Physiological Stress Indicators Research Articles

Testing the Savanna Hypothesis: Effect of Desert Landscape on Physiological Stress Recovery

Background: Evidence suggests that green environments are protective of health and wellbeing. Many of these studies evoke prospect-refuge theory that poses that savanna-like landscapes offer opportunities for restorative experiences. However, evidence is still limited on how environments that do not match these criteria, and that instead may offer cues of danger (e.g., desert landscapes) affect health. In this study we quantified the effects of a desert landscape on physiological stress recovery and compared those with the effects of a green environment. Methods: Between-subjects experiments were conducted in El Paso, TX with 95 healthy adult men using virtual reality. Participants experienced an acute stressor (The Trier Social Stress Test) followed by one of three randomly assigned immersive virtual environments (IVEs: desert, green or control [office]) for 10-min. After the IVE, they then rested for 40-min. Physiological indicators of stress including systolic and diastolic blood pressure (SBP & DBP), pulse, mean arterial pressure (MAP) and salivary cortisol, were repeatedly measured throughout the experiment. Results: After the IVE, participants exposed to desert and green environments showed larger decreases in pulse rate than participants in the control group. Effects were similar between desert and green conditions. Additionally, participants in the desert condition experienced greater decreases in SBP, DBP and MAP than participants in the green condition. After the first 20 min of rest, participants in both the desert and green conditions showed greater decreases in SBP, DBP, MAP and cortisol than those in the control group. Conclusions: A desert landscape promoted similar or even greater physiological recovery from an acute stressor than a green landscape. These novel findings suggest that prospect-refuge theory does not adequately explain the protective effects of natural environments, and that exposure to environments such as savannas are by no means the only natural landscapes that may lead to stress recovery.

Morphological correlates of invasion in Florida cane toad (Rhinella marina) populations: Shortening of legs and reduction in leg asymmetry as populations become established

Exotic organisms have traits that allow them to effectively disperse and propagate into novel environments. The ability to adapt to new environments has enabled the cane toad (Rhinella marina) to successfully invade novel ecosystems. Their leg length correlates with dispersal success and is selected for in invading populations. Given their successful invasion of multiple continents, R. marina represent a unique opportunity to understand the generality of invasion strategies within a species. Here we test for spatial and temporal shifts in leg length (length of tibio-fibula relative to snout-vent length) of invasive R. marina in Florida populations to assess their adaptation to novel environments. Individuals experiencing new conditions are susceptible to physiological stress, which may negatively affect their development and inhibit their dispersal potential. To this end, we tested for spatial and temporal trends in fluctuating asymmetry, an indicator of physiological stress during development. We compared patterns between two regions of Florida (central vs southern Florida) with different invasion histories. We found that relative leg length of R. marina decreased over time in both regions, and experienced shifts in fluctuating asymmetry over time from initial colonization to population establishment. Our results suggest that successful invasive species rapidly adjust to novel environments. In addition, our results support predictions that morphological change plays a role in aiding dispersal for rapidly dispersing species.

Unforeseen consequences of conservation management practices: case study on herding rhino as an anti‐poaching measure

AbstractThe current biodiversity crisis calls for effective conservation measures. However, some measures may have unforeseen negative consequences on individual species. Herding, a management practice currently used in some wildlife species to protect animals from poachers, can cause habituation to humans, which unintentionally might increase their risk of being poached at a later time. Herding could also negatively impact animal welfare and physiology when perceived as a stressor, with potential negative consequences at the individual and population level. In this study, we tested the following hypotheses: 1) herding elicits habituation to humans in white rhino, and 2) this practice affects the behavior and physiological state of rhino, but they can habituate to it. To that aim, we investigated the effects of herding on the response of rhino to initially unfamiliar people, expression of aggressive and discomfort behaviors, and fecal glucocorticoid metabolite (fGCM) concentrations (a commonly used indicator of physiological stress) in two cohorts of six and 10 semi‐wild orphan white rhino. Rhino did not interrupt their activity to an approaching person on foot (99%) or in a vehicle (94%), indicating habituation to humans. Aggressive and discomfort behaviors were displayed more often while being herded, and their frequency increased significantly with increasing herding pressure. Finally, overall mean fGCM concentrations were 16.1% higher under herding compared to non‐herding conditions, but individual fGCM levels varied up to 17‐fold under each scenario, suggesting that herding might not elicit a physiological stress response in these animals. While rhino security is paramount in the current poaching crisis, management practices must ensure that they do not impact negatively at the individual and population level.

Investigation of the 2018 thick-billed murre (Uria lomvia) die-off on St. Lawrence Island rules out food shortage as the cause

Die-offs of seabirds in Alaska have occurred with increased frequency since 2015. In 2018, on St. Lawrence Island, seabirds were reported washing up dead on beaches starting in late May, peaking in June, and continuing until early August. The cause of death was documented to be starvation, leading to the conclusion that a severe food shortage was to blame. We use physiology and colony-based observations to examine whether food shortage is a sufficient explanation for the die-off, or if evidence indicates an alternative cause of starvation such as disease. Specifically, we address what species were most affected, the timing of possible food shortages, and food shortage severity in a historical context. We found that thick-billed murres (Uria lomvia) were most affected by the die-off, making up 61% of all bird carcasses encountered during beach surveys. Thick-billed murre carcasses were proportionately more numerous (26:1) than would be expected based on ratios of thick-billed murres to co-occurring common murres (U. aalge) observed on breeding study plots (7:1). Concentrations of the stress hormone corticosterone, a reliable physiological indicator of nutritional stress, in thick-billed murre feathers grown in the fall indicate that foraging conditions in the northern Bering Sea were poor in the fall of 2017 and comparable in severity to those experienced by murres during the 1976–1977 Bering Sea regime shift. Concentrations of corticosterone in feathers grown during the pre-breeding molt indicate that foraging conditions in late winter 2018 were similar to previous years. The 2018 murre egg harvest in the village of Savoonga (on St. Lawrence Is.) was one-fifth the 1993–2012 average, and residents observed that fewer birds laid eggs in 2018. Exposure of thick-billed murres to nutritional stress in August, however, was no different in 2018 compared to 2016, 2017, and 2019, and was comparable to levels observed on St. George Island in 2003–2017. Prey abundance, measured by the National Oceanic and Atmospheric Administration in bottom-trawl surveys, was also similar in 2018 to 2017 and 2019, supporting the evidence that food was not scarce in the summer of 2018 in the vicinity of St. Lawrence Island. Of two moribund thick-billed murres collected at the end of the mortality event, one tested positive for a novel re-assortment H10 strain of avian influenza with Eurasian components, likely contracted during the non-breeding season. It is not currently known how widely spread infection of murres with the novel virus was, thus insufficient evidence exists to attribute the die-off to an outbreak of avian influenza. We conclude that food shortage alone is not an adequate explanation for the mortality of thick-billed murres in 2018, and highlight the importance of rapid response to mortality events in order to document alternative or confounding causes of mortality.

Relationship between cortisol and glucose as physiological stress indicators during growth season in juvenile Siberian sturgeon Acipenser baerii

The relationship between cortisol and glucose was studied in two-year old farmed Siberian sturgeon Acipenser baerii with a body weight of 340±30 g (mean ± SD) and total length of 45±1 cm from August to November 2017. Thirty-six individuals were randomly selected and stocked in some 3×300 L fiberglass tanks. Blood samples were collected monthly from the tagged fish. The mean cortisol in August, September, October and November were 4.7±0.9, 23.5±3.0, 6.3±0.9 and 7.4±0.9 ng mL–1 respectively whereas glucose concentrations were 44.6±0.4, 27.3±0.6, 49.2±0.7 and 48.5±0.7 mg dL–1 respectively indicating a significant increase in cortisol and decrease in glucose in September, may be due to the exposure to prolonged high temperature (26–28.5°C). Although it was expected to happen naturally due to hyperglycemia of cortisol but no such phenomena was detected. Our results suggest that the consumption of glucose for maintenance of homeostasis and physiological status is a mechanism against the non-optimal thermal regime. This mechanism consumes glucose at a rate higher than that produced by cortisol, causing significant decrease of plasma glucose. In general, there was a reverse relationship between cortisol and glucose concentration during the experiment in Siberian sturgeons.

Mother-Infant Skin-to-Skin Contact: Short- and Long-Term Effects for Mothers and Their Children Born Full-Term.

This brief report reviews findings from a longitudinal study of skin-to-skin contact (SSC) with mothers and full-term infants and a follow-up study of these dyads when the children were 9 years. Findings infer the positive influence of SSC on mother–child interactions in infancy and into children’s middle childhood. Mothers and infants in SSC and control groups were seen when infants were 1 week, 1 month, 2 months, and 3 months. SSC group mothers reported fewer depressive symptoms in infants’ early weeks and had a greater reduction in salivary cortisol, a physiological stress indicator, in infants’ first month (Bigelow et al., 2012). SSC group mothers who initially chose to breastfeed continued to breastfeed their infants throughout the 3 months, whereas breastfeeding mothers in the control group declined over the visits (Bigelow et al., 2014). When engaged in the Still Face Task with their mothers, SSC group infants showed the still face effect with their affect at 1 month, a month before the control group infants did so (Bigelow and Power, 2012). At 3 months, SSC group infants were social bidding to their mothers during the still face phase. When the children were 9 years, the mother–child dyads engaged in conversations about the children’s remembered emotional events (Bigelow et al., 2018). Mother–child dyads who had been in the SSC group showed more engagement and reciprocity in the conversations than mother–child dyads who had been in the control group. Oxytocin, which is induced by SSC, is hypothesized to be an underlying factor that helped the mother–infant relationship have a positive trajectory with long-term benefits.

A Comparison of the Acute Effects of Different Forms of Yoga on Physiological and Psychological Stress: A Pilot Study.

Yoga is a frequently recommended stress management strategy; however, the acute stress response to varying types of yoga are not fully clear. Thus, the purpose of this study was to compare the acute effects of meditative and power yoga on indices of physiological and psychological stress. In a crossover counterbalanced design, physically active females (n = 13; age = 20.8 yrs ± 0.8, height = 164.5 cm ± 6.1, body mass = 65.0 kg ± 13.8) who did not regularly participate in yoga or mindful training enrolled in this study. Participants completed two visits each, with a standardized instructional-video 30-min yoga session with either A) meditative (Hatha style) yoga or B) power (Vinyasa style) yoga. Prior to and immediately after each yoga bout, psychological stress was assessed using the State–Trait Anxiety Inventory (STAI) questionnaire, and salivary cortisol samples were obtained to measure indices of physiological stress. State anxiety scores were significantly lower following meditative yoga (p = 0.047) but were not different following power yoga (p = 0.625). Salivary cortisol levels were significantly lower following meditative yoga (p = 0.020) but not following power yoga (p = 0.242). Results indicate that acute engagement in meditative yoga decreases markers of psychological and physiological stress, while power yoga does not impart a significant stress-relieving benefit. Findings indicate that differing types of yoga may have various stress-relieving capabilities and should be considered by individuals seeking anxiolytic benefits.

Sceletium tortuosum (Zembrin® ) ameliorates experimentally induced anxiety in healthy volunteers.

To investigate the anxiolytic properties of a standardized extract of Sceletium tortuosum (trademarked-Zembrin® ). Two studies utilized a placebo-controlled, double-blind, between-subject experimental design to investigate the effects of a single dose of Sceletium tortuosum (25 mg, Zembrin® ) on laboratory stress/anxiety responding in 20 young healthy volunteers. To elicit feelings of stress/anxiety, participants completed 20 min of the multitasking framework in study 1 and a 5-min simulated public speaking task in study 2. Study 1 measured subjective experiences of mood at baseline, prestress induction, and poststress induction. Study 2 measured subjective experiences of anxiety and physiological indicators of stress (heart rate [HR] and galvanic skin response) at baseline, prestress induction, during stress induction, and poststress induction. A series of analysis of covariances (baseline entered as the covariate) revealed no treatment effect in study 1; however, study 2 revealed subjective anxiety levels to be significantly lower in the Zembrin® group at the prestress induction point and a significant interaction between treatment and time on HR. Taken together, results indicate that a single dose of Zembrin® can ameliorate laboratory stress/anxiety responding in healthy volunteers. We provide the first tentative behavioral evidence to support the anxiolytic properties of Sceletium tortuosum (25 mg Zembrin® ).

Empathy and job resources buffer the effect of higher job demands on increased salivary alpha amylase awakening responses in direct-care workers

The job demands-resources (JD-R) model has rarely been used in conjunction with physiological indicators of stress and ill-health. This study explored the associations between the JD-R model and physiological indicators of the stress response, while considering potential moderators of this relationship. Across 2 timepoints (summer-winter) direct-care workers completed questionnaires assessing job demands, job resources, empathy and self-efficacy, and provided morning saliva samples to assess physiological indices of stress and ill-health. Changes in job resources and empathy were positively correlated with changes in the cortisol awakening response (CAR). Further, changes in both job resources and empathy independently buffered the impact of higher job demands on increased salivary alpha amylase awakening response (sAA-AR) concentrations. These findings suggest that despite increased job demands, the sAA-AR decreased for direct-care workers that had perceived high job resources or who reported higher empathy. Potentially, job resources and empathy may act as a protective factor against the development of poor health associated with workplace stress.

Effectiveness of Partial Sedation to Reduce Stress in Captured Mule Deer

ABSTRACTInformation garnered from the capture and handling of free‐ranging animals helps advance understanding of wildlife ecology and can aid in decisions on wildlife management. Unfortunately, animals may experience increased levels of stress, injuries, and death resulting from captures (e.g., exertional myopathy, trauma). Partial sedation is a technique proposed to alleviate stress in animals during capture, yet efficacy of partial sedation for reducing stress and promoting survival post‐capture remains unclear. We evaluated the effects of partial sedation on physiological, biochemical, and behavioral indicators of acute stress and probability of survival post‐capture for mule deer (Odocoileus hemionus) that were captured via helicopter net‐gunning in the eastern Greater Yellowstone Ecosystem, Wyoming, USA. We administered 10–30 mg of midazolam and 15 mg of azaperone intramuscularly (IM) to 32 mule deer in 2016 and 53 mule deer in 2017, and maintained a control group (captured but not sedated) of 38 mule deer in 2016 and 54 mule deer in 2017. To evaluate indicators of acute stress, we measured heart rate, blood‐oxygen saturation, body temperature, respiration rate, and levels of serum cortisol. We recorded number of kicks and vocalizations of deer during handling and evaluated behavior during release. We also measured levels of fecal glucocorticoids as an indicator of baseline stress. Midazolam and azaperone did not reduce physiological, biochemical, or behavioral indicators of acute stress or influence probability of survival post‐capture. Mule deer that were administered midazolam and azaperone, however, were more likely to hesitate, stumble or fall, and walk during release compared with individuals in the control group, which were more likely to trot, stot, or run without stumbling or falling. Our findings suggest that midazolam (10–30 mg IM) and azaperone (15 mg IM) may not yield physiological or demographic benefits for captured mule deer as previously assumed and may pose adverse effects that can complicate safety for captured animals, including drug‐induced lethargy. Although we failed to find efficacy of midazolam and azaperone as a method for reducing stress in captured mule deer, the efficacy of midazolam and azaperone or other combinations of partial sedatives in reducing stress may depend on the dose of tranquilizer, study animal, capture setting, and how stress is defined. © 2020 The Wildlife Society.

Stress coping styles: Is the basal level of stress physiological indicators linked to behaviour of sea bream?

Stress coping style (SCS) is defined as a coherent set of individual physiological and behavioural differences in stress responses that are consistent across context and over time. SCS in fish has been studied, including because it has direct implications for aquaculture productivity and welfare. The fish physiological responses upon stress between different SCS are overall well known. In contrast, the basal level of the physiological indicators of stress and welfare are understudied. Therefore, the purpose of our study was to investigate the relationship between SCS and the basal levels of stress, health and welfare indicators of sea breams (Sparus aurata). To this end, we first screened the fish SCS, by measuring the boldness behaviour of fish during both risk-taking and hypoxia tests. The tests were each run two times to evaluate the behavioural consistency over time (7 days). One week after the last behavioural measurement, a blood sample was taken to measure the basal level of several physiological stress indicators. We observed that the behavioural response in the hypoxia test was not consistent over time, while the behavioural response was consistent in the risk-taking test. Moreover, no behavioural consistency was observed between these two tests. Among fish that exited the safe area during risk taking test, bolder individuals displayed lower basal levels of cortisol, noradrenaline, and lactate while no correlation was found between physiological parameters and the behavioural response in the hypoxia test. In conclusion, the risk-taking test seems more appropriate for screening SCS in sea bream because the behavioural response is consistent over time. In addition, this behavioural response is linked with the basal level of the stress hormones (cortisol, noradrenaline, and lactate). This study contributes to bring new information about the link between behaviour and resting physiology of SCS.

Best practices for stress measurement: How to measure psychological stress in health research.

Despite the strong evidence linking psychological stress to disease risk, health researchers often fail to include psychological stress in models of health. One reason for this is the incorrect perception that the construct of psychological stress is too vague and broad to accurately measure. This article describes best practices in stress measurement, detailing which dimensions of stressor exposures and stress responses to capture, and how. We describe when to use psychological versus physiological indicators of stress. It is crucial that researchers across disciplines utilize the latest methods for measuring and describing psychological stress in order to build a cumulative science.

Preliminary Indications That First Semester Students From Academic Households Exhibit Higher Hair Cortisol Concentrations Than Their Peers From Nonacademic Households.

Previous research has extensively addressed social disparity in education using certain aspects, including the stress differences between students from nonacademic families and those from academic families during the transition from secondary school to a university. However, this issue has not yet been fully understood; the current literature suggests contradictory predictions, and physiological indicators of stress have never been assessed. Therefore, we tested whether hair cortisol concentrations (HCCs) in first semester students from nonacademic families are different from those of first semester students from academic families during their first six weeks at university. We analyzed hair samples and parental educational background reports from 71 female first semester students at a university in Switzerland in two waves (n = 34 in the autumn of 2016 and n = 37 in the autumn of 2017). The HCCs were extracted from the hair using a well-established protocol. The analyses revealed higher HCCs in the students from the academic families across the two cohorts. This difference could not be attributed to different control variables (e.g., age, migration background). These preliminary findings were in line with the sociological theory that an academic parental background is associated with pressure to avoid a drop in one's social status.

Effects of alpha-lipoic acid on the behavior, serum indicators, and bone quality of broilers under stocking density stress

The objective of present study was to investigate the effects of alpha-lipoic acid (ALA) dietary supplementation on the behavior, physiological and oxidant stress indicators, and bone quality in broilers under high stocking density (HSD) stress. A total of one thousand eight hundred 22-day-old Arbor Acres male broiler chicks were randomly allocated to 18 pens (2.97 × 2.03 m) in 3 groups: 14 birds/m2 (NSD, normal stocking density) or 18 birds/m2 (HSD) or 18 birds/m2 plus 300 mg/kg ALA dietary supplement (HSD + ALA, high stocking density + alpha-lipoic acid). Each treatment had 6 replicates, and the experiment lasted 3 wk. The HSD group was significantly lower than the NSD group (P < 0.05) in the frequency of eating, walking, and preening behavior. The alkaline phosphatase activity and serum calcium content were significantly higher, and the parathyroid hormone (PTH) level was significantly lower in the HSD group than in the NSD group (P < 0.05). When compared with the NSD group, the HSD group showed an increase (P < 0.05) in serum heterophil/lymphocyte ratio (H/L ratio), corticosterone (CORT), malondialdehyde (MDA) content, and catalase (CAT) activity, whereas a decrease (P < 0.05) in total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) concentrations. The HSD group was also significantly lower (P < 0.05) than the NSD group in the tibia and femur breaking strength, bone mineral density, and BMC. Importantly, the addition of ALA into the diets of the HSD group enabled the HSD + ALA group to recover to the levels of NSD group (P > 0.05) in the standing and preening behavior, alkaline phosphatase activity, PTH concentration, H/L ratio, CAT, T-AOC, MDA, SOD, and GSH-Px. These results indicate that the increase of stocking density lowered the bone quality, increased the physiological and oxidative stress indicators, and modified the behavior of broilers, whereas ALA dietary supplementation could counteract the reduction in the performance and physiological responses of broilers under high-density environmental stress.

HNP-1 and HBD-1 as Biomarkers for the Immune Systems of Elite Basketball Athletes.

Acute or strenuous exercise is sometimes related to upper respiratory tract infections in athletes. Practicing intense and regular exercise can lead to incorrect activation of the immune system, causing athletes to be excluded from training programs and competitions. Defensins are small antimicrobial peptides that are part of the innate immune system and dynamically involved in several biological activities. In this study, we highlight the role of human defensins in competitive basketball athletes. In particular, we consider the behavior of alpha- and beta-defensins together with white blood cells in a cohort of players. Moreover, we focus our attention on cortisol, a physiological indicator of stress, and testosterone, both of which are human hormones involved in muscle metabolism. The free-testosterone/cortisol ratio is considered to be an indicator of overtraining among athletes. This paper provides an up-to-date information of the role of human defensins as self-defense molecules during a continuous stressor such as long-term exercise, and it recognizes them as potential markers of infection.

Dietary Supplementation of Postbiotics Mitigates Adverse Impacts of Heat Stress on Antioxidant Enzyme Activity, Total Antioxidant, Lipid Peroxidation, Physiological Stress Indicators, Lipid Profile and Meat Quality in Broilers.

Simple SummaryTo mitigate the adverse impacts of stressful environmental conditions on poultry and to promote the animal’s health and growth performance, antibiotics at sub-therapeutic doses have been added to poultry diets as growth promoters. Nevertheless, the improper and overuse of antibiotics as feed additives have played a major role in the emergence of antibiotic-resistant bacteria and increased levels of antibiotic residues in animal products, which have disastrous effects on the health of both animals and humans. Postbiotics, used as dietary additives for livestock, could be potential alternatives to antibiotics. Postbiotics produced from the probiotic Lactobacillus plantarum have been the subject of several recent kinds of research. However, the researchers have very rarely considered the effect of postbiotics on the broilers under heat stress.The purpose of this work was to evaluate the impacts of feeding different postbiotics on oxidative stress markers, physiological stress indicators, lipid profile and meat quality in heat-stressed broilers. A total of 252 male Cobb 500 (22-day-old) were fed with 1 of 6 diets: A basal diet without any supplementation as negative control (NC); basal diet + 0.02% oxytetracycline served as positive control (PC); basal diet + 0.02% ascorbic acid (AA); or the basal diet diet + 0.3% of RI11, RS5 or UL4 postbiotics. Postbiotics supplementation, especially RI11 increased plasma activity of total-antioxidant capacity (T-AOC), catalase (CAT) and glutathione (GSH), and decreased alpha-1-acid-glycoprotein (α1-AGP) and ceruloplasmin (CPN) compared to NC and PC groups. Meat malondialdehyde (MDA) was lower in the postbiotic groups than the NC, PC and AA groups. Plasma corticosterone, heat shock protein70 (HSP70) and high density lipoprotein (HDL) were not affected by dietary treatments. Postbiotics decreased plasma cholesterol concentration compared to other groups, and plasma triglyceride and very low density lipoprotein (VLDL) compared to the NC group. Postbiotics increased breast meat pH, and decreased shear force and lightness (L*) compared to NC and PC groups. The drip loss, cooking loss and yellowness (b*) were lower in postbiotics groups compared to other groups. In conclusion, postbiotics particularly RI11 could be used as an alternative to antibiotics and natural sources of antioxidants for heat-stressed broilers.

May Salivary Chromogranin A Act as a Physiological Index of Stress in Transported Donkeys? A Pilot Study.

Simple SummaryTransportation is recognized as a stressful animal husbandry procedure, inducing both short term and prolonged effects on welfare. Donkeys are transported for several purposes; therefore, validating a reliable and non-invasive stress indicator is pivotal. This study aimed to investigate whether salivary chromogranin A (CgA) concentration, known as an index of stress in humans and pigs, could represent a novel index of transportation-induced stress in donkeys. The research involved the measurement of salivary CgA in 19 donkeys, 15 min before and 15 min after two transportations. The transportation, which took place on two consecutive days, followed the routine procedures of the farm. The analysis of salivary CgA was carried out by an enzyme-linked immunosorbent assay test. Results showed that CgA salivary levels significantly decreased after both transportations. The physiological mechanisms underlying this result may be related to catestatin acting as an inhibitor of catecholamine release; however, due to the limited number of subjects involved, this hypothesis requires further investigation. Road transport is known to be a stressful animal husbandry procedure as it induces the activation of two main physiological stress-related pathways: the hypothalamic-pituitary-adrenal cortex axis and the sympathetic-adrenal medulla axis. This preliminary study aimed to investigate whether salivary chromogranin A (CgA) concentration, known as a biomarker of the sympathetic activity system during psychological stress, may represent a novel physiological index of transportation-induced stress in donkeys. Nineteen Romagnolo donkeys, raised in groups on paddocks, were subject to two transportations, following the farm’s routine procedures, for a mean duration of 64 min each on two consecutive days. Salivary samples were gently collected 15 min before and 15 min after each transportation. Salivary CgA was measured by a commercially available enzyme-linked immunosorbent assay test. Results showed that CgA salivary levels significantly decreased after both transportations. The physiological mechanisms underlying this result may be related to catestatin activity, a bioactive product of the proteolytic cleavage of CgA, that acts as an inhibitor of catecholamine release. This hypothesis requires further investigation, particularly considering the limited number of subjects involved in this preliminary study. The identification of a reliable and non-invasive stress-marker would represent a useful tool for improving farm animals’ welfare in transport conditions.

Validity of stress assessment using heart-rate variability in newborns.

The process of birth causes stress for neonates, but additional stressors for sick neonates are a matter of concern. As analysis of heart-rate variability (HRV), which reflects autonomic activity, has demonstrated that low-frequency (LF) activity reflects overall autonomic activity, high-frequency (HF) activity reflects parasympathetic activity, and the LF/HF ratio reflects sympathetic activity, HRV has been clinically applied as a non-invasive index of physical stress. In this study, we evaluated whether HRV is useful as a stress index for neonates by analyzing it in comparison with their salivary cortisol level. We measured the salivary cortisol level and HRV in 12 healthy neonates and 37 neonates born during between 2014 and 2016 and admitted to the neonatal intensive care unit. These examinations were performed at birth and after approximately 1week. The changes in parameters with time were examined. The LF and HF values in both groups exhibited significant negative correlations with the salivary cortisol level. In those admitted to the neonatal intensive care unit, the LF and HF values were correlated with gestational age and height. In the healthy neonates, a reduced salivary cortisol level and increase in the LF and HF values were observed approximately 1week after birth compared with the values at birth, whereas the LF/HF ratio was not correlated with the salivary cortisol level and did not change over time. The LF and HF values were significantly correlated with the cortisol level, suggesting their usefulness as physiological indices of stress in clinical neonatal care.

BIOMEDICAL INDICATORS OF PRE-COMPETITIVE STRESS IN FEMALE AND MALE JUDO PLAYERS

The aim of the present paper is to monitor changes of selected mental and physiological stress indicators in both female and male sportsmen in the subsequent days prior to an International Judo Tournament in Poland and on the competition day. The study included 9 men and 9 women, participants of the training camp that ended with a tournament. Every morning, on the three consecutive days preceding the competition (day -3, -2, -1) and on the competition day (day 0) capillary blood was sampled to determine serum cortisol (C) and testosterone (T) levels, then the subjects assessed their night sleep quality (SQ) with the use of a 5-point Likert scale, and perceived anxiety using the State-Trait Anxiety Inventory questionnaire by Spielberger (STAI - Polish version). SQ insignificantly deteriorated, and C and anxiety levels increased with the time to event. The inter-group analysis for the entire period showed higher scores in average anxiety and higher average level of C in women than men. The relative changes in these biomarkers could indicate higher pre-competitive stress in women, however without taking into account the sports class of the opponents individually for each of the groups one cannot imply gender-specific susceptibility to stress as a general principle.

Infants of mothers with higher physiological stress show alterations in brain function.

Chronic stress has been increasingly linked with aberrations in children's behavioral, cognitive, and social development, yet the effect of chronic physiological stress on neural development during the first year of life is largely unknown. The present study aims to link a physiological index of chronic stress (maternal hair cortisol concentration) to maturational differences in infant functional brain development during the first year of life. Participants were 94 mother-infant dyads. To index chronic physiological stress, maternal hair samples were assayed for the previous three months' cortisol output. To examine the development of brain function during the first year of life, six-to-twelve-month-old infants (N=94) completed a resting electroencephalography (EEG) recording. Infants of mothers with evidence of higher physiological stress showed increased relative low-frequency (theta) power and reduced relative high-frequency (alpha, high-gamma) power, compared to infants of mothers with evidence of low physiological stress. This pattern of findings is consistent with other studies suggesting that early life stress may lead to alterations in patterns of infant brain development. These findings are important given that maturational lags in brain development can be long-lasting and are associated with deficits in cognitive and emotional development. The present research also suggests that reducing maternal physiological stress may be a useful target for future interventions aiming to foster neurodevelopment during the first year of life.