Increase In Rectal Temperature Research Articles

Serum Metabolomics and NF-κB Pathway Analysis Revealed the Antipyretic Mechanism of Ellagic Acid on LPS-Induced Fever in Rabbits.

Fever is one of the most common clinical conditions and is characterized by pyrogenic infection, malignancy, inflammation, and tissue damage, among others. Ellagic acid (EA) can inhibit the expression of related proteins on the pathway by blocking the nuclear factor kappa-B(NF-κB) signaling pathway, inhibit the levels of pro-inflammatory factors interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α), increase the level of anti-inflammatory factor IL-10, and effectively alleviate inflammatory symptoms. In addition, EA can also reduce the levels of malondialdehyde(MDA) and nitric oxide(NO) in the body, increase the activities of superoxide dismutase (SOD), glutathione (GSH), and catalase(CAT), scavenge oxidative free radicals, inhibit lipid oxidation, and achieve antipyretic and anti-inflammatory effects. The purpose of this study was to establish the relationship between EA and various inflammatory markers, such as TNF-α, IL-6, IL-1β, prostaglandin E2(PGE2), and cyclic adenosine monophosphate(cAMP), and clarify the mechanism of the cyclooxidase-2(COX-2)/NF-κB signaling pathway. Combined with the metabolomics analysis, our study revealed the effects of EA on multiple endogenous biomarkers, reflecting the characteristics of a multi-component, multi-target, and multi-pathway mechanism. Compared to lipopolysaccharide (LPS)- treated animals, subsequent administration of EA significantly lowered the LPS-induced rectal temperature increase (p < 0.05 or p < 0.01), significantly increased serum SOD and GSH levels (p < 0.05 or p < 0.01), and significantly decreased serum MDA, IL-1β, IL-6, and TNF-α levels (p < 0.05 or p < 0.01). In addition, compared to LPS-treated animals, subsequent administration of EA significantly decreased cerebrospinal fluid cAMP and PGE2 levels (p < 0.05 or p < 0.01), significantly decreased cAMP, significantly increased 5-HT levels (p < 0.05 or p < 0.01), and significantly down-regulated p-NF-κB p65 and COX-2 protein levels in the hypothalamus. Subsequent gas chromatography mass spectrometry(GC-MS) metabolite analysis indicated that 12 differential metabolites were detected in serum isolated 4 h after LPS treatment, and 10 differential metabolites were detected in serum collected 7 h after LPS treatment. Next, Pearson correlation analysis was used to systematically characterize the relationship between the identified metabolites and TNF-α, IL-6, MDA, SOD, PGE2, and cAMP. The levels of propionic acid, pyridine, and L-valine were up-regulated by EA, which inhibited the expression of MDA, IL-1β, and TNF-α and increased the activity of GSH. The levels of inositol, urea, and 2-monopalmitin were down-regulated by EA, which inhibited the expression of MDA, IL-1β, and TNF-α, increased the activity of SOD and GSH, reduced the inflammatory response, and alleviated the oxidative stress state. Combined with the results of the metabolic pathway analysis, we suggest that the pathways of the galactose metabolism, synthesis and degradation of ketone bodies, as well as ascorbic acid and aldehyde acid metabolism are closely related to the antipyretic and anti-inflammatory effects of EA. Our study established the relationship between EA and various inflammatory markers, such as TNF-α, IL-6, IL-1β, PGE2, and cAMP, and clarified the mechanism of the COX-2/NF-κB signaling pathway. Combined with the metabolomics analysis, our study revealed the effects of EA on multiple endogenous biomarkers, reflecting the characteristics of a multi-component, multi-target, and multi-pathway mechanism.

Effects of Local Heating and Whole-Body Hyperthermia on Neuromuscular and Cognitive Function in Young and Old Healthy Adults

Background and objectives: Aging population is growing fast in European Union and worldwide (Shimizu et al., 2020). A progressive decline in neuromuscular function (Lexell et al., 1983), structural changes in the brain ( Smith et al., 2010; Zahra et al., 2019)aged 30 to 99 years, were studied with MRI. Age was related to estimated volumes of: gray matter, white matter, and CSF of the cerebrum and cerebellum; gray matter, white matter, white matter abnormality, and CSF within each cerebral lobe; and gray matter of eight subcortical structures. The results were: 1, and inefficiencies in thermoregulatory regulation (Blatteis, 2012; Yamashiro et al., 2020) were found in the old population. We conducted three experiments to investigate the effects of short-term and long-term passive heating on motor performance, as well as the impact of whole-body passive heating on cognitive functioning in both healthy older and young adults. Methods: In the first study, weight (kg), body fat (%), height (cm), body mass index (BMI), skinfold thickness (mm), and the mean subcutaneous fat thickness were calculated (McArdle et al., 1984). Ankle muscle torque production and contractile properties were determined by isometric torque of the ankle plantar flexion and the isokinetic (dynamic) torque of the ankle plantar flexion/dorsiflexion muscles using an isokinetic dynamometer (System 4; Biodex Medical Systems, Shirley, NY, USA). In the second study, body surface area, heart rate, muscle temperature, and thermal sensation were measured. Prolactin, interleukin-6, dopamine and cortisol concentrations were obtained via venous blood samples. The isometric torque of ankle plantar flexion muscles was assessed as the first study. In the third study, body weight, sweating rate, rectal temperature, heart rate, physiological strain index (PSI), thermal sensations were investigated. A programmed cognitive test to assess cognitive functioning (Brazaitis et al., 2015). Results: In the first study, for the older adults (vs. younger adults), the application of local heating (vs. control trial) was accompanied by a significant increase in maximal voluntary peak torque, rate of torque development, and isokinetic peak torque of plantar flexion/dorsiflexion muscle contraction. In the second study, older males demonstrated greater neuromuscular fatigability resistance and faster maximal voluntary contraction (MVC) torque recovery after a 2-min sustained isometric MVC task under thermoneutral and severe hyperthermic conditions. In the third study, PSI was lower and cortisol concentration was greater after whole-body heating in the older group compared with the younger group. Surprisingly, hyperthermia improved cognitive flexibility only in old adults, whereas short-term and visual recognition memories were maintained in both age groups. Conclusions: In the first study, the spinal and supraspinal reflex excitability of older adults increased during local knee-heating application. The improved motor drive transmission observed in older adults was accompanied by increased voluntarily induced torque production of the ankle muscles during isometric/isokinetic contractions. In the second study, neuromuscular performance during fatigue-provoking sustained isometric exercise under severe whole body hyperthermia conditions appears to decline in both age groups, but a lower relative decline in torque production for older males may relate to lower psychological and thermophysiological strain along with a diminished dopamine response and prolactin release. In the third study, A ≈ 2.5 ◦C increase in rectal temperature can improve executive function in old adults, and this increase parallels the increased cortisol concentration and the lower thermophysiological strain under severe whole-body hyperthermia conditions.

The Impact of Ventilation System Type on the Microclimate of Boar's Pen and Their Clinical Triad Parameters

The purpose of the study was the impact of different types of ventilation systems in boar`s pen on the microclimate and their physiological parameters. The control group of boars was kept in a house with a transverse ventilation system, and the animals of the experimental group were kept in a geothermal air supply. It was found that, regardless of the season, transverse ventilation provides a significantly higher air velocity and relative humidity: in Winter - 0.15 m s–1 and 5.4%; in Spring - 0.35 m s–1 and 5.3%; in Summer - 0.41 m s–1 and 0.7%; in Autumn - 0.28 m s–1 and 8.1%. Maintaining a stable temperature by the normative values in the boar housing was due to geothermal ventilation, regardless of the season, especially the "basement effect" was observed in the summer months, where the air temperature was cooled to 4.5°C (P &amp;lt; 0.001), compared to the transverse ventilation system. Compared with the boars in the experimental group, under the influence of the temperature increase in Summer, the boars in the control group increased significantly the respiratory rate to 50.9 ppm (P &amp;lt; 0.001) and heartbeat rate of 45.7 ppm (P &amp;lt; 0.001). An increase in rectal temperature in boars at elevated ambient temperature under both air ventilation systems was not found. The obtained results make it possible to introduce the use of cost-effective geothermal air supply technology in pig farms to harmonize the physiological parameters of boars to meet their biological needs, even in closed housing to improve their welfare.

Embryo thermal manipulation enhances mitochondrial function in the skeletal muscle of heat-stressed broilers by regulating transient receptor potential V2 expression

Heat stress induces mitochondrial dysfunction, thereby impeding skeletal muscle development and significantly impacting the economic efficiency of poultry production. This study aimed to investigate the effects of embryo thermal manipulation (TM, 41.5°C, 65% RH, 3 h/d during 16-18th embryonic age) on the mitochondrial function of the pectoralis major (PM) in broiler chickens exposed to thermoneutral (24 ± 1°C, 60% RH) or cyclic heat stress (35 ± 1°C, 60% RH, 12 h/d) from day 22 to 28, and to explore potential mechanisms involving transient receptor potential V2 (TRPV2). Additionally, in vitro experiments were conducted to assess the regulatory effects of TRPV2 pharmacological activation and inhibition on mitochondrial function in primary myotubes. The results revealed that TM had no discernible effect on the body weight and feed intake of broiler chickens under heat stress conditions (P > 0.05). However, it did delay the increase in rectal temperature and accelerate the decrease in serum T3 levels (P < 0.05). Furthermore, TM promoted the development of PM muscle fibers, significantly increasing myofiber diameter and cross-sectional area (P < 0.05). Under heat stress conditions, TM significantly upregulated the expression of mitochondrial electron transport chain (ETC) genes and TRPV2 in broiler PM muscle (P < 0.05), with a clear positive correlation observed between the two (P < 0.05). In vitro, pharmacological activation of TRPV2 not only increased its own expression but also enhanced mitochondrial ETC genes expression and oxidative phosphorylation function by upregulating intracellular calcium ion levels (P < 0.05). Conversely, TRPV2 inhibition had the opposite effect. Overall, this study underscores the potential of prenatal thermal manipulation in regulating postnatal broiler skeletal muscle development and mitochondrial function through the modulation of TRPV2 expression.

Effects of systemic or uterine endotoxin challenge in Holstein cows at 5 or 40 days postpartum on clinical responses, uterine and systemic inflammation, and milk yield

Our objective was to investigate the effects of intravenous (IV) or intrauterine (IU) lipopolysaccharide (LPS) challenge at 5 or 40 d postpartum (DPP) on clinical signs, systemic and uterine inflammation, dry matter intake (DMI), and milk yield (MY). Holstein cows at 5 DPP (n = 23) or at 40 DPP (n = 24) were blocked by parity and randomly assigned to 1 of 3 treatments: (1) IV-LPS (0.0625 μg/kg BW [5 DPP] or 0.1 μg/kg BW [40 DPP] over 1h), (2) IU-LPS (100 μg [5 DPP] or 300 μg [40 DPP] in 20 mL of saline), or (3) 20 mL of saline IU (IU-SAL; same for 5 and 40 DPP). The proportion of polymorphonuclear (PMN) cells was measured by endometrial cytology at d -1, 1, 4, and 7 relative to treatment. Blood haptoglobin (Hp), serum amyloid A (SAA), and LPS-binding protein (LBP), DMI, and MY were measured from d -1 through d 7. Data were analyzed separately for each DPP group in multivariable linear regression models accounting for repeated measures. Both DPP groups showed increases in rectal temperature and heart and respiratory rates, and decrease in rumination rate following IV-LPS, but not following IU-LPS. At 5 DPP, endometrial PMN proportion was similar in IU-LPS and IU-SAL. Serum Hp was unaffected by LPS challenge, SAA was greater in IV-LPS from 12 h to 24 h after challenge, and LBP was greater in IV-LPS from 8 h to 24 h. At 40 DPP, PMN was greater in IU-LPS (37 ± 4%) than in IU-SAL (15 ± 4%) 1 d after LPS challenge. Serum Hp was greater from 24 h to 72 h after challenge in IV-LPS than in the other groups, SAA was greater in IV-LPS from 6 h to 48 h, and LBP was greater in IV-LPS from 8 h to 24 h. At both 5 and 40 DPP, treatment did not affect DMI, but MY was lesser in IV-LPS cows at 12 h and 24 h than in IU-SAL or IU-LPS. The IV-LPS challenge resulted in more pronounced changes in clinical signs and acute phase protein (APP) concentrations than IU-LPS or IU-SAL at 40 DPP, but more subtle or inconsistent changes at 5 DPP. These may be due to the different doses of LPS used at 5 and 40 DPP or possibly due to the high variation in baseline clinical signs and APP observed in all groups at 5 DPP. The IU-LPS increased uterine PMN 1 d after challenge at 40 DPP but not at 5 DPP. At each time, IU-LPS did not produce changes in clinical signs or markers of systemic inflammation.

Cold-water foot immersion and physiological strain of adults with coronary artery disease during hot and humid heat exposure

Introduction: Heat extremes are associated with a greater risk of adverse cardiovascular outcomes, especially among adults with coronary artery disease. While air-conditioning provides exceptional protection during heat extremes, it is neither sustainable nor widely accessible. Cold-water foot immersion reduces physiological heat strain in healthy young adults but its effect in more vulnerable populations remains unknown. Objective and hypotheses: This study aims to identify the effect of cold-water foot immersion on markers of physiological heat strain in adults with coronary artery disease. We hypothesized that cold-water foot immersion would reduce physiological heat strain when used on its own and that this effect would be greater when combined with an electric fan. Methods: 17 adults living with stable coronary artery disease (2 females/15 males; 67±8 years) were exposed to a 38°C, 60% relative humidity environment for 3 hours on three separate, randomized occasions: i) no cooling (control; CON); ii) cold-water foot immersion (20 min of immersion each 30 min, ~30 cm in water kept at ~18°C; FI); iii) cold-water foot immersion and fan use (FI+FAN). Rectal and skin temperatures, heart rate (5-lead ECG), and whole-body sweat loss (change in nude weight) were measured. Results: The increase in rectal temperature did not differ between conditions (CON: 0.40±0.24°C, FI: 0.41±0.29°C, and FI+FAN: 0.36±0.22°C; p≥0.49). The increase in skin temperature was reduced with FI and FI+FAN compared to CON (CON: 4.9±0.8°C, FI: 4.1±1.2°C, and FI+FAN: 4.3±0.8°C; p≤0.01), with no difference between FI and FI+FAN (p=0.15). Similarly, the increase in heart rate was reduced with FI and FI+FAN compared to CON (CON: 8±6 bpm, FI: 4±6 bpm, and FI+FAN: 3±6 bpm; p≤0.01), with no difference between FI and FI+FAN (p=0.45). Sweat loss was also reduced by FI and FI+FAN compared with CON (CON: 823±114 g, FI: 544±174 g, and FI+FAN: 671±255 g; p≤0.03), with sweat loss during FI sweat loss being lower than during FI+FAN (p=0.03). Conclusion: The results show that cold-water foot immersion, used alone or in combination with an electric fan, reduces the increase in heart rate and whole-body sweat loss of adults living with coronary artery disease exposed to a hot and humid environment for 3 hours. This could be linked to the lower increase in skin temperature with foot immersion. National Health and Medical Research Council of Australia (APP1147789). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Does menthol independently modify thermoregulatory control during passive heat stress in humans?

Introduction: Physical cooling within the gastrointestinal (GI) tract attenuates sudomotor activity likely by activation of the cold-sensitive transient receptor potential melastatin 8 (TRPM8). In the absence of physical cooling, it remains unknown whether stimulation of TRPM8 receptors within the GI tract during heat stress alters sudomotor control. Objective and Hypothesis: The purpose of this study is to assess whether a TRPM8 agonist (e.g., menthol) independently modulates the sudomotor response during heat stress. Relative to 37°C water, It was hypothesized that menthol would i) delay the sweating onset, and ii) attenuate the sweating response during heat stress. Methods: To date, a total of 9 participants (5 females; 22±5 y; 72.7±10.5 kg; 1.8±0.1 m) have completed three passive heating protocols on separate days. The participant’s rectal temperature was increased by 1.0°C above baseline using a water perfused suit circulating 49°C water. Participants consumed 3.2 ml per kg of body mass of either: i) 37°C water (37C), ii) 1.5°C water (1.5C), or iii) 37°C menthol solution (0.05%, 37M), 5 minutes before passive heating, and following a 0.5°C and 1.0°C increase in rectal temperature. Mean skin temperature (4 sites) and local sweat rate of the forearm and forehead were recorded during the baseline period and passive heating protocol. Mean body temperature was calculated as the weighted average between skin (20%) and rectal (80%) temperature, and whole-body sweat rate expressed as the net difference in body mass relative to heating time (in g/h). Results: Mean body temperature at baseline was not different between the three conditions (37C: 36.21±0.41˚C, 1.5C: 36.24±0.38˚C, and 37M: 36.30±0.43˚C, P=0.32). Forearm sweating onset was attenuated with 37M (36.97±0.42˚C, P=0.04), and trending to be attenuated with 1.5C (36.96±0.26˚C, P=0.07) relative to 37C (36.69±0.40˚C). Similarly, forehead sweating onset was attenuated with 37M (36.95±0.44˚C, P=0.02), and trending to be attenuated with 1.5C (36.84±0.35˚C, P=0.09), relative to 37C (36.70±0.43˚C). Thermosensitivity was not different between all three fluid conditions for the arm (37C: 1.4±0.7 mg/cm2/min/˚C; 1.5C: 1.7±1.0 mg/cm2/min/˚C; 37M: 1.5±1.0 mg/cm2/min/˚C, P=0.59) and head (37C: 1.7±0.9 mg/cm2/min/˚C; 1.5C: 1.6±1.2 mg/cm2/min/˚C; 37M: 1.7±1.1 mg/cm2/min/˚C, P=0.88). Lastly, whole-body sweat rate was not significantly different between all three conditions (37C: 631±288 g/h; 1.5C: 580±270 g/h; 37M: 635±440 g/h, P=0.63). Conclusion: Preliminary results suggest that consumption of a TRPM8 agonist in advance of passive heat stress may attenuate the sudomotor onset similarly to 1.5˚C water relative to 37˚C. However, the sweating response remains largely unaffected during passive heat stress between all three fluids assessed. Funding: This research was supported by Dr. Nicholas Ravanelli’s Natural Sciences and Engineering Research Council of Canada Discovery Grant (PIN#2022-05096). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

High variation in the response of calves to a low-dose lipopolysaccharide challenge is associated with early-life measurements

Lipopolysaccharide (LPS) challenges are commonly used in animal studies as a model for infection with gram-negative bacteria and innate immune activation. We used a low-dose LPS challenge for evaluating interindividual variation in innate immune responses in calves. This was part of a larger study aimed at predicting interindividual variation in feed efficiency in veal calves by variation in feeding motivation, digestion, metabolism, immunology, and behavioral traits. However, due to unexpected high mortality, this LPS challenge was performed in 32 calves rather than in 130 calves, which was initially intended in that larger study, and the 32 calves subjected to the LPS challenge were removed from that larger study. The objective of this short communication is to report the effects of a low-dose LPS challenge in those 32 calves and to examine whether the high variation in calves' responses to LPS could be explained by parameters related to feeding motivation, digestion, behavior, and immunology measured in early life. Thirty-two male Holstein-Friesian calves of Dutch origin were intravenously injected with LPS (0.05 μg/kg of body weight) at an age of 72 ± 0.6 d. Rectal temperature and respiratory frequency were recorded before injection and every hour after injection up to 6 h. In the 8 wk before the LPS challenge, measurements were performed related to general health, feeding motivation, digestion, behavior, and immunity. Following LPS administration, 3 calves died of shock, a fourth calf was euthanized because of severe symptoms of shock and 3 other calves were treated with corticosteroids to counteract observed symptoms of shock. Within the group of 25 relatively mild-responding calves, large interindividual variation in clinical responses to LPS was observed. The maximum increase in rectal temperature varied from 0.6 to 1.9°C and averaged 1.2 ± 0.39°C (coefficient of variation was 32%). The maximum increase in respiratory frequency varied from 16 to 132 bouts/min and averaged 60 ± 28 bouts/min (coefficient of variation was 48%). Little differences were found in early-life measurements between the 7 heavy and 25 mild responders, although heavy responders tended to have a better umbilical hernia score, and had a lower score in a human approach test (i.e., were less reactive) and lower presence of fecal pathogens. The maximum increase in rectal temperature correlated negatively with blood hemoglobin concentration at arrival of the calves at the facilities (r = −0.59) and in wk 4 (r = −0.53). The maximum increase in respiratory frequency correlated negatively with fecal color score (r = −0.43) and positively with fur score in wk 5 (r = 0.50). Overall, mortality (12.5%) and variation in clinical response was high after a low-dose LPS challenge in clinically healthy calves and some hematological and health measurements in early life were related to the clinical response of calves to LPS.

Exploring Thermoregulatory Responses and Hormonal Changes in Heat Stressed Assam Hill Goats

Background: Livestock productivity and health are adversely affected by heat stress (HS). The aim of this study was to determine the effects of HS on the thermoregulation and hormonal profile in Assam Hill Goats reared in the subtropical hilly regions of Meghalaya so as to arrive at a conclusion on its heat adaptation abilities. Methods: An experiment was conducted during the year 2022 for 120 days with twelve (12) Assam Hill Goats, aged between 3-5 months, randomly divided into 2 groups (n=6 per group). The goats in group I were exposed to HS through natural exposure to sunlight during the extreme summer months (May to August) for 07 hours (8 AM to 3 PM) during grazing. The control animals (CON, group II) were maintained under shade with no exposure to sunlight. Thermoregulatory responses viz., rectal temperature, respiratory rate and pulse rate and body weight data were recorded every 15 days interval of the sampling period. The hormonal profile viz., serum T3 (nmol/L), T4 (nmol/L) and Cortisol (ng/mL) were also determined. Result: Results revealed a significant (p less than 0.05) increase in rectal temperature, pulse rate (day 45 onwards to day 120) and respiratory rate in HS group in comparison to CON. A significantly (p less than 0.05) lower average daily gain was recorded in HS group. Serum T3 and T4 concentrations were significantly (p less than 0.05) reduced and cortisol concentration was significantly (p less than 0.05) elevated in HS group in comparison to CON. In conclusion, Assam Hill Goats exposed to environmental HS shows elevated thermoregulatory responses, decreased thyroid hormone activity and increased cortisol activity to reduce production to support life sustaining activities in the hilly regions.

High dietary cation and anion difference formulation increased heat dissipation in non-lactating goats fed at high ambient temperature.

In our previous study, we observed that a high dietary cation and anion difference (DCAD) of 40 mEq/kg dry matter (DM) in the diets of lactating dairy goats increased heat dissipation. In the present study, we believe that the level of DCAD fed to non-lactating and non-pregnant goats was twice as high as that fed to lactating goats in our previous study. This increase could have resulted in a greater water balance due to increased intake of water and unchanged urinary excretion. Therefore, this study aimed to determine the behavioral and heat dissipation effects of a dietary shift from low to high DCAD levels in dairy goats under tropical conditions. Seven non-lactating and non-pregnant crossbred goats were used in this study. All animals were initially fed a low DCAD (15 mEq/100 g DM) diet from days 0-6 and then switched to a high DCAD (89 mEq/100 g DM) diet from day 7 (high DCAD-7) to day 18 (high DCAD-18). The results revealed that a high DCAD increased DM intake from days 13-18 (p < 0.05). The larger daily meal size associated with the high DCAD-18 group was due to increased daytime meal sizes, not nighttime when compared to the low DCAD group. Dietary cation and anion difference supplementation did not affect daily water intake; however, drinking patterns differed between the low DCAD group and the high DCAD-7 group from 07:00 to 09:00 and during nighttime. Similarly, daily urine volume was unaffected by DCAD supplementation, but urinary patterns differed between the low DCAD and high DCAD-18 groups. The daily water balance remained unchanged across all treatments, yet, a higher morning water balance was observed in the high DCAD group. The high DCAD diet led to an increase in respiration rate and rectal temperature compared to the low DCAD diet. The observed eating, drinking, and urinary patterns collectively suggested that high DCAD supplementation mitigates the effects of heat stress in non-lactating goats fed at high ambient temperatures.

102 Growth Performance in Pigs fed a High Soybean Meal Diet During Heat Stress

Abstract In the U.S. swine industry, feeding programs are focused on using feed ingredients that are easily digestible and cost effective. With the predicted increases in soybean processing, pig producers may have increased availability of a cost-effective protein source in soybean meal (SBM). This expanded availability of SBM may result in feeding protein above the ostensible requirements, which would likely intensify the thermic effect of digestion, potentially increasing the susceptibility of the pig to heat stress (HS). Heat stress has damaging effects on feed intake and growth performance, costing the swine industry &amp;gt;$900 million annually. Therefore, the study objectives were to evaluate the effects of dietary crude protein diets (in the form of SBM) during HS on growth performance in growing pigs. Growing pigs (n = 40; initial BW = 55 ± 5.6 kg) were allocated into six treatments: 1) thermoneutral (TN) ad libitum control diet (TN-Ctl; n = 6), 2) TN pair-fed (PF) control diet (PF-Ctl; n = 6), 3) HS ad libitum control diet (HS-Ctl; n = 8), 4) TN ad libitum high SBM diet (TN-SBM; n = 6), 5) TN PF high SBM diet (PF-SBM; n = 6), and 6) HS ad libitum high SBM diet (HS-SBM; n = 8). The control diet included 15% crude protein (CP) while the high SBM diet included 23% CP with excess amino acids. The study consisted of two periods: Period 1 (P1; 7 d) in which all pigs were housed in TN environments (26.7 ± 1.4°C) with ad libitum access to respective diets. Period 2 (P2; 21 d), HS groups were exposed to cyclical HS with daytime temperatures reaching 35°C and evening temperatures decreased to 29.4°C. During P2, PF groups were fed to respective HS-Ctl or HS-SBM equivalents in TN conditions. Pigs exposed to HS had an overall increase in rectal temperature and respiration rate (0.91°C and 45 bpm, respectively; P ≤ 0.01) and HS-SBM pigs had increased evening rectal temperature (± 0.13°C; P ≤ 0.01), relative to HS-Ctrl. Overall, HS decreased ADFI (19%; P ≤ 0.01), ADG (26%; P ≤ 0.01) and increased F:G (10%; P ≤ 0.01) irrespective of dietary CP levels. Loin muscle area (P = 0.19) and backfat (P = 0.98) were not different between the TN and HS pigs regardless of diet. Circulating blood urea nitrogen levels did not differ between HS and TN pigs (P = 0.68), but an increase was observed in pigs fed the SBM diet relative to the control diet (P ≤ 0.01). In summary, these results demonstrate that HS decreases growth performance, but the negative effects are not augmented by feeding a high SBM diet.

An Early Treatment With BKI-1748 Exhibits Full Protection Against Abortion and Congenital Infection in Sheep Experimentally Infected With Toxoplasma gondii.

Congenital toxoplasmosis in humans and in other mammalian species, such as small ruminants, is a well-known cause of abortion and fetal malformations. The calcium-dependent protein kinase 1 (CDPK1) inhibitor BKI-1748 has shown a promising safety profile for its use in humans and a good efficacy against Toxoplasma gondii infection in vitro and in mouse models. Ten doses of BKI-1748 given every other day orally in sheep at 15 mg/kg did not show systemic or pregnancy-related toxicity. In sheep experimentally infected at 90 days of pregnancy with 1000 TgShSp1 oocysts, the BKI-1748 treatment administered from 48 hours after infection led to complete protection against abortion and congenital infection. In addition, compared to infected/untreated sheep, treated sheep showed a drastically lower rectal temperature increase and none showed IgG seroconversion throughout the study. In conclusion, BKI-1748 treatment in pregnant sheep starting at 48 hours after infection was fully effective against congenital toxoplasmosis.

Expression of &lt;i&gt;TSPO&lt;/i&gt; and &lt;i&gt;HIF-1α&lt;/i&gt; genes as predictors of the organism’s resistance to hyperthermia

BACKGROUND: One of the key transcriptional regulators that determine the bodys resistance to hypoxia is the hypoxia-inducible factor HIF-1, the study of the role of which in the bodys resistance to extreme influences can justify new directions in medical technologies for its increase. The bodys resistance to hypoxia largely determines the resistance to other critically significant influences (hyperthermia, hypothermia, hyperbaria, ionizing radiation, chemicals, etc.). However, it was not possible to find a quantitative assessment of this effect in the literature studied by us, which served as the basis for this study.&#x0D; AIM: To assess the role of the level of expression of the hypoxia-inducible factor HIF-1 in various tissues of laboratory animals in increasing the resistance of animals to the effects of extreme hyperthermia.&#x0D; MATERIALS AND METHODS: The study was carried out on outbred white laboratory rats obtained from the Rappolovo nursery weighing 180220 g. For the study, preliminary laboratory animals were tested for an individual level of resistance to hyperthermia (40 animals), which made it possible to form experimental groups from highly resistant and low resistant to extreme animal influences. The definition of resistance to hyperthermia was carried out by the rate of increase in rectal temperature in animals during 20-minute air hyperthermia (40C). 4 groups of laboratory animals were formed (2 each with high and low resistance), half of which were exposed to a pronounced adverse effect of hyperthermia. Biological material was taken from all animals (whole blood, plasma, tissues of the heart, liver, kidneys, brain), in which the expression of the HIF-1 and TSPO genes (housekeeping gene) was determined by the Real-Time-PCR method. Statistical processing of the obtained data was carried out using the ANOVA analysis of variance.&#x0D; RESULTS: It has been established that the level of resistance of animals to hyperthermia is largely determined by their genetic characteristics. Even under thermocomfort conditions, the expression of the TSPO housekeeping gene in animals with a high level of resistance to hyperthermia differed with a high degree of reliability from low-resistant animals (in the kidneys, liver, and brain, on average, by 4060%; in the heart, by 25%). The expression values of this gene, determined in whole blood or plasma, make it possible to differentiate groups of animals according to the level of resistance to hyperthermia. A similar relationship between animals with high and low resistance is also observed in tissues obtained immediately after thermal exposure.&#x0D; CONCLUSIONS: The main organ that provides a high level of resistance to both hypoxia and hyperthermia associated with the basic (under thermal comfort conditions) expression of HIF-1 is the brain. The expression of the hypoxia-inducible factor in it is more than 300 times higher than the expression of the housekeeping genes. The second most important organ is the liver, in which HIF-1 expression activity is more than 15 times higher than the expression of housekeeping genes. Under conditions of hyperthermia, low-resistant animals show a compensatory-adaptive reaction associated with the activation of hypoxic defense mechanisms in blood cells, kidneys, and liver, in the absence of such a reaction in the tissues of the heart and brain. Animals highly resistant to hyperthermia were characterized by a significant (30 times) increase in the relative activity of HIF-1 expression mechanisms in blood cells, 2.5 times in liver cells, and a decrease in expression by 25% in the kidneys and almost 2 times in brain tissues. A high level of basal expression of the transcription factor HIF-1 under everyday (thermocomfortable) conditions may be a predictor of a high level of resistance to hyperthermia in a given animal. Probably, to increase the bodys resistance to extreme impacts, it is advisable to use medical technologies that increase the level of HIF-1 expression in everyday (thermocomfortable) conditions in key tissues the brain, liver, and myocardium.

Age-Related Difference in Cognitive Performance under Severe Whole-Body Hyperthermia Parallels Cortisol and Physical Strain Responses.

Background and Objectives: To date, understanding age-related changes in cognitive processes during heat exposure still needs to be better-understood. Thus, the main aim of the current study was to evaluate the effects of whole-body hyperthermia (WBH), i.e., a ≈ 2.5 °C increase in rectal temperature (Tre) from overnight-fast baseline value, on cognitive functioning in old and young men and to explore factors, such as stress and thermophysiological strain, that could influence such changes. Materials and Methods: Ten young (19-21 years of age) and nine old (61-80 years of age) healthy men underwent an experimental trial with passive lower-body heating in hot water immersion (HWI) at 43 °C (HWI-43 °C) until Tre reached 39 °C in old adults and 39.5 °C in young adults. Cognitive performance and cortisol concentration were assessed before and after HWI, and the physiological strain index (PSI) was assessed during HWI-43 °C. Results: PSI was lower and cortisol concentration was greater after HWI-43 °C in the old group compared with the young group (p < 0.05). Surprisingly, hyperthermia improved cognitive flexibility only in old adults, whereas short-term and visual recognition memories were maintained in both age groups. Conclusions: A ≈ 2.5 °C increase in rectal temperature can improve executive function in old adults, and this increase parallels the increased cortisol concentration and the lower thermophysiological strain under severe WBH conditions.

Excessive whole-body exposure to 28 GHz quasi-millimeter wave induces thermoregulation accompanied by a change in skin blood flow proportion in rats.

Limited information is available on the biological effects of whole-body exposure to quasi-millimeter waves (qMMW). The aim of the present study was to determine the intensity of exposure to increase body temperature and investigate whether thermoregulation, including changes in skin blood flow, is induced in rats under whole-body exposure to qMMW. The backs of conscious rats were extensively exposed to 28 GHz qMMW at absorbed power densities of 0, 122, and 237 W/m2 for 40 minutes. Temperature changes in three regions (dorsal and tail skin, and rectum) and blood flow in the dorsal and tail skin were measured simultaneously using fiber-optic probes. Intensity-dependent temperature increases were observed in the dorsal skin and the rectum. In addition, skin blood flow was altered in the tail but not in the dorsum, accompanied by an increase in rectal temperature and resulting in an increase in tail skin temperature. These findings suggest that whole-body exposure to qMMW drives thermoregulation to transport and dissipate heat generated on the exposed body surface. Despite the large differences in size and physiology between humans and rats, our findings may be helpful for discussing the operational health-effect thresholds in the standardization of international exposure guidelines.

Effects of long-snake moxibustion on the HPA axis and liver 11β-HSD1 expression in rats with kidney yang deficiency: 长蛇灸对肾阳虚大鼠HPA轴及肝脏11β-HSD1的影响

ObjectiveTo observe the effects of long-snake moxibustion on the hypothalamic-pituitary-adrenocortical (HPA) axis and hepatic 11β-hydroxy steroid dehydrogenase type 1 (11β-HSD1) expression in rats with kidney yang deficiency to provide a basis for later in-depth exploration of the action mechanism of long-snake moxibustion on such rats. MethodsFifteen SPF-grade, male, SD rats were randomly divided into a blank control group, a model group, and a long-snake moxibustion treatment group, with five rats in each group. Hydrocortisone powder (30 mg/kg) was administered by gavage at a volume of 10 mL/kg to prepare the rat model of kidney yang deficiency. After successful modeling, the rats in the long-snake moxibustion treatment group underwent long-snake moxibustion treatment every other day (along the governor vessel from Dazhui (GV14) to Shenshu(BL23), for a period of 14 days. The remaining two groups were secured in the same way as the long-snake moxibustion treatment group, although they did not receive any treatment. The body weight, rectal temperature, and spontaneous activity count of the rats, as well as serum levels of corticotropin releasing hormone (CRH) and corticosterone (CORT) were detected by ELISA before modeling, after modeling, and after treatment. The amount of 11β-HSD1 protein in rat liver was determined by immunohistochemistry and Western blot analysis. ResultsCompared with the rats in the blank control group, those in the model group exhibited a significant decrease in the trend of body weight growth and in rectal temperature (P <0.05), as well as a slight yet non-significant decrease in spontaneous activity count (P >0.05); compared with the rats in the model group, the rats in the treatment group exhibited a significant increase in rectal temperature (P <0.05) and in spontaneous activity count (P <0.05). Moreover, after 14 days of treatment, compared with the rats in the blank, the rats in the model group exhibited a significant decrease in serum CORT content (P <0.05) and in the expression of 11β-HSD1 in the liver (P <0.05), as well as a slight yet non-significant decrease in serum CRH content (P >0.05); compared with the rats in the model group, the rats in the treatment group exhibited a significant increase in serum CRH content (P <0.05) and in the expression of 11β-HSD1 in the liver (P <0.05), as well as a slight yet non-significant increase in serum CORT content (P >0.05). ConclusionLong-snake moxibustion can increase the rectal temperature and spontaneous activity count of rats with kidney yang deficiency, improve the function of the HPA axis, and increase the expression of 11β-HSD1 in the liver.

Artificial ovaries constructed from biodegradable chitin-based hydrogels with the ability to restore ovarian endocrine function and alleviate osteoporosis in ovariectomized mice

BackgroundArtificial ovary (AO) is an alternative approach to provide physiological hormone to post-menopausal women. The therapeutic effects of AO constructed using alginate (ALG) hydrogels are limited by their low angiogenic potential, rigidity, and non-degradability. To address these limitations, biodegradable chitin-based (CTP) hydrogels that promote cell proliferation and vascularization were synthesized, as supportive matrix.MethodsIn vitro, follicles isolated from 10–12-days-old mice were cultured in 2D, ALG hydrogels, and CTP hydrogels. After 12 days of culture, follicle growth, steroid hormone levels, oocyte meiotic competence, and expression of folliculogenesis-related genes were monitored. Additionally, follicles isolated from 10–12-days-old mice were encapsulated in CTP and ALG hydrogels and transplanted into the peritoneal pockets of ovariectomised (OVX) mice. After transplantation, steroid hormone levels, body weight, rectal temperature, and visceral fat of the mice were monitored every two weeks. At 6 and 10 weeks after transplantation, the uterus, vagina, and femur were collected for histological examination.ResultsThe follicles developed normally in CTP hydrogels under in vitro culture conditions. Additionally, follicular diametre and survival rate, oestrogen production, and expression of folliculogenesis-related genes were significantly higher than those in ALG hydrogels. After one week of transplantation, the numbers of CD34-positive vessels and Ki-67-positive cells in CTP hydrogels were significantly higher than those in ALG hydrogels (P < 0.05), and the follicle recovery rate was significantly higher in CTP hydrogels (28%) than in ALG hydrogels (17.2%) (P < 0.05). After two weeks of transplantation, OVX mice implanted with CTP grafts exhibited normal steroid hormone levels, which were maintained until week eight. After 10 weeks of transplantation, CTP grafts effectively ameliorated bone loss and atrophy of the reproductive organs, as well as prevented the increase in body weight and rectal temperature in OVX mice, which were superior to those elicited by ALG grafts.ConclusionsOur study is the first to demonstrate that CTP hydrogels support follicles longer than ALG hydrogels in vitro and in vivo. The results highlight the clinical potential of AO constructed using CTP hydrogels in the treatment of menopausal symptoms.

Glucagon-Like Peptide-1 Is Involved in the Thermic Effects of Dietary Proteins in Male Rodents.

Protein intake potently increases body temperature and energy expenditure, but the underlying mechanism thereof remains incompletely understood. Simultaneously, protein intake potently stimulates glucagon-like peptide-1 (GLP-1) secretion. Here, we examined the involvement of GLP-1 in the thermic effects of dietary proteins in rodents by measuring rectal temperature and energy expenditure and modulating GLP-1 signaling. Rectal temperature of rats or mice fasted for 4 or 5 hours were measured using a thermocouple thermometer before and after an oral administration of nutrients. Oxygen consumption after oral protein administration was also measured in rats. Rectal temperature measurements in rats confirmed an increase in core body temperature after refeeding, and the thermic effect of the oral administration of protein was greater than that of a representative carbohydrate or lipid. Among the five dietary proteins examined (casein, whey, rice, egg, and soy), soy protein had the highest thermic effect. The thermic effect of soy protein was also demonstrated by increased oxygen consumption. Studies using a nonselective β-adrenergic receptor antagonist and thermal camera suggested that brown adipose tissue did not contribute to soy protein-induced increase in rectal temperature. Furthermore, the thermic effect of soy protein was completely abolished by antagonism and knockout of the GLP-1 receptor, yet potentiated via augmentation of intact GLP-1 levels through inhibition of dipeptidyl peptidase-4 activity. These results indicate that GLP-1 signaling is essential for the thermic effects of dietary proteins in rats and mice, and extend the metabolic actions of GLP-1 ensuing from nutrient ingestion to encompass the thermic response to ingested protein.

The effects of a single and a series of Finnish sauna sessions on the immune response and HSP-70 levels in trained and untrained men

Background The aim of the study was to investigate the effect of a Finnish sauna on the immune status parameters. The hypothesis was that hyperthermia would improve immune system’s functioning by changing the proportion of lymphocyte subpopulations and would activate heat shock proteins. We assumed that the responses of trained and untrained subjects would be different. Material and methods Healthy men (20–25 years old) were divided into groups: the trained (T; n = 10), and the untrained group (U; n = 10). All participants were subjected to 10 baths (each one consisted of: 3 × 15-minute exposure with cooled down for 2 min. Body composition, anthropometric measurements, VO2 peak were measured before 1st sauna bath. Blood was collected before the 1st and 10th sauna bath, and 10 min after their completion to asses an acute and a chronic effect. Body mass, rectal temperature and heart rate (HR) were assessed in the same time points. The serum levels of cortisol, Il-6, HSP70 were measured with use of ELISA method, IgA, IgG and IgM by turbidimetry. White blood cells (WBC), leukocyte populations counts: neutrophils, lymphocytes, eosinophils, monocytes, and basophils were determined with use of flow cytometry as well as T-cell subpopulations. Results No differences were found in the increase in rectal temperature, cortisol and immunoglobulins between groups. In response to the 1st sauna bath, a greater increase in HR was observed in the U group. After the last one, the HR value was lower in the T group. The impact of sauna baths on WBC, CD56+, CD3+, CD8+, IgA, IgG and IgM was different in trained and untrained subjects’ responses. A positive correlation between the increase in cortisol concentrations and increase in internal temperatures after the 1st sauna was found in the T (r = 0.72) and U group (r = 0.77), between the increase in IL-6 and cortisol concentrations in the T group after the 1st treatment (r = 0.64), between the increase in IL-10 concentration and internal temperature (r = 0.75) and between the increase in IL-6 and IL-10 (r = 0.69) concentrations, also. Conclusions Sauna bathing can be a way to improve the immune response, but only when it is undertaken as a series of treatments.

Relationship of Meteorological Data with Heat Stress Effect on Dairy Cows of Smallholder Farmers

Global warming has been increasing heat stress threat in animals, which can be monitored via the Temperature Humidity Index (THI). The present study describes the THI pattern and the relationship between THI and the production performances of dairy cows in a selected area of Bangladesh. The THI value was calculated using weather station data gathered over 35 years. Based on the THI pattern, January and June were identified as the coolest and hottest months, respectively. Consequently, the production performances of 10 crossbred cows with homogenous characteristics were monitored every January and June for a 5-year period. The average THIMEAN was found to be 17% higher in June when compared to January; with this increment of THIMEAN, average milk production was decreased by 24.4% (p &lt; 0.05). The milk fat and protein content were also reduced (p &lt; 0.05) by 14.5 and 15.2%, respectively, suggesting a negative correlation. However, ash content increased by 15.3%, which indicates a positive correlation. In addition, multiple regression analysis revealed that, with each point increase in THIMEAN and rectal temperature, there was a decrease in milk yield of 0.04 and 1.17 kg ECM, respectively. In contrary, each point increase in THIMEAN resulted in 0.059 °C increase of rectal temperature. Taken together, THIMEAN calculated using meteorological station data has a distinct relationship with the production performances of lactating crossbred dairy cows.