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Susceptibility to obesity differs depending on the genetic background and housing temperatures. We have recently reported that CETP expressing female mice are leaner due to increased lipolysis, brown adipose tissue (BAT) activity, and body energy expenditure compared to nontransgenic (NTg) littermates under standard housing temperature (22°C). The aim of this study is to evaluate how CETP expression affects body temperature, composition, and metabolism during cold exposure (4°C) and thermoneutrality (30°C). When submitted to cold, CETP mice maintained rectal temperature, body weight, and food intake similarly to NTg mice along acute or chronic exposure to 4°C. The body oxygen consumption in response to an isoproterenol challenge was 21% higher at 22°C, and 41% higher after 7 days of cold exposure in CETP than in NTg mice. In addition, BAT biopsies from CETP mice showed reduced lipid content and increased basal oxygen consumption rates. Under thermoneutrality (30°C), when BAT activity is inhibited, CETP mice showed higher rectal and tail temperatures, increased food intake, and increased energy expenditure. Lean mass was elevated and fat mass reduced in CETP mice kept at 30°C. In this thermoneutral condition, soleus muscle, but not gastrocnemius or liver of CETP mice, showed increased mitochondrial respiration rates. These data indicate that CETP expression confers a greater capacity of elevating body metabolic rates at both cold exposure, through BAT activity, and at thermoneutrality, through increased muscle metabolism. Thus, the CETP expression levels in females should be considered as a new influence in the contexts of obesity and metabolic disorders propensity.

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To evaluate the efficacy and safety of different wavelengths of high-power diode lasers for the treatment of dentin hypersensitivity by analyzing morphological changes and temperature variation. Human third molars were irradiated with five different commercially available lasers at wavelengths of 808 nm, 940 nm, 976 nm, and 980 nm, both with and without the use of a photoinitiator (activated charcoal). Temperature variations were monitored using thermocouples, and morphological changes were assessed through scanning electron microscopy. Lasers with wavelengths of 940 nm, 976 nm, and 980 nm, used without a photoinitiator, promoted dentinal tubule obliteration without causing thermal damage. Lasers with wavelengths of 808 nm, 940 nm, 976 nm, and 980 nm, when combined with a photoinitiator, resulted in even lower temperature variation compared to the non-photoinitiator groups, although no regular fused surface was observed. Diode laser parameters, except Group 1(808 nm without photoinitiator), are potentially safe for dentinal tubule obliteration. The use of a photoinitiator continues to be an effective strategy for minimizing temperature variations during irradiation.

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Infrared thermography (IRT) is a noninvasive method that is one of the main indirect tools to optimize livestock measurements, as most changes in physiological conditions affect body temperature. This study aimed to evaluate the use of IRT to estimate residual feed intake (RFI) and residual intake and gain (RIG) of hair lambs, in addition to variations in performance, feed efficiency estimates, and gas emissions. Forty lambs were monitored during two feed efficiency tests to assess performance, feed efficiency estimates, and enteric gas emissions. These metrics were associated with IRT measurements from different body regions (eyes, hooves, rumen, and left flank). Temperatures were measured using infrared images collected with a Fluke camera, employing the non-steady-state rapid detection measurement method. Lambs were grouped into high (RFI-; RIG+), medium (RFI±; RIG±), and low (RFI+; RIG-) classes based on ± 0.5 standard deviations of adjusted RFI and RIG. To assess group differences, Tukey's test (P < 0.05) was applied, along with Pearson correlation and multivariate analyses to determine relationships between variables. In the 2nd test, differences in RIG classification were observed for eye and left flank temperatures. Some performance variables and feed efficiency estimates, such as dry matter intake, feed efficiency, and feed conversion, differed by RFI and RIG classifications. In the 1st test, only N2O and NH4 emissions differed between RFI classifications, while in the 2nd test, CO2 emissions were higher in RFI + animals. Performance and feed efficiency estimates were the primary variables, whereas temperatures measured by IRT had the lowest discriminatory power for RFI and RIG categories, followed by enteric gas emissions. Limitations related to animal numbers and environmental temperature variation in this study suggest that further investigation of the relationship between infrared thermography and animal performance efficiency is warranted.

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Habitat degradation from human activities affects essential microhabitats, threatening ecological processes like foraging, mating, locomotion, predator evasion, and competition among reptiles. We assessed how microhabitat selection and body temperature of the endangered lizard Liolaemus cuyumhue respond to differences in vegetation composition and thermal conditions between a disturbed site and an undisturbed site impacted by oil and gas activities in Argentina. During five expeditions between September 2022 and March 2023, we searched for L. cuyumhue and collected data on body temperature, substrate and air temperatures, body mass, snout-vent length, sex, and habitat characteristics. We also measured operative temperatures and assessed vegetation cover and microhabitat availability at each site. Our results showed significant differences in microhabitat characteristics and selection between sites. The undisturbed site had higher vegetation and lower operative temperatures, while the disturbed site had higher temperatures and lower vegetation, especially in summer. Lizards at the disturbed site showed higher body temperatures, suggesting stressful thermal conditions, and preferred microhabitats with lower bare ground cover. Capturing lizards in the disturbed site required more effort than in the undisturbed site. This study emphasizes the impact of habitat disturbance on the thermal environment and behavior of L. cuyumhue. Conservation efforts should prioritize maintaining and restoring vegetation to support the species' thermoregulation needs, especially under global warming.

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Heterogeneous environments provide different daily and seasonal thermal conditions for snakes, resulting in temporal and spatial variations in body temperature (Tb). This study analyzes the Tb of Thamnophis eques in the forest and grassland of a Mexican locality through daily and seasonal profiling. The patterns were obtained from seminatural enclosures in the field with a point sampling strategy to analyze temporal and spatial variations in Tb. The variation of Tb throughout the day was correlated with air and substrate temperatures, both in the grassland and in the forest. The average Tb in the grassland was 0.88 °C greater than in the forest. Our results indicate that T. eques showed differences in Tb between grassland and forest, principally in late spring and early summer during the early rise and late plateau phases, coinciding with the presence of foliage on the willow trees present in the study area, while in late summer and early autumn, the Tb was similar when willow trees canopy cover was absent (May-September). Our results support the hypothesis that the Tb of snakes differ between forests when the willows have leaves and is similar when canopy cover is equivalent, in this case, when tree canopy cover was absent. Our results also shown that T. eques presented daily and seasonal warming patterns similar to other Arizona populations and like those of other northern Gartersnakes. However, this result may not be valid for the entire wide distribution and consequent diversity of habitats of T. eques. The information of Tb in T. eques through daily and seasonal profiles in different habitats could aid in understanding the effects of environmental conditions on the ecological strategies deployed by snakes on habitat selection.

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Animal thermoregulation may have significant costs and compete directly or indirectly with other energetically demanding processes, such as immune function. Although the subterranean environment is characterized by thermally stable conditions, small changes in ambient temperature could be critical in shaping immunity. However, little is known about the effects of ambient temperature, in naturally varying ranges, on immunity of wild species. Therefore, to evaluate the effect of short-term exposure to ambient temperatures on energy metabolism and body temperature during the acute phase immune response (APR) in the subterranean rodent Ctenomys talarum, 70 adult animals were divided into three experimental groups and exposed twice for 1 h to 15, 25 or 32°C (below, at or near the upper limit of the thermoneutral zone, respectively) before and after injection with saline (control) or lipopolysaccharide (LPS, which induces the APR). Animals exposed to 25 and 32°C showed a similar APR pattern, characterized by fever (average: 37.1 and 37.7°C, respectively), a 16% increase in O2 consumption and an increase in the neutrophil/lymphocyte ratio (N/L). Body mass loss and symptoms of sickness behavior were detected from 3 and 1 h post-injection, respectively. Individuals exposed to 15°C increased their metabolic rate by 60%, showed frequent hypothermia (34.3°C on average) and the characteristic N/L increase was attenuated. Body mass loss and sickness behavior were mostly detected 24 h post-injection. Our results suggest that the thermoregulation costs in C. talarum may limit the energy available for immunity, leading to different strategies to cope with infection.

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Single-variable analyses have limited ability to explain complex phenomena such as the regulation of prolonged physical (aerobic) performance. Our study aimed to identify predictors of performance in rats subjected to incremental-speed running exercise. Notably, most variables assessed were associated with rats' thermoregulation. We extracted data from 355 records obtained in 216 adult Wistar rats. Hierarchical multiple linear regression analyses were conducted to identify the predictive power of eight variables. The distance traveled, a performance index, was the dependent variable. The independent variables included body mass, biological sex, body core temperature (TCORE) measurement site, and the following thermoregulation-related variables: ambient temperature (TAMB), initial TCORE, exercise-induced change in TCORE (ΔTCORE), ΔTCORE from 0 to 10 min (ΔTCORE 0-10; when TCORE increase is fastest), and heat loss index (HLI). This analysis with eight variables revealed an adjusted R2 of 0.495; TAMB, ΔTCORE, body mass, and ΔTCORE 0-10 had the highest predictive powers (ß values: -0.700, 0.463, -0.353, and -0.130, respectively). Additional analyses consisted of separate regressions for each TCORE index measured: abdominal (TABD), brain (TBRAIN), and colonic (TCOL) temperature. These analyses yielded adjusted R2 values of 0.608 (TABD), 0.550 (TBRAIN), and 0.437 (TCOL). Again, the distance traveled was primarily predicted by body mass and thermoregulation-related variables (TAMB, ΔTCORE, and ΔTCORE 0-10). Among these four variables, ΔTCORE was the only one with a positive ß value (directly predicted performance), while the others had negative values. Collectively, these findings advance our understanding of performance regulation in rats, especially regarding the role of thermoregulation-related variables.

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The objectives of this study were: (i) to verify and compare the coat surface temperature (CST) of regions of interest (ROI) measured through infrared pyrometer (IRP) and thermography (IRT) under two environmental conditions, to evaluate (ii) reliability and (iii) sensitivity of the two infrared equipments to the environmental effect. Twenty hair ewes (Ovis aries), multiparous, non-lactating, non-pregnant, with body weight 59.38 ± 6.23 kg and body score condition ranging from 2.5 to 4.5 were evaluated. All CST, in both infrared methods, were higher (P < 0.001) in the afternoon (2 to 3 p.m.), with the exception of eyes surface temperature (TSEY) from IRT, which was higher (P < 0.001) in the morning (8 to 9 a.m.). Regarding the infrared methods at different times (twice a day, morning and afternoon), of the day, CST values for all ROIs were significantly higher (P < 0.001) in thermography, regardless of the time shift, except for ear pinna surface temperature (TSE) and rectum surface temperature (TSR), which showed no significant difference (P > 0.05) between the infrared methods during the morning shift. The thermal environment significantly influences (P < 0.001) the surface temperature of various anatomical regions in both infrared methods. The correlation coefficients between IRT and IRP were moderate. The IRT is more sensitive to the thermal environment, as it presented higher canonical coefficients in the environmental variables. Among surface temperatures, eye surface temperature is the most influenced by variables in the thermal environment, especially THI. All three methods (digital thermometer-DT, IRT and IRP) showed >80 % of the data variation in the first two components. Using the DT, we observed an association between vaginal temperature (VT) and RT with air temperature (AT) and temperature humidity index (THI), which was similar to the infrared thermography pattern, in which all ROIs were highly correlated with AT and THI. The opposite was observed in the pyrometer, in which an association between eye temperature and RH and lower factor loadings of the other ROIs with AT and THI in the first component was observed. In conclusion, while IRP and IRT showed similar performance in the morning, IRT proved to be more accurate in the afternoon, demonstrating a higher success rate in classifying the group of origin. Therefore, it is concluded that IRT is more reliable than IRP in detecting surface temperature changes under high temperatures.

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BACKGROUND: Trypanosoma rangeli is a haemoflagellate parasite that infects triatomine bugs and mammals in South and Central America. Trypanosoma cruzi, the etiological agent of Chagas disease, has a partially overlapping geographical distribution with T. rangeli, that leads to mixed human infections and cross-reactivity in immunodiagnosis. Although T. rangeli can be detected long after mammal infection, its multiplicative forms have not yet been described. OBJECTIVES: To enhance our understanding of T. rangeli development in mammals, this study assessed various infection parameters in mice over time. METHODS: The parasitaemia, body temperature, and weight of Swiss Webster mice were monitored over 120 days after exposing them to the bites of Rhodnius prolixus nymphs containing metacyclic trypomastigotes in their salivary glands. On day 132 post-infection, spleens and mesenteric lymph nodes were analysed for T. rangeli DNA using polymerase chain reaction (PCR) and quantitative PCR (qPCR). FINDINGS: Parasites were detectable in mice blood since day 2 post-infection, detection peaking on day 5 and becoming undetectable by day 120. PCR and qPCR detected T. rangeli DNA in the spleens and mesenteric lymph nodes of infected mice. Infected mice showed higher body temperatures and a slower weight gain over time compared to controls. MAIN CONCLUSIONS: The study confirmed that T. rangeli establishes a persistent infection in mice, detectable in lymphoid organs long after parasites had disappeared from blood. In addition, infected mice exhibited physiological changes, suggesting potential subclinical effects. These findings highlight the need for further studies on the immune response and potential impacts of T. rangeli infection in mammalian hosts.

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BACKGROUND: Temperature fluctuations are critical indicators of a patient's condition in intensive care units (ICUs). While invasive methods offer a more reliable measurement of core temperature, they carry greater risks of complications, limiting their use in most situations. This underscores the need for research evaluating the reliability of non-invasive temperature monitoring methods. OBJECTIVES: This study aimed to assess the accuracy and precision of four non-invasive temperature measurement techniques compared to pulmonary artery temperature, considered the gold standard. DESIGN AND SETTING: We conducted a cross-sectional clinical study with repeated measures in the ICUs at Hospital das Clínicas da Universidade Federal de Minas Gerais and Hospital Felício Rocho, Belo Horizonte, Brazil. METHODS: All patients admitted with a pulmonary artery catheter were included. We simultaneously recorded temperatures from the pulmonary artery, axillary area, oral cavity, temporal artery, and tympanic membrane. Bland-Altman plots were employed to assess the agreement between the different temperature measurements. RESULTS: A total of 48 patients participated, with a mean age of 54 years. Females comprised 66.67% of the sample. Compared to pulmonary artery temperature, the accuracy and precision (mean and standard deviation) of the non-invasive methods were: axillary (-0.42°C, 0.59°C), oral (-0.30°C, 0.37°C), tympanic membrane (-0.21°C, 0.44°C), and temporal artery (-0.25°C, 0.61°C). Notably, in patients with abnormal body temperature (non-normothermic), only oral and tympanic membrane methods maintained their accuracy and precision. CONCLUSIONS: The non-invasive thermometers evaluated in this study demonstrated acceptable accuracy and precision (within the clinically relevant threshold of 0.5°C) compared to pulmonary artery temperature. Among the non-invasive methods, the tympanic membrane measurement proved to be the most reliable, followed by the oral method.

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In mammals, the central circadian oscillator is located in the suprachiasmatic nucleus (SCN). Hypothalamus-pituitary-thyroid axis components exhibit circadian oscillation, regulated by both central clock innervation and intrinsic circadian clocks in the anterior pituitary and thyroid glands. Thyroid disorders alter the rhythmicity of peripheral clocks in a tissue-dependent response; however, whether these effects are influenced by alterations in the master clock remains unknown. This study aimed to characterize the effects of hypothyroidism on the rhythmicity of SCN, body temperature (BT) and metabolism, and the possible mechanisms involved in this signalling. C57BL/6J adult male mice were divided into Control and Hypothyroid groups. Profiles of spontaneous locomotor activity (SLA), BT, oxygen consumption ( V ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ ) and respiratory quotient (RQ) were determined under free-running conditions. Clock gene expression, and neuronal activity of the SCN and medial preoptic nucleus (MPOM) area were investigated in light-dark (LD) conditions. Triiodothyronine (T3) transcriptional regulation of Bmal1 promoter activity was evaluated in GH3-transfected cells. Hypothyroidism delayed the rhythmicity of SLA and BT, and altered the expression of core clock components in the SCN. The activity of SCN neurons and their outputs were also affected, as evidenced by the loss of circadian rhythmicity in V ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ and RQ and alterations in the neuronal activity pattern of MPOM. In GH3 cells, T3 increased Bmal1 promoter activity in a time-dependent manner. Thyroid hormone may act as a temporal cue for the central circadian clock, and the uncoupling of central and peripheral clocks might contribute to a wide range of metabolic and thermoregulatory impairments observed in hypothyroidism. KEY POINTS: Hypothyroidism alters clock gene expression in the suprachiasmatic nucleus (SCN). Thyroid hypofunction alters the phase of spontaneous locomotor activity and body temperature rhythms. Thyroid hormone deficiency alters the daily pattern of SCN and medial preoptic nucleus neuronal activities. Hypothyroidism alterations are extended to daily oscillations of oxygen consumption and metabolism, which might contribute to the development of metabolic syndrome. Triiodothyronine increases Bmal1 promoter activity acting as temporal cue for the central circadian clock.

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The presence of cardiac shunts in ectothermic tetrapods is thought to be consistent with active vascular modulations for proper hemodynamic support. Local control of blood flow modulates tissue perfusion and thus systemic conductance (Gsys) is assumed to increase with body temperature (Tb) to accommodate higher aerobic demand. However, the general increase of Gsys presses for a higher right-to-left (R-L) shunt, which reduces arterial oxygen concentration. In contrast, Tb reduction leads to a Gsys decrease and a left-to-right shunt, which purportedly increases pulmonary perfusion and plasma filtration in the respiratory area. This investigation addressed the role of compensatory vascular adjustments in the face of the metabolic alterations caused by Tb change in the South American rattlesnake (Crotalus durissus). Cardiovascular recordings were performed in decerebrated rattlesnake preparations at 10, 20 and 30°C. The rise in Tb increased metabolic demand, and correlated with an augmentation in heart rate. Although cardiac output increased, systemic stroke volume reduced while pulmonary stroke volume remained stable. Although that resulted in a proportionally higher increase in pulmonary blood flow, the R-L shunt was maintained. While the systemic compliance of large arteries was the most relevant factor in regulating arterial systemic blood pressure, peripheral conductance of pulmonary circulation was the major factor influencing the final cardiac shunt. Such dynamic adjustment of systemic compliance and pulmonary resistance for shunt modulation has not been demonstrated before and contrasts with previous knowledge on shunt control.

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This study aimed to investigate the behavioral responses and circadian rhythms of mice to both rapid and gradual increases in photoperiod, mimicking the transition from winter to summer, which is associated with a heightened prevalence of hospitalizations for mania and suicidal behavior. Behavioral tests were performed in C57BL/6 male mice exposed to a transitional photoperiod, from short to long durations. To determine if circadian rhythms are affected, we measured spontaneous locomotor activity and body temperature. Mice exhibited heightened exploratory and risk-taking behaviors compared with equatorial and static long (16:8 h of light-dark cycle for several days) groups. These behaviors were prevented by lithium. Spontaneous locomotor activity and body temperature rhythms persisted and were effectively synchronized; however, the relative amplitude of activity and interdaily stability were diminished. Additionally, the animals displayed increased activity during the light phase. Photoperiodic transition modulates behavior and circadian rhythms, mirroring certain features observed in bipolar disorder patients. This study introduces an animal model for investigating mania-like behavior induced by photoperiodic changes, offering potential insights for suicide prevention strategies and the management of mood disorders.

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Body temperature (Tb) variation and environmental temperature gradients are more intense in small individuals because their body size allows for a more intimate relationship between Tb and the environment. To contribute to a methodological consensus on the ecophysiology of small ectotherms, we aimed to investigate whether different approaches and methodological techniques affect the measurement of critical temperatures in a small lizard (Coleodactylus meridionalis, Sphaerodactylidae) from the Atlantic Forest of southern Bahia, Brazil, and subsequently its vulnerability assessment. We measured two metrics of thermal physiology: critical thermal minimum (CTmin) and critical thermal maximum (CTmax). In total, four types of temperature measurements (protocols) were defined. In the first protocol, we estimated CTmax/CTmin without heating/cooling rate by directly measuring the lizard's midbody temperature. In the other three protocols, we used a ramping assay with a heating/cooling rate to estimate CTmax/CTmin in the chamber (height: 11.3 cm), substrate, and Tb of the lizard, respectively. In total 116 individuals of Coleodactylus meridionalis were collected, of which 177 CTmax and 131 CTmin were performed. C. meridionalis showed a mean CTmax of 41 °C and a mean CTmin of 8.9 °C when considering the Tb protocol, which is intermediate compared to the other protocols. The substrate temperature protocol was the closest to Tb, and for this, the best method for the small lizards using an infrared thermometer.

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BACKGROUND: Perioperative hypothermia in plastic surgery has underestimated risks, including increased risk of infection, cardiac events, blood loss, prolonged recovery time, and increased nausea, pain, and opioid usage. Inadequate preventive measures can result in up to 4 hours of normothermia restoration. OBJECTIVES: The aim was to compare the impact of different strategies for normothermia during plastic surgery procedures and their relationship with clinical outcomes. METHODS: A nonrandomized clinical trial was conducted in a single center in Bogota, Colombia. We enrolled adult patients undergoing body contouring surgery and divided them into 4 intervention groups with different measures to control body temperature. Univariate and bivariate analyses were performed, comparing several clinical symptoms to evaluate outcomes. RESULTS: A total of 197 patients were analyzed. Most of them were females (84.3%). Mean age was 38.6 years, and the median procedure duration was 260 minutes. Demographic and clinical characteristics did not exhibit significant differences between the groups. There were notable variations in temperature measurements at crucial moments during the surgical procedure among the groups, attributed to the implementation of distinct thermal protective strategies. Group comparisons showed a relationship between hypothermia and increased nausea, vomiting, shivering, pain, and additional analgesia requirements. CONCLUSIONS: Incorporation of active thermal protective measures, such as Blanketrol or HotDog, during body contouring procedures, markedly diminishes the risk of hypothermia and enhances overall clinical outcomes. Implementing these active measures to maintain the patient in a state of normothermia not only improves operating room efficiency but also leads to a reduction in recovery room duration.

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Recent heatwaves have highlighted the importance of accurate and continuous core temperature (TCORE) monitoring in sports settings. For example, accentuated rises in TCORE 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 TCORE 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. TCORE was recorded simultaneously every minute using a gastrointestinal capsule (TGi) and the CRS (TSENSOR). 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 TGi) and reproducible in estimating TCORE in both sexes at various intensities of cycling exercise in the heat.

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Numerous body locations have been utilized to obtain an accurate body temperature. While some are commonly used, their accuracy, response time, invasiveness varies greatly, and determines their potential clinical and/or research use. This review discusses human body temperature locations, their accuracy, ease of use, advantages, and drawbacks. We explain the concept of core body temperature and which of the locations achieve the best correlation to this temperature. The body locations include axilla, oral cavity, rectum, digestive and urinary tracts, skin, tympanic, nasopharynx, esophagus, and pulmonary artery. The review also discusses the latest temperature technologies, heat-flux technology and telemetric ingestible temperature pills, and the body locations used to validate these devices. Rectal and esophageal measurements are the most frequently used.

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We assessed newborn lambs from two hair-coat sheep breeds, the black Santa Ines (n = 29) and white Dorper (n = 26), to determine how they behaviourally and physiologically respond to the prevailing thermal conditions in an equatorial semi-arid environment. Measurements of hair-coat surface temperature, rectal temperature and the lambs' exposure to sun were recorded across the first 24 h of life every hour, after the lambs had received colostrum. Lambs and ewes were kept in a lambing pen and could freely move between a shaded area or be exposed to sun. During the study period, the air temperature ranged between 20 ºC and 34 ºC. When exposed to sun, lambs and ewes could experience as much as 1200 W m-2 of solar irradiance. Santa Ines lambs exhibited higher (highest density interval at 95%, HDI) hair-coat surface temperatures than did Dorper lambs. Overall, both Santa Ines and Dorper lambs sustained homeothermy, with a mean rectal temperature ranging from 38.7 ºC to 39.1 ºC between night and daytime phase, and a mean amplitude of ~ 0.8 ºC. Nevertheless, from 10:00 to 15:00, some lambs were found to be moderately hyperthermic. Five Santa Ines and three Dorper lambs had rectal temperatures above 40 ºC, and one Santa Ines lamb, while exposed to sun, had a rectal temperature of 41.3 ºC. Over this time period, lambs were more likely to move to shade (HDI at 95%). From 00:00 to 06:00, despite the air temperature being lower than the hair-coat surface, favouring high rates of sensible heat loss to the environment, no lamb exhibited signs of hypothermia (rectal temperature < 37.5 ºC). In conclusion, haired newborn lambs coped well with high levels of radiant heat during the daytime and lower temperatures at night. However, providing access to shade during the daytime is important to improve the welfare of newborn lambs delivered in equatorial semi-arid regions.

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Esse trabalho tem como objetivo investigar se o período do dia influencia no desempenho dos indivíduos numa bateria de TAF. A amostra foi composta por dez indivíduos de ambos os sexos (24,10 ± 0,96 anos), que realizaram o TAF nos três períodos do dia: manhã, tarde e noite, em três dias não consecutivos no decorrer de uma semana. O TAF foi composto por cinco testes (teste de preensão manual, teste na barra fixa, teste de flexão abdominal, teste de impulsão horizontal e Shuttle-run) para homens e quatro testes para as mulheres, que não realizaram o teste de força na barra fixa. No primeiro dia da bateria de testes, eles foram submetidos a avaliação antropométrica e de composição corporal com bioimpedância. Em cada dia de avaliação, os participantes tiveram a temperatura corporal aferida antes de iniciar os testes e responderam à percepção subjetiva de esforço (PSE) após cada teste. Para a análise estatística foi utilizado a anova one-way com post-hoc de bonferroni para comparar as diferenças de performance ao longo dos três períodos do dia. Não foram encontradas diferença significativas (P>0,05) no desempenho entre os testes realizados, nem na PSE nas comparações entre os três períodos do dia. A temperatura corporal foi significativamente (P<0,01) menor no período da manhã (36,28 ± 0,08 ºC) quando comparada ao período da tarde (36,54 ± 0,69 ºC) e da noite (36,70 ± 0,10 ºC). Assim, é possível concluir que o período do dia não influência o desempenho de adultos jovens em uma bateria de TAF.

This work aims to investigate whether the time of day influences the performance of individuals in a TAF battery. The sample consisted of ten individuals of both genders (24.10±0.96 years), who performed the FAT in three periods of the day: morning, afternoon and night, on three non-consecutive days over the course of a week. The FAT consisted of five tests (handgrip test, fixed bar test, abdominal flexion test, horizontal impulsion test and Shuttle-run) for men and four tests for women, who did not perform the strength test on the bar. fixed. On the first day of the battery of tests, they underwent an anthropometric and body composition assessment with bioimpedance. On each evaluation day, the participants had their body temperature measured before starting the tests and answered the subjective perception of exertion (RPE) after each test. For the statistical analysis, one-way anova with Bonferroni post-hoc was used to compare performance differences over the three periods of the day. No significant differences (P>0.05) were found in the performance between the tests performed, nor in the PSE in the comparisons between the three periods of the day. Body temperature was significantly (P<0.01) lower in the morning (36.28±0.08 ºC) when compared to the afternoon (36.54±0.69 ºC) and night (36.70 ±0.10 ºC). Thus, it is possible to conclude that the time of day does not influence the performance of young adults in a TAF battery.

Este trabajo tiene como objetivo investigar si la hora del día influye en el rendimiento de los individuos en una batería de pruebas de aptitud física (BAF). La muestra estuvo conformada por diez individuos de ambos sexos (24,10±0,96 años), quienes realizaron el BAF en tres momentos del día: mañana, tarde y noche, en tres días no consecutivos en el transcurso de una semana. La BAF constaba de cinco pruebas (handgrip test, test de barra fija, test de flexión abdominal, test de impulsión horizontal y Shuttle-run) para hombres y cuatro pruebas para mujeres, que no realizaron la prueba de fuerza en barra fija. El primer día de la batería de pruebas se les realizó una valoración antropométrica y de composición corporal con bioimpedancia. En cada día de evaluación, a los participantes se les tomó la temperatura corporal antes de comenzar las pruebas y respondieron la percepción subjetiva de esfuerzo (PSE) después de cada prueba. Para el análisis estadístico, se utilizó Anova unidireccional con Bonferroni post-hoc para comparar las diferencias de rendimiento en los tres períodos del día. No se encontraron diferencias significativas (P>0,05) en el rendimiento entre las pruebas realizadas, ni en el PSE en las comparaciones entre los tres períodos del día. La temperatura corporal fue significativamente (P<0,01) más baja en la mañana (36,28 ± 0,08 ºC) en comparación con la tarde (36,54 ± 0,69 ºC) y la noche (36,70 ± 0,10 ºC). Por lo tanto, es posible concluir que la hora del día no influye en el rendimiento de los adultos jóvenes en una BAF.

RESUMO

Resilience of mammals to anthropogenic climate and land-use changes is associated with the maintenance of adequate responses of several fitness-related traits such as those related to immune functions. Isolated and combined effects of decreased food availability and increased ambient temperature can lead to immunosuppression and greater susceptibility to disease. Our study tested the general hypothesis that decreased food availability, increased ambient temperature and the combined effect of both factors would affect selected physiological and behavioral components associated with the innate immune system of fruit-eating bats (Carollia perspicillata). Physiological (fever, leukocytosis and neutrophil/lymphocyte ratio) and behavioral (food intake) components of the acute phase response, as well as bacterial killing ability of the plasma were assessed after immune challenge with lipopolysaccharide (LPS: 10 mg/kg) in experimental groups kept at different short-term conditions of food availability (ad libitum diet or 50% food-deprived) and ambient temperature (27 and 33°C). Our results indicate that magnitude of increase in body temperature was not affected by food availability, ambient temperature or the interaction of both factors, but the time to reach the highest increase took longer in LPS-injected bats that were kept under food restriction. The magnitude of increased neutrophil/lymphocyte ratio was affected by the interaction between food availability and ambient temperature, but food intake, total white blood cell count and bacterial killing ability were not affected by any factor or interaction. Overall, our results suggest that bacterial killing ability and most components of acute phase response examined are not affected by short-term changes in food availability and ambient temperature within the range evaluated in this study, and that the increase of the neutrophil/lymphocyte ratio when bats are exposed to low food availability and high ambient temperature might represent an enhancement of cellular response to deal with infection.