active)、特殊动力作用(SDA)时间和特殊动力作用(SDA)总量均不相关(所有P0.05)。研究表明,较高标准代谢率(SMR)的鲤幼鱼个体表现较高的活跃性和较强的摄食代谢能力,可能有助于其更易发现食物、逃避天敌以及加快食物处理。     

Corticosterone, locomotor performance, and metabolism in side-blotched lizards (Uta stansburiana)

Elevated levels of circulating corticosterone commonly occur in response to stressors in wild vertebrates. A rise in corticosterone, usually in animals of subordinate rank, results in a variety of effects on behavior and physiology. Behavioral and physiological responses to short-term increases in corticosterone are well studied. In contrast, the effects of chronic elevated levels of corticosterone are poorly understood, particularly in lizards. Here, we examined the long-term effects of exogenous corticosterone on locomotor performance, resting and active metabolic rate, and hematocrit in male side-blotched lizards Uta stansburiana. Corticosterone implantation resulted in higher levels of stamina relative to sham-surgery controls. In addition, lizards with elevated corticosterone exhibited lower resting metabolic rates relative to controls. Corticosterone had no effect on peak activity metabolism but did result in faster recovery times following exhaustive exercise. We suggest that elevated levels of corticosterone in response to dominance interactions promote enhanced locomotor abilities, perhaps as a flight response to avoid agonistic interactions. Furthermore, stressed lizards are characterized by lower resting metabolic rates, which may serve as strategy to conserve energy stores and enhance survival.     

Seasonal acclimation in resting metabolism of the skink, Mabuya brevicollis (Reptilia: Scincidae) from southwestern Saudi Arabia

The resting metabolic rate (RMR) of seasonally-acclimated Mabuya brevicollis of various body masses was determined at 20, 25, 30, 35 and 40 °C, using open-flow respirometry. RMR (ml g⁻¹ h⁻¹) decreased with increasing mass at each temperature. RMRs increaProd. Type: FTPsed as temperature increased. The highest and lowest Q₁₀ values were obtained for the temperature ranges 20–25 °C and 30–35 °C for the summer-acclimated lizards. The exponent of mass “b” in the metabolism-body mass relation ranged from 0.41 to 0.61. b values were lower in the autumn and winter-acclimated lizards than in spring and summer-acclimated lizards. Seasonal acclimation effects were evident at all temperatures (20–40 °C) for M. brevicollis. Winter-acclimated skinks had the lowest metabolic rates at different temperatures. The pattern of acclimation exhibited by M. brevicollis may represent a useful adaptation for lizards inhabiting subtropical deserts to promote activity during their active seasons.     

Changes in egg and body temperature indicate triggering of egg desertion at a body mass threshold in fasting incubating blue petrels (Halobaena caerulea)

The triggering of transitory egg desertion in fasting and incubating blue petrels (Halobaena caerulea, nocturnal burrowing seabirds living in the subantarctic region) was investigated by continuously monitoring both body temperature (T _sto) and egg temperature (T _egg) with a telemetry system, and by measuring body mass (BM) loss. The birds were kept captive in their burrow and incubated day and night without any interruption; there was no day-night cycle in T _sto and T _egg, which averaged 39.9 °C and 32.0 °C, respectively. There was no evidence of hypothermia as a way to save energy in this fasting situation. Egg desertion occurred at night and was an abrupt and definitive phenomenon reflected by a simultaneous fall in T _egg and a peak in T _sto. After egg desertion, a distinct day-night cycle of body temperature was observed, T _sto being 0.6 °C higher during night-time (P < 0.05), probably reflecting increased nocturnal activity. BM at egg desertion averaged 166.7 ± 3.8 g in telemetered birds and 164.4 ± 1.6 g in␣a group of free-living birds. Throughout fasting, the␣specific daily BM loss remained at 46 ± 1 g · kg⁻¹ · day⁻¹, but increased sharply below a critical BM of 160.0 ± 2.5 g. Thus, fasting incubating blue petrels spontaneously desert their egg when reaching a BM threshold. This BM is very close to a critical value in fasting birds and mammals that corresponds to a critical depletion of fat stores and to a shift from lipid to protein utilization. This strongly suggests that such a metabolic shift triggers behavioural changes leading to egg desertion and refeeding, which is of great relevance to the understanding of the long-term control of food intake and BM. Accepted: 16 July 1998     

Seasonal changes in body mass and thermogenesis in tree shrews (Tupaia belangeri): The roles of photoperiod and cold

Environmental factors play an important role in the seasonal adaptation of body mass and thermogenesis in small, wild mammals. To determine the contributions of photoperiod and cold on seasonal changes in energy metabolism and body mass, the resting metabolic rates (RMR), nonshivering thermogenesis (NST), energy intake and gut morphology of the tree shrews were determined in winter and summer and in laboratory acclimated animals. Body mass, RMR and NST increased in winter, and these changes were mimicked by exposing animals to short-day photoperiod or cold in the animal house. Energy intake and digested energy also increased significantly in winter, and also during exposure of housed animals to both short-day photoperiod and cold. The lengths and weights of small intestine increased in winter. These results indicated that Tupaia belangeri overcomes winter thermoregulatory challenges by increasing energy intake and thermogenesis, and adjusted gut morphology to balance the total energy requirements. Short-day photoperiod and cold can serve as environmental cues during seasonal acclimatization.     

Assimilation and oxygen uptake associated with two different feeding habits of Munida gregaria (=M. subrugosa) (Crustacea, Decapoda)

Munida gregaria is the most abundant galatheid crab species in the Beagle Channel (55 °S 68 °W) off Tierra del Fuego, Argentina. This species has two different and simultaneous feeding habits: predator and deposit feeder. The objectives of this work were to determine whether either of the two different feeding habits imply differences in assimilation and oxygen consumption. Subsamples of 40 and 20 crabs of each sex were randomly selected, transported to the laboratory, and used in assimilation and oxygen consumption experiments, respectively. Animals were placed in individual chambers at 8 ± 1 °C. The assimilation experiment was conducted using four types of diet: isopods (CRU), algae (ALG), pulverized fish food (PFF), and particulate organic matter (POM). The crabs' routine metabolism and postprandial oxygen consumption - or specific dynamic action SDA - were measured using Clark-type polarographic electrodes. Two kinds of food were offered: CRU and PFF to simulate both feeding habits. Assimilation in M. gregaria for both feeding habits presented values > 90% for dry mass and energetic content. Consumption rate varied between 15 and 50 mg_ingested g_DM^− 1, and was significantly higher for CRU and PFF diets. Females showed significantly higher consumption rates than males for all diets. On average, the routine metabolism of M. gregaria was 15 ± 5 μlO₂ h^− 1 g^− 1. Deposit feeding may confer energetic advantages to female M. gregaria, especially because this diet has a low energetic cost of assimilation. Deposits of high-energy content showed the highest consumption rates among four the experimental diets. In terms of mass and energy, the deposit diet also showed the highest assimilation efficiency. The postprandial oxygen consumption was lower in females and in the deposit feeding experiment. We suggest that females may prefer the deposit feeding habit to maximize their ingested energy, allowing them to devote more energy to reproduction. This is attained by a high consumption rate and by minimizing the energy used in assimilation.     

Effect of meal size on postprandial metabolic response in Chinese catfish (Silurus asotus Linnaeus)

The effect of relative meal size (0.5–24% body mass) on specific dynamic action (SDA) was assessed in Chinese catfish (Silurus asotus Linnaeus) (30.90±1.30 g) at 25.0°C; the cutlets of freshly killed loach without viscera, head and tail were used as a test meal. There was no significant difference in either SDA duration or peak oxygen consumption (VO₂) among low meal size ranges. But both increased linearly as meal size increased from 2 to 24% without reaching a plateau. Factorial metabolic scope was 5.92 in fish fed with 24% body mass, the highest documented feeding metabolic scope value in fish till now. The Peak VO₂ of satiated meal size groups (175.85±10.55 mg O₂ h⁻¹) was above 80% of maximum metabolic rate during locomotion recovery process (215.48±7.07 mg O₂ h⁻¹). The relationship between energy expended on SDA (E) and energy ingested (I) was described as: E=0.0000432I ²+0.140I+2.12. The lowest value of SDA coefficient appeared at 2% body mass group.     

Field metabolic rates and water uptake in the blossom-bat Syconycteris australis (Megachiroptera)

Blossom-bats, Syconycteris australis (18 g) are known to be highly active throughout the night. Since this species frequently enters torpor, we postulated that their use of heterothermy may be related to a high energy expenditure in the field. To test this hypothesis we measured field metabolic rates (FMR) of S. australis at a subtropical site using the doubly labelled water (DLW) method. We also measured DLW turnover in captive animals held at constant ambient temperature (T _a) with ad libitum food to estimate whether T _a and food availability affect energy expenditure under natural conditions. The FMR of S. australis was 8.55 ml CO₂ g⁻¹h⁻¹ or 76.87 kJ day⁻¹ which is 7.04 times the basal metabolic rate (BMR) and one of the highest values reported for endotherms to date. Mass-specific energy expenditure by bats in the laboratory was about two-thirds of that of bats in the field, but some of this difference was explained by the greater body mass in captive bats. This suggests that foraging times in the field and laboratory were similar, and daily energy expenditure was not strongly affected by T _a or ad libitum food. Water uptake in the field was significantly higher than in the laboratory, most likely because nectar contained more water than the laboratory diet. Our study shows that S. australis has a FMR that is about double that predicted for its size although its BMR is lower than predicted. This supports the view that caution must be used in making assumptions from measurements of BMR in the laboratory about energy and other biological requirements in free-ranging animals. Accepted: 4 January 1999     

Thermoregulatory responses in seasonally acclimatized captive Southern White-faced Scops-owls

Seasonal thermoregulatory responses that are associated with cold tolerance have been reported for many species that inhabit regions where winters are severe (e.g. Holarctic), but relatively few studies have focused on species from regions where the climate is more unpredictable (e.g. Southern Africa). In this study, metabolic rate (VO₂) and body temperature (T_b) was measured during summer and winter in captive Southern White-faced Scops-owl (Ptilopsis granti), to test for thermoregulatory responses representing energy conservation in winter. During winter the Southern White-faced Scops-owls increased resting metabolic rate (RMR) by 45% to regulate a set point T_b—a result similar to what had been shown in small passerines from the Holarctic region. Increased RMR and increased conductance at cold T_a's are suggestive of improved cold tolerance. Basal metabolic rate (BMR) was 0.60 mL O₂ g⁻¹ h⁻¹ and showed no seasonal flexibility. Thus, contrary to expectation, the Southern White-faced Scops-owls showed seasonal thermoregulatory responses that are unlikely to represent energy conservation which was expected for a medium-sized bird inhabiting unpredictable climates in Southern Africa.     

The effects of meal size on postprandial metabolic response and post-exercise metabolic recovery process in juvenile black carp (Mylopharyngodon piceus)

The effects of meal size on the postprandial metabolic response and of digestion on the post-exercise metabolic recovery process were investigated in juvenile black carp (Mylopharyngodon piceus) . Experimental fish were forcedly fed with compound feed (meal sizes: 0.5%, 1% and 2% body weight). Then, the postprandial oxygen consumption rate and excess post-exercise oxygen consumption (EPOC) of the experimental fish were measured. Both the duration and the peak of oxygen consumption rate (PMR) increased with increasing meal size. The peak post-exercise metabolic rate of digesting fish were significantly higher, whereas EPOC magnitude and its duration were significantly smaller or (shorter) than those in the fasting fish. It is suggested that (1) this fish fulfills the increased energy demand during the digestive process by increasing PMR and by prolonging SDA duration with increasing meal size and (2) digesting fish might decrease their anaerobic exhaustive activity but increase the post-exercise recovery capacity.     

Seasonal variation in the metabolism-temperature relation of House Sparrows (Passer domesticus) in KwaZulu-Natal,South Africa

Many birds exhibit considerable phenotypic flexibility in metabolism to maintain thermoregulation or to conserve energy. This flexibility usually includes seasonal variation in metabolic rate. Seasonal changes in physiology and behavior of birds are considered to be a part of their adaptive strategy for survival and reproductive success. House Sparrows (Passer domesticus) are small passerines from Europe that have been successfully introduced to many parts of the world, and thus may be expected to exhibit high phenotypic flexibility in metabolic rate. Mass specific Resting Metabolic Rate (RMR) and Basal Metabolic Rate (BMR) were significantly higher in winter compared with summer, although there was no significant difference between body mass in summer and winter. A similar, narrow thermal neutral zone (25–28 °C) was observed in both seasons. Winter elevation of metabolic rate in House Sparrows was presumably related to metabolic or morphological adjustments to meet the extra energy demands of cold winters. Overall, House Sparrows showed seasonal metabolic acclimatization similar to other temperate wintering passerines. The improved cold tolerance was associated with a significant increase in VO₂ in winter relative to summer. In addition, some summer birds died at 5 °C, whereas winter birds did not, further showing seasonal variation in cold tolerance. The increase in BMR of 120% in winter, compared to summer, is by far the highest recorded seasonal change so far in birds.