Acclimatory responses of thermal physiological performances in hatchling yellow pond turtles (Mauremys mutica)

2020 ◽  
Vol 70 (1) ◽  
pp. 55-65
Author(s):  
Hongliang Lu ◽  
Yingchao Hu ◽  
Shuran Li ◽  
Wei Dang ◽  
Yongpu Zhang

Abstract Temperature is a crucial environmental factor that can strongly impact animal physiology. Here, we acclimated hatchling of Asian yellow pond turtles (Mauremys mutica) to one of two different temperatures (25 or 30°C) for four weeks to determine temperature acclimation effects on their physiology. All four measured physiological variables (righting time, resting metabolic rate, critical thermal minimum and critical thermal maximum) were significantly affected by temperature acclimation. Turtles acclimated to 25°C righted themselves more slowly and had a lower mean metabolic rate than 30°C-acclimated turtles. Turtles acclimated to 25°C were more resistant to low temperatures, but less resistant to high temperatures than 30°C-acclimated turtles, as measured by critical thermal limits. The thermal resistance range (i.e., the difference between critical thermal minimum and maximum) did not differ between the two acclimation groups. Compared with other semi-aquatic turtles, M. mutica had relatively higher acclimation response ratios for its critical thermal minimum and critical thermal maximum. Our results indicate that acclimation to relatively moderate temperatures could also produce significant responses in the thermal physiology of turtles.

1990 ◽  
Vol 259 (2) ◽  
pp. E233-E238 ◽  
Author(s):  
N. K. Fukagawa ◽  
L. G. Bandini ◽  
J. B. Young

The relationship between fat-free mass (FFM) and resting metabolic rate (RMR) was compared in young men (n = 24; age 18-33 yr), old men (n = 24; 69-89 yr), and old women (n = 20; 67-75 yr). Body composition was assessed using anthropometry, bioelectrical impedance analysis (BIA), and isotope dilution with 18O-labeled water. RMR was measured at least twice using an open-circuit indirect calorimetry system with a ventilated hood. The results indicate that the different methods for assessing body composition vary substantially and should not be used interchangeably. Anthropometry was not adequate to assess group differences in body fatness, although skinfold measures may be appropriate for within-group comparisons. BIA correlated well with the isotope-dilution technique and may be a useful measure of FFM. Finally, RMR was lower in the old men than the young (1.04 +/- 0.02 vs. 1.24 +/- 0.03 kcal/min, P less than 0.001) and remained lower even when adjusted for FFM estimated by isotope dilution (P less than 0.001). RMR in the women was also lower (0.84 +/- 0.02 kcal/min), but in contrast to the difference between young and old men, RMR adjusted for FFM did not differ (P = 0.16) between old men and women. Therefore, it is clear that differences in FFM cannot fully account for the lower RMR in the old, suggesting that aging is associated with an alteration in tissue energy metabolism.


2015 ◽  
Vol 11 (2) ◽  
pp. 20141032 ◽  
Author(s):  
Rebecca E. Holt ◽  
Christian Jørgensen

The difference between maximum metabolic rate and standard metabolic rate is referred to as aerobic scope, and because it constrains performance it is suggested to constitute a key limiting process prescribing how fish may cope with or adapt to climate warming. We use an evolutionary bioenergetics model for Atlantic cod ( Gadus morhua ) to predict optimal life histories and behaviours at different temperatures. The model assumes common trade-offs and predicts that optimal temperatures for growth and fitness lie below that for aerobic scope; aerobic scope is thus a poor predictor of fitness at high temperatures. Initially, warming expands aerobic scope, allowing for faster growth and increased reproduction. Beyond the optimal temperature for fitness, increased metabolic requirements intensify foraging and reduce survival; oxygen budgeting conflicts thus constrain successful completion of the life cycle. The model illustrates how physiological adaptations are part of a suite of traits that have coevolved.


2020 ◽  
Author(s):  
Chantelle M. Penney ◽  
Gary Burness ◽  
Joshua Robertson ◽  
Chris C. Wilson

AbstractThe capacity of ectotherms to cope with rising temperatures associated with climate change is a significant conservation concern as the rate of warming is likely too fast for adaptation to occur in some populations. Transgenerational plasticity, if present, could potentially buffer some of the negative impacts of warming on future generations. We examined transgenerational plasticity in lake trout to assess their inter-generational potential to cope with anticipated warming. We acclimated adult lake trout to cold or warm temperatures for several months, then bred them to produce offspring from parents of matched and mismatched temperatures. At the fry stage, offspring were also acclimated to cold or warm temperatures and their thermal performance was assessed by measuring their critical thermal maximum and metabolic rate during an acute temperature challenge. Overall, transgenerational plasticity was evident: thermal performance of offspring reflected both maternal and paternal environmental conditions, and offspring performed better when their environment matched that of their parents. There was little variation in offspring critical thermal maximum or peak metabolic rate, although cold-acclimated offspring from warm-acclimated parents exhibited elevated standard metabolic rates, suggesting that transgenerational effects can be detrimental when parent and offspring environments mismatch. These results demonstrate both the occurrence and limitations of transgenerational plasticity in a coldwater salmonid in response to elevated temperature, as well as potential ecological risks associated with transgenerational plasticity when an environmental change experienced by the parents does not persist with the next generation.


Author(s):  
Shayok ◽  
Teresa Wu ◽  
Erica Forzani ◽  
Corrie Whisner ◽  
David Jackemeyer

In this paper, we first studied the change in resting metabolic rate (RMR) of 4 women during their pregnancy period. We retrospectively analyzed published data, which lacked rigorous statistical analysis. We introduced new data that helps to define RMR baseline variabilities and further compare the RMR fluctuations in steady physiological conditions (no pregnancy, no weight/diet/exercise regime change) to assess “true” RMR changes that can guide healthy weight management in pregnancy and other conditions. For each subject, the change in the RMR values were computed as the difference between the values during the metabolic rate inspection period and the baseline values. This difference was compared against the difference values of a reference subject, using a two-sided paired t-test at the significance level of 5%. Our results indicated that some subjects exhibit a statistically significant increase, some exhibit a decrease while others show no significant statistical variation in RMR values during pregnancy. These are important findings that demystify the old idea that the RMR of a pregnant woman “always” increases since she is generating a new life; rather, individualized physiological processes can produce metabolic changes that cannot be generalized and need individual RMR measurements throughout pregnancy. The insights gained from this study were then applied to retrospectively analyze the RMR of 20 subjects during a 6-month pilot weight loss intervention with 89% efficiency in weight loss. Our analysis revealed that there was no significant decrease in metabolic activities at the end of the program. Although this contradicts the belief that weight loss is associated with a decrease in metabolic activities, our results can be explained by the fact that subjects adhered to a healthy nutritional diet and regular exercise during the pro- gram; thus, the effect of weight loss on decreasing the RMR was counter-balanced by the effect of healthier diet and exercise on increasing the RMR, which helped in maintaining a steady and healthy metabolic rate. Both studies, pregnancy and weight loss interventions indicated that changes in the metabolic rate of pregnant women and individuals undergoing weight loss interventions are unpredictable, therefore there is an urgent need to implement personalized practices of weight management by periodically measuring RMR and adjusting food caloric intakes based on the individual’s metabolic rate.


2016 ◽  
Vol 26 (5) ◽  
pp. 454-463 ◽  
Author(s):  
Amy L. Woods ◽  
Laura A. Garvican-Lewis ◽  
Anthony J. Rice ◽  
Kevin G. Thompson

The aim of the current study was to determine if a single ParvoMedics TrueOne 2400 metabolic cart provides valid and reliable measurement of RMR in comparison with the criterion Douglas Bag method (DB). Ten endurance-trained participants completed duplicate RMR measurements on 2 consecutive days using the ParvoMedics system in exercise mode, with the same expirate analyzed using DB. Typical error (TE) in mean RMR between the systems was 578.9 kJ or 7.5% (p = .01). In comparison with DB, the ParvoMedics system over-estimated RMR by 946.7 ± 818.6 kJ. The bias between systems resulted from ParvoMedics VE(STPD) values. A regression equation was developed to correct the bias, which reduced the difference to -83.3 ± 631.9 kJ. TE for the corrected ParvoMedics data were 446.8 kJ or 7.2% (p = .70). On Day 1, intraday reliability in mean RMR for DB was 286.8 kJ or 4.3%, (p = .54) and for ParvoMedicsuncorrected, 359.3 kJ or 4.4%, (p = .35), with closer agreement observed on Day 2. Interday reliability for DB was 455.3 kJ or 6.6% (p = .61) and for ParvoMedicsuncorrected, 390.2 kJ or 6.3% (p = .54). Similar intraday and interday TE was observed between ParvoMedicsuncorrected and ParvoMedicscorrected data. The ParvoMedics TrueOne 2400 provided valid and reliable RMR values compared with DB when the VE(STPD) error was corrected. This will enable widespread monitoring of RMR using the ParvoMedics system in a range of field-based settings when DB is not available.


2018 ◽  
Vol 285 (1891) ◽  
pp. 20181685 ◽  
Author(s):  
Ummat Somjee ◽  
H. Arthur Woods ◽  
Meghan Duell ◽  
Christine W. Miller

Sexually selected weapons are among the most exaggerated traits in nature. Sexual selection theory frequently assumes a high cost of this exaggeration; yet, those costs are rarely measured. We know very little about the energetic resources required to maintain these traits at rest and the difference in energetic costs for the largest individuals relative to the smallest individuals. Knowledge in this area is crucial; resting metabolic rate can account for 30–40% of daily energy expenditure in wild animals. Here, we capitalized on the phenomenon of autotomy to take a unique look at weapon maintenance costs. Using Leptoscelis tricolor (Hemiptera: Coreidae), we measured CO 2 production rates before and after a weapon was shed. Males in this insect species use enlarged hind femora as weapons in male–male combat, and yet can shed them readily, without regeneration, upon entrapment. We found that metabolic rate decreased by an average of 23.5% in males after leg loss and by 7.9% in females. Notably, larger males had less of a drop in metabolic rate per gram of weapon lost. Our findings suggest that sexually selected weapons contribute to a large portion of resting metabolic rate in males, but these costs do not scale in direct proportion to size; larger males can have larger weapons for a reduced metabolic cost. These energetic maintenance costs may be integral to the evolution of the allometries of sexually selected weapons, and yet they remain largely unexplored.


2021 ◽  
Vol 12 ◽  
Author(s):  
Leonardo S. Longhini ◽  
Lucas A. Zena ◽  
Elias T. Polymeropoulos ◽  
Aline C. G. Rocha ◽  
Gabriela da Silva Leandro ◽  
...  

Amphibians may be more vulnerable to climate-driven habitat modification because of their complex life cycle dependence on land and water. Considering the current rate of global warming, it is critical to identify the vulnerability of a species by assessing its potential to acclimate to warming temperatures. In many species, thermal acclimation provides a reversible physiological adjustment in response to temperature changes, conferring resilience in a changing climate. Here, we investigate the effects of temperature acclimation on the physiological performance of tadpoles of a stream-breeding savanna tree frog (Bokermannohyla ibitiguara) in relation to the thermal conditions naturally experienced in their microhabitat (range: 18.8–24.6°C). We quantified performance measures such as routine and maximum metabolic rate at different test (15, 20, 25, 30, and 34°C) and acclimation temperatures (18 and 25°C). We also measured heart rate before and after autonomic blockade with atropine and sotalol at the respective acclimation temperatures. Further, we determined the critical thermal maximum and warming tolerance (critical thermal maximum minus maximum microhabitat temperature), which were not affected by acclimation. Mass-specific routine and mass-specific maximum metabolic rate, as well as heart rate, increased with increasing test temperatures; however, acclimation elevated mass-specific routine metabolic rate while not affecting mass-specific maximum metabolic rate. Heart rate before and after the pharmacological blockade was also unaffected by acclimation. Aerobic scope in animals acclimated to 25°C was substantially reduced, suggesting that physiological performance at the highest temperatures experienced in their natural habitat is compromised. In conclusion, the data suggest that the tadpoles of B. ibitiguara, living in a thermally stable environment, have a limited capacity to physiologically adjust to the highest temperatures found in their micro-habitat, making the species more vulnerable to future climate change.


2017 ◽  
Vol 42 (10) ◽  
pp. 1073-1081 ◽  
Author(s):  
Matthew M. Schubert ◽  
Holly E. Clarke ◽  
Rebekah F. Seay ◽  
Katie K. Spain

Resting metabolic rate (RMR) and substrate oxidation (respiratory exchange ratio; RER) are important indicators of health. The effects of interval training on RMR have not been thoroughly investigated, which was the purpose of the present study. Thirty men and women (mean ± SD age and maximal oxygen uptake: 28.8 ± 7.6 years and 33.0 ± 8.3 mL·kg−1·min−1) completed 4 weeks of Wingate-based sprint interval training (SIT), repeated 1-min high-intensity intervals (HIIT), or served as controls. Before and after training, RMR, resting RER, maximal oxygen uptake, body composition, physical activity, and energy intake were recorded. Data were analyzed using a repeated-measures ANOVA. RMR increased in response to 4 weeks of SIT training (1789 ± 293 to 1855 ± 320 kcal·day−1; p = 0.003) but did not increase after HIIT (1670 ± 324 to 1704 ± 329 kcal·day−1; p = 0.06). While SIT increased RMR by ∼2× the magnitude of HIIT, the difference was not significant (p = 0.5). Fasting substrate oxidation and RER did not change (p > 0.05). Maximal oxygen uptake increased, and small changes were also observed in percent body fat and fat mass (p < 0.05 for all). In conclusion, SIT provided a time-efficient stimulus to increase RMR after 4 weeks in healthy adults. However, the clinical relevance of the changes observed in this study remains to be determined. Further studies should be conducted in obese individuals and those with diabetes or insulin resistance to examine if interval training (≥4 weeks) influences resting metabolic rate in magnitudes similar to that reported here.


2009 ◽  
Vol 55 (4) ◽  
pp. 258-265 ◽  
Author(s):  
Hong Li ◽  
Zheng Wang ◽  
Wenbin Mei ◽  
Xiang Ji

Abstract We acclimated adult males of three Eremias lizards from different latitudes to 28°C, 33 °C or 38°C to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference and tolerance of these lizards correspond with their latitudinal distributions. Overall, selected body temperature (Tsel) and viable temperature range (VTR) were both highest in E. brenchleyi and lowest in E. multiocellata, with E. argus in between; critical thermal minimum (CTMin) was highest in E. multiocellata and lowest in E. brenchleyi, with E. argus in between; critical thermal maximum (CTMax) was lower in E. multiocellata than in other two species. Lizards acclimated to 28°C and 38 °C overall selected lower body temperatures than those acclimated to 33°C; lizards acclimated to high temperatures were less tolerant of low temperatures, and vice versa; lizards acclimated to 28 °C were less tolerant of high temperatures but had a wider VTR range than those acclimated to 33°C and 38°C. Lizards of three species acclimated to the three temperatures always differed from each other in CTMin, but not in Tsel, CTMax and VTR. Our results show that: temperature acclimation plays an important role in influencing thermal preference and tolerance in the three Eremias lizards, although the degrees to which acclimation temperature affects thermal preference and tolerance differ among species; thermal preference rather than tolerance of the three Eremias lizards corresponds with their latitudinal distributions.


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