Effects of ocean acidification on the metabolic rates of three species of bivalve from southern coast of China

Oceanic uptake of anthropogenic carbon dioxide results in a decrease in seawater pH, a process known as "ocean acidification". The pearl oyster Pinctada fucata, the noble scallop Chlamys nobilis, and the green-lipped mussel Perna viridis are species of economic and ecological importance along the southern coast of China. We evaluated the effects of seawater acidification on clearance, respiration, and excretion rates in these three species. The animals were reared in seawater at pH 8.1 (control), 7.7, or 7.4. The clearance rate was highest at pH 7.7 for P. fucata and at pH 8.1 for C. nobilis and P. viridis. The pH had little effecton the respiration rate of P. fucata and P. viridis. In contrast, the respiration rate was significantly lower atpH 7.4 in C. nobilis. The excretion rate was significantly lower at pH 7.4 than pH 8.1 for all species. Theresults indicate that the reduction in seawater pH likely affected the metabolic process (food intake, oxygenconsumption, and ammonia excretion) of these bivalves. Different species respond differently to seawateracidification. Further studies are needed to demonstrate the exact mechanisms for this effect and evaluateadaptability of these bivalves to future acidified oceans.

Sources and significance of variation in basal,summit and maximal metabolic rates in birds

The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates （e.g., lower and upper limits of metabolic power output） present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate （BMR; minimum normothermic metabolic rate）, summit metabolic rate （Msum; maximal thermoregulatory metabolic rate）, and maximal metabolic rate （MMR; maximal exercise metabolic rate）], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate （or daily energy expenditure） in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of： （1） the functional and mechanistic links between lower and upper limits of metabolic power output; （2） the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; （3） the shapes of metabolic reaction norms and their association with environmental variability; and （4） the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 （6）： 741-758, 2010].

Effects of Diet with"Lianhuang"Additive of Chinese Herb Medicine on Growth Performance and Metabolic Rates of Dietary Nutrients in Donglan Black Chicken

[Objectives]The study was conducted to evaluate the effects of diet with"Lianhuang"additive of Chinese herbal medicine(LACHM)on growth performance and metabolic rates of dietary nutrients in Donglan black chickens(DBCs).[Methods]80 DBCs aged 1 d were blocked into 4 groups randomly and assigned to 6 replicates in each group with 20 chicks in each replicate.Group A as control group fed basal diet.Groups B,C and D as treatment groups consumed the basal diet added with 0.25%,0.50%and 1.00%of LACHM,respectively during the test period of 70 d.In the end of feeding test,24 DBCs with similar body weight from each group were chosen out and used for a metabolism test to determine the metabolic rates of dietary nutrients from each treatment.The metabolism test was conducted as the same design as the feeding test and the DBCs from each group were fed the same diet as previous test.[Results]The ADG of chickens in the test increased by 5.00%-9.15%(P<0.05)except the stage of 50-70 d,and the individual average body weight(IABW)at 70 d in group B also increased by 4.86%(P<0.05).Compared with group A,the ADG of group C in the stages of 36-49,1-49 and 1-70 d and the IABW in the end of 70 d increased by 5.90%,2.66%,2.68%and 2.57%(P>0.05),respectively.The ADFI in the stage of 36-49 d from group A was 6.04%more than that from group B(P<0.01),and 5.12%and 4.13%more than those from groups C and D(P<0.05),respectively,and the ADFI of group A in the stage of 1-49 d was still 2.86%more than that from group C(P<0.05).However,no differences in ADFI were found in other stages in the test among the 4 groups(P>0.05).The F/G in the stages of 22-35 and 1-70 d from group B was 6.32%and 3.41%lower than those from group A(P<0.05),respectively,and even 11.43%and 7.31%lower in the stages of 36-49 and 1-49 d from group B than those from group A(P<0.01),respectively.The F/G of group C in the stage of 36-49 d was also 10.15%lower than that of group A(P<0.05),and still 5.29%lower than that from group A in 1-49 d(P<0.01),but no differences were found in other stages between the two groups(P>0.05).The metabolic rates of MD,CP,CF,NFE,CA,TE,Ca and P in the 3 treatment diets for group B,C and D all increased to some extent.Among them,the increasing extents of diets with 0.25%and 0.50%of LACHM for groups B and C were much greater.Therefore,the diet with 0.25%of LACHM could improve the growth performance and metabolic rates of dietary nutrients in DBCs significantly.[Conclusions]This study provides a theoretical reference for the effects of traditional Chinese medicine additives on the growth and metabolic rates of DBCs.

Short-term captivity influences maximal cold-induced metabolic rates and their repeatability in summer-acclimatized American goldfinches Spinus tristis

Studies of metabolic variation in birds have involved both wild and captive individuals, but few studies have investi- gated whether captivity directly influences metabolic rates, despite such variation potentially confounding conclusions regarding how metabolic rates respond to the conditions under study. In addition, whether short-term captivity influences metabolic rate re- peatability in birds is currently uninvestigated. In this study, we measured Msum （maximal cold-induced metabolic rates） in sum- mer acclimatized American goldfinches Spinus tristis directly after capture from wild populations, after approximately 2 weeks of indoor captivity （Captive 1）, and again after an additional 1-2 weeks of captivity （Captive 2）. M~ increased significantly （16.9%） following the initial captive period, but remained stable thereafter. Body mass （Mb） also increased significantly （9.2%） during the initial captive period but remained stable thereafter, suggesting that muscle growth and/or remodeling of body composition pro- duced the observed metabolic variation. Mb and Msum were not significantly repeatable between wild and Captive 1 birds, but were significantly repeatable between Captive 1 and Captive 2 groups. These data suggest that caution must be exercised when extrapolating metabolic rates from short-term captive to wild populations. In addition, Msum was a repeatable trait for birds under conditions where mean metabolic rates remained stable, but Msum repeatability disappeared during acclimation to conditions pro- moting phenotypically flexible metabolic responses. This suggests that the capacity for phenotypic flexibility varies among indi- viduals, and such variation could have fitness consequences

Effect of Carbohydrate Content in Feed on the Daily Metabolic Rate of S. meridionalis

The routine metabolic rate in southern catfish juvenile(24.3-250.8 g)fed with saccharine feed(CHO)was measured in this study.Fish were fed with iso-nitrogenous(40 % crude protein)and iso-lipidic(10% crude lipid)experimental feed containing 0(control feed),15%,30% of carbohydrate level.The routine metabolic rates of 15 % and 30% dietary carbohydrate group were significantly higher than that of 0% dietary carbohydrate group.The relationship between body mass(Wt)and routine metabolic rate(Rr)of southern catfishfed with different test feed could be described as:(1)0% CHO:ln(Rr)=0.986 ln(Wt)+1.419 r2=0.922,n=25,P<0.001;(2)15% CHO:ln(Rr)=0.912 ln(Wt)+1.741 r2=0.966,n=21,P<0.001;(3)30% CHO:ln(Rr)=0.762 ln(Wt)+2.378 r2=0.958,n=21,P<0.001.The intercept was increased and mass coefficient was decreased with the increase of carbohydrate level in feed.It could be concluded that southern Silurus meridionalis had poor metabolic capacity which led the increase of routine metabolic rate of fish with small size.But with the increase of body size southern Silurus meridionalis might had a better adaptation to high carbohydrate concentration.

The Relation of Standard Metabolic Rate to Water Temperature and Body Weight of Schlegels Black Rockfish(Sebastodes Fuscescens)

Standard metabolic rates of Schlegels black rockfish with different body weights are determined in laboratory by using the flow-through respirometer at 11.2 ℃, 14.7℃ , 18.0 ℃ and 23.6 ℃ . The results indicate that the standard metabolic rates increase with the increase of body weight at different temperatures. Relationship between them could be described as Rs = a ln W b. The mean of standard metabolic rate is significantly different among groups, but the b values are not. The standard metabolic rates of amended standard body weights decrease with the increase of temperature, and the mean of standard metabolic rate is also significantly different among groups when the standard body weights are 48.6 g, 147.9 g, and 243.1 g. Relationship between them could be described as Rsw = m e-b/T. The relations of standard metabolic rate ( Rs ) or relative metabolic rate ( Rs ) to body weight and temperature yield the following equations: Rs = 1.160 W 0.752 e -9.494/ T and Rs’= 1.160 W 0.254 e -9.494/ T.

The role of temperature as a driver of metabolic flexibility in the Red-billed Leiothrix(Leiothrix lutea)

Background:The thermoregulatory ability of animals is strongly influenced by the temperature of their environment.Acclimation to cold requires a range of physiological and morphological adjustments.In this study,we tested the hypothesis that a small passerine,the Red-billed Leiothrix(Leiothrix lutea),can maintain homeothermy in cold conditions by adjusting the physiology and biochemistry of its tissue and organs and return to its former physiological and biochemical state when moved to a warm temperature.Methods:Phenotypic variation in thermogenic activity of the Red-billed Leiothrixs(Leiothrix lutea)was investigated under warm(35℃),normal(25℃)or cold(15℃)ambient temperature conditions.Oxygen consumption was measured using an open-circuit respirometry system.Mitochondrial state-4 respiration and cytochrome-c oxidase(COX)activity in liver,kidney heart and pectoral muscle were measured with a Clark electrode.Results:Birds acclimated to an ambient temperature of 15℃ for 4 weeks significantly increased their basal metabolic rate(BMR)compared to a control group kept at 25℃.Birds acclimated to 35℃ decreased their BMR,gross energy intake(GEI)and digestible energy intake(DEI).Furthermore,birds acclimated to 15℃ increased state-4 respiration in their pectoral muscles and cytochrome-c oxidase(COX)activity in their liver and pectoral muscle,compared to the 25℃ control group.Birds acclimated to 35℃ also displayed lower state-4 respiration and COX activity in the liver,heart and pectoral muscles,compared to those kept at 25℃.There was a positive correlation between BMR and state-4 respiration,and between BMR and COX activity,in all of the above organs except the liver and heart.Conclusions:Our study illustrates that the morphological,physiological,and enzymatic changes are associated with temperature acclimation in the Red-billed Leiothrix,and supports the notion that the primary means by which small birds meet the energetic challenges of cold conditions is through metabolic adjustments.

Short photoperiod increases energy intake, metabolic thermogenesis and organ mass in silky starlings Sturnus sericeus

Environmental cues play important roles in the regulation of an animal＇s physiology and behavior. One such cue, photoperiod, plays an important role in the seasonal acclimatization of birds. It has been demonstrated that an animal＇s body mass, basal metabolic rate （BMR）, and energy intake, are all affected by photoperiod. The present study was designed to examine photoperiod induced changes in the body mass, metabolism and metabolic organs of the silky starling, Stumus sericeus. Captive silky starlings increased their body mass and BMR during four weeks of acclimation to a short photoperiod. Birds acclimated to a short photopedod also increased the mass of certain organs （liver, gizzard and small intestine）, and both gross energy intake （GEl） and digestible energy intake （DEI）, relative to those acclimated to a long photoperiod. Furthermore, BMR was positively correlated with body mass, liver mass, GEl and DEI. These results suggest that silky starlings increase metabolic thermogenesis when exposed to a short photoperiod by increasing their body and metabolic organ mass, and their GEl and DEI. These findings support the hypothesis that bird species from temperate climates typically display high phenotypic flexibility in thermogenic capacity.

Metabolic rate and evaporative water loss in the silky starling （Sturnus sericeus）

To better understand the physiological characteristics of the silky starling（Sturnus sericeus）, its body temperature（Tb）, basal metabolic rate（BMR）, evaporative water loss（EWL） and thermal conductance（C） elicited by different ambient temperatures（Ta）（5-30 ℃） were determined in the present study. Our results showed that they have a high Tb（41.6±0.1 ℃）, a wide thermal neutral zone（TNZ）（20-27.5 ℃） and a relatively low BMR within the TNZ（3.37±0.17 mL O2/g·h）. The EWL was nearly stable below the TNZ（0.91±0.07 mg H2O/g·h） but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14±0.01 mL O2/g·h·℃. These findings indicate that the BMR, Tb and EWL of the silky starling were all affected by Ta, especially when Ta was below 20℃ and the EWL plays an important role in thermal regulation.

Seasonal acclimatization and temperature acclimation in small passerine birds is achieved via metabolic adjustments

Temperature and other environmental factors play an integral role in the metabolic adjustments of animals and drive a series of morphological,physiological,and behavioral adaptions essential to survival.However,it is not clear how the capacity of an organism for temperature acclimation translates into seasonal acclimatization to maintain survival.Basal metabolic rate(BMR),evaporative water loss(EWL),and energy budget were measured in the Chinese Hwamei(Garrulax canorus)following winter and summer acclimatization,and in those acclimatized to 15℃(cold)and 35℃(warm)under laboratory conditions for 28 days.In addition to the above indicators,internal organ masses,as well as state 4 respiration and cytochrome c oxidase(COX)activity were also measured for the liver,skeletal muscle,heart,and kidney.Both winter-acclimatized and cold-acclimated birds exhibited significantly higher BMR,EWL,and energy budget,as well as organ masses,state 4 respiration,and COX activity compared with the summer-acclimatized and warm-acclimated birds.This indicated that the Chinese Hwamei could adapt to seasonal or just temperature changes through some physiological and biochemical thermogenic adjustments,which would be beneficial to cope with natural environmental changes.A general linear model showed that body mass,BMR,GEI,state 4 respiration in the liver and kidney,and COX activity in the skeletal muscle,liver,and kidney were significantly affected by temperature and acclimation.A positive correlation was observed between BMR and each of the other parameters(body mass,EWL,energy budget,heart dry mass,kidney dry mass,state 4 respiration)in the muscle,heart,and kidney and also between BMR and COX activity in the muscle and kidney.The results suggested that similar to seasonal acclimatization,Chinese Hwameis subjected to temperature acclimation also exhibited significant differences in metabolism-related physiological and biochemical parameters,depending on the temperature.The data also supported the prediction that metabolic adjustment might be the primary means by which small birds meet the energetic challenges triggered by cold conditions.

Modeling on Metabolic Rate and Thermoregulation in Three Layered Human Skin during Carpentering, Swimming and Marathon

Metabolisms play a vital role in thermoregulation in the human body. The metabolic rate varies with the activity levels and has different behaviors in nature depending on the physical activities of the person. During the activity, metabolic rate increases rapidly at the beginning and then increases slowly to become almost constant after a certain time. So, its behavior is as logistics in nature. The high metabolic rate during activity causes the increase of body core temperature up to 39˚C [1] [2]. The logistic model of metabolic rate is used to re-model Pennes’ bioheat equation for the study of temperature distribution in three layered human dermal parts during carpentering, swimming and marathon. The finite element method is used to obtain the solution of the model equation. The results demonstrate that there is a significant change in tissue temperature due to sweating and ambient temperature variations.

Incubation temperature induced developmental plasticity of cold responsive physiological phenotypes in Japanese Quails

Embryonic development is a critical period for phenotype formation.Environmental variation during embryonic development can induce changes in postnatal phenotypes of animals.The thyroxine secretion and aerobic metabolic activity of small birds are important phenotypes closely related to their winter survival.In the context of climate change,it is necessary to determine whether temperature variation during incubation in birds leads to developmental plasticity of these cold responsive phenotypes.We incubated Japanese Quail(Coturnix japonica)eggs at 36.8℃,37.8℃,and 38.8℃,and raised the chicks to 35-day old at 22℃with same raising conditions,then all the quails were exposed to gradually temperature dropping environment(from 15℃to 0℃).After cold treatment,serum T3 level,resting metabolic rate,skeletal muscle and liver metabolomes of the birds were measured.The serum T3 levels were significantly lower in the 38.8℃group and significantly higher in the 36.8℃group compared to the 37.8℃group.The metabolic rate in the 38.8℃group was significantly lower compared to the 37.8℃group.Compared with the 37.8℃group,metabolites involved in the tricarboxylic acid cycle in the liver were significantly lower in the 38.8℃group,and metabolites related to lipid oxidation metabolism and fatty acid biosynthesis were significantly lower in the skeletal muscles in the 38.8℃group but significantly higher in the 36.8℃group.These results indicate that incubation temperature variation can lead to developmental plasticity in cold responsive physiological phenotypes.Higher incubation temperature may impair the capacity of birds coping with cold challenge.

Application of ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in recurrent anastomotic tumors after surgery in digestive tract tumors

BACKGROUND This study was to investigate the application value of whole-body dynamic ^(18)F-fluorodeoxyglucose(FDG)positron emission tomography/computed tomogra-phy(PET/CT)imaging in recurrent anastomotic tumors of digestive tract after gastric and esophageal cancer surgery.Postoperative patients with gastric and esophageal cancer have a high risk of tumor recurrence,and traditional imaging methods have certain limitations in early detection of recurrent tumors.Whole-body dynamic ^(18)F-FDG PET/CT imaging,due to its high sensitivity and specifi-city,can provide comprehensive information on tumor metabolic activity,which is expected to improve the early diagnosis rate of postoperative recurrent tumors,and provide an important reference for clinical treatment decision-making.METHODS A retrospective analysis was performed on 53 patients with upper digestive tract tumors after operation and systemic dynamic ^(18)F-FDG PET/CT imaging indi-cating abnormal FDG uptake by anastomosis,including 29 cases of gastric cancer and 24 cases of esophageal cancer.According to the follow-up results of gas-troscopy and other imaging examinations before and after PET/CT examination,the patients were divided into an anastomotic recurrence group and anastomotic inflammation group.Patlak multi-parameter analysis software was used to obtain the metabolic rate(MRFDG),volume of distribution maximum(DVmax)of anastomotic lesions,and MRmean and DVmean of normal liver tissue.The lesion/background ratio(LBR)was calculated by dividing the MRFDG and DVmax of the anastomotic lesion by the MRmean and DVmean of the normal liver tissue,respectively,to obtain LBR-MRFDG and LBR-DVmax.An independent sample t test was used for statistical analysis,and a receiver operating characteristic curve was used to analyze the differential diagnostic efficacy of each parameter for anastomotic recurrence and inflammation.RESULTS The dynamic ^(18)F-FDG PET/CT imaging parameters MRFDG,DVmax,LBR-MRFDG,and LBR-DVmax of postoperative anastomotic lesions in gastric cancer and esophageal cancer showed statistically significant differences between the recurrence group and the inflammatory group(P<0.05).The parameter LBR-MRFDG showed good diagnostic efficacy in differentiating anastomotic inflammation from recurrent lesions.In the gastric cancer group,the area under the curve(AUC)value was 0.935(0.778,0.993)when the threshold was 1.83,and in the esophageal cancer group,the AUC value was 1.When 86 is the threshold,the AUC value is 0.927(0.743,0.993).CONCLUSION Whole-body dynamic ^(18)F-FDG PET/CT imaging can accurately differentiate the diagnosis of postoperative anastomotic recurrence and inflammation of gastric cancer and esophageal cancer and has the potential to be an effective monitoring method for patients with upper digestive tract tumors after surgical treatment.

Metabolism and thermoregulation between Mrs Hume's Pheasant(Syrmaticus humiae) and Elliot's Pheasant(S.ellioti)

To understand metabolic adaptations,the basal metabolic rate（BMR） of Mrs Hume＇s Pheasant（Syrmaticus humiae） and Elliot＇s Pheasant（Syrmaticus ellioti） were investigated.Metabolic rate（MR）,body temperature（Tb） and thermal conductance（C） were determined in both species at a temperatrue range of 5-35 ℃,respectively.Oxygen consumption was measured with a closed circuit respirometer.The thermal neutral zones（TNZ） were 24.5-31.6 ℃,and 23.0-29.2 ℃,respectively.With a temperature range of 5-35 ℃,Mrs Hume＇s Pheasant and Elliot＇s Pheasant could maintained stable Tb at a mean of（40.47±0.64） and（40.36±0.10） ℃,respectively.Mean BMRs within TNZs were（1.36±0.84） mLO2/（g.h） for Mrs Hume＇s Pheasant and（2.03±0.12） mLO2/（g.h） for Elliot＇s Pheasant,which were 77% and 86% of the expected value based on their body mass,respectively.Thermal conductance of Mrs Hume＇s Pheasant and Elliot＇s Pheasant were（0.12±0.01） and（0.17±0.01） mLO2/（g.h.℃）,below the lower critical temperature,respectively,which were 119% and 124% of the expected value based on their body mass,respectively.The ecophysiological characteristics of these species were low metabolic rate,high body temperature,and high thermal conductance,which allow both species to better adapt to the warmer climate environment in south China.

Effects of Different Energy Levels on Nutrient Utilization and Serum Biochemical Parameters of Early-Weaned Calves

Current study was performed to investigate the effects of different energy levels on nutrient digestion metabolism and serum biochemical parameters of early-weaned calves. Twelve neonatal Holstein calves were selected and assigned randomly to receive 1 of 3 treatments that contained 18.51, 19.66 and 20.80 MJ kg^-1 gross energy, respectively （n=4 per treatment）. Digestion and metabolism trials were carried out in 5 phases （12-20, 22-30, 32-40, 42-50, and 52-60 d of age）. At the same time, blood metabolites were determined at 21, 31, 41, 51, and 61 d of age prior to morning feeding. The results indicated that either dry matter （DM）, organic matter （OM） and gross energy （GE） apparent digestibility or N and P retention tended to increase as age advanced; the average value of DM and OM apparent digestibility and Ca retention in high-energy treatment was significantly lower than that of other groups （P 〈 0.05）; there were no significant differences in the concentration of serum glucose, triglyceride and urea N among treatments, whereas a significant effect of age was found on the level of triglyceride （P 〈 0.05）. To sum up, medium-energy milk replacer seems to be more beneficial for GE digestibility and N utilization, whereas low-energy milk replacer appears to be more rewarding for Ca and P utilization.

Seasonal phenotypic flexibility in body mass,basal thermogenesis,and tissue oxidative capacity in the male Silky Starling(Sturnus sericeus)

Background: Acclimatization to winter conditions is an essential prerequisite for the survival of small birds in the northern temperate zone.Changes in photoperiod,ambient temperature and food availability trigger seasonal physiological and behavioral acclimatization in many passerines.Seasonal trends in metabolic parameters are well known in avian populations from temperate environments;however,the physiological and biochemical mechanisms underlying these trends are incompletely understood.In this study,we used an integrative approach to measure variation in the thermogenic properties of the male Silky Starling(Sturnus sericeus) at different levels or organization,from the whole organism to the biochemical.We measured body mass(Mb),basal metabolic rate(BMR),energy budget,the mass of selected internal organs,state 4 respiration and cytochrome c oxidase(COX) activity in the heart,liver and muscle.Methods: Oxygen consumption was measured using an open-circuit respirometry system.The energy intake of the birds were then determined using an oxygen bomb calorimeter.Mitochondrial state 4 respiration and COX activity in heart,liver and pectoral muscle were measured with a Clark electrode.Results: The results suggest that acclimatization to winter conditions caused significant change in each of the measured variables,specifically,increases in Mb,organ mass,BMR,energy intake and cellular enzyme activity.Furthermore,BMR was positively correlated with body mass,energy intake,the mass of selected internal organs,state 4 respiration in the heart,liver and muscle,and COX activity in the heart and muscle.Conclusions: These results suggest that the male Silky Starling's enhanced basal thermogenesis under winter conditions is achieved by making a suite of adjustments from the whole organism to the biochemical level,and provide further evidence to support the notion that small birds have high phenotypic plasticity with respect to seasonal changes.

The Effects of Chronic Hypoxia on Thermoregulation and Metabolism in Phrynocephalus vlangalii

Phrynocephalus vlangalii are widely distributed on Tibetan plateau spanning diverse altitudes and habitats. In the present study, P vlangalii were exposed to 8% oxygen concentration in a hypoxic chamber for 6 weeks. Then the body temperature （Tb）, standard metabolic rate （SMR）, heart rate and metabolic enzyme activities of the lizards were measured at 20℃ and 30℃. The results indicated that hypoxia exposure decreased Tb, SMR and heart rate. Lactate dehydrogenase （LDH） activity of 8% 02 group became significant elevated in liver and skeletal muscle compared with control group at 20℃, but descended significantly in heart. Using electrophoresis we found that LDH contains five isozymes （LDH1, LDH2, LDH3, LDH4 and LDH5） and are expressed specifically in liver, skeletal muscle and heart. Citrate synthase （CS） activity in the liver also decreased at 20℃ and 30℃. No significant difference of CS activity was found between the two groups in skeletal muscle and heart.

Interspecific variation of thermoregulation between small migratory and resident passerines in Wenzhou

Physiological adaptation arises from several fundamental sources of phenotypic variation. Most analyses of metabolic adaptation in birds have focused on the basal metabolic rate （BMR）, the lower limit of avian metabolic heat production. In this study, we investigated thermoregulation in three passerine species; the yellow-billed grosbeak Eophona migratoria, white-rumped munia Lonchura striata and black-throated bushtit Aegithalos concinnus, in Wenzhou, China. Metabolic rate was measured using the closed-circuit respirometer containing 3.5 L animal chambers. Body temperature （Tb） was measured during metabolic measurements using a lubricated thermocouple. The minimum thermal conductance of these species was calculated by measuring their Tb and metabolic rates. The yellow-billed grosbeak remained largely normothermic, and the white-rumped munia and black-throated bushtit exhibited variable Tb at ambient temperatures （Ta）. Mean metabolic rates within thermal neutral zone were 2.48±0.09 02 （mL）/g/h for yellow-billed grosbeaks, 3.44±0.16 02 （mL）/g/h for white-rumped munias, and 3.55±0.20 O2 （mL）/g/h for black-throated bushtits, respectively. Minimum thermal conductance of yellow-billed grosbeak, white-rumped munia and black-throated bushtit were 0.13±0.00, 0.36±0.01, and 0.37±0.01 02 （mL）/g/h/℃, respectively. The ecophysiological characteristics of these species were： （1） the yellowbilled grosbeak had relatively high Tb and BMR, a low lower critical temperature and thermal conductance, and a metabolic rate that was relatively insensitive to variation in Ta; all of which are typical of cold adapted species and explain its broader geographic distribution; （2） the white-rumped munia and black- throated bushtit had high thermal conductance, lower critical temperature, and relatively low BMR, all which are adapted to warm environments where there is little selection pressure for metabolic thermogenesis. Taken together, these data illustrate small migratory and resident passerines that exhibit the different characteristics of thermoregulation.

Effect of food restriction on the energy metabolism of the Chinese bulbul（Pycnonotus sinensis）

Food resources play an important role in the regulation of animals’ physiology and behavior. We investigated the effect of short-term food restriction on metabolic thermogenesis of Chinese bulbuls（Pycnonotus sinensis） by measuring changes in body mass, body fat, basic metabolic rate（BMR）, and organ mass of wild-caught Chinese bulbuls from Wenzhou, China. Short-term food restriction induced a significant decrease in body mass and body fat but body mass returned to normal levels soon after food was no longer restricted. Food restriction caused a significant reduction in BMR after 7 days（P〈0.05）, which returned to normal levels after food restriction ceased. Log total BMR was positively correlated with log body mass（r2=0.126, P〈0.05）. The dry masses of livers and the digestive tract were higher in birds that had been subject to temporary food restriction than in control birds and those subject to continual food restriction（P〈0.001 and P〈0.05, respectively）. There was also significant differences in the dry mass of the lungs（P〈0.05）, heart（P〈0.01）, and spleen（P〈0.05） in birds subject to short-term food restriction compared to control birds and those subject to continual food restriction. BMR was positively correlated with body and organ（heart, kidney and stomach） mass. These results suggest that the Chinese bulbul adjusts to restricted food availability by utilizing its energy reserves, lowering its BMR and changing the weight of various internal organs so as to balance total energy requirements. These may all be survival strategies that allow birds to cope with unpredictable variation in food abundance.

Thermogenic responses in Eurasian Tree Sparrow(Passer montanus)to seasonal acclimatization and temperature-photoperiod acclimation

Background:Small birds in temperate habitats must either migrate,or adjust aspects of their morphology,physiology and behavior to cope with seasonal change in temperature and photoperiod.It is,however,difficult to accurately measure how seasonal changes in temperature and photoperiod affect physiological processes such as basal metabolic rate(BMR)and metabolic activity.To address this problem,we collected data in each month of the year on body mass(Mb)and BMR,and conducted a series of experiments to determine the effect of temperature and photoperiod on Mb,BMR and physiological markers of metabolic activity,in the Eurasian Tree Sparrow(Passer montanus).Methods:In one experiment,we measured monthly change in Mb and BMR in a captive group of birds over a year.In another experiment,we examined the effects of acclimating birds to two different temperatures,10 and 30℃,and a long and a short photoperiod(16 h light:8 h dark and 8 h light:16 h dark,respectively)for 4 weeks.Results:We found that these treatments induced sparrows to adjust their Mb and metabolic rate processes.Acclimation to 30℃for 4 weeks significantly decreased sparrows’Mb,BMR,and energy intake,including both gross energy intake and digestible energy intake,compared to birds acclimated to 10℃.The dry mass of the liver,kidneys and digestive tract of birds acclimated to 30℃also significantly decreased,although their heart and skeletal muscle mass did not change significantly relative to those acclimated to 10℃.Birds acclimated to 30℃also had lower mitochondrial state-4 respiration(S4R)and cytochrome c oxidase(COX)activity in their liver and skeletal muscle,compared to those acclimated to 10℃.Birds acclimated to the long photoperiod also had lower mitochondrial S4R and COX activity in their liver,compared to those acclimated to the short photoperiod.Conclusions:These results illustrate the changes in morphology,physiology,and enzyme activity induced by seasonal change in temperature and photoperiod in a small temperate passerine.Both temperature and photoperiod probably have a strong effect on seasonal variation in metabolic heat production in small birds in temperate regions.The effect of temperature is,however,stronger than that of photoperiod.