Pub Date : 2025-11-29DOI: 10.1016/j.jtherbio.2025.104345
Xiaoyu Yu , Changping Li , Ruixi Ming , Bin Wang , Hongzhou Guo , Bin Li
Heat stress represents a critical environmental and occupational hazard that impairs male reproductive capacity across mammalian species, including humans. It primarily exerts its deleterious effects by inducing oxidative stress and apoptosis in testicular Leydig cells, ultimately disrupting testosterone biosynthesis. In this study, primary Leydig cells (PLCs) were subjected to heat stress, which significantly elevated intracellular ROS, MDA, and XO levels while reducing TAC and SOD activities, leading to increased apoptosis. Pretreatment with 0.1 μM melatonin effectively restored redox homeostasis, lowering ROS, MDA, and XO and enhancing TAC and SOD, thereby markedly decreasing apoptotic cell death. Mechanistic studies showed that melatonin increased NRF2 expression, and NQO1 levels, while decreasing KEAP1, and reversed heat-induced upregulation of Bax and γH2AX and downregulation of Bcl-2. In vivo, melatonin-treated mice exhibited preservation of 3β-HSD-positive Leydig cell number, reduced seminiferous tubule vacuolization, normalized serum testosterone levels, and restoration of STAR, CYP11A1, and 3β-HSD protein expression. These findings demonstrate that melatonin alleviates heat stress-induced oxidative injury and apoptosis via activation of the KEAP1-NRF2 pathway and thereby protects Leydig cell function and testosterone production.
{"title":"Melatonin attenuates heat stress-induced oxidative stress and apoptosis in mouse testicular Leydig cells via the KEAP1-NRF2 pathway","authors":"Xiaoyu Yu , Changping Li , Ruixi Ming , Bin Wang , Hongzhou Guo , Bin Li","doi":"10.1016/j.jtherbio.2025.104345","DOIUrl":"10.1016/j.jtherbio.2025.104345","url":null,"abstract":"<div><div>Heat stress represents a critical environmental and occupational hazard that impairs male reproductive capacity across mammalian species, including humans. It primarily exerts its deleterious effects by inducing oxidative stress and apoptosis in testicular Leydig cells, ultimately disrupting testosterone biosynthesis. In this study, primary Leydig cells (PLCs) were subjected to heat stress, which significantly elevated intracellular ROS, MDA, and XO levels while reducing TAC and SOD activities, leading to increased apoptosis. Pretreatment with 0.1 μM melatonin effectively restored redox homeostasis, lowering ROS, MDA, and XO and enhancing TAC and SOD, thereby markedly decreasing apoptotic cell death. Mechanistic studies showed that melatonin increased NRF2 expression, and NQO1 levels, while decreasing KEAP1, and reversed heat-induced upregulation of Bax and γH2AX and downregulation of Bcl-2. <em>In vivo</em>, melatonin-treated mice exhibited preservation of 3β-HSD-positive Leydig cell number, reduced seminiferous tubule vacuolization, normalized serum testosterone levels, and restoration of STAR, CYP11A1, and 3β-HSD protein expression. These findings demonstrate that melatonin alleviates heat stress-induced oxidative injury and apoptosis via activation of the KEAP1-NRF2 pathway and thereby protects Leydig cell function and testosterone production.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"135 ","pages":"Article 104345"},"PeriodicalIF":2.9,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-20DOI: 10.1016/j.jtherbio.2025.104340
Simon C. Griffith , Carmen R.B. da Silva , Riccardo Ton
The zebra finch has been used in laboratory studies to understand the effects of ambient temperature on development and reproduction. We characterize the thermal range in which the species breeds in the wild in Australia. Our data reveal that zebra finches breed over an extremely wide range of ambient temperatures (−5.2 °C to 46.2 °C), and that embryos are not as buffered from ambient temperatures as generally considered, regularly spending time at temperatures between 10 °C and 40 °C.
To place the zebra finch in a broader context we examined the thermal breeding range of 327 other Australian terrestrial species. These thermal ranges vary extensively, but there was no indication of a phylogenetic signal for this trait, suggesting it is a relatively labile trait. The range of temperatures in which zebra finch breeds is at the 90th percentile of Australian terrestrial species, indicating that it has a relatively high level of plasticity in coping with thermal conditions. We also found that the zebra finch breeds in relatively high temperatures, with 10 % of observed zebra finch breeding attempts being made in conditions with a 30-day average maximum temperature of 31–38.2 °C. Again, however, around 20 % of Australian bird species were found to breed in higher average maximum temperatures. Nevertheless, the temperatures we have characterized provide insight into the capacity of embryo, nestling, and adult zebra finches to cope across a wide range of ambient temperatures. The zebra finch is a good species for further experimental work in the laboratory to understand tolerance, plasticity, and the effects of temperature on development and physiology. Our findings will help to interpret past and future studies in this important area of research, and provide the appropriate context for future studies to design ecologically relevant manipulations of temperature.
{"title":"The thermal range of the wild zebra finch in developmental, reproductive, and phylogenetic contexts","authors":"Simon C. Griffith , Carmen R.B. da Silva , Riccardo Ton","doi":"10.1016/j.jtherbio.2025.104340","DOIUrl":"10.1016/j.jtherbio.2025.104340","url":null,"abstract":"<div><div>The zebra finch has been used in laboratory studies to understand the effects of ambient temperature on development and reproduction. We characterize the thermal range in which the species breeds in the wild in Australia. Our data reveal that zebra finches breed over an extremely wide range of ambient temperatures (−5.2 °C to 46.2 °C), and that embryos are not as buffered from ambient temperatures as generally considered, regularly spending time at temperatures between 10 °C and 40 °C.</div><div>To place the zebra finch in a broader context we examined the thermal breeding range of 327 other Australian terrestrial species. These thermal ranges vary extensively, but there was no indication of a phylogenetic signal for this trait, suggesting it is a relatively labile trait. The range of temperatures in which zebra finch breeds is at the 90th percentile of Australian terrestrial species, indicating that it has a relatively high level of plasticity in coping with thermal conditions. We also found that the zebra finch breeds in relatively high temperatures, with 10 % of observed zebra finch breeding attempts being made in conditions with a 30-day average maximum temperature of 31–38.2 °C. Again, however, around 20 % of Australian bird species were found to breed in higher average maximum temperatures. Nevertheless, the temperatures we have characterized provide insight into the capacity of embryo, nestling, and adult zebra finches to cope across a wide range of ambient temperatures. The zebra finch is a good species for further experimental work in the laboratory to understand tolerance, plasticity, and the effects of temperature on development and physiology. Our findings will help to interpret past and future studies in this important area of research, and provide the appropriate context for future studies to design ecologically relevant manipulations of temperature.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104340"},"PeriodicalIF":2.9,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-20DOI: 10.1016/j.jtherbio.2025.104342
Vrindha Madhavan , Varuna P. Panicker , Jini Roy , M.V. Chinnu , R. Uma
Heat stress and its impacts adversely affect all living organisms, especially domestic animals. Rising body temperature above core temperature has been reported to affect the production, reproduction and disease resistance capacity in animals. The present study was conducted to investigate the impact of heat stress on milk fatty acid synthesis, serum lipid profile, thyroid hormone levels, glucose concentration and oxidative stress parameters in Malabari and Attappady Black goats. Six Malabari and six Attappady Black goats of uniform age and parity were selected for the study. Serum metabolite profiling showed no significant differences between the breeds. The gene expression of ACACA and COX-2 was analysed using quantitative real-time PCR. ACACA exhibited no significant difference (P > 0.05) between the breeds, whereas COX-2 showed a significant difference (P ≤ 0.05). A four-fold increase was observed in COX-2 gene expression in Attappady Black goats. Breed-specific responses to heat stress were observed, with significant changes in oxidative stress parameters and insignificant effects on milk fatty acid synthesis and serum metabolite profile. These findings revealed that Attappady Black goats have higher stress-related gene activation, indicating breed-specific physiological adaptations to heat stress. This may help in selective breeding and management practices for increased resilience.
{"title":"Expression dynamics of Acetyl Coenzyme A Carboxylase-Alpha and Cyclooxygenase-2 genes in two indigenous goat breeds of Kerala under heat stress","authors":"Vrindha Madhavan , Varuna P. Panicker , Jini Roy , M.V. Chinnu , R. Uma","doi":"10.1016/j.jtherbio.2025.104342","DOIUrl":"10.1016/j.jtherbio.2025.104342","url":null,"abstract":"<div><div>Heat stress and its impacts adversely affect all living organisms, especially domestic animals. Rising body temperature above core temperature has been reported to affect the production, reproduction and disease resistance capacity in animals. The present study was conducted to investigate the impact of heat stress on milk fatty acid synthesis, serum lipid profile, thyroid hormone levels, glucose concentration and oxidative stress parameters in Malabari and Attappady Black goats. Six Malabari and six Attappady Black goats of uniform age and parity were selected for the study. Serum metabolite profiling showed no significant differences between the breeds. The gene expression of <em>ACACA</em> and <em>COX-2</em> was analysed using quantitative real-time PCR. <em>ACACA</em> exhibited no significant difference (P > 0.05) between the breeds, whereas <em>COX-2</em> showed a significant difference (P ≤ 0.05). A four-fold increase was observed in <em>COX-2</em> gene expression in Attappady Black goats. Breed-specific responses to heat stress were observed, with significant changes in oxidative stress parameters and insignificant effects on milk fatty acid synthesis and serum metabolite profile. These findings revealed that Attappady Black goats have higher stress-related gene activation, indicating breed-specific physiological adaptations to heat stress. This may help in selective breeding and management practices for increased resilience.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104342"},"PeriodicalIF":2.9,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-18DOI: 10.1016/j.jtherbio.2025.104319
Jia Luo , Qiang Pu , Zihan Ma , Zhenhao Wen , Jie Chai , Li Chen , Xiaoqian Wu , Zonggang Luo , Tenghao Wang , Jingyong Wang
Global climate warming elevates temperatures, increasing pigs' heat stress susceptibility and metabolic heat production, thereby intensifying heat-related challenges. This study examines chronic heat stress (HS) effects on hematological traits and hepatic responses in gilts. During HS, respiratory rate and surface temperature rose significantly, while rectal temperature stabilized. In the HS group, white blood cell count, aonocyte percentage, eosinophil percentage, absolute eosinophil count, absolute neutrophil count, absolute monocyte count, absolute basophil count, hematocrit, and mean corpuscular hemoglobin concentration decreased markedly, whereas mean platelet volume increased. Blood Beecf and PO2 levels rose, and PCO2 levels dropped. HS elevated cortisol, altered thyroid function (higher TSH, lower T3/T4), reduced ACTH indicating adrenal dysfunction, and disrupted reproductive hormones (higher LH, lower FSH) alongside elevated insulin (INS) and estradiol (E2) levels. Furthermore, Albumin/Globulin Ratio (A/G ratio) and Albumin (ALB) decreased, while Alkaline Phosphatase (ALP), Gamma-Glutamyl Transferase (GGT), Globulin (GLB), Total Bile Acids (TBA), and Total Bilirubin (TBIL) increased. Histopathology revealed hepatic punctate necrosis, lymphocyte infiltration, sinusoidal dilation, and hydropic degeneration. Immunofluorescence showed increased Bax+ and CD3+ cells but decreased Bcl-2+ and CD3+ cells. Hepatocyte HSP70/90 levels surged. Multi-omics analysis indicated HS enriched oxidative phosphorylation, steroid biosynthesis, lipid metabolism, and thyroid hormone synthesis in the liver. Pro-inflammatory pathways (Calcitriol, LPC 19:0) were activated, while protective molecules (Cholecalciferol, L-Glutathione) countered oxidative stress. As expected, chronic HS impairs liver function, induces an inflammation-antioxidant imbalance. More importantly, HS accelerates the conversion of cholesterol to sex hormones to compensate for ovarian suppression, ultimately affecting gilt reproductive performance.
{"title":"Chronic heat stress induces hepatic injury, alters hematological parameters, thermotolerance response in gilts through liver multi-omics analysis","authors":"Jia Luo , Qiang Pu , Zihan Ma , Zhenhao Wen , Jie Chai , Li Chen , Xiaoqian Wu , Zonggang Luo , Tenghao Wang , Jingyong Wang","doi":"10.1016/j.jtherbio.2025.104319","DOIUrl":"10.1016/j.jtherbio.2025.104319","url":null,"abstract":"<div><div>Global climate warming elevates temperatures, increasing pigs' heat stress susceptibility and metabolic heat production, thereby intensifying heat-related challenges. This study examines chronic heat stress (HS) effects on hematological traits and hepatic responses in gilts. During HS, respiratory rate and surface temperature rose significantly, while rectal temperature stabilized. In the HS group, white blood cell count, aonocyte percentage, eosinophil percentage, absolute eosinophil count, absolute neutrophil count, absolute monocyte count, absolute basophil count, hematocrit, and mean corpuscular hemoglobin concentration decreased markedly, whereas mean platelet volume increased. Blood Beecf and PO<sub>2</sub> levels rose, and PCO<sub>2</sub> levels dropped. HS elevated cortisol, altered thyroid function (higher TSH, lower T3/T4), reduced ACTH indicating adrenal dysfunction, and disrupted reproductive hormones (higher LH, lower FSH) alongside elevated insulin (INS) and estradiol (E2) levels. Furthermore, Albumin/Globulin Ratio (A/G ratio) and Albumin (ALB) decreased, while Alkaline Phosphatase (ALP), Gamma-Glutamyl Transferase (GGT), Globulin (GLB), Total Bile Acids (TBA), and Total Bilirubin (TBIL) increased. Histopathology revealed hepatic punctate necrosis, lymphocyte infiltration, sinusoidal dilation, and hydropic degeneration. Immunofluorescence showed increased Bax<sup>+</sup> and CD3<sup>+</sup> cells but decreased Bcl-2<sup>+</sup> and CD3<sup>+</sup> cells. Hepatocyte HSP70/90 levels surged. Multi-omics analysis indicated HS enriched oxidative phosphorylation, steroid biosynthesis, lipid metabolism, and thyroid hormone synthesis in the liver. Pro-inflammatory pathways (Calcitriol, LPC 19:0) were activated, while protective molecules (Cholecalciferol, L-Glutathione) countered oxidative stress. As expected, chronic HS impairs liver function, induces an inflammation-antioxidant imbalance. More importantly, HS accelerates the conversion of cholesterol to sex hormones to compensate for ovarian suppression, ultimately affecting gilt reproductive performance.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104319"},"PeriodicalIF":2.9,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145564482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-17DOI: 10.1016/j.jtherbio.2025.104316
Bo Wang , Wenlong Zhang , Yutong Guo , Guoqiang Ai , Hongyu Zhao , Wanqi Tao , Bingbing Han
Extreme winter conditions in severe cold regions impose significant physiological strain, challenging human temperature regulation and limiting outdoor space utilisation. This study investigates how vertically stratified thermal environments influence the physiological and perceptual responses of young adults on campus rooftops. Using synchronised microclimate monitoring and thermal perception assessments, we analysed human thermal adaptation across elevation gradients. Key findings are mentioned here: (i) winter thermal regulation is primarily driven by temperature–wind interactions, posing distinct physiological challenges compared to radiation-dominated summer conditions, (ii) the universal thermal climate index demonstrates superior predictive accuracy for thermal sensation across heights compared with physiological equivalent temperature (PET), modified PET and standard effective temperature, especially in east-oriented spaces at high elevations, (iii) thermal neutrality exhibits a non-linear altitudinal pattern, declining from 7.67 °C at 1.5 m to 1.47 °C at 9.5 m before rising to 9.73 °C at 13.5 m, with reduced sensitivity at heights, indicating physiological acclimatisation and (iv) biological and adaptive factors significantly modulate thermal responses, as females and participants from southern origins show broad physiological tolerance limitsand enhanced cold adaptation. These findings enhance our understanding of human thermal adaptation in extreme cold environments and offer physiological evidence for designing thermally optimised vertical spaces in severe cold regions.
{"title":"Vertical thermal responses of young adults in campus rooftop spaces during winter in the severe cold regions of China","authors":"Bo Wang , Wenlong Zhang , Yutong Guo , Guoqiang Ai , Hongyu Zhao , Wanqi Tao , Bingbing Han","doi":"10.1016/j.jtherbio.2025.104316","DOIUrl":"10.1016/j.jtherbio.2025.104316","url":null,"abstract":"<div><div>Extreme winter conditions in severe cold regions impose significant physiological strain, challenging human temperature regulation and limiting outdoor space utilisation. This study investigates how vertically stratified thermal environments influence the physiological and perceptual responses of young adults on campus rooftops. Using synchronised microclimate monitoring and thermal perception assessments, we analysed human thermal adaptation across elevation gradients. Key findings are mentioned here: (i) winter thermal regulation is primarily driven by temperature–wind interactions, posing distinct physiological challenges compared to radiation-dominated summer conditions, (ii) the universal thermal climate index demonstrates superior predictive accuracy for thermal sensation across heights compared with physiological equivalent temperature (PET), modified PET and standard effective temperature, especially in east-oriented spaces at high elevations, (iii) thermal neutrality exhibits a non-linear altitudinal pattern, declining from 7.67 °C at 1.5 m to 1.47 °C at 9.5 m before rising to 9.73 °C at 13.5 m, with reduced sensitivity at heights, indicating physiological acclimatisation and (iv) biological and adaptive factors significantly modulate thermal responses, as females and participants from southern origins show broad physiological tolerance limitsand enhanced cold adaptation. These findings enhance our understanding of human thermal adaptation in extreme cold environments and offer physiological evidence for designing thermally optimised vertical spaces in severe cold regions.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104316"},"PeriodicalIF":2.9,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145557122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-15DOI: 10.1016/j.jtherbio.2025.104336
Atakan Çortu, Gökhan Bozkurt
Infrared thermography (IRT) offers a non invasive method to assess skin surface temperature (SST) and detect physiological changes in teat tissue. However, segment specific SST dynamics in dairy goats during milking have not been previously characterised. This study aimed to quantify the magnitude and direction of SST changes in different teat segments before and after milking. Twenty four clinically healthy Saanen goats, aged 2–5 years (mean body weight 63.10 ± 5.65 kg) in mid lactation, were evaluated. Thermal images were captured immediately before milking (T1), and at 30 s (T2), 5 min (T3), and 10 min (T4) after milking. Each teat was divided into base (B), centre (C), and tip (T) segments, and average (Tavg) and maximum (Tmax) SST were extracted from rectangular regions of interest (5 x 25 pixels). Time significantly affected both Tavg and Tmax across all segments (P < 0.001). SST declined between T1/T2 and T3, followed by partial recovery at T4. The teat tip exhibited the largest changes (Tavg d range: 1.76 to +1.84; Tmax d range: 2.11 to +1.11), indicating high mechanical and vascular responsiveness. No left–right asymmetry was detected (P > 0.05), and intra-observer repeatability was excellent (ICC = 0.92–0.97). These findings indicate pronounced cooling followed by rewarming, reflecting transient vascular and mechanical stress at the teat end. IRT effectively detected these rapid, segment-specific SST changes in dairy goats during milking. The established 10-min response profile provides reliable baseline data for welfare assessment and milking equipment evaluation, supporting the use of IRT as a sensitive, non-invasive tool for monitoring udder health and physiological responses in small-ruminant dairy systems.
红外热成像（IRT）提供了一种非侵入性的方法来评估皮肤表面温度（SST）和检测皮肤组织的生理变化。然而，在挤奶期间，奶山羊的特定节段海温动态以前没有被描述过。本研究旨在量化挤奶前后不同乳段海温变化的幅度和方向。选取24只临床健康、年龄2-5岁、平均体重63.10±5.65 kg、泌乳中期的沙宁山羊。分别在挤奶前（T1）、挤奶后30 s （T2）、5 min （T3）和10 min （T4）采集热图像。每个样本被划分为基底(B)、中心(C)和尖端(T)，并从感兴趣的矩形区域（5 x 25像素）提取平均（Tavg）和最大（Tmax）海温。时间对Tavg和Tmax均有显著影响（p0.05），且观察者内重复性极好（ICC = 0.92-0.97）。这些发现表明明显的冷却之后再升温，反映了瞬态血管和机械应力在末端。IRT有效地检测了挤奶期间奶山羊体内这些快速的、特定部位的SST变化。建立的10分钟反应谱为福利评估和挤奶设备评估提供了可靠的基线数据，支持将IRT作为一种灵敏、非侵入性的工具，用于监测小反刍动物乳制品系统的乳房健康和生理反应。
{"title":"First characterisation of segment-specific teat thermography in dairy goats: rapid temperature dynamics before and after milking","authors":"Atakan Çortu, Gökhan Bozkurt","doi":"10.1016/j.jtherbio.2025.104336","DOIUrl":"10.1016/j.jtherbio.2025.104336","url":null,"abstract":"<div><div>Infrared thermography (IRT) offers a non invasive method to assess skin surface temperature (SST) and detect physiological changes in teat tissue. However, segment specific SST dynamics in dairy goats during milking have not been previously characterised. This study aimed to quantify the magnitude and direction of SST changes in different teat segments before and after milking. Twenty four clinically healthy Saanen goats, aged 2–5 years (mean body weight 63.10 ± 5.65 kg) in mid lactation, were evaluated. Thermal images were captured immediately before milking (T1), and at 30 s (T2), 5 min (T3), and 10 min (T4) after milking. Each teat was divided into base (B), centre (C), and tip (T) segments, and average (Tavg) and maximum (Tmax) SST were extracted from rectangular regions of interest (5 x 25 pixels). Time significantly affected both Tavg and Tmax across all segments (P < 0.001). SST declined between T1/T2 and T3, followed by partial recovery at T4. The teat tip exhibited the largest changes (Tavg <em>d</em> range: 1.76 to +1.84; Tmax <em>d</em> range: 2.11 to +1.11), indicating high mechanical and vascular responsiveness. No left–right asymmetry was detected (P > 0.05), and intra-observer repeatability was excellent (ICC = 0.92–0.97). These findings indicate pronounced cooling followed by rewarming, reflecting transient vascular and mechanical stress at the teat end. IRT effectively detected these rapid, segment-specific SST changes in dairy goats during milking. The established 10-min response profile provides reliable baseline data for welfare assessment and milking equipment evaluation, supporting the use of IRT as a sensitive, non-invasive tool for monitoring udder health and physiological responses in small-ruminant dairy systems.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104336"},"PeriodicalIF":2.9,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145534727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.jtherbio.2025.104334
Wissem Baccouri , George Wanjala , Violetta Tóth , István Komlósi , Edit Mikó
Rising temperatures and humidity increasingly challenge the welfare and productivity of dairy cows worldwide. Behavioural changes are among the earliest responses to heat stress, reflecting animals’ efforts to reduce heat load. This study investigated how heat stress and lactation stage interact to influence the behaviour of Holstein Friesian cows. Data were collected from 60 cows between 20 June and July 20, 2024, with 1680 records of eating, ruminating, and inactivity times. Cows were grouped by lactation stage: early (days in milk, (DIM) ≤ 60), mid (DIM 61–180), and late (DIM >180). Behaviour was assessed under moderate (temperature–humidity index, (THI) 72–76) and severe heat stress (THI ≥77). A significant interaction was observed between the level of heat stress and lactation stage. Under severe heat stress, eating time declined significantly across all lactation groups, with the largest reduction observed in late-lactation cows. Ruminating time decreased significantly only in late-lactation cows, while remaining relatively stable in early and mid-lactation. Conversely, inactivity time increased in all groups, with the duration of inactivity rising as lactation advanced. These results suggest that behavioural responses to heat stress intensify with advancing lactation. In conclusion, late-lactation cows are more susceptible to heat stress than those in earlier stages, indicating a need for targeted mitigation strategies to support cow welfare and productivity.
{"title":"The effect of different levels of heat stress on the behaviour of cows at different stage of lactation","authors":"Wissem Baccouri , George Wanjala , Violetta Tóth , István Komlósi , Edit Mikó","doi":"10.1016/j.jtherbio.2025.104334","DOIUrl":"10.1016/j.jtherbio.2025.104334","url":null,"abstract":"<div><div>Rising temperatures and humidity increasingly challenge the welfare and productivity of dairy cows worldwide. Behavioural changes are among the earliest responses to heat stress, reflecting animals’ efforts to reduce heat load. This study investigated how heat stress and lactation stage interact to influence the behaviour of Holstein Friesian cows. Data were collected from 60 cows between 20 June and July 20, 2024, with 1680 records of eating, ruminating, and inactivity times. Cows were grouped by lactation stage: early (days in milk, (DIM) ≤ 60), mid (DIM 61–180), and late (DIM >180). Behaviour was assessed under moderate (temperature–humidity index, (THI) 72–76) and severe heat stress (THI ≥77). A significant interaction was observed between the level of heat stress and lactation stage. Under severe heat stress, eating time declined significantly across all lactation groups, with the largest reduction observed in late-lactation cows. Ruminating time decreased significantly only in late-lactation cows, while remaining relatively stable in early and mid-lactation. Conversely, inactivity time increased in all groups, with the duration of inactivity rising as lactation advanced. These results suggest that behavioural responses to heat stress intensify with advancing lactation. In conclusion, late-lactation cows are more susceptible to heat stress than those in earlier stages, indicating a need for targeted mitigation strategies to support cow welfare and productivity.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104334"},"PeriodicalIF":2.9,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.jtherbio.2025.104337
Pandey Harsh , Tasaduq Hussain Shah , Alexander Ciji , Pramod Kumar Pandey , Arya Mukul , Md Shahbaz Akhtar
The effects of varying temperature regimes on the ontogenic and early larval development of golden mahseer in captive conditions were investigated. For this, after fertilization, eggs of golden mahseer from a single pair of broodstock were randomly distributed into four incubation temperature regimes (20 °C, 23 °C, 26 °C, and 29 °C) in triplicates, and key parameters like fertilization rates, ontogenic events, hatching windows, yolk-sac absorption, larval growth, survival and fitness were assessed. The embryos of T. putitora developed most rapidly at 29 °C, followed by 26 °C, 23 °C, and 20 °C. No notable differences were observed in the time taken to progress from the 2-cell stage to the late morula stage across temperatures. However, incubation temperatures significantly influenced later stages of development, such as blastodisc formation, notochord onset, twitching, segmentation, optic formation, and hatching. At 29 °C, blastodisc formation, twitching, notochord onset, somite formation, and hatching occurred approximately 1, 9, 6, 11 and 29 h earlier, respectively, compared to 20 °C. Despite the faster development at 29 °C, there was a marked reduction in fertilization, hatching success, and survival. The incubation period was the longest at lower temperatures and decreased significantly as the temperature rose, with a corresponding reduction in the hatching window. Complete yolk-sac absorption was the slowest at 20 °C and faster at higher temperatures. The critical thermal maximum (CTmax) and minimum (CTmin) of larvae increased with incubation and rearing temperatures, peaking at 26 °C. Rearing temperatures also affected the anti-oxidative enzyme activities in the larvae. Overall, these findings highlight the vulnerability of golden mahseer to elevated temperatures and provide insights into how future warming scenarios could further threaten this endangered species.
{"title":"Temperature-induced ontogenic plasticity and larval fitness of golden mahseer (Tor putitora) in captivity","authors":"Pandey Harsh , Tasaduq Hussain Shah , Alexander Ciji , Pramod Kumar Pandey , Arya Mukul , Md Shahbaz Akhtar","doi":"10.1016/j.jtherbio.2025.104337","DOIUrl":"10.1016/j.jtherbio.2025.104337","url":null,"abstract":"<div><div>The effects of varying temperature regimes on the ontogenic and early larval development of golden mahseer in captive conditions were investigated. For this, after fertilization, eggs of golden mahseer from a single pair of broodstock were randomly distributed into four incubation temperature regimes (20 °C, 23 °C, 26 °C, and 29 °C) in triplicates, and key parameters like fertilization rates, ontogenic events, hatching windows, yolk-sac absorption, larval growth, survival and fitness were assessed. The embryos of <em>T. putitora</em> developed most rapidly at 29 °C, followed by 26 °C, 23 °C, and 20 °C. No notable differences were observed in the time taken to progress from the 2-cell stage to the late morula stage across temperatures. However, incubation temperatures significantly influenced later stages of development, such as blastodisc formation, notochord onset, twitching, segmentation, optic formation, and hatching. At 29 °C, blastodisc formation, twitching, notochord onset, somite formation, and hatching occurred approximately 1, 9, 6, 11 and 29 h earlier, respectively, compared to 20 °C. Despite the faster development at 29 °C, there was a marked reduction in fertilization, hatching success, and survival. The incubation period was the longest at lower temperatures and decreased significantly as the temperature rose, with a corresponding reduction in the hatching window. Complete yolk-sac absorption was the slowest at 20 °C and faster at higher temperatures. The critical thermal maximum (CTmax) and minimum (CTmin) of larvae increased with incubation and rearing temperatures, peaking at 26 °C. Rearing temperatures also affected the anti-oxidative enzyme activities in the larvae. Overall, these findings highlight the vulnerability of golden mahseer to elevated temperatures and provide insights into how future warming scenarios could further threaten this endangered species.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104337"},"PeriodicalIF":2.9,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145549677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.jtherbio.2025.104333
Melissa Skein , Jayden Hunter , Alexander Carney
The aim of this study was to investigate the effect of cold-water immersion (CWI) between consecutive bouts of simulated rugby seven's matches on performance, physiology and perception. Using a randomised crossover counterbalanced design, 10 male recreational team-sport athletes completed two trials involving two 14 min simulated self-paced intermittent-sprint protocol (ISP) bouts with a 45 min recovery between each bout including a 15 min recovery intervention. Participants completed resting measures, 15 m sprints and vertical jumps (VJ) followed by the first ISP (ISP1) in a hot environment. After ISP1 participants were either seated in an ice-bath (CWI; 11.6 ± 1.8 °C) (CWI) or sat in a thermo-neutral environment (CONT) for 15 min. Measures of heart rate (HR), core temperature (Tcore), skin temperature (Tskin), thermal sensation (TS) and ratings of perceived exertion (RPE) were recorded during ISP1, ISP2 and the recovery period. Statistical significance was set at P = 0.05. Vertical jump height was lower and 15 m sprint times slower during ISP2, following CWI (P = 0.01–0.02). While jogging self-paced efforts from ISP1 to ISP2 were maintained, sprint times were slower, and bounding distance was increased in CWI compared to CONT. Tskin was reduced during recovery for CWI (P = 0.001). Tcore, RPE, and TS were lower throughout ISP2 for CWI (P = 0.001–0.04). Therefore, CWI as a recovery modality between successive bouts of simulated rugby sevens in the heat may negatively affect initial high intensity performance compared to passive recovery yet may attenuate thermoregulatory stress through a pre-cooling effect still present 30 min after CWI, leading to higher intensity during the jogging efforts.
{"title":"Cold-water recovery between bouts of simulated rugby sevens matches in the heat","authors":"Melissa Skein , Jayden Hunter , Alexander Carney","doi":"10.1016/j.jtherbio.2025.104333","DOIUrl":"10.1016/j.jtherbio.2025.104333","url":null,"abstract":"<div><div>The aim of this study was to investigate the effect of cold-water immersion (CWI) between consecutive bouts of simulated rugby seven's matches on performance, physiology and perception. Using a randomised crossover counterbalanced design, 10 male recreational team-sport athletes completed two trials involving two 14 min simulated self-paced intermittent-sprint protocol (ISP) bouts with a 45 min recovery between each bout including a 15 min recovery intervention. Participants completed resting measures, 15 m sprints and vertical jumps (VJ) followed by the first ISP (ISP1) in a hot environment. After ISP1 participants were either seated in an ice-bath (CWI; 11.6 ± 1.8 °C) (CWI) or sat in a thermo-neutral environment (CONT) for 15 min. Measures of heart rate (HR), core temperature (T<sub>core</sub>), skin temperature (T<sub>skin</sub>), thermal sensation (TS) and ratings of perceived exertion (RPE) were recorded during ISP1, ISP2 and the recovery period. Statistical significance was set at P = 0.05. Vertical jump height was lower and 15 m sprint times slower during ISP2, following CWI (P = 0.01–0.02). While jogging self-paced efforts from ISP1 to ISP2 were maintained, sprint times were slower, and bounding distance was increased in CWI compared to CONT. Tskin was reduced during recovery for CWI (P = 0.001). Tcore, RPE, and TS were lower throughout ISP2 for CWI (P = 0.001–0.04). Therefore, CWI as a recovery modality between successive bouts of simulated rugby sevens in the heat may negatively affect initial high intensity performance compared to passive recovery yet may attenuate thermoregulatory stress through a pre-cooling effect still present 30 min after CWI, leading to higher intensity during the jogging efforts.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104333"},"PeriodicalIF":2.9,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145549692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.jtherbio.2025.104318
Dominique D. Gagnon , Alexus McCue , Juha E. Peltonen , David Marsh , David MacLean , Olivier Serresse
Purpose
Muscle blood flow (Q̇) and O2 delivery to local active muscles during exercise are primarily regulated by oxygen consumption (V̇O). Skeletal muscle tissue heating and cooling also independently influence local oxygen transport and uptake but whether tissue temperature regulates the Q̇/V̇O2 relationship during exercise is unclear. The purpose of this study was to assess the effects of skeletal muscle temperature on local Q̇, V̇O2, tissue oxygen saturation (%TSI), and the Q̇/V̇O2 relationship during single-leg isokinetic exercise at increasing intensities.
Methods
Eleven men exercised for 3-min intervals under localized muscle heating (HT; +Δ3°C), cooling (CO; -Δ6°C), and thermoneutral (TN) conditions at 10 %, 30 %, and 50 % of their maximal voluntary contraction (MVC) during single-leg isokinetic contractions. Blood flow occlusions and near-infrared spectroscopy techniques were used to estimate Q̇, V̇O2, and %TSI before and after each exercise bout.
Results
Q̇ significantly increased with muscle heating, whereas muscle cooling decreased V̇O2 across MVC intensities. Muscle temperature did not significantly change %TSI during exercise. Moreover, the Q̇/V̇O2relationship was steeper in CO compared to HT (TN: 0.173 ± 0.101, CO: 0.187 ± 0.0655, and HT:0.107 ± 0.0413) (p = 0.009).
Conclusion
This study demonstrated that muscle temperature regulates the local Q̇/V̇O2 relationship during submaximal incremental isokinetic single-leg exercise.
{"title":"The effects of muscle temperature on the muscle blood flow-oxygen consumption relationship during single leg isokinetic exercise","authors":"Dominique D. Gagnon , Alexus McCue , Juha E. Peltonen , David Marsh , David MacLean , Olivier Serresse","doi":"10.1016/j.jtherbio.2025.104318","DOIUrl":"10.1016/j.jtherbio.2025.104318","url":null,"abstract":"<div><h3>Purpose</h3><div>Muscle blood flow (Q̇) and O<sub>2</sub> delivery to local active muscles during exercise are primarily regulated by oxygen consumption (V̇O). Skeletal muscle tissue heating and cooling also independently influence local oxygen transport and uptake but whether tissue temperature regulates the Q̇/V̇O<sub>2</sub> relationship during exercise is unclear. The purpose of this study was to assess the effects of skeletal muscle temperature on local Q̇, V̇O<sub>2</sub>, tissue oxygen saturation (%TSI), and the Q̇/V̇O<sub>2</sub> relationship during single-leg isokinetic exercise at increasing intensities.</div></div><div><h3>Methods</h3><div>Eleven men exercised for 3-min intervals under localized muscle heating (HT; +Δ3°C), cooling (CO; -Δ6°C), and thermoneutral (TN) conditions at 10 %, 30 %, and 50 % of their maximal voluntary contraction (MVC) during single-leg isokinetic contractions. Blood flow occlusions and near-infrared spectroscopy techniques were used to estimate Q̇, V̇O2, and %TSI before and after each exercise bout.</div></div><div><h3>Results</h3><div>Q̇ significantly increased with muscle heating, whereas muscle cooling decreased V̇O<sub>2</sub> across MVC intensities. Muscle temperature did not significantly change %TSI during exercise. Moreover, the Q̇/V̇O<sub>2</sub>relationship was steeper in CO compared to HT (TN: 0.173 ± 0.101, CO: 0.187 ± 0.0655, and HT:0.107 ± 0.0413) (p = 0.009).</div></div><div><h3>Conclusion</h3><div>This study demonstrated that muscle temperature regulates the local Q̇/V̇O<sub>2</sub> relationship during submaximal incremental isokinetic single-leg exercise.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"134 ","pages":"Article 104318"},"PeriodicalIF":2.9,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145557113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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