Journal of thermal biology最新文献

{"title":"Impact of increased pre-start diet density on broiler chick behavior, corticosterone levels, and performance responses under cold stress during early life","authors":"","doi":"10.1016/j.jtherbio.2024.103974","DOIUrl":"10.1016/j.jtherbio.2024.103974","url":null,"abstract":"<div><p>This study assessed the effects of increased pre-start diet density on the metabolism, crop filling, and overall performance of broilers under cold stress during their initial 14 days of life. Using 576 one-day-old Cobb500 male chicks from 27-week-old breeders, the experiment employed a 2 × 2 arrangement, varying thermal conditions (thermoneutrality or cold stress at 18 °C for 8 h) and pre-start diet composition (21.5% crude protein, 2970 kcal/kg or 22.5%, 3050 kcal/kg). The cold stress group exhibited lower cloacal temperature and decreased crop filling rate during the first two days (P &lt; 0.05). Chick behavior was significantly affected at 1 and 5 days (P &lt; 0.05), and corticosterone levels in serum were higher for the cold stress group at 7 days (P &lt; 0.05). Feed intake at 7 days was lower in the high-density feed group (P &lt; 0.05). No significant interactions were observed for feed intake, body weight gain, or feed conversion ratio at 7 and 35 days (P &gt; 0.05). Cold stress resulted in performance losses, impacting feed conversion and the Productive Efficiency Index. The dense diet influenced performance only within the first week, with subsequent diets showing no effect, suggesting dietary manipulation alone was insufficient to mitigate cold stress-induced losses.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How do outside-hosts-overwintering parasitoids, at the adult stage, cope with cold?","authors":"","doi":"10.1016/j.jtherbio.2024.103940","DOIUrl":"10.1016/j.jtherbio.2024.103940","url":null,"abstract":"<div><h3>Introduction</h3><p>When overwintering, most endoparasitoids are protected from the cold inside their hosts. However, some endoparasitoids, along with ectoparasitoids, fall into the category called outside-hosts-overwintering parasitoids (OHOP) at immature or adult stages. We compared the cold-hardiness capacity and strategy between adult OHOP and their hosts (HOST) by examining their supercooling points (SCP), with acclimation periods and acclimation temperatures, and their lower lethal temperatures at 50% mortality (LLT50). We hypothesized that OHOP are more cold-hardy than their HOST, with lower SCP and LLT50.</p></div><div><h3>Materials and methods</h3><p>Throughout the summers of 2020, 2021, and 2022, adult cabbage seedpod weevils (HOST) were sampled with a sweep net at the canola pod stage, and thousands of pods were collected and placed in emergence boxes to retrieve the adult OHOP <em>Trichomalus perfectus</em>. Regarding SCP measures, OHOP and HOST were separated according to various treatments. Each treatment considered a target exposure temperature (5, 10, or 20 °C) or a target exposure period (5, 15 or 25 days) at 5 °C. Regarding LLT measures, OHOP and HOST were categorized into five treatments, each corresponding to a specific exposure temperature (−5, −10, −15, −20 or −25 °C).</p></div><div><h3>Results and conclusion</h3><p>Acclimations to a lower temperature (5 °C) and a longer period (25 days) led to a significantly lower SCP of OHOP than HOST. Regarding OHOP, the average SCP was −19.71 °C when the acclimation temperature was 20 °C and significantly decreased to −23.20 °C when it was 5 °C. The average SCP was −18.82 °C when the acclimation period was five days and significantly decreased to −23.20 °C when it was 25 days. Conversely, the average SCP for HOST was never below −20 °C. At 20 °C acclimation temperature, HOST exhibited a significantly higher SCP of −14.64 °C compared to acclimations at 5 °C (−19.19 °C) and 10 °C (−20.00 °C), but there were no significant differences between 5 and 10 °C nor between acclimation periods. Therefore, the adult OHOP is more cold-hardy than its HOST. OHOP also exhibited a lower LLT50 than HOST, with −19.20 °C <em>versus</em> −17.59 °C. Finally, OHOP and HOST employ the same freeze-avoidance strategy, as evidenced by their SCP values (−19.57 °C <em>versus</em> −16.80 °C) which closely align with their respective LLT50. Adult OHOP better survive winter than their HOST in cold environments.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S030645652400158X/pdfft?md5=6a447b7695cd0399fc9443f484cfbeb5&pid=1-s2.0-S030645652400158X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141988273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal assessment of mastitis in crossbred goats: A thermographic approach","authors":"","doi":"10.1016/j.jtherbio.2024.103947","DOIUrl":"10.1016/j.jtherbio.2024.103947","url":null,"abstract":"<div><p>Sub-clinical mastitis exhibits a higher prevalence in dairy goats than clinical mastitis, necessitating the adoption of non-invasive diagnostic techniques such as infrared thermography (IRT) to detect this economically significant production disease in the dairy sector. Accordingly, this study aims to employ IR imaging of the udder and teat quarters of lactating crossbred goats (Alpine × Beetal and Sanen × Beetal) across various seasons, utilising IRT, to discern cases of sub-clinical (SCM) and clinical mastitis (CM). Over a year, 100–110 lactating crossbred dairy goats underwent consistent IRT screenings, followed by a comprehensive evaluation of udder health status using the California mastitis test and somatic cell count (SCC). The receiver operating characteristic (ROC) analysis was conducted to establish the cut-off values for different thermographic parameters in this study. The results revealed that the SCC increased significantly (p &lt; 0.01) in healthy, SCM, and CM milk samples across the seasons. The analysis of ROC revealed a comparatively higher sensitivity, specificity, and accuracy for udder thermograms during SCM than CM and vice versa for teat thermograms. IRT analysis reflected a difference (p &lt; 0.01) in the udder and teat thermograms among quarters of healthy, SCM, and CM in summer, winter, autumn, and rainy seasons. A significant increase (p &lt; 0.01) in udder thermograms was observed for quarters affected with SCM and CM relative to healthy, with an increase of 1.89 and 2.94 °C in winter, 0.85 and 1.63 °C in summer, 0.73 and 1.41 °C in rainy, and 1.33 and 2.38 °C in autumn, respectively. Similarly, for teat thermograms it was 1.79 and 2.81 °C in winter, 0.76 and 1.41 °C in summer, 0.70 and 1.37 °C in rainy, and 1.09 and 1.93 °C in autumn, respectively. Therefore, regardless of the seasons examined in this study, IRT proves to be an effective and supportive tool for early mastitis detection in lactating crossbred dairy goats.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141992802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling thermal reaction norms for development and viability in Drosophila suzukii under constant, fluctuating and field conditions","authors":"Bréa Raynaud-Berton ,&nbsp;Patricia Gibert ,&nbsp;Christelle Suppo ,&nbsp;Sylvain Pincebourde ,&nbsp;Hervé Colinet","doi":"10.1016/j.jtherbio.2024.103891","DOIUrl":"10.1016/j.jtherbio.2024.103891","url":null,"abstract":"<div><p>Phenological models for insect pests often rely on knowledge of thermal reaction norms. These may differ in shape depending on developmental thermal conditions (e.g. constant vs. fluctuating) and other factors such as life-stages. Here, we conducted an extensive comparative study of the thermal reaction norms for development and viability in the invasive fly, <em>Drosophila suzukii</em>, under constant and fluctuating thermal regimes. Flies, were submitted to 15 different constant temperatures (CT) ranging from 8 to 35 °C. We compared responses under CT with patterns observed under 15 different fluctuating temperature (FT) regimes. We tested several equations for thermal performance curves and compared various models to obtain thermal limits and degree-day estimations. To validate the model's predictions, the phenology was monitored in two artificial field-like conditions and two natural conditions in outdoor cages during spring and winter. Thermal reaction norm for viability from egg to pupa was broader than that from egg to adult. FT conditions yielded a broader thermal breadth for viability than CT, with a performance extended towards the colder side, consistent with our field observations in winter. Models resulting from both CT and FT conditions made accurate predictions of degree-day as long as the temperature remained within the linear part of the developmental rate curve. Under cold artificial and natural winter conditions, a model based on FT data made more accurate predictions. Model based on CT failed to predict adult's emergence in winter. We also document the first record of development and adult emergence throughout winter in <em>D. suzukii</em>. Population dynamics models in <em>D. suzukii</em> are all based on summer phenotype and CT. Accounting for variations between seasonal phenotypes, stages, and thermal conditions (CT vs. FT) could improve the predictive power of the models.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001098/pdfft?md5=8f4d4ca8bceaddb5434a30ad3b2423d8&pid=1-s2.0-S0306456524001098-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141555046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validity and reproducibility of the CALERA Research Sensor to estimate core temperature at different intensities of a cycling exercise in the heat","authors":"William Martins Januário ,&nbsp;Natália Franciele Lessa ,&nbsp;Ana Júlia de Oliveira Schittine ,&nbsp;Emille Rocha Bernardino de Almeida Prata ,&nbsp;João Carlos Bouzas Marins ,&nbsp;Antônio José Natali ,&nbsp;Samuel Penna Wanner ,&nbsp;Thales Nicolau Prímola-Gomes","doi":"10.1016/j.jtherbio.2024.103907","DOIUrl":"10.1016/j.jtherbio.2024.103907","url":null,"abstract":"<div><p>Recent heatwaves have highlighted the importance of accurate and continuous core temperature (T_CORE) monitoring in sports settings. For example, accentuated rises in T_CORE caused by physical exercises under environmental heat stress increase the risk of heat illnesses. Thus, using valid and reproducible devices is essential to ensure safe sports practice. In this study, we assessed the validity and reproducibility of the Calera Research Sensor (CRS) in estimating the T_CORE of male and female participants during cycling exercise in a hot environment. Seven male (age: 36.2 ± 10.1 years) and eight female cyclists (age: 30.1 ± 5.0 years) underwent two identical cycling trials in a dry-bulb temperature of 32 °C and relative humidity of 60%. The protocol consisted of an initial 10-min rest followed by a 60-min exercise comprising 10 min at 20%, 25 min at 55%, and 25 min at 75% of maximal aerobic power, and an additional 25 min of post-exercise recovery. T_CORE was recorded simultaneously every minute using a gastrointestinal capsule (T_Gi) and the CRS (T_SENSOR). Bland–Altman analysis was performed to calculate bias, upper (LCS) and lower (LCI) concordance limits, and the 95% confidence interval (95%CI). The maximum acceptable difference between the two devices was predetermined at ±0.4 °C. A mixed linear model was used to assess the paired differences between the two measurement systems, considering the participants, trials, and environmental conditions as random effects and the cycling stages as fixed effects. An intra-class correlation coefficient (ICC) of 0.98 was recorded when analyzing data from the entire experiment. A non-significant bias value of 0.01 °C, LCS of 0.38 °C, LCI of −0.35 °C, and CI95% of ±0.36 °C were found. When analyzing data according to the participants’ sex, CRS reproducibility was high in both sexes: ICC values of 0.98 and 0.99 were reported for males and females, respectively. CI95% was 0.35 °C in experiments with males and 0.37 °C with females, thereby falling within the acceptable margin of difference. Therefore, CRS was considered valid (compared to T_Gi) and reproducible in estimating T_CORE in both sexes at various intensities of cycling exercise in the heat.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141476887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The heat is on: Thermoregulatory and evaporative cooling patterns of desert-dwelling bats","authors":"","doi":"10.1016/j.jtherbio.2024.103919","DOIUrl":"10.1016/j.jtherbio.2024.103919","url":null,"abstract":"<div><p>For small endotherms inhabiting desert ecosystems, defending body temperatures (<em>T</em>_b) is challenging as they contend with extremely high ambient temperatures (<em>T</em>_a) and limited standing water. In the arid zone, bats may thermoconform whereby <em>T</em>_b varies with <em>T</em>_a, or may evaporatively cool themselves to maintain <em>T</em>_b &lt; <em>T</em>_a. We used an integrative approach that combined both temperature telemetry and flow through respirometry to investigate the ecological and physiological strategies of lesser long-eared bats (<em>Nyctophilus geoffroyi</em>) in Australia's arid zone. We predicted individuals would exhibit desert-adapted thermoregulatory patterns (i.e., thermoconform to prioritise water conservation), and that females would be more conservative with their water reserves for evaporative cooling compared to males. Temperature telemetry data indicated that free-ranging <em>N. geoffroyi</em> were heterothermic (<em>T</em>_skin = 18.9–44.9 °C) during summer and thermoconformed over a wide range of temperatures, likely to conserve water and energy during the day. Experimentally, at high <em>T</em>_as, females maintained significantly lower <em>T</em>_b and resting metabolic rates, despite lower evaporative water loss (EWL) rates compared to males. Females only increased EWL at experimental <em>T</em>_<em>a</em> = 42.5 °C, significantly higher than males (40.7 °C), and higher than any bat species yet recorded. During the hottest day of this study, our estimates suggest the water required for evaporative cooling ranged from 18.3% (females) and 25.5% (males) of body mass. However, if we extrapolate these results to a recent heatwave these values increase to 36.5% and 47.3%, which are likely beyond lethal limits. It appears this population is under selective pressures to conserve water reserves and that these pressures are more pronounced in females than males. Bats in arid ecosystems are threatened by both current and future heatwaves and we recommend future conservation efforts focus on protecting current roost trees and creating artificial standing water sites near vulnerable populations.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001372/pdfft?md5=f8bf70834981855780dd896c72c96d94&pid=1-s2.0-S0306456524001372-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of warming at embryonic and larval stages on tadpole fitness in high-altitude Rana kukunoris","authors":"Zhiyi Niu ,&nbsp;Peng Pu ,&nbsp;Tao Zhang ,&nbsp;Lun Jia ,&nbsp;Xinying Li ,&nbsp;Huihui Wang ,&nbsp;Miaojun Ma ,&nbsp;Xiaolong Tang ,&nbsp;Qiang Chen","doi":"10.1016/j.jtherbio.2024.103895","DOIUrl":"https://doi.org/10.1016/j.jtherbio.2024.103895","url":null,"abstract":"<div><p>Global warming may affect the early developmental stages of high-altitude amphibians, thereby influencing their later fitness. Yet, this has been largely unexplored. To investigate whether and how the temperatures experienced by embryonic and larval stages affect their fitness at later developmental stages, we designed two experiments in which the embryos and larvae were treated with three temperatures (24, 18 and 12 °C), respectively. Then, the life history traits of the tadpoles during the metamorphotic climax in all treatments were evaluated, including growth rate, survival rate, morphology, thermal physiology, swimming performance, standard metabolic rate (SMR), oxidative and antioxidative system, and metabolic enzyme activities. The results revealed that elevated temperature accelerated metamorphosis but decreased body size at metamorphosis. Additionally, warming during the embryonic and larval stages decreased the thermal tolerance range and induced increased oxidative stress. Furthermore, high embryonic temperature significantly decreased the hatching success, but had no significant effect on swimming performance and SMR. Warming during larval periods was harmful to the survival and swimming performance of tadpoles. The effect size analysis revealed that the negative impacts of embryonic temperature on certain physiological traits, such as growth and development, survival and swimming performance, were more pronounced than those of larval temperature. Our results highlight the necessity for particular attention to be paid to the early stages of amphibians, notably the embryonic stages when evaluating the impact of global warming on their survival.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141593393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can upwelling regions be potential thermal refugia for marine fishes during climate warming?","authors":"Luis Enrique Angeles-Gonzalez ,&nbsp;Josymar Torrejón-Magallanes ,&nbsp;Angel Escamilla-Aké ,&nbsp;Luis Osorio-Olvera ,&nbsp;Otilio Avendaño ,&nbsp;Fernando Díaz ,&nbsp;Carlos Rosas","doi":"10.1016/j.jtherbio.2024.103893","DOIUrl":"10.1016/j.jtherbio.2024.103893","url":null,"abstract":"<div><p>Species are expected to migrate to higher latitudes as warming intensifies due to anthropogenic climate change since physiological mechanisms have been adapted to maximize fitness under specific temperatures. However, literature suggests that upwellings could act as thermal refugia under climate warming protecting marine ecosystem diversity. This research aimed to predict the effects of climate warming on commercial and non-commercial fish species reported in official Mexican documents (&gt;200 species) based on their thermal niche to observe if upwellings can act as potential thermal refugia. Present (2000–2014) and Representative Concentration Pathway (6.0 and 8.5) scenarios (2040–2050 and 2090–2100) have been considered for this work. Current and future suitability patterns, species distribution, richness, and turnover were calculated using the minimum volume ellipsoids as algorithm. The results in this study highlight that beyond migration to higher latitudes, upwelling regions could protect marine fishes, although the mechanism differed between the innate characteristics of upwellings. Most modeled species (primarily tropical fishes) found refuge in the tropical upwelling in Northern Yucatan. However, the highest warming scenario overwhelmed this region. In contrast, the Baja California region lies within the Eastern Boundary Upwelling Systems. While the area experiences an increase in suitability, the northern regions have a higher upwelling intensity acting as environmental barriers for many tropical species. Conversely, in the southern regions where upwelling is weaker, species tend to congregate and persist even during elevated warming, according to the turnover analysis. These findings suggest that tropicalization in higher latitudes may not be as straightforward as previously assumed. Nevertheless, climate change affects numerous ecosystem features, such as trophic relationships, phenology, and other environmental variables not considered here. In addition, uncertainty still exists about the assumption of increasing intensity of upwelling systems.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001116/pdfft?md5=a28dce903f5ce458b4757c290eaa5f7c&pid=1-s2.0-S0306456524001116-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141412680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the correlation of skin temperature and body composition in athletes undergoing exhaustive physical exercise","authors":"","doi":"10.1016/j.jtherbio.2024.103918","DOIUrl":"10.1016/j.jtherbio.2024.103918","url":null,"abstract":"<div><p>During strenuous exercise, skin temperature (Tsk) plays an essential role in thermoregulatory processes. As indicated in the literature, its response might be influenced by body composition, among other factors. Hence, the objectives of this investigation were to determine whether there is a correlation between selected body components, specifically fat tissue and muscle tissue, and Tsk during graded exercise and recovery in athletes, and to identify which body component exhibits the strongest correlation with Tsk.</p><p>Participants were grouped according to their aerobic capacity (VO₂max/kg). A significant main effect was observed for the test stages (p &lt; .001, η² = 0.71), with Tsk decreasing from the start of the exercise, significantly decreasing at 12 km/h⁻¹ (p &lt; .001), and then increasing after exercise, especially within the first 5 min of recovery. Weak and non-significant effect for group/stage interaction was detected (p = .374, η² = 0.03). A significant negative correlation was found between Tsk and both total tissue fat [%] (−0.51 &lt; r &lt; −0.63, p &lt; .001) and lower limb tissue fat [%] (−0.50 &lt; r &lt; −0.71, p &lt; .001) across all test stages. The correlation between Tsk and BMI was inconsistent, appearing only during the first stage of exercise and throughout recovery. No correlation was observed between Tsk and skeletal muscle mass, appendicular lean soft tissue, or relative skeletal muscle index.</p><p>Endurance running to exhaustion leads to a progressive decrease in the Tsk of the lower extremity, followed by rewarming during recovery. The observed inverse correlation between adipose tissue and Tsk, along with the distinct temperature trends in groups with varying levels of fat tissue, could imply that the skin and subcutaneous tissue complex may play a more intricate role in thermal energy exchange beyond its insulating function. This implies a multifaceted involvement of these tissues in thermoregulation.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141622658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional role of metabolic suppression in avian thermoregulation in the heat","authors":"","doi":"10.1016/j.jtherbio.2024.103924","DOIUrl":"10.1016/j.jtherbio.2024.103924","url":null,"abstract":"<div><p>Hypometabolism arising from active metabolic suppression occurs in several contexts among endotherms, particularly during heterothermic states such as torpor. However, observed Q₁₀ ≈ 1 for avian resting metabolic rate within the thermoneutral zone, values far below the Q₁₀ = 2–3 expected on the basis of Arrhenius effects, suggests hypometabolism also plays a role in birds’ thermoregulation at environmental temperatures approaching or exceeding normothermic body temperature (<em>T</em>_b). We evaluated the occurrence of hypometabolism during heat exposure among birds by re-analysing literature data to quantify changes in <em>T</em>_b and resting metabolic rate (RMR) near the upper boundary of the thermoneutral zone, at air temperatures (<em>T</em>_air) between the inflection above which <em>T</em>_b increases above normothermic levels (<em>T</em>_b.inf) and the upper critical limit of thermoneutrality (<em>T</em>_uc). Among the ∼55 % of species in which <em>T</em>_uc – <em>T</em>_b.inf &gt; 0, Q₁₀ &lt; 2–3 occurred in nine of 10 orders for which suitable data exist, indicating that hypometabolism during heat exposure is widespread across the avian phylogeny. Values of Q₁₀ &lt; 2–3 were not restricted to small body mass, as previously proposed. Our findings support the idea that metabolic suppression reduces avian metabolic heat production and hence evaporative cooling requirements during heat exposure, with reductions of 20–30 % in RMR in some species. Moreover, these findings add to evidence that hypometabolism is an important component of heat tolerance among endotherms such as birds and tropical arboreal mammals.</p></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0306456524001426/pdfft?md5=19e715e914bc9846eaefd31a8bbdca9d&pid=1-s2.0-S0306456524001426-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141875217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}