Growth rate and thermoregulation in reared king quails (Coturnix chinensis)

Growth rate was investigated in king quails between 1st and 60th day of life. Gompertz growth constants were 0.075 in males and 0.056 in females. Colonic temperature (Tb) was measured in quails divided into four age groups (1-3, 7-10, 16-19, and 44-59 days old) in ambient temperatures set separately for each group. Metabolic rate was measured only in 44-59-day-old birds. The mean value of the thermoneutral body temperature (Tb at TNZ) in the active phase in the youngest quails was 39.0 degrees C. In 44-59-day-old quails, the resting metabolic rate in the thermoneutral zone (RMR at TNZ) was on average 9.44 mW g(-1) (1.66 cm3 O2 g(-1)h(-1)), without sex-specific differences. No such differences were found in this age group neither in Tb at TNZ, nor in minimal thermal conductance (Cmin). However, differences were found in the rate of metabolic heat production below the thermoneutral zone, even when mass-independent units were used. The maximum metabolic rate (Mmax) in 2-month-old males was 34.08 mW g(-1) (5.98 cm3 O2 g(-1)h(-1)), while in females 29.73 mW g(-1) (5.21 cm3 O2 g(-1)h(-1)). Heat-stressed 44-59-day-old quails elevated their Tb to as much as an average 44.1 degrees C in Ta of about 45 degrees C. The obtained growth model and a gradual development of the body temperature regulation mechanism in king quails followed the known strategy of development, typical for precocial birds. The sexual size dimorphism in the studied quails did not result in differences in thermoregulation parameters between the sexes, except for the rate of metabolic rate below thermoneutral zone.     

布氏田鼠静止代谢率特征

本文以布氏田鼠的耗氧量为指标,探讨了布氏田鼠的能量代谢特征。布氏田鼠的热中性区为27.5至32.5℃,最低静止代谢率(RMR)为1.836mlO₂/g·h,是期望RMR的l32.6%。最低热传导率为0.189mlO₂/g·h,是期望热传导率的I14.5%。环境温度（Ta）在5-27.5℃范围内,RMR与Ta呈负相关,回归方程为RMR=6.968 5-0.185 2Ta,体温稍有降低。T_a35℃时,RMR升高,体温升高1.9℃。布氏田鼠较高的RMR和热传导率,较宽的热中性区,及良好的化学体温调节强度等生理生态特征,是对生存环境的适应性反应。     

Seasonal variation in resting metabolic rate and body temperature of streaked tenrecs, Hemicentetes nigriceps and H. Semispinosus (Insectivora: Tenrecidae)

Annual variations in resting metabolic rate (RMR) and body temperature (Tb) were measured in the streaked tenrecs Hemicentetes nigiceps and H. semispinosus. RMR in non-reproducing, non-torpid adults was lower than predicted by the Kleiber (1961) curve, supporting Genoud's (1990) hypothesis on BMR in hibernating mammals. Both species demonstrated a reduction in RMR and Tb during the austral winter and these changes were independent of body mass. H. semispinosus frequently roused from torpor to forage whereas H. nigriceps remained dormant throughout the winter, This contrast in activity patterns may result from altitudinal differences in species distributions. H. nigriceps may be an obligate hibernator whereas H. semispinosus, living at lower, warmer altitudes, may be a facultative hibernator. It is proposed that the ability of H. semispinosus to remain active during favourable climatic conditions allows winter breeding and increases annual reproductive output.     

The effects of body proportions on thermoregulation: an experimental assessment of Allen's rule

Numerous studies have discussed the influence of thermoregulation on hominin body shape concluding, in accordance with Allen's rule, that the presence of relatively short limbs on both extant as well as extinct hominin populations offers an advantage for survival in cold climates by reducing the limb's surface area to volume ratio. Moreover, it has been suggested that shortening the distal limb segment compared to the proximal limb segment may play a larger role in thermoregulation due to a greater relative surface area of the shank. If longer limbs result in greater heat dissipation, we should see higher resting metabolic rates (RMR) in longer-limbed individuals when temperature conditions fall, since the resting rate will need to replace the lost heat. We collected resting oxygen consumption on volunteer human subjects to assess the correlation between RMR and lower limb length in human subjects, as well as to reexamine the prediction that shortening the distal segment would have a larger effect on heat loss and, thus, RMR than the shortening of the proximal segment. Total lower limb length exhibits a statistically significant relationship with resting metabolic rate (p<0.001; R(2)=0.794). While this supports the hypothesis that as limb length increases, resting metabolic rate increases, it also appears that thigh length, rather than the length of the shank, drives this relationship. The results of the present study confirm the widely-held expectation of Allen's rule, that short limbs reduce the metabolic cost of maintaining body temperature, while long limbs result in greater heat dissipation regardless of the effect of mass. The present results suggest that the shorter limbs of Neandertals, despite being energetically disadvantageous while walking, would indeed have been advantageous for thermoregulation.     

Effects of feeding and habitat on resting metabolic rates of the Pacific walrus

Arctic marine mammals live in a rapidly changing environment due to the amplified effects of global warming. Pacific walruses (Odobenus rosmarus divergens) have responded to declines in Arctic sea-ice extent by increasingly hauling out on land farther from their benthic foraging habitat. Energy models can be useful for better understanding the potential implications of changes in behavior on body condition and reproduction but require behavior-specific metabolic rates. Here we measured the resting metabolic rates (RMR) of three captive, adult female Pacific walruses through breath-by-breath respirometry when fed and fasted resting out of water (sitting and lying down) and while fed resting in water. RMR in and out of water were positively related with pretrial energy intake when not fasted and 25% higher than RMR when walruses were fasted and out of water. Overall, RMR was higher than previously estimated for this species. Fasting RMR out of water was only 25% lower than subsurface swimming metabolic rates suggestive of relatively efficient swimming in adult females. Our results identify the importance of considering feeding status and species-specific differences in affecting metabolic costs. Further research is needed to better understand potential energetic costs of thermoregulation at temperatures experienced by wild walruses.     

Energetics of growth in semi-precocial shorebird chicks in a warm environment: the African black oystercatcher, Haematopus moquini

We studied prefledging growth, energy expenditure and time budgets of African Black Oystercatcher, Haematopus moquini, chicks on Robben Island, Western Cape, South Africa. The aim of the study was to investigate the effect of parental feeding on the growth and energetics of semi-precocial shorebird chicks. Chicks reached mean fledging mass, 463 g, in 40 days. The growth rate coefficient of African Black Oystercatcher chicks was 2% below the predicted value for a shorebird species of their body mass, but it was smaller than that of other precocial and semi-precocial shorebirds to date. Resting metabolic rate (RMR, measured through respirometry), daily metabolisable energy (DME), defined as daily energy expenditure (DEE, measured with doubly labelled water) plus energy deposited into tissue (E(tis)), and total metabolisable energy (TME) of African Black Oystercatcher chicks were similar to those expected for a species of their body size. DEE was not influenced by weather (ambient temperature, operative temperature and wind speed), therefore, variations in DEE may be explained by body mass alone. The relative RMR of the African Black Oystercatcher was greater, their TME was approximately the same, their average daily metabolisable energy (ADME) was less, and they spent less time foraging (short periods of parental feeding) and more time inactive than three precocial species in the Western Cape. Therefore, the semi-precocial mode of development of African Black Oystercatcher chicks reduced energy costs from thermoregulation and activity, and they were able to grow relatively faster than precocial, self-feeding shorebird species in similar climatic conditions. The growth rate coefficient of African Black Oystercatcher chicks was smaller than that of Eurasian Oystercatcher, Haematopus ostralegus, chicks, which may be a consequence of differences in body size and latitudinal effects.     

广东罗坑自然保护区鳄蜥的体温调节及静止代谢率的热依赖性

探讨鳄蜥（Shinisaurus crocodilurus）的体温调节和静止代谢率及其热依赖性特征,测定了在自然和实验室条件下的环境温度、鳄蜥体温以及静止代谢率（RMR）等热生物学指标。结果显示：在自然条件下,鳄蜥的野外活动体温（Th）稍高于基质温度（Tc）和空气温度（Td）并与后二者呈正相关关系（Tb=11．65＋0．47Tc,r^2=0．34,F1.75=39．11,P〈0．0001;Tb=11．61＋0．46Td,r^2=0．56,F1.75=96．56,P〈0．0001）。鳄蜥在野外的活动体温存在明显的月份间差异,但无性别及年龄上的差异。环境温度为15℃-30℃的实验条件下,鳄蜥的静止体温（Tb）与环境温度（Ta）呈正相关关系：Tb=12．450＋0．5641Ta（F1.110=11．34,r^2=0．997,P〈0．001）;在缺乏温度梯度的环境中,尽管鳄蜥的体温、空气温度和基质温度都有显著的昼夜差异,但体温、空气温度和基质温度的日平均温度之间无显著差异。鳄蜥的RMR不存在雌雄个体间的差异,并与环境温度呈正相关关系。分析显示鳄蜥的体温既有行为调节也有生理调节,其体温调节及RMR符合变温动物的热生物学特征,但是相对于其他活动较多的蜥蜴而言,鳄蜥的生理调节能力较强,这可能与其活动时间分配中静栖占绝大部分的行为特点是相适应的[动物学报54（6）：964-971,2008]。     

Influence of physical activity and dietary restraint on resting energy expenditure in young nonobese females

An understanding of the physiological and behavioral determinants of resting energy requirements is important to nutritional considerations in females. We examined the influence of endurance training and self-reported dietary restraint on resting metabolic rate and fasting plasma hormones in 44 nonobese females characterized for body composition, maximal aerobic power (VO2 max), and daily energy intake. To examine the association of metabolic rate and dietary restraint with hormonal status, fasting plasma levels of insulin, glucose, and thyroid hormones (total and free fractions of thyroxine and triiodothyronine) were determined. In univariate analysis, resting metabolic rate (kcal.min-1) was positively related to VO2 max (L.min-1) (r = 0.54; p less than 0.01). This relationship, however, was partially dependent on body size, since fat-free mass was also related to resting metabolic rate (r = 0.42; p less than 0.01) and VO2 max (L.min-1) (r = 0.75; p less than 0.01). After controlling for fat-free weight using partial correlation analysis, the relation between RMR and VO2 max was weaker but controlling for fat-free weight using partial correlation analysis, the relation between RMR and VO2 max was weaker but still significant (partial r = 0.38; p less than 0.05). On the other hand, high levels of dietary restraint were associated with higher levels of body fat (r = 0.31; p less than 0.05) and a lower resting metabolic rate (r = -0.29; p = 0.07). These associations persisted after control for differences in fat-free mass. Total energy intake as well as total and free levels of triiodothyronine were not related to resting metabolic rate or level of dietary restraint.(ABSTRACT TRUNCATED AT 250 WORDS)     

Energetics and thermoregulation during digging in the rodent tuco-tuco (Ctenomys talarum)

For subterranean rodents, searching for food by extension of the tunnel system and maintenance of body temperature are two of the most important factors affecting their life underground. In this study we assess the effect of ambient temperature on energetics and thermoregulation during digging in Ctenomys talarum. We measured VO2 during digging and resting at ambient temperature (Ta) below, within, and above thermoneutrality. Digging metabolic rate was lowest at Ta within the thermoneutral zone and increased at both lower and higher temperatures, but body temperature (Tb) remained constant at all Tas. Below thermoneutrality, the cost of digging and thermoregulation are additive. Heat production for thermoregulation would be compensated by heat produced as a by-product of muscular activity during digging. Above thermoneutrality, conduction would be an important mechanism to maintain a constant Tb during digging.     

Energy metabolism and thermoregulation in hand-reared chukars (Alectoris chukar)

Metabolic rate and colonic temperature were measured in chukars between 1st and 108th day of life (divided into six age groups: 1-3-days old, 1, 2, 3, and 4-weeks old and 3.5-months old) in ambient temperatures set separately for each group and ranging from -12 to 41 degrees C. The Gompertz growth constant for growing chukars (0.042) was close to the value obtained in earlier study for the grey partridge. Similarly as in other species of Galliformes, newly hatched chukar chicks had lower T(b) at TNZ (39.5 degrees C) than that found in older birds (41.3 degrees C in 4-weeks old). The body temperatures taken at TNZ in 2-weeks old chicks and older fitted neatly within allometrically predicted limits of body temperatures for adult birds. The values of RMR at TNZ followed closely a biphasic pattern, with the second phase correlating strongly with the body mass. The value of metabolic scope (the level of metabolic efficiency) for the youngest group was high (3.2) and exceeded the values obtained in earlier studies for other gallinaceous species, including the grey partridge. The obtained values of minimum wet thermal conductance for growing chukar chicks exceeded the predicted values by approximately 40% but the slopes of both lines were very similar. In chukars, the key stage in the expression of fully developed thermoregulatory capacities comes immediately after the first week of life (maintaining somewhat constant body temperature, evident drop in the value of RMR at TNZ and minimal thermal conductance). The model of gradual development of thermoregulation which could be derived from the experiments on chukar chicks was characteristic for typical precocial birds.     

Fast molecular evolution associated with high active metabolic rates in poison frogs

Molecular evolution is simultaneously paced by mutation rate, genetic drift, and natural selection. Life history traits also affect the speed of accumulation of nucleotide changes. For instance, small body size, rapid generation time, production of reactive oxygen species (ROS), and high resting metabolic rate (RMR) are suggested to be associated with faster rates of molecular evolution. However, phylogenetic correlation analyses failed to support a relationship between RMR and molecular evolution in ectotherms. In addition, RMR might underestimate the metabolic budget (e.g., digestion, reproduction, or escaping predation). An alternative is to test other metabolic rates, such as active metabolic rate (AMR), and their association with molecular evolution. Here, I present comparative analyses of the associations between life history traits (i.e., AMR, RMR, body mass, and fecundity) with rates of molecular evolution of and mitochondrial loci from a large ectotherm clade, the poison frogs (Dendrobatidae). My results support a strong positive association between mass-specific AMR and rates of molecular evolution for both mitochondrial and nuclear loci. In addition, I found weaker and genome-specific covariates such as body mass and fecundity for mitochondrial and nuclear loci, respectively. No direct association was found between mass-specific RMR and rates of molecular evolution. Thus, I provide a mechanistic hypothesis of the link between AMRs and the rate of molecular evolution based on an increase in ROS within germ line cells during periodic bouts of hypoxia/hyperoxia related to aerobic exercise. Finally, I propose a multifactorial model that includes AMR as a predictor of the rate of molecular evolution in ectothermic lineages.     

Metabolic rate and food availability of the Antarctic amphipod <Emphasis Type="Italic">Gondogeneia antarctica</Emphasis> (Chevreux 1906): seasonal variation in allometric scaling and temperature dependence

Among the few existing works on seasonal variation in metabolic rate of polar species, most have been conducted during summer due to logistic constraints and have been focused on species that cease feeding during winter. In this work, we present the first extensive data set on the seasonal variation in metabolic rate of G. antarctica, an abundant amphipod that feeds throughout the year, and its relationship with body size, potential food availability and temperature. We measured the resting metabolic rate (RMR) of groups of individuals during 6 months from late summer through winter at 4 experimental temperatures and for a wide range of body size. RMR had a negative allometric scaling with body size and showed a tendency to increase with temperature as expected. However, temperature and body size effects on RMR showed a significant temporal variation, and an increase in temperature decreased scaling exponents. RMR at the mean seawater temperature throughout the study showed a strong seasonal variation following food availability: RMR decreased from the end of summer through winter, coinciding with a reduction in microphytobenthos stock, but recovered summer values in August, when an epontic algae boom occurred. The seasonal factorial aerobic scope (×2.37) is lower than benthic Antarctic invertebrates that cease feeding during winter, in agreement with what is expected based on theoretical grounds. Results suggest that seasonal variation of RMR would allow G. antarctica to achieve a high efficiency in energy utilization, while maintaining the ability to exploit sudden changes in food supply.     

黄腹角雉静止代谢率的研究

采用Ｋａｌａｂａｋｈｏｖ－Ｓｋｏｒｔｓｏｖ呼吸计,在不同环境温度下,测定了黄腹角雉雏鸟发育过程中的静止代谢率以及成鸟在不同季节的静止代射率。结果表明,黄腹角雉雏鸟在初始日龄时,体温随环境温度而变化,其化学性体温调节能力基本建成的日龄为９日龄。成体黄腹角雉在春,夏,秋季静止代谢率与温度间均有显著的相关性。三季的化学体温调节强度无显著差异。各季间的代谢水平也无显著差异。     

Influence of body composition on the metabolic rate of nestling European shags (Phalacrocorax aristotelis)

During the early development of avian nestlings, their mass-specific resting metabolic rate (RMR) changes in a biphasic pattern with the peak value often being much higher than that expected for an adult bird of similar body mass. In the present study we examined the possible influence of variations in the size of internal organs in “setting” the high RMR and peak metabolic rate (PMR) during development in a large altricial species, the European shag (Phalacrocorax aristotelis). Thermoneutral RMR and cold-exposure induced PMR were measured in nestlings 15 days old, the age at which the highest RMR occurred during development. Body mass averaged 414 g. Mean values of RMR and PMR were 5.75 W and 9.08 W, respectively; the RMR value corresponds to approximately 250% of the expected value for an adult non-passerine bird of similar body mass. The masses of all the organs measured (breast and leg muscles, heart, liver, intestine, and kidney) varied isometrically with total body mass. However, large chicks had a significantly lower fractional water content than small chicks, suggesting that the former had achieved a higher level of functional maturity. In contrast to what has been suggested for adult birds in general, the heart and kidney masses of shag nestlings were not significantly correlated with the metabolic rates. The intestine length, in contrast, was highly and positively correlated with both the RMR and the PMR, i.e. intestine length was a better predictor of RMR and PMR than was total body mass. In addition, liver mass was positively correlated with RMR. The results of the present study suggest that the liver in particular may play a key role in establishing the high, mass-specific RMR which is attained during development in bird chicks. Our results also support previous suggestions that early in their development, altricial chicks mainly allocate energy to the growth of `energy-processing' organs (such as the intestine and liver) rather than to `energy-consuming' organs. Accepted: 3 March 1999     

Energetics in a solitary subterranean rodent, the silvery mole-rat, Heliophobius argenteocinereus, and allometry of RMR in African mole-rats (Bathyergidae)

Low resting metabolic rate (RMR) in subterranean rodents used to be considered as a physiological adaptation to cope with stresses of the belowground environment. In African mole-rats (Bathyergidae, Rodentia), RMR was reported to be independent of body mass. This deviation from a general mammalian pattern was considered a precondition for evolution of eusociality, occurring in some bathyergids. We measured metabolic rate and thermoregulation in the silvery mole-rat, Heliophobius argenteocinereus, the only bathyergid genus for which well-supported, comparable data were still missing. Low RMR (154.04 mL O(2) h(-1), which is 82% of the value predicted for a rodent) corresponds to the value expected in a subterranean rodent. Broad range of the thermoneutral zone (25-33 degrees C) and only slightly higher conductance (17.3 mL O(2) h(-1) degrees C(-1), i.e. 112.5% of that predicted for subterranean mammals) indicate that H. argenteocinereus is adapted to lower burrow temperatures rather than to high temperatures. Low RMR in this solitary species, as in other subterranean rodents in general, is probably associated particularly with high energetic cost of foraging. Our results combined with data on other mole-rats show clearly that RMR within the Bathyergidae is mass-dependent.     

Comparative growth rates and oxygen consumption in young Galliformes

The high correlation between growth rate and adult body weight has been much more thoroughly documented for altricial birds than for precocial species. This paper gathers data from the literature for precocial Galliformes and also reports new growth data on six galliform species for analysis. The onset of homeothermic ability is investigated in Galliformes over a range of body size. The results confirm that (1) large species' chicks grow at a slower rate than those of smaller species, and (2) larger species' chicks can thermoregulate earlier than smaller species' chicks under cold stress situations. Published embryonic body weights are also analysed to determine when growth rate differences appear in the development of precocial species. No interspecific differences appeared in the relative growth rates of embryos, and therefore species body size does not appear to influence growth rate before hatching.     

Metabolic and organ mass responses to selection for high growth rates in the domestic chicken (Gallus domesticus)

Evolutionary hypotheses suggest that higher rates of postembryonic development in birds should either lower the resting metabolic rate (RMR) in a trade-off between the costs of growth and maintenance or increase RMR because of a buildup of metabolic machinery. Furthermore, some suggest that higher rates of postembryonic development in birds should reduce peak metabolic rate (PMR) through delayed tissue maturation and/or an increased energy allocation to organ growth. We studied this by comparing metabolic rates and organ sizes of fast-growing meat-type chickens (broilers) with those of birds from a laying strain, which grow much slower. During the first week of life, despite growing six times faster, the RMR of the broiler chickens was lower than that of birds of the laying strain. The difference between strains in RMR disappeared thereafter, even though broilers continued to grow twice as fast as layers. The differences between strains in growth rate during the first week after hatching were not reflected in similar differences in the relative masses of the heart, liver, and small intestine. However, broilers had heavier intestines once they reached a body mass of 80 g. In contrast, broilers had relatively smaller brains than did layers. There was a positive correlation, over both strains, between RMR and the masses of leg muscles, intestine, and liver. Furthermore, despite delayed maturation of muscle tissue, broilers exhibited significantly higher PMR. We hypothesize that a balance between the larger relative muscle mass but lower muscle maturation level explains this high PMR. Another correlation, between leg muscle mass and PMR, partly explained the positive correlation between RMR and PMR.     

Presence of a conspecific causes divergent changes in resting metabolism,depending on its relative size

It is well established that the average metabolism of many species of fish varies with group size. However, it is not clear whether all individuals respond in the same way. Here, we use a newly calibrated method of measuring the metabolic rate of fish from opercular (ventilatory) movements that allows for the first-time estimation of changes in resting metabolic rate (RMR) of each individual within different social groups and when alone. The presence of a conspecific had divergent effects on the RMR of juvenile Atlantic salmon Salmo salar, depending on its relative body size: the presence of a smaller fish caused a 40 per cent reduction, whereas the presence of a slightly larger fish approximately doubled RMR. These effects occurred in the absence of activity and were sustained at lower magnitude in the case of the relatively smaller conspecific even if a transparent barrier prevented any physical interactions between fish. Changes in RMR were mirrored by changes in eye colour that indicate they were linked to stress levels. These contrasting and strong responses show that even the nearby presence of a conspecific can have profound and variable effects on an individual''s energy budget; they also highlight the complex trade-offs involved in social interactions.     

Energy expenditure in Crocidurinae shrews (Insectivora): is metabolism a key component of the insular syndrome?

A cascade of morphological, ecological, demographical and behavioural changes operates within island communities compared to mainland. We tested whether metabolic rates change on islands. Using a closed circuit respirometer, we investigated resting metabolic rate (RMR) of three species of Crocidurinae shrews: Suncus etruscus, Crocidura russula, and C. suaveolens. For the latter, we compared energy expenditure of mainland and island populations. Our measurements agree with those previously reported for others Crocidurinae: the interspecific comparison (ANCOVA) demonstrated an allometric relation between energy requirements and body mass. Energy expenditure also scaled with temperature. Island populations (Corsica and Porquerolles) of C. suaveolens differed in size from mainland (gigantism). A GLM showed a significant relationship between energy expenditure, temperature, body mass and locality. Mass specific RMR allometrically scales body mass, but total RMR does not significantly differ between mainland and island, although island shrews are giant. Our results are consistent with other studies: that demonstrated that the evolution of mammalian metabolism on islands is partially independent of body mass. In relation to the insular syndrome, we discuss how island selective forces (changes in resource availability, decrease in competition and predation pressures) can operate in size and physiological adjustments.     

Metabolism and thermoregulation in the Cabrera vole (Rodentia: Microtus cabrerae)

Metabolism and thermoregulation were studied for the first time in the Cabrera vole (Microtus cabrerae), an endemic and threatened rodent of the Iberian Peninsula. Low values of resting metabolic rate (RMR) were registered (1.13 mlO(2) g(-1) h(-1)) at the lower limit of the thermoneutral zone (TNZ) (around 33.5 degrees C). Body temperature increased near the TNZ up to 37.3 degrees C but remained stable, around 36 degrees C, at ambient temperatures below 25 degrees C. Values of thermal conductance remained quite stable at ambient temperatures of 10-25 degrees C (0.144-0.160 mlO(2) g(-1) h(-1) degrees C) and increased to 0.301 mlO(2) g(-1) h(-1) degrees C at 33.5 degrees C. Data revealed that M. cabrerae developed a highly adaptive ability of conserving energy and lowering the metabolic cost of thermoregulation at high ambient temperatures, allowing the body temperature to approximate that of the environment and exhibiting low resting metabolic rate and high conductance.