Rectal Temperature Research Articles

Effects of Heat Stress on Growth Performance, Physiological Responses, and Carcass Traits in Broilers

High environmental temperatures lead to metabolic changes, body weight reduction, and high mortality in chickens, affecting poultry production worldwide. This study aimed to evaluate the effects of heat stress, assessed by the temperature–humidity index (THI), on the growth performance, physiological response, carcasses, and hematological traits of broilers. A total of 200 broilers (between 17 and 31 days old) were kept in thermoneutral conditions (21 °C; 60% relative humidity, RH) for 3 days during the adaptation period, followed by 14 days of exposure to the experimental treatments. The broilers were randomly assigned to 4 groups of equal size and raised in a temperature–humidity controlled chamber with THI ranging from 67 (21 °C; RH 60%) to 84 (33 °C; RH 60%). In boilers subjected to severe heat stress (THI 84), feed intake (-30%) and body weight gain (-51%) were decreased (P<0.05) in comparison with the performance parameters of broilers under thermoneutral conditions (THI 67). Moreover, under heat stress, the respiration rate and rectal temperature significantly increased (P<0.05), whereas blood parameters showed reduced levels of red blood cells, hemoglobin, white blood cells, lymphocytes, and electrolytes (K+, Na+). Regarding carcass traits, differences were observed in broilers exposed to severe heat stress, particularly in the reduction of the bursa of Fabricius as an immune organ growth index (P<0.05). This study shows that severe heat stress, as revealed by the high THI levels, alters the physiological reactions and metabolic processes of broiler chickens, leading to negative effects on their growth.

Effect of cold beverages on whole-body heat exchange in young and older males during intermittent exercise in the heat.

To mitigate health risks associated with occupational heat stress, workers are advised to adhere to a work-rest regimen, and hydrate regularly. However, it remains unclear if beverage temperature influences whole-body heat exchange during work-rest cycles, and if responses differ in older workers who have a blunted heat loss capacity. Ten young (mean [SD]: 22 [3] years) and 10 older (60 [4] years) males performed four 15-min bouts of moderate-intensity cycling at a fixed rate of metabolic heat production (200 W·m-2), each interspersed by 15-min rest in dry heat (40°C, ~12% relative humidity). On separate days, participants consumed either ice-slurry (~0°C), standardized to provide a heat transfer capacity of 75 kJ·m-2, or an identical mass of warm fluid (37.5°C) before the first and third exercise bouts. Evaporative and dry heat exchange (direct calorimetry) and metabolic heat production (indirect calorimetry) were measured continuously to determine cumulative heat storage (summation of heat loss and heat gain) over the entire protocol. Rectal temperature was also measured continuously. Relative to warm fluid, ice-slurry ingestion reduced cumulative heat storage in young (69 [181] vs. 216 [94] kJ) and older males (90 [104] vs. 254 [140] kJ, main effect: p < 0.01), but was unaffected by age (p = 0.49). However, rectal temperature was unaffected by beverage temperature in both groups (all p ≥ 0.15). We show that cold fluid ingestion is an appropriate administrative control for both young and older males as it can mitigate increases in body heat content during moderate-intensity work-rest cycles in dry heat.

Regulation of 11β-HSD1 reductase and the HPA axis by long-snake moxibustion in kidney-yang deficiency rats

BackgroundLong-snake moxibustion can improve hypothalamic-pituitary-adrenal (HPA) axis function in patients with kidney-yang deficiency (KYDS). 11β-HSD1 controls the HPA axis by boosting CORT production via reductase activity. However, the interaction and mechanism of long snake moxibustion and 11β-HSD1 remain unknown. This study examined the impact of lengthy snake moxibustion on the hypothalamus-pituitary-adrenal axis in KYDS rats. The potential significance of 11β-HSD1 in this process was explored. MethodsRats were randomly divided into two groups: the blank group and the experimental group. The KYDS model was established with an intramuscular injection of hydrocortisone. Rats were randomly assigned to four groups: model, sham intervention, long snake moxibustion, and long snake moxibustion plus 11β-HSD1 inhibitor. Physical indicators included body weight, toe temperature, rectal temperature, and spontaneous movement. The serum levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and CORT were measured. Immunohistochemical examination reveals 11β-HSD1 protein expression in the liver. Western blotting (WB) detected the levels of 11β-HSD1, H6PDH and NADPH/NADP + protein in the liver. ResultsThe experimental rats' body weight, toe temperature, rectal temperature, time and frequency of spontaneous activity all dropped, as did their serum ACTH, CORT, and CRH levels. The protein expressions of 11β-HSD1, H6PDH, and NADPH/NADP+ in the liver decreased significantly. Long-snake moxibustion improved HPA axis function in rats, boosting expression of 11β-HSD1, H6PDH, and NADPH/NADP+. Adding an 11β-HSD1 inhibitor to Long-snake moxibustion decreased its effect on the HPA axis. ConclusionLong-snake moxibustion improves KYDS symptoms in rats by increasing 11β-HSD1 expression and reductase activity, which regulates the HPA axis.

Performance and Physiological Responses of Pre-Weaning Peranakan Etawa Goats Fed Milk Replacer with Maggot Flour

Pre-weaning growth is crucial for achieving high weaning weights, which are expected to positively correlate with the overall performance of does/ewes. Milk replacer, designed to meet the nutritional needs of pre-weaning kids, offers a solution to this challenge. This study aimed to analyze and evaluate the impact of incorporating maggot flour into milk replacer on the performance of pre-weaned Peranakan Etawa (PE) crossbreed goats. The parameters observed included milk replacer intake, nutrient consumption, body weight gain, weaning weight, rectal temperature, respiratory rate, and feed cost per gain. The study involved 10 two-week-old local pre-weaned PE goats, each with an average body weight of 5.33 ± 0.93 kg, divided into two treatment groups with five replicates each. The treatments included a commercial milk replacer (P0) and a milk replacer containing maggot flour (P1). Data were analyzed using an independent t-test at a 5% significance level. The results showed that daily body weight gain in pre-weaned PE goats fed milk replacer containing maggot flour did not differ significantly (P0.05) from those fed the commercial milk replacer. The physiological responses of the pre-weaned goats, including rectal temperature and respiratory rate, were similar between treatments and did not negatively affect their physiological status. The lowest feed cost per gain was observed in the group fed the maggot flour-based milk replacer (P1), indicating its potential economic advantage.

Adaptive capability of slow-growing backyard poultry as indicated by physiological and molecular responses in a hot and humid coastal climate

Assessing the adaptability of slow-growing rural chickens for improving thermotolerance to suit the global climate change is a major research need. This work was aimed to evaluate the adaptability of CARI-Debendra chickens and to identify the polymorphism as well as expression profiling of thermotolerant genes (HSP70 and GRP78) under prevailing temperature-humidity indices and thermal stress in a coastal environment. One hundred sixty straight run chicks were reared at THI≥75 (control) and THI>80 under coastal climate till 12 weeks. Polymorphism of HSP70 and GRP78 candidate genes were explored using restriction enzymes TaqI and HaeIII to identify possible thermotolerance markers. Expression profiling of both the genes in liver, intestine and pectoralis muscle was determined through quantitative real-time PCR. Rectal and body surface temperature recorded in the neck and back showed significant differences (P < 0.01) with higher temperature in THI>80 group. Comparatively lower live weights (P < 0.05) and poor FCR were recorded in THI>80 group. The villi height in all intestinal segments was significantly lower (P < 0.01), but deeper crypt depth was observed in THI>80 than control group. A lowest thymus weight (P < 0.05) was noted with no significant differences in immune response in treatment group. Serum levels of cholesterol, activities of lactate dehydrogenase, creatinine kinase and concentration of potassium, sodium and thyroxine hormone were not different between the 2 groups. The concentration of triiodothyronine and chloride ion was lower in THI>80 group indicating adaptive changes for thermoregulation. HSP70 gene expressions in the three tissues were differentially increased (P < 0.01) by temperature-humidity indices, but the expression of GRP78 was not different between the 2 groups. The results concluded that the environmental factors interact with genetics on adaptability towards thermotolerance in slow-growing chickens.

Facial cooling improves thermal perceptions and maintains the interleukin-6 response during passive heating: A sex comparison

ABSTRACT Passively elevating body temperature can trigger a potentially beneficial acute inflammatory response. However, heat therapy often causes discomfort and negative thermal perceptions, particularly in females who generally have lower heat tolerance than males. This study aimed to evaluate the impact of facial cooling on thermal comfort and interleukin-6 concentration in response to 60 minutes of dry heat exposure, and to investigate sex differences in physiological responses and perceptions. 22 healthy young adults (10 females, 12 males; age: 24.4 ± 3.3 years) completed three trials in randomized order using a dry sauna device: 1) Hyperthermia (71.1 ± 1.9°C; HEAT), 2) Hyperthermia with facial cooling via fans (71.1 ± 3.0°C; FAN), and 3) Normothermia (27.0 ± 0.9°C; CON). Blood samples to determine interleukin-6 (IL-6) plasma concentration were collected before and after exposure; basic affect and thermal comfort, rectal and skin temperature were assessed throughout the intervention. Rectal temperature following HEAT (38.0 ± 0.3°C) and FAN (37.8 ± 0.3°C) did not differ between males and females (p = 0.57). Females had higher forehead skin temperatures than males (p ≤ 0.019). Thermal comfort remained more positive in FAN compared to HEAT (p ≤ 0.002). Females felt more thermal discomfort than males in HEAT (p ≤ 0.03), but not in FAN (p = 0.28). The increase in IL-6 plasma concentration was similar between HEAT and FAN (p = 1.00), and higher than CON (p ≤ 0.02); there was no difference between males and females (p = 0.69). This study showed that facial cooling alleviated the thermal discomfort during heat exposure, particularly benefitted females, and did not impede the acute IL-6 response.

A survey on the diagnosis and management of neonatal hypoxic ischaemic encephalopathy in sub-saharan Africa

Sub-Saharan Africa (SSA) has the highest burden of neonatal hypoxic ischemic encephalopathy (HIE) in the world. However, there are few descriptions of HIE management in SSA and therapeutic hypothermia (TH) is considered controversial. A web-based survey was distributed to doctors across SSA in 2023. Adequate responses were received from 136 doctors across 43 of 48 countries. Therapeutic hypothermia was available in 13 countries, most frequently in private institutions compared to other settings (69% vs. 28%; P = 0.004). Over 90% of respondents who provided TH, appropriately cooled neonates to rectal temperatures of 33.5 °C before age 6 h, for 72 h, and 79% used automated cooling methods. Intubated ventilation and electroencephalograms were more available where TH was used (81% vs. 55%; p = 0.004 and 65% vs. 8%; p < 0.001 respectively). Indicators of intrapartum hypoxia were more frequently defined with TH provision, including early pH (79% vs. 21%; p < 0.001), base deficit (76% vs. 20%; p < 0.001), and ventilation at age 10 min (87% vs. 53%; p = 0.001). Despite the variation in resources and management of HIE, most respondents had standardised protocols (76%). Most respondents who provided TH, followed evidence-based methods, and had stricter criteria and more resources than institutions who did not cool.

Confirmation of epidural anesthesia with bupivakain in cats by ınfrared thermographic ımaging and SEP

In this study, the usability of electromyelography and infrared thermography was tested to confirm the success of epidural anesthesia. The cats were randomly divided into 2 groups as experimental and control groups. Cats were intubated and placed under inhalation anesthesia in the anesthesia device. SEP recordings were obtained from L7-S1, L6-L7, L6-L5 and L5-L4 intervals before epidural injection. Before epidural injection, infrared thermographic images and rectal temperature were taken from a distance of 50 cm where the areas where surface temperatures were to be measured were clearly visible. Following asepsis and antisepsis, 0.5% bupivacaine in the experimental group and saline in the control group were injected from the lumbosacral region. Infrared thermograms and rectal temperature were taken from each cat 7 times (0.min, 5.min, 10.min, 15.min, 20.min, 25.min and 30.min) for 30 minutes at 5 min intervals after injection. After the last infrared thermogram was recorded, post-epidural SEP was recorded. Rectal temperature values decreased gradually in all cats throughout the anesthesia period and no difference was observed between the groups. A decrease in potential duration and an increase in latency values were recorded in 10 cats with epidural 0.5% bupivacaine administration compared to 10 cats with epidural saline administration. Although there were only statistically significant values the amplitude values were not found to be kinetically significant. No clinically or statistically significant difference was observed in the infrared thermograms taken before epidural injection and 5 minutes after epidural injection in both groups.

Thermal response in Boer goats differing in coat colour

Context The coat is the first defense layer protecting animals from direct sunlight, influencing radiant-heat absorption and loss. Dark coat colour may increase animal heat impact because of higher absorption of solar radiation. Aims We investigated the impact of pigmentation intensity on the heads of animals and their thermal responses to solar radiation. Furthermore, we compared the thermal responses between dark and light brown-coloured animals, to determine whether the duration of sun and shade exposure (3 h each) is sufficient to differentiate the heat gain and losses between the two groups. Methods The effect of coat colour on rectal and surface temperatures in Boer goats, classified according to their head pigmentation pattern as dark (DB, N = 11) or light brown (LB, N = 11), exposed to sun and shade, was evaluated. The animals’ body and head surface temperatures were measured the same day before, during, and after sun exposure by using infrared thermography. Individual thermographic images were analysed by body regions (rump, leg, neck) and head areas (eye, ear, upper and lower part of the head, and the muzzle). Key results During solar radiation, all measured variables increased. In the shade, the rump, leg, and neck surfaces remained elevated, whereas the head area cooled down faster, with the highest temperature changes measured for the ear of about 10%. Most surface cooling occurred within 30 min after returning to the shade. Coat colour groups differed only in higher overall muzzle temperature of DB than that of LB goats (P = 0.048). Correlations between rectal and surface temperatures were low to medium, ranging from −0.02 (eye) to 0.31 (muzzle). Conclusions The head area is suggested as the important thermal window for heat dissipation and selective brain cooling. Light brown-headed animals were more efficient in eliminating the heat gained from solar radiation when returned to shade. Implications The colouration of the animal’s head may play an important role for its heat tolerance. As an easy-to-recognise characteristic, coat colour can serve as a selection trait for local goat populations. In view of global warming, selection for lighter coat colour in domestic ruminants may also become important even under temperate climates.

Intranasal vs. intramuscular administration of azaperone, midazolam and ketamine in pigs.

To compare the efficacy of intranasal (IN) and intramuscular (IM) administrations of azaperone (3 mg kg-1), midazolam (0. 3 mg kg-1), and ketamine (7 mg kg-1) combination (AMK) in pigs. Study design: Randomized clinical trial. Animals: sixteen adult male pigs, immunocastrated, of mixed lineage. In phase I, these animals were randomly assigned to intranasal (GIN, n = 8) and intramuscular (GIM, n = 8) groups for arterial blood sample collection at 10, 20, 30, 45, 60, and 90 min after AMK administrations for gas and electrolyte analysis. In phase II, performed 1 week after phase I, the 16 pigs were allocated to both groups (GIM, n = 16/GIN, n = 16) and submitted to the same chemical restraint (CR) protocol, with a 96-h interval between administrations. Behavioral parameters (degree of CR, muscle relaxation, loss of postural reflex, and sound stimulus response) and vital parameters (pulse rate, respiratory rate, oxygen saturation, and rectal temperature) were evaluated after recumbency (Trec) and at 5, 15, 30, 45, 60, and 90 min after administrations. In addition, the latency period and duration of CR were determined. Latency to recumbency and duration of CR in GIN were shorter. CR scores did not vary between groups. Muscle relaxation was more intense in GIN at Trec. An initial tachycardia was observed, followed by a reduction in heart rate from T5 to T90 in both treatments (p < 0.05). The respiratory rate was higher at T45, T60, and T90 in GIN compared to baseline. Rectal temperature reduced in GIM from T45 onwards. elevated at T90 in the GIM (p < 0.05) and there was an incidence of mild hypoxemia in 47% of the animals in the GIM. IN administration was as effective as IM administration in promoting safe chemical restraint, with minimal changes in homeostasis, with a shorter duration and latency period.

The repeatability of a cycling exercise-heat stress test in a male population

IntroductionThere is considerable inter-individual variability in the physiological responses to environmental stressors and so to accurately assess and monitor changes in an individual's ability to cope with exercise-heat stress, a reliable protocol is required. The aim of this study was to examine the repeatability of a 90-min steady-state heat exercise bout with physiological and subjective variables, and performance during an incremental test to exhaustion post 90-min steady-state exercise. MethodSixteen mixed ability males (Age: 39 ± 15yrs; Height: 176.5 ± 4.8 cm; BM: 79.7 ± 10.3 kg; V˙O2peak: 46.2 ± 8.6 ml/kg/min; PPO: 309 ± 39W) who trained at least three times a week undertook two 90-min steady-state – followed by an incremental protocol to exhaustion – cycling heat stress tests (HSTs) in a hot-humid environment (35 °C, 60%RH). Heart rate (HR), rectal (T‾re) and skin temperature (T‾sk), rating of perceived exertion (RPE), thermal sensation (TS), and thermal comfort (TC) were measured throughout. Data was analysed using Intraclass Correlation Coefficients (ICC), technical error of measurement (TEM), Bland-Altman plots, t-tests, and Cohen's d to indicate magnitude of change. ResultsPhysiological variables indicated good repeatability evident through moderate to strong ICC ratings, low magnitudes of change (d), lower mean biases compared to their respective calculated TEMs, and statistical non-significance, except HR90, ₸sk90, and ₸sk. Hydration status showed good repeatability except for urine osmolality (osmu90) and resting urine colour (colu). Perceptual variables showed encouraging repeatability apart from resting TS and mean TS. Performance data showed good repeatability overall, however 11 participants progressed to the incremental test to exhaustion in the second visit compared to 7 in the first. ConclusionCurrent data demonstrated favourable physiological, perceptual, and performance repeatability during repeated cycling HSTs in hot-humid conditions. However, given more participants progressed to the incremental trial to exhaustion protocol in the second visit, at least one familiarisation trial may improve the reliability of exercise capacity assessment.

Effects of relative humidity on physiology and behavior of laying hens exposed to high ambient temperatures.

This study investigated how different relative humidity (RH) would impact behavior and physiology of laying hens. One hundred-eighty laying hens (Hy-Line Brown), aged 68-week-old (1,908 ± 78g), were exposed to daily ambient temperatures of 30°C with RH set at 25% (RH25), 50% (RH50), or 75% (RH75) for 12h a day (9:00 am to 9:00 pm) from 70 to 74 weeks of age. All hens had been raised at 24°C and 50% RH during 2-week adaptation period. Each RH treatment consisted of 10 replicates with 6 hens each in a completely randomized design. Results indicated that rectal temperature, respiratory rate, and heart rate were increased (P ≤ 0.05) in the RH75 group compared with the RH25 and RH50 groups. Plasma malondialdehyde concentrations were elevated in the RH75 group compared RH50 at 3, 7, and 21 days (P ≤ 0.05) following the RH exposure. Plasma glutathione peroxidase activity was lowered (P ≤ 0.05) in the RH75 group compared with the RH25 and RH50 groups at 21 days. Increasing RH led to decreased feeding behavior but showed a tendency to increase drinking behavior. Wings elevated and panting behaviors were higher in the RH75 group compared with the RH25 and RH50 groups (P ≤ 0.05). In conclusion, these findings suggest that elevated RH at constant ambient temperature could negatively influence the behavior and physiology of laying hens.

Saliva as a Potential Source of Biomarkers in Cows with Metritis: A Pilot Study.

Metritis affects 5-20% of cows after parturition, negatively impacting animal welfare and the profitability of dairy farms, increasing culling rates and costs, and decreasing productivity and reproduction rates. This study compared the results of a comprehensive biochemical panel consisting of 25 salivary and 31 serum analytes between healthy cows (n = 16) and cows with metritis (n = 12). Descriptive parameters such as depression, rectal temperature, body condition score (BCS), heart rate, respiratory rate, mucous color, ruminal motility, vaginal discharge, milk production, and complete hematology analyses were also assessed for comparative purposes. The biochemistry analytes comprised five analytes related to stress, five to inflammation, five to oxidative status, and nineteen to general metabolism. The two-way ANOVA analysis revealed that, in saliva, eight biomarkers (lipase, adenosine deaminase (ADA), haptoglobin (Hp), total proteins, g-glutamyl transferase (gGT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and creatine kinase (CK)) were significant higher in cows with metritis. In serum, eight biomarkers (ADA, Hp, serum amyloid A (SAA), fibrinogen, ferritin, AOPPs/albumin ratio, non-esterified fatty acids (NEFAs), and bilirubin) were significantly higher in cows with metritis, whereas six (total esterase (TEA), albumin, urea, lactate, phosphorus, and calcium) were lower. Of the total number of 23 biomarkers that were measured in both saliva and serum, significant positive correlations between the two biofluids were found for six of them (Hp, FRAP, CUPRAC, AOPPs, urea, and phosphorus). Urea showed an R = 0.7, and the correlations of the other analytes were weak (R < 0.4). In conclusion, cows with metritis exhibited differences in biomarkers of stress, inflammation, cellular immune system, and general metabolism in both salivary and serum biochemistry profiles. These changes were of different magnitudes in the two biofluids. In addition, with the exception of ADA and Hp, the analytes that showed changes in the saliva and serum profiles of cows affected by metritis were different. Overall, this report opens a new window for the use of saliva as potential source of biomarkers in cows with metritis.

Calf immunization protocols with low-virulence isolates of Anaplasma marginale: Analysis of post-inoculation effects and protection against natural challenge

Bovine anaplasmosis is endemic and is of fundamental importance worldwide. Therefore, measures for controlling and preventing clinical diseases are warranted to ensure the reduction of associated economic losses. The objective of the present study was to assess the post-inoculation effects and protection conferred by three different protocols of inoculation of low-virulence live strains of Anaplasma marginale (UFMG1 and UFMG3) in field-challenged cattle. Sixty-eight Holstein calves with an average age of 17 days were randomly divided into four groups. The groups received two subcutaneous administrations spaced 40 days apart, at a dosage of 2 × 106 infected erythrocytes of the following A. marginale strains: G1 (UFMG1 + UFMG1); G2 (UFMG3 + UFMG3); G3 (UFMG1 + UFMG3); and G4 (control). Every two days, the animals were evaluated for rectal temperature, Packed Cell Volume (PCV), and blood smears. Blood samples were collected prior to inoculation, before the field challenge, and after the challenge period, nPCR and IFAT techniques were performed. There were no significant differences in rickettsemia levels, reduction in PCV, or antibody detection among the different inoculation strategies. Forty days after the second inoculation, 90 %, 84.6 %, and 90.9 % of the animals in G1, G2, and G3, respectively, tested positive using nPCR. After inoculation, the group G2, which received the UFMG3 inoculum, had a higher frequency of treatment (odds ratio of 6.7; 1.198-38.018 CI; p = 0.03), while groups G1 and G3 demonstrated similar treatment frequencies compared to the control. During the natural challenge phase, 13.3 % of animals in group G1 required treatment (odds ratio of 0.108; 0.018-0.635 CI; p = 0.014) compared to 58.8 % of the control group. Considering the results collectively, the protocol using the UFMG1 strain (G1) stands out for its potential to be safe and induce some degree of immunization against A. marginale, reducing the incidence of clinical disease and the need for treatment during natural challenge.

Rearing pigs with play opportunities: the effects on disease resilience in pigs experimentally inoculated with PRRSV.

Positive emotions can reduce disease susceptibility during infectious challenges in humans, and emerging evidence suggests similar effects in farm animals. Because play behaviour may support a positive emotional state in pigs, this study investigates whether rearing pigs with regular intermittent play opportunities enhances disease resilience when challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Litters were assigned to either play (PLY; n = 5 L) or control (CON; n = 4 L) treatments at birth. In PLY, play was promoted with extra space and enrichment items for three hours daily from five days of age (doa). At weaning (25 ± 2 doa; mean ± SD), 28 pigs (14/treatment) were selected for a disease challenge, based on weight, sex, and sow. The pigs were transported to a disease containment facility and at 43 ± 2 doa (day 0 post-inoculation, DPI) inoculated with PRRSV. Skin lesions, blood, rectal temperature, clinical signs, body weight, and behaviour were collected pre- and post-inoculation. Play opportunities for PLY continued every other day until euthanasia of all pigs at 65 ± 2 doa (22 DPI). PLY pigs exhibited fewer skin lesions following transport and throughout the infection compared to CON. Although the viral load did not differ between treatments, PLY pigs had a lower probability of experiencing moderate and severe respiratory distress, with a shorter duration. PLY also performed better throughout the infection, showing higher ADG and greater feed efficiency. The immune response differed as well. PLY pigs had fewer monocytes on 8 DPI than CON, with levels returning to baseline by 21 DPI, whereas CON levels exceeded baseline. Regardless of day of infection, lymphocyte counts tended to be lower in PLY than in CON, and white blood cells and neutrophils were also lower, but only in slow-growing pigs. PLY pigs continued to play during the infection, demonstrating less sickness behaviour and emphasizing the rewarding properties of play. Results suggest that PLY pigs were less affected by PRRSV and developed increased resilience to PRRSV compared to CON. This study demonstrates that rearing pigs in an environment supporting positive experiences through provision of play opportunities can enhance resilience against common modern production challenges, underscoring the value of positive welfare in intensive pig farming.

Justification of the possibility of using liquid artificial lung ventilation for the treatment of acute respiratory distress syndrome of toxic genesis

Introduction. Pulmonotoxicants are chemicals that cause bronchospasm and damage to the alveolar capillary membrane. Lesions of the respiratory system with pulmonotoxicants in industrial accidents are especially relevant at the present time. Existing methods of treatment for the defeat of pulmonotoxicants and the development of acute respiratory distress syndrome (ARDS) are becoming ineffective, therefore, one of the tasks of modern medicine is to develop new methods of treating ARDS. One of these methods may be the creation of a "therapeutic window" by using perfluorocarbon (PFC) liquids. This article will present an experimental assessment of the use of liquid artificial lung ventilation (LALV) PFC liquids on the ARDS lung model. The study aims to explore the possibility of using liquid artificial lung ventilation to create a therapeutic window in the treatment of acute respiratory distress syndrome of a chemical nature. Materials and methods. The authors conducted a study on male Wistar rats aged 4 months, weighing 180–190 g. Toxic pulmonary edema was caused by endotracheal administration of 0.1 m HCl solution. The anesthetized patients were intubated using a cannula, after which the researchers intratracheally injected 0.1 M HCl solution at a dose of 2 ml/kg, a decrease in saturation below 80 was expected. Then the experts randomized the animals by weight into groups of 6 individuals each. They connected the animals of the control group to a ventilator. The animals of the experimental group were treated with PFC liquids for an hour, then transferred to a ventilator. Perfluorodecalin was used as a PFC liquid. The scientists recorded heart rate, blood oxygen saturation, rectal temperature, life expectancy and overall survival by group. Results. In the control group, after instillation of 0.1 M HCl solution and connection to a ventilator during the first 25–30 minutes, there was a gradual decrease in SpO2 to 74.0±5.6% (background — 95.0±3.5%) and an increase in heart rate to 182.0±8.6 beats/min., (background — 278.0±14.8 beats/min.) after which there was decompensation of the animal condition. In animals of the experimental group, after connecting to the LALV device, a sharp decrease in heart rate was recorded during the first 5 minutes to 61.0±8.5 beats/min. In turn, saturation did not change significantly throughout the LALV and was in the range from 95 to 100%. As a result of the experiments, it was noted that the average survival time in the experimental group was 256.0±34.5 minutes, which was significantly (p&lt;0.001) more than 5 times higher than this indicator in the control animals — 45.3±4.3 minutes. There were no significant changes in the study of rectal temperature in the animals of the control group. In turn, the animals of the experimental group showed a sharp decrease in rectal temperature during the first 30 minutes from the beginning of LALV, on average by 5.8±1.60°С. As a result of the pathoanatomic autopsy, differences in lung mass coefficients were revealed in different groups. Thus, in the control group and the experimental groups, it was 1.67±0.06 and 2.4±0.045%, respectively. Conclusion. On the model of ARDS caused by endotracheal administration of 0.1M hydrochloric acid solution, it was shown that living with the use of PFC of low temperature liquids, unlike conventional mechanical ventilation, allows for a long time to maintain a stable condition of animals; evacuate a significant amount of edematous fluid from the lungs and thereby increase the duration of their survival. The data presented above indicate that the use of hypothermic LALV can be used to create a "therapeutic window" for ARDS, including its most severe form — the alveolar stage of toxic pulmonary edema. Ethics. Studies involving laboratory animals were conducted in compliance with the following regulations: the Helsinki Declaration of 2000 "On humane treatment of animals", Order No. 755 of the Ministry of Health of the USSR dated 08/12/1977 "Rules for carrying out work using experimental animals", Order No. 199n of the Ministry of Health of the Russian Federation dated 04/01/2016 "On approval of the rules of laboratory practice". The protocol of the study was approved by the Ethics Committee of the Izmerov Research Institute of Occupational Health. Protocol No. 4 dated May 25, 2022.

PSVII-5 Heat shock protein 70 gene expression and association with morphometric and heat tolerance traits in three plumage colors of Noiler chicken exposed to acute heat stress

Abstract Heat stress is one of the most difficult climatic conditions chickens faces and is a direct result of climate change. It is important to research poultry thermotolerance because it may help find genetic lines resistant to heat stress. This study investigated the influence of plumage colors on heat shock protein 70 gene expression in Noiler chickens exposed to acute heat stress. Noiler is a dual-purpose breed developed for smallholder poultry production in Nigeria. A total of 150 birds of three plumage colors (black, brown and white) of mixed sexes were used for the experiment. The birds were raised in deep litter house separated into six groups of 25 birds each and fed with commercial broiler diets from 0-8 wk and broiler finisher diets from 8 to 12 wk old. The birds were shared into treatments in 3 x 2 x 2 factorial arrangements with 3 plumage colors (black, brown, white), two temperature regimens (Control/thermoneutral, Heat stress) and sex of birds (male, female). The heat stressed birds were exposed to 41oC for 8 h from 0600 h to 1400 h for 7 d while control group maintained a thermoneutral temperature range of 30 oC to 32 oC for the same period. At 13 wk old, two birds were selected per treatment, slaughtered and the spleen removed and stored in RNA later for heat shock protein (HSP) 70 gene expression. Data collected were analyzed with Microsoft excel code for fold expression of HSP70 gene while GLM procedure in SAS was used to determine difference in expression of gene. The relative expression of HSP70 brown plumage was greater, upregulated compared with black and white. White plumage birds in control/thermoneutral group were significantly greater in HSP70 expression than other plumage colors and heat stressed birds. Association of HSP70 delta threshold cycle (DCT) values with morphometric and heat tolerance traits were investigated (Figure 1). High negative correlations emerged between HSP70DCT expression and body weight (-0.65), body temperature (-0.73) with moderate positive correlation for rectal temperature (0.55) in black birds (Table 1). HSP70 DCT positively correlated with body weight (0.70), breast/leg circumferences but negatively with wing length, suggesting reduced surface area during heat stress and a supportive role in maintaining protein integrity (Figure 2). For white Noiler birds, HSP70DCT associated negatively with body weight (-0.94) and positively with rectal temperature during heat stress (Table 2). Thermoneutral birds were positively correlated with heat tolerance traits except temperature while heat stressed birds showed low positive correlation with respiratory and pulse rates and very low positive relationship with body and rectal temperatures (Table 4). Sex-based differences emerged, with potential compromise between HSP70-mediated growth/composition in males versus muscle maintenance in females, although leg length/circumference showed shared developmental regulation (Figure 3, Table 3). These findings highlight HSP70’s versatile roles in systemic heat tolerance mechanisms influenced by plumage color, temperature regime and sex.

PSX-16 The effect of short-term heat stress on physiological, hematological, and immunological parameters of Florida Cracker Sheep

Abstract Florida Cracker sheep are a heritage sheep breed that was developed under natural selection in Florida, US. The objective of this study was to evaluate the effect of short-term heat stress on rectal temperature, respiration rate, hematological parameters, and IgA concentrations of Florida Cracker ewes (2 yr of age). A total of fourteen ewes were allocated to heat stress (HT, n = 7) or cooling (CTL, n = 7) conditions for 6 wk during the summer season. Treatment groups were grouped in covered concrete floor pens with similar dimensions and characteristics and had access to shelter, feed, and freshwater ad libitum. The HT pen was exposed to regular ambient temperatures, and for the cooling pen, an evaporative cooling fan was used. Data for ambient temperature and relative humidity of HT and CTL pens were recorded every week to estimate the temperature humidity index (THI). Blood samples were collected from each experimental ewe 1 wk before the start of the experiment (baseline) and at wk 1, wk 2, wk 3, wk 4, wk 5, and wk 6 post-treatment. Blood samples were analyzed using a hematology analyzer (Vetscan HM5, Zoetis). Plasma was extracted from the blood and was used to evaluate IgA concentrations with a commercial kit. For the statistical analysis of the physiological, hematological, and immunological parameters, a mixed model with repeated measures was used. Fixed effects included treatment (HT or CTL), wk (1 to 6), and the treatment by week interaction. Animal was fitted as a random effect and the baseline data was used as a covariate. The THI for the HT and CTL groups ranged from 81.3 to 89.5 and from 73.5 to 75.6, respectively. The HT group presented a significant (P &amp;lt; 0.05) increase in respiratory rate when compared with the CTL group. No significant changes were observed for rectal temperature and IgA concentrations in the experimental groups. However, for wk 3, a significant (P &amp;lt; 0.05) increase of neutrophils and a decrease in lymphocyte % was observed for the HT group. In conclusion, short-term heat stress increased respiratory rate and neutrophil % and decreased the lymphocyte % in Florida Cracker ewes. It is possible that heat stress could have a detrimental impact on immune mechanisms in Florida Cracker ewes. Further studies are required to investigate the effects of long-term heat stress.

Wet Military Uniforms Pose Low Risk of Hypothermia while Static in Mild Cold Air.

Wet clothing is less insulative than dry clothing and increases heat loss in cold air. Tactical necessity can render removal of wet clothing impossible and/or require Warfighters to remain static to avoid detection, limiting heat production and posing a threat of hypothermia (core temperature <35°C). This study aimed to characterize body temperatures and evaluate hypothermia risk while statically exposed to 5°C air wearing three wet military uniforms. Further, low-speed loaded walking was evaluated as a strategy to raise end-static temperatures. Twelve adults (11M, 1F) randomly completed three wet-cold trials wearing either the Improved Hot Weather Combat Uniform (IHWCU), Army Combat Uniform (ACU), or ACU with silk-weight base layer (ACU+). Each trial involved 180 minutes of cold air (5.3±0.3°C, 0.8 m·s-1) exposure after a clothed 2-minute head-out immersion (34.0 ± 0.2°C). Volunteers were static for 60 minutes followed by 120 minutes of loaded walking. Rectal temperature (Tre) area under the curve did not differ among the three wet uniforms when static (p=0.431) with Tre increasing, rather than decreasing, across the 60 minutes (IHWCU: +0.26±0.19°C, ACU: +0.37±0.21°C, ACU+: +0.36±0.20°C). Hypothermia risk with 60-minute static wet-cold exposure therefore appears minimal, regardless of the military uniform worn. End-static finger temperatures (IHWCU: 9.48±2.30°C, ACU: 9.99±1.82°C, ACU+: 9.27±1.66°C, p >0.999) were reduced by ~20-23°C posing a considerable dexterity concern. Heat production of ~210 W·m2 appeared sufficient to begin to reverse negative cumulative heat storage and initiate slight elevation of rectal and peripheral temperatures, although finger temperatures increased < 2°C after 120 minutes. ClinicalTrials.gov ID:NCT05409937.

Acute nicotine exposure attenuates neurological deficits, ischemic injury and brain inflammatory responses and restores hippocampal long-term potentiation in ischemic stroke followed by lipopolysaccharide-induced sepsis-like state

Ischemic stroke is followed by an increased susceptibility to bacterial infections, which exacerbate histological stroke outcome, neurological deficits and memory impairment due to increased neuroinflammation and neurotransmitter dysfunction. Pharmacological activation of nicotinic acetylcholine receptors was suggested to mitigate brain inflammatory responses in ischemic stroke. The functional responses associated with nicotinic acetylcholine receptor activation were unknown. In this study, male NMRI mice subjected to transient intraluminal middle cerebral artery occlusion (MCAO) were intraperitoneally exposed to vehicle treatment or Escherichia coli lipopolysaccharide (LPS; 4 mg/kg)-induced sepsis-like state 24 h post-MCAO, followed by intraperitoneal administration of vehicle or nicotine (0.5 mg/kg) 30 min later. Over 96 h, rectal temperature, neurological deficits, spontaneous locomotor activity, working memory, ischemic injury, synaptic plasticity, and brain inflammatory responses were evaluated by temperature measurement, behavioral analysis, infarct volumetry, electrophysiological recordings, and polymerase-chain reaction analysis. LPS-induced sepsis induced hypothermia, increased general and focal neurological deficits, reduced spontaneous exploration behavior, reduced working memory, and increased infarct volume post-MCAO. Additional treatment with nicotine attenuated LPS-induced hypothermia, reduced neurological deficits, restored exploration behavior, restored working memory, and reduced infarct volume. Local field potential recordings revealed that LPS-induced sepsis decreased long-term potentiation (LTP) in the dentate gyrus post-MCAO, whereas concomitant nicotine exposure restored LTP in the contralateral dentate gyrus. LPS-induced sepsis increased microglial/ macrophage Iba-1 mRNA and astrocytic GFAP mRNA levels post-MCAO, whereas add-on nicotine treatment reduced astrocytic GFAP mRNA. Taken together, these findings indicate that acute nicotine exposure enhances functional stroke recovery. Future studies will have to evaluate the effects of (1) chronic nicotine exposure, a clinically relevant vascular risk factor, and (2) the cessation of nicotine exposure, which is widely recommended post-stroke, but might have detrimental effects in the early stroke recovery phase.