Reduction In Body Temperature Research Articles

Reduction of Interior Body Temperature of Car When Exposed to Direct Sunlight

Reduction of Interior Body Temperature of Car When Exposed to Direct Sunlight

0015 Manipulating Body Temperature: Effects on Sleep in Postmenopausal Women

Abstract Introduction A decline in sleep quality and reduction in slow wave sleep (SWS) and slow wave activity (SWA) are common in older adults. Prior studies have shown that manipulating body temperature during sleep can increase SWS/SWA. The aim of this study was to determine the effects of manipulation of body temperatures during sleep, using a high heat capacity mattress, on SWS/SWA and heart rate variability in post-menopausal women. Methods Twenty-four healthy postmenopausal women between 40–75 years of age (mean age 62.4 ± 8.2 years, mean BMI 25.4 ± 3.5 kg/m2) were randomized in a single-blind, counterbalanced, cross-over manner to sleep on either a high heat capacity mattress (HHCM) or a low heat capacity mattress(LHCM) a week apart. Sleep was recorded using polysomnography during an 8-hour sleep opportunity. Core and peripheral temperatures were recorded using Equivital and ibutton respectively. Results In comparison to the LHCM, sleep on HHCM exhibited a selective increase in SWS (average increase in Stage N3 of 9.6 minutes (2.1%), p = 0.04) and in slow oscillatory activity (0.5-1Hz) in the first NREM/REM cycle (p=0.04). In addition, the HHCM induced a greater reduction in core body temperature (p=0.002), and delayed the increase in mattress surface temperature (maximal difference LHCM-HHCM: 4.66±0.17°C). Average heart rate was 2.7 beats/minute lower across the night on the HHCM compared to the LHCM (p=0.001). Conclusion The results of this study indicate that manipulation of body temperature during sleep may be a useful approach to enhance SWS sleep and cardiovascular function in postmenopausal women. Support Technogel

Regulation of the α-ketoglutarate dehydrogenasecomplex during hibernation in a small mammal, the Richardson's ground squirrel (Urocitellus richardsonii)

The citric acid cycle (CAC) is a central metabolic pathway that links carbohydrate, lipid, and amino acid metabolism in the mitochondria and, hence, is a crucial target for metabolic regulation. The α-ketoglutarate dehydrogenase complex (KGDC) is the rate-limiting step of the CAC, the three enzymes of the complex catalyzing the transformation of α-ketoglutarate to succinyl-CoA with the release of CO2 and reduction of NAD to NADH. During hibernation, the metabolic rate of small mammals is suppressed, in part due to reduced body temperature but also active controls that suppress aerobic metabolism. The present study examined KGDC regulation during hibernation in skeletal muscle of the Richardson's ground squirrel (Urocitellus richardsonii). The KGDC was partially purified from skeletal muscle of euthermic and hibernating ground squirrels and kinetic properties were evaluated at 5°, 22°, and 37 °C. KGDC from hibernator muscle at all temperatures compared with euthermic controls exhibited a decreased affinity for CoA as well as reduced activation by Ca2+ ions at 5 °C from both euthermic and hibernating conditions. Co-immunoprecipitation was employed to isolate the E1, E2 and E3 enzymes of the complex (OGDH, DLST, DLD) to allow immunoblot analysis of post-translational modifications (PTMs) of each enzyme. The results showed elevated phospho-tyrosine content on all three enzymes during hibernation as well as increased ADP-ribosylation and succinylation of hibernator OGDH. Taken together these results show that the KGDC is regulated by posttranslational modifications and temperature effects to reorganize enzyme activity and mitochondrial function to aid suppression of mitochondrial activity during hibernation.

Do rabbits need each other? Effects of single versus paired housing on rabbit body temperature and behaviour in a UK shelter

AbstractIn the wild, rabbits (Oryctolagus cuniculus) are social but territorial. Recent surveys suggest that over half of pet rabbits are housed singly. We aimed to compare welfare in single versus paired rabbits. We predicted singletons would show more abnormal or escape behaviour, greater stress responses to handling, and reduced body temperature (being unable to huddle with another individual when cold), but that pairs may show aggression. This study was conducted during winter at a rabbit-only rescue centre, and included 45 rabbits, comprising 15 housed singly and 15 pairs. Like most pet rabbits, they were housed either outdoors or in unheated outbuildings. Singletons were mostly in smaller enclosures than pairs. Home-pen observations (40 min) revealed bar-biting in 8/15 single rabbits compared with 0/30 of the paired ones. No other behavioural effects of social housing reached significance, and enclosure size showed no significant effects. Body temperature was significantly lower in singletons than pairs, with at least 0.5°C mean difference. On colder days, rabbits adopted compact postures more, and relaxed postures less frequently. After handling, pairs resumed normal behaviour significantly more quickly than singletons in the home-pen (3.0 [± 0.3] versus 8.3 [± 1.3] s, respectively). Aggression was never observed. The results indicate that social housing reduces bar-biting, aids thermoregulation, and may help buffer stress. Rabbit owners should be encouraged to meet the need for rabbits to be housed with an appropriate conspecific in a suitably large, sheltered enclosure.

Effectiveness of Giving Compress Against Reduction of Body Temperature In Children: Systematic Review

Background: Fever is a clinical manifestation that is often experienced by sick children. Fever can be dangerous if there is a high fever. Seizures can occur as a result of high fever which is not treated early, causing hypoxia of brain tissue and ultimately damage. According to WHO estimates that around 17 million cases of fever worldwide, there are 600,000 deaths each year.Purpose: This study aimed to find out effective interventions to reduce body temperature in children.Methods: This research used quantitative descriptive design with systematic review approach. The research instrument uses Duffy’s Research Appraisal Checklist Approach.Results: After searching the article, there were 9 articles related to giving warm compresses, 6 articles with the location of administration in the axilla and tepid songe areas (wiping the whole body), 7 articles by giving compresses for 30 minutes and 10 articles with compressed water temperature 37oC.Conclusions: Of the 15 articles that have been traced successfully, the most interventions given were warm compresses in the axilla and tepid sponge areas by giving compresses for 30 minutes and compressed water temperature of 37oC

Neuroprotective and anti-inflammatory activity of DAT inhibitor R-phenylpiracetam in experimental models of inflammation in male mice.

R-phenylpiracetam (R-PhP, (4R)-2-(4-phenyl-2-oxopyrrolidin-1-yl)acetamide) is an optical isomer of phenotropil, a clinically-used nootropic drug that improves physical condition and cognition. Recently, R-PhP was shown to bind to the dopamine transporter (DAT). Since growing evidence suggests that dysfunction of the dopaminergic system is associated with persistent neuroinflammation, the aim of this study was to determine whether R-PhP, an inhibitor of DAT, has neuroprotective and anti-inflammatory effects in male mice. The pharmacokinetic profiles ofR-PhPin mouse plasma and its bioavailability in brain tissue were assessed. To study possible molecular mechanisms involved in the anti-inflammatory activity of R-PhP, target profiling was performed using radioligand binding and enzymatic activity assays. To clarify the neuroprotective and anti-inflammatory effects of R-PhP, we used a lipopolysaccharide (LPS)-induced endotoxaemia model characterized by reduced body temperature and overexpression of inflammatory genes in the brain. In addition, the antinociceptive and anti-inflammatory effects of R-PhP were tested using carrageenan-induced paw oedema and formalin-induced paw-licking tests. R-PhP (50mg/kg) reached the brain tissue 15min after intraperitoneal (ip) and peroral (po) injections. The maximal concentration of R-PhP in the brain tissues was 28µg/g and 18µg/g tissue after ip and po administration, respectively. In radioligand binding assays, DAT was the only significant molecular target found for R-PhP. A single ip injection of R-PhP significantly attenuated the LPS-induced body temperature reduction and the overexpression of inflammatory genes, such as tumour necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β) and inducible nitric oxide synthase (iNOS). Seven-day po pretreatment with R-PhP dose-dependently reduced paw oedema and the antinociceptive response, as shown by the carrageenan-induced paw oedema test. In addition, R-PhP decreased the nociceptive response during the inflammatory phase in the formalin-induced paw-licking test. Our study showed that R-PhP possesses neuroprotective and anti-inflammatory effects, demonstrating the potential of DAT inhibitors as effective therapeutics.

Aurora kinase inhibitor tozasertib suppresses mast cell activation in vitro and in vivo.

Mast cells are important in allergic reactions. Here, we assessed the anti-allergic effects of the anti-cancer drug tozasertib specifically regarding regulatory effects on mast cell activation. Tozasertib effects on mast cell degranulation were determined by measuring β-hexosaminidase and histamine release and by assessing morphological changes in RBL-2H3 and mouse bone marrow-derived mast cells (BMMCs) stimulated with mouse anti-dinitrophenyl (DNP)-IgE/DNP-human serum albumin or human LAD2 cells activated with phorbol-12-myristate 13-acetate plus calcium ionophore (PMACI). Western blots were performed to detect the expression of molecules involved in NF-κB, MAPK, and Aurora kinase signalling. in vivo anti-allergic effects of tozasertib were determined in the murine IgE-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) models. Tozasertib treatment decreased high-affinity IgE receptor (FcεRI) or PMACI-mediated degranulation in RBL-2H3 cells and in BMMCs or LAD2 cells as shown by β-hexosaminidase or histamine levels. Similarly, tozasertib prevented morphological changes in mast cells, such as particle release and F-actin reorganization. In addition, tozasertib markedly decreased expression of phosphorylated (p)-NF-κB p65, p-Erk1/2, p-p38, and p-Aurora A/B, indicating that tozasertib can inhibit the signalling pathway mediating mast cell activation. Tozasertib attenuated IgE/Ag-induced PCA dose-dependently, as shown by reduced Evans blue staining. Similarly, tozasertib reduced body temperature levels and serum histamine levels in OVA-challenged ASA mice. The Aurora kinase inhibitor tozasertib suppressed mast cell activation in vitro and in vivo. Tozasertib may be a potential drug, targeting mast cell activation, to treat allergic diseases or mastocytosis.

Comparison of Fever-reducing Effects in Self-reported Data from the Mobile App: Antipyretic Drugs in Pediatric Patients

We compared the fever-reducing efficacy of acetaminophen (AA), ibuprofen (IBU), and dexibuprofen (DEX) using data collected from the mobile healthcare application FeverCoach, which provides parents with guidelines for determining their child’s health condition, according to body temperature. Its dataset includes 4.4 million body temperature measurement records and 1.6 million antipyretics treatment records. Changes in body temperature over time were compared after taking one of three different antipyretics (AA, IBU, and DEX), using a one-way ANOVA followed by a post-hoc analysis. A multivariate linear model was used to further analyze the average body temperature differences, calibrating for the influences of age, weight, and sex. Children administered IBU had average body temperatures that were 0.18 °C (0.17–0.19 °C), 0.25 °C (0.24–0.26 °C), and 0.18 °C (0.17–0.20 °C) lower than those of children administered AA, at time intervals of 1–2 hours, 2–3 hours, and 3–4 hours, respectively. Similarly, children administered DEX had average body temperatures that were 0.24 °C (0.24–0.25 °C), 0.28 °C (0.27–0.29 °C), and 0.12 °C (0.10–0.13 °C) lower than those of children administered AA, at time intervals of 1–2, 2–3, and 3–4 hours, respectively. Although the data were collected from the application by non-professional parents, the analysis showed that IBU and DEX were more effective in reducing body temperature than AA was.

A mechanistic study of the tremor associated with epidural anaesthesia for intrapartum caesarean delivery

BackgroundIt is not known if the tremor associated with an epidural top-up dose for intrapartum caesarean delivery is thermoregulatory shivering. A tremor is only shivering if it has the same frequency profile as cold stress-induced shivering. Thermoregulatory shivering is a response to a reduction in actual body temperature, whereas non-thermoregulatory shivering may be triggered by a reduction in sensed body temperature. This mechanistic study aimed to compare: 1. the frequency profiles of epidural top-up tremor and cold stress-induced shivering; and 2. body temperature (actual and sensed) before epidural top-up and at the onset of tremor. MethodsTwenty obstetric patients received an epidural top-up for intrapartum caesarean delivery and 20 non-pregnant female volunteers underwent a cold stress. Tremor, surface electromyography, core temperature, skin temperature (seven sites) and temperature sensation votes (a bipolar visual analog score ranging from −50 to +50 mm) were recorded. ResultsThe mean (SD) primary oscillation (9.9 (1.9) Hz) frequency of epidural top-up tremor did not differ from that of cold stress-induced shivering (9.0 (1.6) Hz; P=0.194), but the mean (SD) burst frequency was slower (6.1 (1.2) × 10−2 Hz vs 6.9 (0.7) × 10−2 Hz, respectively; P=0.046). Before the epidural top-up dose, the mean (SD) core temperature was 37.6 (0.6) °C. Between the epidural top-up dose and the onset of tremor the mean (SD) core temperature did not change (–0.1 (0.1) °C; P=0.126), the mean (SD) skin temperature increased (+0.4 (0.4) °C; P=0.002) and the mean (SD) temperature sensation votes decreased (−12 (16) mm; P=0.012). ConclusionThese results suggest that epidural top-up tremor is a form of non-thermoregulatory shivering triggered by a reduction in sensed body temperature.

Activation of Preoptic GABAergic or Glutamatergic Neurons Modulates Sleep-Wake Architecture, but Not Anesthetic State Transitions.

The precise mechanism of general anesthesia remains unclear. In the last two decades, there has been considerable focus on the hypothesis that anesthetics co-opt the neural mechanisms regulating sleep. This hypothesis is supported by ample correlative evidence at the level of sleep-promoting nuclei, but causal investigations of potent inhaled anesthetics have not been conducted. Here, we tested the hypothesis that chemogenetic activation of discrete neuronal subpopulations within the median preoptic nucleus (MnPO) and ventrolateral preoptic nucleus (VLPO) of the hypothalamus would modulate sleep/wake states and alter the time to loss and resumption of consciousness associated with isoflurane, a potent halogenated ether in common clinical use. We show that activating MnPO/VLPO GABAergic or glutamatergic neurons does not alter anesthetic induction or recovery time. However, activation of these neuronal subpopulations did alter sleep-wake architecture. Notably, we report the novel finding that stimulation of VLPO glutamatergic neurons causes a strong increase in wakefulness. We conclude that activation of preoptic GABAergic or glutamatergic neurons that increase sleep or wakefulness does not substantively influence anesthetic state transitions. These data indicate that the correlative evidence for a mechanistic overlap of sleep and anesthesia at the level of an individual nucleus might not necessarily have strong causal significance.

Berberine attenuated olanzapine-induced metabolic alterations in mice: Targeting transient receptor potential vanilloid type 1 and 3 channels

Transient receptor potential vanilloid type 1 (TRPV1) channels are emerging therapeutic targets for metabolic disorders. Berberine, which is a modulator of TRPV1, has proven antiobesity and antidiabetic potentials. The present study was aimed to investigate the protective effects of berberine in olanzapine-induced alterations in hypothalamic appetite control, inflammation and metabolic aberrations in mice targeting TRPV1 channels. Female BALB/c mice (18–23 g) were treated with olanzapine (6 mg/kg, p.o.) for six weeks to induce metabolic alterations, while berberine (100 and 200 mg/kg, p.o.) and metformin (100 mg/kg, p.o) were used as test and standard interventions respectively. Weekly assessment of feed-water intake, body temperature and body weight was done, while locomotion was measured at the end of week 1 and 6. Serum glucose and lipid profile were assessed by biochemical methods, while other serum biomarkers were assessed by ELISA. qPCR was used to quantify the mRNA expression in the hypothalamus. Olanzapine treatment significantly increased the feed intake, weight gain, adiposity index, while reduced body temperature and locomotor activity which were reversed by berberine treatment. Berberine treatment reduced serum ghrelin and leptin levels as well decrease in hypothalamic mRNA expression of orexigenic neuropeptides, inflammatory markers and ghrelin receptor in olanzapine-treated mice. Olanzapine treatment increased expression of TRPV1/TRPV3 in the hypothalamus which was significantly decreased by berberine treatment. Our results suggest that berberine, by TRPV1/TRPV3 modulation, attenuated the olanzapine-induced metabolic alterations in mice. Hence berberine supplementation in psychiatric patients could be a preventive approach to reduce the metabolic adverse effects of antipsychotics.

Antimalarial Activity of Meriandra dianthera Leaf Extracts in Plasmodium berghei-Infected Mice.

Objective To evaluate the antimalarial effect of aqueous methanolic extract and solvent fractions of Meriandra dianthera leaves against Plasmodium berghei in mice model. Method M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the in vivo antimalarial activity of the extract and fractions. Result The crude leaf extract of Meriandra dianthera leaves against P < 0.001) chemosuppression compared to the negative control. Both the extract and fractions were able to prevent P. berghei induced body weight loss and body temperature reduction and also increased the survival time of the mice as compared to the negative control. The aqueous methanolic leaf extract of M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the Conclusion The extracts of M. dianthera leaves showed promising antimalarial activity, with no sign of toxicity and therefore may support its traditional use for the treatment of malaria.M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the

Artepillin C, a Key Component of Brazilian Propolis, Induces Thermogenesis in Inguinal White Adipose Tissue of Mice through a Creatine-Metabolism-Related Thermogenic Pathway.

Induction of beige adipocytes in white adipose tissue (WAT) is a potential therapeutic target for the treatment of obesity because beige adipocytes release excess energy via uncoupling-protein-1-associated thermogenesis. In this study, we investigated how artepillin C (ArtC) promotes thermogenesis in vivo. We demonstrated that 28 day administration of ArtC (10 mg/kg of body weight) to mice significantly induced thermogenesis in beige adipocytes in inguinal WAT (iWAT) and suppressed reductions in core body temperature induced by cold exposure at 4 °C. Moreover, ArtC-induced thermogenesis in iWAT was significantly inhibited by treatment with a creatine metabolism inhibitor, and ArtC significantly upregulated the expression of creatine-metabolism-related enzymes in the thermogenic pathway. These results indicate that ArtC induces thermogenesis in beige adipocytes in iWAT, and the observed ArtC-induced thermogenesis is associated with the creatine-metabolism-related thermogenic pathway, which is characteristically observed in beige adipocytes.

Phytogenic feed- and water-additives improve feed efficiency in broilers via modulation of (an)orexigenic hypothalamic neuropeptide expression

Fueled by consumer preference for natural and antibiotic-free products, phytogenics have become the fastest growing segment of the animal feed additives. Yet, their modes of action are not fully understood. This study was undertaken to determine the effect of 5 phytogenics (3 feed- and 2 water-supplements) on the growth performance of commercial broilers, and their potential underlying molecular mechanisms. Day-old male Cobb 500 chicks (n = 576) were randomly assigned into 48 pens consisting of 6 treatments (Control; AVHGP; SCP; BHGP; AVSSL; SG) in a complete randomized design (12 birds/pen, 8 pens/treatment, 96 birds/treatment). Chicks had ad libitum access to feed and water. Individual body weight (BW) was recorded weekly and feed intake was measured daily. Core body temperatures were continuously recorded using thermo-loggers. At d 35, hypothalamic tissues were excised from the thermo-logger-equipped chickens (n = 8 birds/treatment) to determine the expression of feeding-related neuropeptides.Both feed (AVHGP, SCP, BHGP) and water-supplemented (AVSSL, SG) phytogenics significantly improved feed efficiency (FE) compared to the control birds. This higher FE was achieved via a reduction in core body temperature and improvement of market BW, without changes in feed intake in broilers supplemented with phytogenic water additives as compared to the control group. Broilers fed dietary phytogenics, however, attained higher feed efficiency via a reduction in feed intake while maintaining similar BW as the control group. At the molecular levels, the effects of the phytogenic water additives seemed to be mediated by the activation of the hypothalamic AgRP-ORX-mTOR-S6k1 and inhibition of CRH pathways. The effect of the phytogenic feed additives appeared to be exerted through the activation of AdipoQ, STAT3, AMPK, and MC1R pathways.This is the first report describing the likely central mechanisms through which phytogenic additives improve the growth performance and feed efficiency in broilers.

Effectiveness of hot water footbath therapy in reducing body temperature amongst patients with fever

Fever has been recognised as a symptom and not a disease in itself. The thermoregulatory centre in the hypothalamus regulates body temperature. Hydrotherapy in the form of cold and tepid applications has been historically used for reducing increased body temperature. Many studies have looked at effect of hydrotherapy over pharmacological measures and have found that tepid or cold sponging reduces body temperature rapidly, but are associated with discomfort for the patients. There is some evidence that hot water soaks to foot reduces body temperature effectively. Hot water footbath is considered as a non-pharmacological, safe, side effect-free, cost-effective and easy-to-administer therapy to reduce fever. The aim of this study was to assess the effectiveness of hot water footbath therapy (HWFBT) in reducing the body temperature in adult patients with fever. Sixty patients were selected by convenient sampling technique, of which thirty patients were allotted to experimental group and thirty to control group by random method. HWFBT was given to experimental group. The control group received the standard care as per practice of the hospital. The findings showed that the difference in the mean body temperature in the post-test was significantly lower in the experimental group (P

Ангидротическая эктодермальная дисплазия у новорожденного ребенка (клиническое наблюдение)

The article describes step-by-step diagnostic approach for identifying the cause of fever in a newborn: from excluding infections and noninfectious factors provoking impaired thermoregulation to the diagnosis of a rare congenital disorder, anhidrotic ectodermal dysplasia (EDA) confirmed by genetic testing. EDA is a hereditary condition caused by mutations in the EDA gene encoding prenatal development of ectodermal derivatives. The main phenotypic signs of EDA are aplasia (hypoplasia) of sweat glands, dysplasia of skin and its appendages (hypotrichosis, nail hypoplasia etc.), and hypodontia. Hypoplasia or aplasia of the sweat glands results in impaired thermoregulation and, therefore, hyperthermia. Since hair and dental dysplasia do not manifest in newborns, EDA is commonly missed in newborns and diagnosed lately. Fever is one of the dangerous manifestations of EDA that, in tight swaddling, may result in death. Nonspecific clinical presentations of EDA in newborns require consultations with other specialists. Recognition of EDA clinical signs in newborns and infants (craniofacial dysmorphism, thin and dry skin, periorbital hyperpigmentation, reduction in body temperature after external cooling observed in the child) allows for early diagnosis and determines cooling strategy and further lifestyle. KEYWORDS: newborn, hyperthermia, anhidrotic ectodermal dysplasia, fever in newborns, differential diagnosis, causes of fever, molecular genetic testing. FOR CITATION: Akhmina N.I., Nikopol’skaya A.V., Bragina E.M. et al. Anhidrotic ectodermal dysplasia in a newborn: case history. Russian Journal of Woman and Child Health. 2020;3(4):340–343. DOI: 10.32364/2618-8430-2020-3-4-340-343.

Integrating bioenergetics and conservation biology: thermal sensitivity of digestive performance in Eastern Collared Lizards (Crotaphytus collaris) may affect population persistence.

Information on bioenergetics can provide valuable insight into the ecology, life history and population dynamics of organisms. For ectothermic animals, thermal sensitivity of digestion is an important determinant of net assimilated energy budgets. A recent study in the Ozark Mountains indicated that eastern collared lizards (Crotaphytus collaris) restricted to encroached glades (characterized by woody vegetation encroachment) experience reduced environmental heat loads and have reduced age-specific growth and reproductive rates compared to populations in intact glades. To assess the potential impact of reduced body temperatures on assimilation rates of C. collaris in encroached glades, we conducted feeding trials across four temperature treatments (28, 31, 34 and 37°C). We tested for temperature effects on voluntary feeding rates, passage times, apparent assimilated energy (AE) and metabolizable energy (ME). Passage times decreased and voluntary feeding rates increased significantly with increasing temperature. Consumption explained the majority of variance in AE and ME, followed by the effect of temperature treatments. Using data on voluntary feeding rates, passage times and ME as a function of temperature, we estimated over a 10-fold increase in predicted daily assimilated energy across temperature treatments (28°C = 0.58 kJ/day, 31°C = 1.20 kJ/day, 34°C = 4.30 kJ/day, 37°C = 7.95 kJ/day). Thus, lower heat loads in encroached glades may cause reduced body temperature and result in restricted energy assimilation rates. Our study provides a novel approach to the integration of bioenergetics and conservation and shows the efficacy of using information on digestive performance to investigate underlying mechanisms in a conservation context.

Do small precocial birds enter torpor to conserve energy during development?

Precocial birds hatch feathered and mobile, but when they become fully endothermic soon after hatching, their heat loss is high and they may become energy depleted. These chicks could benefit from using energy-conserving torpor, which is characterised by controlled reductions of metabolism and body temperature (Tb). We investigated at what age the precocial king quail Coturnix chinensis can defend a high Tb under a mild thermal challenge and whether they can express torpor soon after achieving endothermy to overcome energetic and thermal challenges. Measurements of surface temperature (Ts) using an infrared thermometer showed that king quail chicks are partially endothermic at 2-10 days, but can defend high Tb at a body mass of ∼13 g. Two chicks expressed shallow nocturnal torpor at 14 and 17 days for 4-5 h with a reduction of metabolism by >40% and another approached the torpor threshold. Although chicks were able to rewarm endogenously from the first torpor bout, metabolism and Ts decreased again by the end of the night, but they rewarmed passively when removed from the chamber. The total metabolic rate increased with body mass. All chicks measured showed a greater reduction of nocturnal metabolism than previously reported in quails. Our data show that shallow torpor can be expressed during the early postnatal phase of quails, when thermoregulatory efficiency is still developing, but heat loss is high. We suggest that torpor may be a common strategy for overcoming challenging conditions during development in small precocial and not only altricial birds.

Oral Administration of Watermelon Rind Extract to Induce Hypothermia in Chicks.

Oral administration of l-citrulline (l-Cit) caused hypothermia, but l-Cit is not recommended in poultry diets in Japan. Watermelon is a natural source of l-Cit. The objective of this study is to examine the effect of watermelon waste, i.e., watermelon rind (WR) on the body temperature and plasma free amino acids of chicks. In Experiment 1, 14-day-old chicks were subjected to acute oral administration of WR extract (WRE) (2 ml) under control thermoneutral temperature (CT). In Experiment 2, 15-day-old chicks were orally administered 1.6 ml of either WRE, lowdose l-Cit (7.5 mmol/10 ml), or high-dose l-Cit (15 mmol/10 ml) under CT. In both experiments, rectal temperature (RT) and plasma free amino acids were analyzed. In Experiment 3, after dual oral administration of (1.6 ml) WRE or l-Cit (15 mmol/10 ml), 15-day-old chicks were exposed to high ambient temperature (HT; 35±1°C, 2 h) to monitor changes in RT. Acute oral administration of WRE significantly reduced RT under CT. The degree of RT reduction by WRE was similar to that by high l-Cit. Moreover, RT was significantly low at HT owing to the oral administration of WRE. However, the reduced RT was difficult to explain by the content of Cit in WRE alone. In conclusion, WRE could be used as a dietary ingredient to reduce body temperature for imparting thermotolerance in chicks.

Temperature-related heart rate in water and air and a comparison to other temperature-related measures of performance in the fiddler crab Leptuca pugilator (Bosc 1802).

Performance in poikilotherms is known to be sensitive to temperature, often with a low-sloping increase with temperature to a peak, and a steep decline with increasing temperature past the peak. We complemented past measures of performance by measuring heartbeat rates of the fiddler crab Leptuca pugilator in water and in air as a function of a range of temperatures previously shown to affect other measures of performance. In water over a range of 20-50°C, heartbeat increased steadily to a peak at 40°C and then steeply declined to near zero at 50°C. In air, heartbeat also increased, but to a peak at 35°C and then with a gentler decline than was found in water. Part of this different response may be due to evaporative water loss, which reduced body temperature in air, and therefore thermal stress, relative to body temperature when crabs were immersed in water. Increased availability of oxygen from air, according to the oxygen and capacity-limited thermal tolerance hypothesis, likely increased aerobic scope past the thermal peak, relative to within water, where oxygen delivery at higher temperatures may have been curtailed. We compared the heart rate performance relations to two previous measures of performance - endurance on a treadmill and sprint speed, both done in air. The peak performance temperature increased in the order: treadmill endurance time, sprint speed, heart rate in air, and heart rate in water, which demonstrates that different performance measures give different perspectives on the relation of thermal tolerance and fitness to temperature. Endurance may therefore be the limiting upper thermal stress factor in male fiddler crabs, when on hot sand flats. Temperature preference, found to be for temperatures <30°C in air, could be a bet-hedging evolutionary strategy to avoid aerobic scope affecting endurance.