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Introduction Winter warfare training (WWT) is a critical component of military training that trains warfighters to operate effectively in extreme environments impacted by snow and mountainous terrain. These environmental factors can exacerbate the disruption to the hormone milieu associated with operating in multi-stressor settings. To date, there is limited research on the physiological responses and adaptations that occur in elite military populations training in arduous environments. The purpose of this study was to quantify hormone responses and adaptations in operators throughout WWT. Materials and Methods Participants engaged in baseline laboratory metrics at their home station, Fort Carson, located in Colorado (CO) prior to WWT, for one week in Montana (MT) and one week in Alaska (AK). WWT periods were separated by approximately one month. Blood was collected upon wake at baseline (CO) and on the first and last day of WWT at each location (MT and AK). Plasma was analyzed for stress, metabolic, and growth-related hormones via enzyme-linked immunoassay (ELISA). Sleep quality was assessed via the Pittsburg Sleep Quality Index (PSQI) at baseline (CO) and on the first day of training in MT and AK. Cognitive function was evaluated using the Defense Automated Neurobehavioral Assessment (DANA) at baseline (CO) and on the first and last day of WWT in both MT and AK. Results Fourteen US Army operators in 10th Special Forces Group (SFG) Operational Detachment participated in winter warfare training (WWT; age: 31.5 years; 95%CI[28.1, 34.3]; height: 180.6 cm; 95%CI[177.3, 183.4]; weight: 87.4 kg.; 95%CI[80.6, 97.7]; body fat: 18.9%; 95%CI[13.7, 23.1]; male: n=13; female: n=1). Plasma adrenocorticotropic hormone (ACTH) levels increased from baseline (19.9 pg/mL; 95%CI[8.6, 24.2])  to pre-WWT (26.9 pg/mL; 95%CI [16.2, 37]; p=0.004), decreased from pre-  (26.9 pg/mL; 95%CI [16.2, 37]) to post-WWT in MT (22.3 pg/mL; 95% CI [8, 23.7]; p=0.004;), and increased from pre-  (25 pg/mL; 95%CI[ 28.4) to post-WWT (36.6 pg/mL; 95%CI [17.9, 48.9]) in AK (p=0.005). Plasma cortisol levels decreased from pre- (174 ng/mL; 95%CI[106.2, 233.6])  to post-WWT (94.5 ng/mL; 95%CI[54.8, 101.7]) in MT (p=0.001) and, conversely, increased from pre- (123.1 ng/mL; 95%CI[97.5, 143.9]) to post-WWT  (162.8 ng/mL; 95%CI[128, 216.7]) in AK (p<0.001). Alterations in growth-related hormones (insulin-like growth factor 1 [IGF-1], insulin-like growth factor binding protein 3 [IGFBP-3], and sex hormone binding globulin [SHBG]) were observed throughout WWT (p<0.05). The Total Testosterone / Cortisol ratio (TT / CORT; molar ratio) was lower pre-WWT in MT (0.04; 95%CI[0.01,0.04) compared to baseline in CO (0.07; 95%CI[0.04, 0.07]; p=0.042). Triiodothyronine (T3) levels increased from pre-  (101.7 ng/dL; 95%CI[93.7, 110.4]) to post-WWT  (117.8 ng/dL; 95%CI[105.1, 129.4]) in MT (p=0.042). No differences in sleep quality were reported between locations (CO, MT, and AK). Alterations in cognitive function were exhibited between locations and during WWT in both MT and AK (p<0.05). Conclusions Over the course of WWT, elite operators experienced alterations in stress, metabolic, and growth-related hormones, as well as cognitive performance. The increase in stress hormones (i.e. ACTH and cortisol) and reduction in cognitive performance following training in AK are suggestive of heightened physiological strain, despite similarities in physical workload, self-reported sleep quality, and access to nutrition. The variation in hormone levels documented between MT and AK may stem from differences in environmental factors, such as lower temperatures and harsh terrain. Further research is warranted to provide more information on the combined effects of military training in extreme environments on operator health and performance. [ABSTRACT FROM AUTHOR]

Acute and chronic stress each have physical manifestations in the human body that can lead to many negative health impacts. Today, reported stress levels worldwide are at an all-time high, spurring the search for non-pharmaceutical interventions to maintain healthy stress levels. In this study, we examined whether a pet dog's presence influences healthy adults' acute stress responses as assessed through self-reports, heart rate, plasma cortisol, and salivary alpha-amylase. Participating pet dog owners were randomly assigned to undergo the Trier Social Stress Test either with their pet dog or alone. While there was no group difference in perceived anxiety levels, participants undergoing the acute psychological stressor with their pet dogs present had significantly lower heart rates, lower plasma cortisol responses, and higher salivary alpha-amylase responses than people without their dogs. Those who participated without their dogs had a statistically flat alpha-amylase response, which is typically associated with extreme or pathological stress. These findings extend the potential effects of pet dogs beyond merely lowering their owner's stress levels to maintaining a healthier, balanced response across the sympathoadrenal medullary axis and hypothalamic–pituitary-adrenal axis. [ABSTRACT FROM AUTHOR]

Acute and chronic stress each have physical manifestations in the human body that can lead to many negative health impacts. Today, reported stress levels worldwide are at an all-time high, spurring the search for non-pharmaceutical interventions to maintain healthy stress levels. In this study, we examined whether a pet dog’s presence influences healthy adults’ acute stress responses as assessed through self-reports, heart rate, plasma cortisol, and salivary alpha-amylase. Participating pet dog owners were randomly assigned to undergo the Trier Social Stress Test either with their pet dog or alone. While there was no group difference in perceived anxiety levels, participants undergoing the acute psychological stressor with their pet dogs present had significantly lower heart rates, lower plasma cortisol responses, and higher salivary alpha-amylase responses than people without their dogs. Those who participated without their dogs had a statistically flat alpha-amylase response, which is typically associated with extreme or pathological stress. These findings extend the potential effects of pet dogs beyond merely lowering their owner’s stress levels to maintaining a healthier, balanced response across the sympathoadrenal medullary axis and hypothalamic–pituitary-adrenal axis.

Background: Using anaesthetics is an important application in aquaculture especially where the fish transportation, vaccination, grading, sorting activities and many other handling operations have been conducted during the different stages of production periods in the farms or hatcheries. Objectives: This study aimed to evaluate the efficacy of oregano essential oil (OO) as an anaesthetic for Nile tilapia and to determine the optimal concentration and post‐application stress effects compared to clove oil (CO). Methods: Nile tilapia juveniles were exposed to different concentrations of OO (20–40–60–80–100 mg L−1) and CO (50 mg L−1) for different time periods to determine the optimal concentration and exposure time. After the effective concentration of OO was determined, in the second experiment, stress parameters (glucose, plasma cortisol) were analysed after 0, 2, 6, 12 and 24 h of application. The results compared to the control group and CO results. Results: The study found that OO which has carvacrol compound higher than 78% was an efficient anaesthetic for Nile tilapia, and the effective concentration was found to be 60 mg L−1. No significant differences were found between opercular beats in any concentration of OO and CO. Basal glucose level in blood without anaesthesia application and recorded at 39.33 mg dL−1 and significantly lower than OO and CO at first two sampling points, 0 and 2 h (p < 0.05). According to plasma cortisol level results, although CO experimental group showed secondary stress response at 12 h (17.91 ± 4.21 ng mL−1), OO and CO group cortisol levels decreased at 24 h after anaesthesia application 7.13 ± 0.14and 7.01 ± 0.54 ng mL−1, respectively, below the control group cortisol concentration (12.28 ± 1.81 ng mL−1). Conclusions: These findings have important implications for the aquaculture industry as the use of OO as an anaesthetic could reduce the stress and mortality associated with traditional anaesthetics. Further research is needed to evaluate the efficacy of OO as an anaesthetic agent for other fish species and to determine the optimal concentration and exposure time for different species. [ABSTRACT FROM AUTHOR]

Pair bonding in humans and other socially monogamous species can have positive effects on health and well-being. These attachments also come with the potential for challenges such as separation, jealousy, or grief. Much of the work on the neurobiology of pair bonding in non-human primates has been carried out in coppery titi monkeys (Plecturocebus cupreus), a monogamous South American monkey, although these studies have been primarily in males. In the current study, we utilized female titi monkeys to experimentally examine responses to their monogamous male partner vs. a male stranger or being alone. Positron emission tomography (PET) scans were performed on eight adult female titi monkeys from well-established pairs. We used a within-subjects design in which each female underwent three different conditions after the fluorodeoxyglucose F18 (FDG) injection: a) the subject was reunited with her partner, b) encountered a stranger, or c) was alone in the experimental cage. Behavioural observations were recorded, and plasma assayed for cortisol. Females housed alone showed higher cortisol compared with either the partner or stranger conditions. FDG uptake was higher in the amygdala and hippocampus when interacting with the stranger than the partner. Proximity modulated the relationship between social condition and FDG uptake in several areas. Females entered into mutual proximity more frequently with the partner than with the stranger. Female titi monkeys have different physiological, neural, and behavioural reactions to being with their partner, a stranger male, or being alone.

Abstract Background Using anaesthetics is an important application in aquaculture especially where the fish transportation, vaccination, grading, sorting activities and many other handling operations have been conducted during the different stages of production periods in the farms or hatcheries. Objectives This study aimed to evaluate the efficacy of oregano essential oil (OO) as an anaesthetic for Nile tilapia and to determine the optimal concentration and post‐application stress effects compared to clove oil (CO). Methods Nile tilapia juveniles were exposed to different concentrations of OO (20–40–60–80–100 mg L−1) and CO (50 mg L−1) for different time periods to determine the optimal concentration and exposure time. After the effective concentration of OO was determined, in the second experiment, stress parameters (glucose, plasma cortisol) were analysed after 0, 2, 6, 12 and 24 h of application. The results compared to the control group and CO results. Results The study found that OO which has carvacrol compound higher than 78% was an efficient anaesthetic for Nile tilapia, and the effective concentration was found to be 60 mg L−1. No significant differences were found between opercular beats in any concentration of OO and CO. Basal glucose level in blood without anaesthesia application and recorded at 39.33 mg dL−1 and significantly lower than OO and CO at first two sampling points, 0 and 2 h (p

Few studies have longitudinally assessed the relationship between infant stress reactivity and future parenting style. Studies show that stress-induced plasma cortisol concentrations are stable over development and that they can be utilized as a marker for stress reactivity. This study investigates the relationship between stress-induced plasma cortisol concentrations in infancy and later parenting behavior in a translational nonhuman primate model. We hypothesized that higher stress-induced cortisol levels in infancy would predict impairments in maternal behaviors in adulthood. Subjects were rhesus macaque females (N = 122; Macaca mulatta), assessed as infants and again as mothers. At 3-4 months of age, subjects underwent a standardized BioBehavioral Assessment during which blood samples were obtained and they were assessed for behaviorally inhibition. Approximately 7 years later, subjects were observed as they interacted with their own offspring for four 300-s sessions. Typical rhesus monkey mother-offspring behaviors were recorded, including approaches and leaves and maternal cradling. Results showed that subjects' stress-induced cortisol concentrations and whether they exhibited behavioral inhibition as infants predicted later maternal behavior, with high cortisol concentrations and behavioral inhibition predicting high rates of offspring approaches and leaves and low rates of maternal cradling. Results also showed that higher stress-induced cortisol concentrations in infancy predicted higher scores on the Brown Index, an indication that the subjects' offspring, rather than the subject themselves, initiated changes in proximity. Taken together, these results suggest that individuals that exhibit higher stress-induced cortisol concentrations and behavioral inhibition at 3-4 months of age are at risk for engaging in less sensitive parenting behaviors as adults. To the extent that these findings generalize to humans, they suggest an important link between stress-induced cortisol concentrations and behavioral inhibition in infancy and behavior later in life, such that early-life stress reactivity can serve as a marker for later parenting behavior.

In this study, lead (Pb) and cadmium (Cd) were used as chemical stressors. Healthy A. testudineus were exposed to Pb (20, 30, and 40 mg/L) and Cd (3, 5, and 10 mg/L) for 7, 14, 21, and 28 days to assess the response of A. testudineus elicited by these metals. The tendency of Pb and Cd accumulation in the tissues of A. testudineus was as follows: gill >> liver > muscle for Pb and liver >> gill > muscle for Cd. Endocrine stress response was characterized by varying the levels of cortisol and glucose plasma. Exposure to both Pb and Cd caused significantly increase levels of plasma cortisol (p

Background: Many clinical studies have shown a correlation between plasma cortisol and neurological disorders. This study explored the causal relationship between plasma cortisol and dementia, epilepsy and multiple sclerosis based on Mendelian randomization (MR) method. Methods: Data were taken from the summary statistics of a genome-wide association study, FinnGen consortium and United Kingdom Biobank. Dementia, epilepsy, and multiple sclerosis were used as outcomes, and genetic variants associated with plasma cortisol were used as instrumental variables. The main analysis was performed using the inverse variance weighted method, and the results were assessed according to the odds ratio (OR) and 95% confidence interval. Heterogeneity tests, pleiotropy tests, and leave-one-out method were conducted to evaluate the stability and accuracy of the results. Results: In two-sample MR analysis, the inverse variance weighted method showed that plasma cortisol was associated with Alzheimer's disease (AD) [odds ratio (95% confidence interval) = 0.99 (0.98-1.00), P = 0.025], vascular dementia (VaD) [odds ratio (95% confidence interval) = 2.02 (1.00-4.05), P = 0.049)], Parkinson's disease with dementia (PDD) [odds ratio (95% confidence interval) = 0.24 (0.07-0.82), P = 0.023] and epilepsy [odds ratio (95% confidence interval) = 2.00 (1.03-3.91), P = 0.042]. There were no statistically significant associations between plasma cortisol and dementia with Lewy bodies (DLB), frontotemporal dementia (FTD) and multiple sclerosis. Conclusion: This study demonstrates that plasma cortisol increase the incidence rates of epilepsy and VaD and decrease the incidence rates of AD and PDD. Monitoring plasma cortisol concentrations in clinical practice can help prevent diseases, such as AD, PDD, VaD and epilepsy. [ABSTRACT FROM AUTHOR]

Hair cortisol concentrations are increasingly being used in both humans and nonhuman animals as a biomarker of chronic stress. However, many details regarding how hair cortisol concentrations relate to the dynamic activity and regulation of the HPA axis are still unknown. The current study explores 1) how the regulation of the HPA axis in infancy relates to hair cortisol concentrations (HCC) in infancy 2) whether this relationship persists into adulthood under conditions of social stability, and 3) how social instability impacts these relationships. All subjects were rhesus monkeys housed in large social groups at the California National Primate Research Center, and all had participated in a 25-hr. long BioBehavioral Assessment (BBA) at 3-4 months of age when four plasma samples were taken to assess HPA regulation, in particular cortisol responses to 1) 2-hour social separation and relocation, 2) sustained challenge, 3) dexamethasone and 4) ACTH administration. In Study 1, hair samples were collected at the end of the BBA testing from 25 infant rhesus monkeys from 2 different stable social groups. In Study 2, hair samples were obtained at three timepoints from 108 adults from 3 different stable social groups (1 in the Spring/Summer and 2 in the Fall/Winter) to examine the temporal stability of the relationship between HCC and HPA axis regulation. In Study 3, subjects included 31 infants and 33 adults from a single social group experiencing social instability following the same procedures as in Studies 1 and 2. Generalized linear models were used to determine if infants' HPA axis activity and regulation predicted HCC in infancy (Study 1), in adulthood with animals living in stable social conditions (Study 2) or in animals living in an unstable social group (Study 3). Results indicated that for both infants and adults living in stable social groups, HCC are associated with the adrenal response to ACTH in infancy. Samples collected in the winter also had higher HCC than those collected in summer. In the unstable social group, adult hair cortisol levels were higher than in the stable social groups. Additionally, there were no consistent relationships between HCC and infant HPA axis regulation among adults or infants living in a group experiencing social instability. These results suggest that the aspects of the HPA axis that drive HCC may differ depending on context. Under stable, non-stressed conditions there seems to be a trait-like association between adrenal responsivity and HCC in infancy and adulthood. However, this association may be reduced or eliminated under conditions of social stress.

Farmed Atlantic salmon (Salmo salar) welfare and performance can be strongly influenced by stress episodes caused by handling during farming practices. To better understand the changes occurring after an acute stress response, we exposed a group of Atlantic salmon parr to an acute stressor, which involved netting and transferring fish to several new holding tanks. We describe a time-course response to stress by sampling parr in groups before (T0) and 10, 20, 30, 45, 60, 120, 240, 300, and 330 min post-stress. A subgroup of fish was also subjected to the same stressor for a second time to assess their capacity to respond to the same challenge again within a short timeframe (ReStressed). Fish plasma was assessed for adrenocorticotropic hormone (ACTH), cortisol, and ions levels. Mucus cortisol levels were analyzed and compared with the plasma cortisol levels. At 5 selected time points (T0, 60, 90, 120, 240, and ReStressed), we compared the head kidney transcriptome profile of 10 fish per time point. The considerably delayed increase of ACTH in the plasma (60 min post-stress), and the earlier rise of cortisol levels (10 min post-stress), suggests that cortisol release could be triggered by more rapidly responding factors, such as the sympathetic system. This hypothesis may be supported by a high upregulation of several genes involved in synaptic triggering, observed both during the first and the second stress episodes. Furthermore, while the transcriptome profile showed few changes at 60 min post-stress, expression of genes in several immune-related pathways increased markedly with each successive time point, demonstrating the role of the immune system in fish coping capacity. Although many of the genes discussed in this paper are still poorly characterized, this study provides new insights regarding the mechanisms occurring during the stress response of salmon parr and may form the basis for a useful guideline on timing of sampling protocols. [ABSTRACT FROM AUTHOR]

Acute stress response in the European bitterling, Rhodeus amarus, to glochidia parasitism by the invasive unionid mussel, Sinanodonta woodiana, was quantified by analysing cortisol plasma levels using liquid chromatography coupled to mass spectrometer. We tested a novel method which required as little as 4 µL of plasma by increasing the volume using charcoal-treated plasma. Bitterling were observed to increase cortisol levels significantly in response to glochidia infestation. Overall, this technique allows the precise measurement of steroid hormone plasma concentrations in small fish. [ABSTRACT FROM AUTHOR]

In this study, lead (Pb) and cadmium (Cd) were used as chemical stressors. Healthy A. testudineus were exposed to Pb (20, 30, and 40 mg/L) and Cd (3, 5, and 10 mg/L) for 7, 14, 21, and 28 days to assess the response of A. testudineus elicited by these metals. The tendency of Pb and Cd accumulation in the tissues of A. testudineus was as follows: gill >> liver > muscle for Pb and liver >> gill > muscle for Cd. Endocrine stress response was characterized by varying the levels of cortisol and glucose plasma. Exposure to both Pb and Cd caused significantly increase levels of plasma cortisol (p < 0.05), while blood glucose levels slightly increased at the beginning and then decreased sharply. Based on the erratic changes in levels of plasma cortisol and blood glucose, it can be concluded that exposure to high concentrations of Pb and Cd does not cause death; however, it adversely affects the interrenal and pancreatic activities of A. testudineus. Biochemical changes can be used as biomarkers for stress assessment and management in fish. [ABSTRACT FROM AUTHOR]

The swimming activity, although an essential trait in the life cycle of fish, is still poorly understood in farmed fish. The current study aimed to investigate the impact of short-term induced swimming on the immune and antioxidant defence systems in European eel (Anguilla anguilla). Sixteen male yellow European eels (total length: 39.9 ± 0.7 cm; body weight: 108.8 ± 6.1 g) were individually placed in swimming flumes and divided into two groups: i) no swimming (n = 8); and ii) induced-swimming (n = 8) at 0.3 body lengths (BL)·s−1 for 7 h. Swimming resulted in a 2-fold lower cortisol concentration in plasma, whereas plasma glucose, lactate, and several immune-related parameters did not present variations between groups. Interestingly, swimming led to higher lysozyme, peroxidase, and protease activities in skin mucus, whereas bactericidal activity did not show differences among groups. Additionally, the gene expression of interleukin 1 beta showed an up-regulation in the skin of fish with induced swimming, while no differences were observed in the head-kidney or gills. Furthermore, modulation of the antioxidant status was observed in the liver and posterior skeletal muscle after induced swimming. Fish subjected to swimming showed lower lipid peroxidation and higher reduced glutathione levels, increasing the reduced/oxidized glutathione ratio. However, no variations in the antioxidant status were observed between groups in the anterior skeletal muscle. This study showed modulation of immune and oxidative stress markers in European eels upon short-term induced swimming compared to non-swimming fish. [Display omitted] • Plasma cortisol levels were lower in European eels induced to swim at 0.3 BL·s−1. • Lysozyme, peroxidase, and protease activities were higher in the skin mucus of swimming eels. • Expression of il1β gene was up-regulated in the skin of fish induced to swim. • Swimming led to lower LPO and higher GSH levels and GSH/GSSG ratio in the liver and posterior skeletal muscle. • This study highlights the benefits of induced swimming in the welfare of European eel. [ABSTRACT FROM AUTHOR]

Depression is associated with hyperactivity of the hypothalamo pituitary adrenal axis. Cortisol is a steroid hormone, released from the adrenal gland and is considered to be a biological marker of stress and anxiety. Serum or plasma cortisol levels have been previously studied in depressive patients but reported contradictory results. The present meta analysis aims to assess the serum or plasma concentration of cortisol in depressive patients compared with controls. We have conducted a systematic review with sequential meta analysis according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Web of Science, PubMed, Scopus, and PsycINFO databases, and published reference lists were searched up to January 2021. We have conducted a systematic review on PubMed for the following search (MeSH) terms ("Hydrocortisone"[Mesh]) AND "Depressive Disorder"[Mesh]). The RevMan 5.3 and Open Meta Analyst software was used with the standard mean difference (SMD) and 95% confidence intervals (CIs). The Jamovi and Open Meta Analyst Software were used to evaluate the publication bias, sensitivity analysis, and meta regression as possible sources of heterogeneity. Seventeen studies having a combined population (n) of 1400 (743 depressive patients and 657 controls) had satisfied the inclusion criteria for serum or plasma cortisol. The pooled SMD of the serum or plasma cortisol levels in depressive patients compared with controls was 1.18, (95% CI: 0.84, 1.52; P < 0.00001) with I2 = 85% (Ph < 0.00001). This meta analysis indicates a statistically significant mean difference in serum or plasma cortisol between depressed patients and controls. Meta analysis concluded that serum or plasma cortisol can differentiate depressed patients from nondepressed controls. [ABSTRACT FROM AUTHOR]

Monitoring stress levels of farmed Atlantic salmon (Salmo salar) is important to ensure fish welfare and optimize farm operations. Feces could be a promising matrix for assessing stress responses in fish, based on their properties of low-invasive sampling and allowing repeated sampling over time. Meanwhile, elevated levels of cortisol metabolites (CMs) in feces indicate the increases in plasma cortisol levels (PLA) after exposure to acute stress. However, the dynamics of fecal CMs following acute stress in Atlantic salmon remain unclear. In this study, a confinement stress involving chasing and crowding was conducted to investigate the responses of gastrointestinal CMs to an acute stressor in Atlantic salmon. The post-smolts, with an average weight of 155.21 g, were sampled before and at 30 min, 1.5, 6, 12, 18, 24, 36, and 48 h after the onset of stress. Blood and gastrointestinal contents from the stomach, proximal intestine, and distal intestine of each fish were collected and subsequently analyzed, using competitive enzyme-linked immunosorbent assay (ELISA). The results demonstrated that the pre-stress level of PLA was low (4.28 ± 6.13 ng/ml) and reached a peak within 30 min following stress. The levels of CMs in gastrointestinal contents from stomach (SCMs), proximal intestine (PCMs), and distal intestine (DCMs) in pre-stress group were 0.82 ± 0.50, 18.31 ± 6.14 and 16.04 ± 6.69 ng/g, respectively. Gastrointestinal CMs increased significantly within 30 min and the peak levels of SCMs (3.51 ± 3.75 ng/g), PCMs (68.19 ± 23.71 ng/g) and DCMs (65.67 ± 23.37 ng/g) were found at 1.5 h post-stress. The significant increases in PCMs and DCMs post-stress validate the biological relevance of measuring intestinal CMs for assessing acute stress responses in Atlantic salmon. No significant difference was noted between PCMs and DCMs across all samples, suggesting that intestinal contents can serve as a suitable matrix compared with feces when measuring the responses of CMs to acute stress. The time lag between the peak of PLA levels and their reflection in the intestinal contents exceeded 1 h, indicating that using intestinal contents as a matrix to assess stress levels in fish can extend and delay the sampling window. This study highlights valuable guidance for determining the optimal times to utilize intestinal contents for measuring stress responses, providing further insights into the dynamics of fecal CM following acute stress. • Significant differences were not found between cortisol metabolites in proximal (PCMs) and distal intestine (DCMs). • PCMs and DCMs exhibited a similar pattern of variation as plasma cortisol (PLA) in response to acute stress. • Over 1-h delay was detected between the peak of PLA and its reflection in the intestinal content. • The results verify the biological relevance of measuring intestinal cortisol metabolites levels to assess stress responses. [ABSTRACT FROM AUTHOR]

This study was directed to explore the impact of salinity on growth and endurance of Nile tilapia. Different salinity levels as 6‰, 10‰, 14‰, 18‰, 22‰ and control were tested. Plasma cortisol, plasma glucose, osmotic pressure, and growth performance parameters were estimated throughout the experimental period of 50 days. The results revealed that growth and survival were influenced by high salinity level. Moreover, cortisol, glucose, and osmotic pressure were directly proportional to the salinity level. Therefore, it was concluded that increased salinity level influences growth and survival of Nile tilapia (Oreochromis niloticus). [ABSTRACT FROM AUTHOR]

Background: Heart rate variability (HRV), a sensitive marker of stress and autonomic nervous disorders, was significantly decreased in cardiovascular disease, inflammation, and surgical injury. However, the effect of radical gastrectomy on HRV parameters needs to be further investigated. Methods: A prospective, observational study including 45 consecutive enrolled patients undergoing radical gastrectomy in our enhanced recovery after surgery (ERAS) programs was conducted. Frequency‐ and time‐domain parameters of HRV from 1 day prior to operation to 4 days postoperatively were continuously measured. Meanwhile, plasma cortisol and inflammatory markers were recorded and correlated to HRV parameters. Results: Heart rate variability showed a solidly circadian rhythm. Anesthesia severely disturbed HRV parameters, resulting in a reduction of most of the HRV parameters. Frequency‐domain parameter (including VLF) and time‐domain parameters (including the SDNN, SDANN, and triangular index) of HRV demonstrated a significant reduction compared to preoperative values on the postoperative day 1 (Pod1), and these HRV parameters could return to baseline on Pod2 or Pod3, indicating surgical stress and autonomic nerve dysfunction existed in the early postoperative period. Inflammatory biomarkers were significantly elevated on Pod1 and Pod3. Plasma cortisol decreased significantly on Pod1 and Pod3. Both inflammatory biomarkers and plasma cortisol had no significant correlation with HRV parameters. Conclusions: Compared with plasma cortisol and inflammation biomarkers, HRV is more sensitive to detect surgical stress and autonomic nervous dysfunction induced by radical gastrectomy in patients with gastric cancer. [ABSTRACT FROM AUTHOR]

Abstract Background Heart rate variability (HRV), a sensitive marker of stress and autonomic nervous disorders, was significantly decreased in cardiovascular disease, inflammation, and surgical injury. However, the effect of radical gastrectomy on HRV parameters needs to be further investigated. Methods A prospective, observational study including 45 consecutive enrolled patients undergoing radical gastrectomy in our enhanced recovery after surgery (ERAS) programs was conducted. Frequency‐ and time‐domain parameters of HRV from 1 day prior to operation to 4 days postoperatively were continuously measured. Meanwhile, plasma cortisol and inflammatory markers were recorded and correlated to HRV parameters. Results Heart rate variability showed a solidly circadian rhythm. Anesthesia severely disturbed HRV parameters, resulting in a reduction of most of the HRV parameters. Frequency‐domain parameter (including VLF) and time‐domain parameters (including the SDNN, SDANN, and triangular index) of HRV demonstrated a significant reduction compared to preoperative values on the postoperative day 1 (Pod1), and these HRV parameters could return to baseline on Pod2 or Pod3, indicating surgical stress and autonomic nerve dysfunction existed in the early postoperative period. Inflammatory biomarkers were significantly elevated on Pod1 and Pod3. Plasma cortisol decreased significantly on Pod1 and Pod3. Both inflammatory biomarkers and plasma cortisol had no significant correlation with HRV parameters. Conclusions Compared with plasma cortisol and inflammation biomarkers, HRV is more sensitive to detect surgical stress and autonomic nervous dysfunction induced by radical gastrectomy in patients with gastric cancer.

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Stress is an inevitable element of everyday living. Developmental studies suggested that adolescents are more vulnerable and sensitive to the effect of stress due to their developing brains, especially in areas related to stress perception and processing. This voxel-based morphometry study examined the association between various neurobiological markers and the level of perceived stress experienced by adolescents (n = 26) and middle-aged adults (n = 26). Our findings indicated that differences existed in the relationships between perceived stress and the structural volume of the orbitofrontal cortex (OFC) extending to the insula and amygdala. Specifically, the levels of perceived stress and the grey matter volume of the orbitofrontal cortex, the insula, and the amygdala were positively related in adolescents but negatively related for adults. Furthermore, a significant negative correlation between perceived stress and cortisol levels was observed in adults, whereas the relationship between perceived stress and cortisol levels was not significant for adolescents. Perceived stress measurement may be better than cortisol levels in terms of reflecting the emotional states of adolescents. In sum, the relationships between perceived stress and neurobiological markers were different between adolescents and middle-aged adults and thus appeared to be age dependent. [ABSTRACT FROM AUTHOR]

Overwintering is one of an important stage for aquatic animals, and light intensity has an important effect on the conservation of Scylla paramamosain during overwintering. Three different light intensity levels (0, 1.43 and 40.31 μmol m−2 s−1) were used to explore the effects of light intensity on digestion and immune responses, plasma cortisol and amino acid composition of S. paramamosain. This is the first report that the adult S. paramamosain can be effect by the light intensity. The results showed that S. paramamosain has a strong stress response under high light intensity. Compared with darkness condition, digestive enzyme activity was higher under light condition. S. paramamosain reared under low light conditions had enhanced immunity, and it raised in light conditions exhibited superior qualities to those cultured in dark conditions. The results of this study demonstrated that low light levels are most suitable for breeding and improving the quality of S. paramamosain. [ABSTRACT FROM AUTHOR]

Elevated temperatures resulting from climate change are expected to disproportionately affect ectotherms given their biological function has a direct link to environmental temperature. Thus, as climate change leads to rapid increases in water temperatures in rivers, aquatic ectotherms, such as fish may be highly impacted. Organisms can respond to these stressors through flexible and rapid phenotypic change induced via developmental and/or transgenerational plasticity. In oviparous species, gravid females may translate environmental stress across generations via increased exposure of eggs to maternally derived glucocorticoids (i.e., maternal stress), which has been shown to result in diverse phenotypic effects in offspring. Recent studies suggest these phenotypic changes from maternal glucocorticoids may elicit predictive adaptive responses, where offspring exposed to maternal stress may be better prepared for the stressful environment they will encounter (i.e., environmental match hypothesis). We applied the environmental match hypothesis to examine whether a prenatal exogenous increase in egg cortisol may prepare Chinook salmon offspring (Oncorhynchus tshawytscha) to cope with thermal challenges after being reared in chronically elevated temperatures. Specifically, we exposed eggs to aqueous bath of cortisol-dosed (1,000 ng/mL) or control (0 ng/ml) solutions, and then raised both treatments at current (+0°C—contemporary ambient river temperature) or elevated (+3°C—projected future river temperature) thermal regimes. We quantified thermal performance in fish 7–9 month post fertilization using two methods: via critical thermal maximum (CTMax), and energetic responses (in plasma cortisol, glucose, and lactate) to environmentally relevant, but challenging thermal spikes over 3 days. Overall, we found that exposure to elevated rearing temperatures had a large impact on thermal tolerance, where elevated-temperature reared offspring had significantly higher CTMax. In comparison, egg cortisol treatment had little to no clear effects on CTMax and blood energetic response. Our study demonstrates the importance of elevated water temperatures as an inducer of offspring phenotypes (via early developmental cues), and highlights the significance of examining offspring performance in environments with ecologically relevant stressors.

Abstract The main objective of this study was to provide anesthetic criteria of clove oil for an effective manipulation and transportation of red spotted grouper, Epinephelus akaara. When anesthesia temperature (20, 24, and 28 °C) and concentration of clove oil (25, 50, and 75 ppm) were increased, the anesthesia and recovery time decreased and tended to be similar to each other between juvenile and adult. Also, as the temperature and concentration increased, the ratio of exposure time and recovery time between juvenile and adult were decreased. When plasma cortisol concentrations were compared for 48 h after anesthesia with 50 ppm of clove oil, both the juvenile and adult fish grew up to 12 h; however, thereafter decreased and there was no significant difference from control at 48 h.

Aim of the work: to evaluate the effect of intravenous dexmedetomidine infusion on patients undergoing open heart surgery regarding stress response markers as plasma interleukin-6 and plasma cortisol. Patents and Methods: Fifty consecutive patients aged 18-70years, scheduled for elective open heart surgery using CPB technique were enrolled in this study at the Cardiothoracic Surgery Unit, Luxor international hospital, from July 2018 to May 2019. Patients randomly assigned using closed envelope technique into two equal groups according to the drug infused intraoperatively: 1st group < br />(25 patients):- Dexmedetomidine group (Group D); received loading dose of intravenous dexmedetomidine infusion of 1 μg/kg IV dissolved in 20ml normal saline over 10 minutes followed by maintenance dose of 0.5 μg/kg/hr. till the end of surgery where 0.5 μg /kg/h was calculated for each patient and dissolved in 12.5 ml normal saline 2nd group ( 25 patients):- placebo group (Group < br />P); receive 20ml intravenous infusion of normal saline 0.9 % over 10 minutes followed by continuous infusion of 12.5 ml of normal saline till the end of surgery. Results: Our study revealed that HR and MAP wasn’t significantly different between the two groups at the baseline, but significantly lowered in Dex. group after induction, during CPB, post CPB, and postoperative.Dexometomedine suppress the intraoperative and postoperative rise of IL-6 which was significantly higher in placebo group relative to Dex. group. Also dexometomedine has effect on stress hormone as serum cortisol and serum glucose decease in Dex. group relative to placebo group. None of studied cases revealed bradycardia or hypotention and there are no significant difference between groups regarding side effect drowsiness, nausea and vomiting Conclusion: This study demonstrated that the continuous administration of dexmedetomidine during open heart surgery with CPB suppressed intraoperative and post-operative cytokine secretion, and improved post-operative inflammatory response indices in the present study. Also it stabilize blood pressure and heart rate and blunt cardiovascular response to CPB. These results could be attributed to the anti-inflammatory effects of dexmedetomidine.

The anesthetic efficacies of natural anesthetic (clove) in forms of powder were evaluated on young common carp (Cyprinus carpio L.) with the mean weight of 60±10 g for handling and health management experiments. These works were conducted in the laboratory of fish research in the Department of Animal Science, Collage of Agricultural Sciences at University of Sulaimani. Safety concentrations of anesthetics type and concentration were assessed by using form of clove (powder); each with three replicates within each replicate five fish used for measuring induction times to anesthesia. The induction time of C. carpio which decrease with increasing concentrations of clove powder, the induction time was less than three minutes for a dose of 400 mg/L, with significant different (P

The silver pomfret, Pampus argenteus is a major economically important marine fish in China. However, P. argenteus is sensitive to many stress factors and susceptible to injury. This problem could be resolved using anesthesia. We determined the lowest effective dose (LED) of tricaine methanesulfonate (MS‐222) and assessed the longest safe deep anesthesia time and effect after chasing. P. argenteus juveniles were exposed to six concentrations of MS‐222 (10, 25, 50, 75, 100, and 125 mg/L); LED was established at 75 mg/L. The juveniles were exposed to different deep anesthesia times (4, 7, 10, 12, and 15 min) at 75 mg/L; the longest safe deep anesthesia time under LED was 10 min. Finally, the juveniles were randomly divided into four groups: Control (no treatment at all) group (CG), Draining stress without MS‐222 group (DG), draining + chasing stress with MS‐222 (MS + DCG), and draining + chasing stress without MS‐222 (DCG). Plasma cortisol levels in the DCG, MS + DCG, DG, and CG groups were 38.739 ± 1.065 (highest), 25.083 ± 0.587, 28.644 ± 0.612, and 22.620 ± 0.836 ng/ml (lowest). When superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and catalase (CAT) activities of the DCG group were compared with those of the other three groups, a significant increase (p <.05) was observed. However, the DG and MS + DCG groups showed no significant increase (p >.05) in SOD, MDA, GSH, and CAT activities. The MS + DCG group showed significantly (p <.05) higher GSH, SOD, CAT, and MDA activities than the control before stress. Before aquaculture treatment, HSP70, HSP90, GR1, and GR2 mRNA levels showed no significant differences (p >.05), whereas HSP70, HSP90, GR1, and GR2 mRNA levels in the DCG group increased sharply. GR1 and GR2 mRNA levels in the MS + DCG group also increased significantly, whereas HSP70 and HSP90 mRNA levels showed no significant differences. Thus, MS‐222 can reduce oxidative damage, stress reaction, and resistance to aquaculture treatment stresses in P. argenteus. [ABSTRACT FROM AUTHOR]

Fish that display schooling and social behaviors are expected to show stress responses when they are challenged by isolation. Medaka exhibit social behavior in group situations, but little is known about the effects of social isolation on their physiological stress responses. Here, we subjected male medaka to several different housing situations and assessed whether the stress responses differed between grouped and isolated fish. Social isolation decreased plasma cortisol and increased brain serotonin [5-hydroxytryptamine (5-HT)] levels in male medaka irrespective of whether or not the isolated fish could visually perceive another individual. However, heat shock treatment, a grouped situation, and a paired situation increased plasma cortisol and decreased brain 5-HT levels. These results suggest that, in male medaka, physical contact among individuals is more stressful than isolation. Moreover, both grouped and paired fish had lower tryptophan hydroxylase 2 (Tph2) expression levels than isolated fish, whereas heat shock downregulated both Tph1 and Tph2. The present study indicates that, in fish, the magnitude of reduction in brain Tph1 and Tph2 expression levels and serotonin concentration varies with the type of stress. [ABSTRACT FROM AUTHOR]

The cumulative effect of seasonal heat stress and peripartum stress in inducing the seasonal alterations in the plasma cortisol levels was studied in Murrah buffaloes (n = 6) on days ±30, ±15, ±5, ±3, ±1 and 0 prepartum and postpartum with respect to the day of parturition (day 0) in each of the two different seasons (hot-humid and spring). The microclimatic Temperature Humidity Index (THI, mean ± SE) during spring season exhibited thermoneutral conditions (60.10 ± 2.56–72.67 ± 0.65) while that in the hot-humid season showed heat stress. Total cortisol in the plasma as assayed by a modified enzymeimmunoassay developed for buffaloes reflected an increase in cortisol level around parturition (days −1, 0 and +1) in both the seasons. Between the two seasons, the cortisol levels were significantly lower in the hot-humid season on days −5 (p < 0.01), +1 (p < 0.055) and +3 (p < 0.051), which indicated adaptation of buffaloes to thermal environment. Substantial exposure to high THI thus plays a significant role in determining the overall stress as reflected by plasma cortisol in circulation during the peripartum periods in Murrah buffaloes in the tropics. [ABSTRACT FROM AUTHOR]

Highlights • Adrenal sensitivity to ACTH predicts Hair cortisol concentrations in infancy. • Adrenal sensitivity in infancy predicts adult hair cortisol concentrations. • Social stress eliminates the adrenal sensitivity - hair cortisol association. • Hair cortisol was higher in winter and fall than summer and spring. Abstract Hair cortisol concentrations are increasingly being used in both humans and nonhuman animals as a biomarker of chronic stress. However, many details regarding how hair cortisol concentrations relate to the dynamic activity and regulation of the HPA axis are still unknown. The current study explores 1) how the regulation of the HPA axis in infancy relates to hair cortisol concentrations (HCC) in infancy 2) whether this relationship persists into adulthood under conditions of social stability, and 3) how social instability impacts these relationships. All subjects were rhesus monkeys housed in large social groups at the California National Primate Research Center, and all had participated in a 25-hr. long BioBehavioral Assessment (BBA) at 3–4 months of age when four plasma samples were taken to assess HPA regulation, in particular cortisol responses to 1) 2-hour social separation and relocation, 2) sustained challenge, 3) dexamethasone and 4) ACTH administration. In Study 1, hair samples were collected at the end of the BBA testing from 25 infant rhesus monkeys from 2 different stable social groups. In Study 2, hair samples were obtained at three timepoints from 108 adults from 3 different stable social groups (1 in the Spring/Summer and 2 in the Fall/Winter) to examine the temporal stability of the relationship between HCC and HPA axis regulation. In Study 3, subjects included 31 infants and 33 adults from a single social group experiencing social instability following the same procedures as in Studies 1 and 2. Generalized linear models were used to determine if infants' HPA axis activity and regulation predicted HCC in infancy (Study 1), in adulthood with animals living in stable social conditions (Study 2) or in animals living in an unstable social group (Study 3). Results indicated that for both infants and adults living in stable social groups, HCC are associated with the adrenal response to ACTH in infancy. Samples collected in the winter also had higher HCC than those collected in summer. In the unstable social group, adult hair cortisol levels were higher than in the stable social groups. Additionally, there were no consistent relationships between HCC and infant HPA axis regulation among adults or infants living in a group experiencing social instability. These results suggest that the aspects of the HPA axis that drive HCC may differ depending on context. Under stable, non-stressed conditions there seems to be a trait-like association between adrenal responsivity and HCC in infancy and adulthood. However, this association may be reduced or eliminated under conditions of social stress. [ABSTRACT FROM AUTHOR]

Major depression is a highly prevalent mood disorder, affecting about 350 million people, and around 30% of the patients are resistant to currently available antidepressant medications. Recent evidence from a randomized controlled trial (RCT) supports the rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression. The aim of this study was to explore the effect of ayahuasca on plasma cortisol and awakening salivary cortisol response, in the same group of treatment-resistant patients (MD) and in healthy volunteers (C). Subjects received a single dose of ayahuasca or placebo (dosing session), and both plasma and awakening salivary cortisol response were measured at baseline (before dosing session) and 48 h after the dosing session. Baseline assessment (D0) showed blunted awakening salivary cortisol response and hypocortisolemia in patients, with respect to healthy controls. Salivary cortisol was also measured during dosing session, and we observed higher increases for both C and MD that ingested ayahuasca than placebo. After 48 h from the dosing session with ayahuasca, patients' awakening salivary cortisol response is similar to the ones detected in controls. No significant changes in plasma cortisol levels were observed 48 h after the sessions. Therefore, these findings point to new evidence on the modulation of salivary cortisol levels as a result of an ayahuasca session, both in healthy and depressive volunteers. Considering that cortisol acts in regulation of distinct physiological pathways, emotional and cognitive processes, it is assumed to be critically involved to the etiology of depression and its regulation seems to be important for the treatment and remission of major depression, ayahuasca use as antidepressant should be further investigated. Moreover, this study highlights the importance of psychedelics in the treatment of human mental disorders.

Background: there are many determinant factors that may play roles in pathophysiology of functional dyspepsia. One of them is psychological stress that can increase plasma cortisol levels, alter inflammation process and affect Helicobacter pylori activity. No study has been conducted to find out the dominant factor among them. This study aimed to find the dominant factor among plasma cortisol levels, IL-6 and IL-8 expressions and H.Pylori activity, as the determinant factors in the pathophysiology of functional dyspepsia. Methods: a cross-sectional study was conducted in 80 patients with dyspepsia syndrome at M. Djamil General Hospital, Padang, West Sumatera, Indonesia. The patients were categorized into two groups, i.e. the stress and non-stress group, which were identified using DASS 42 questionairre criteria. The inflammatory expressions (IL-6 and IL-8 expressions) as well as H. pylori activity were determined using immunohistochemistry of gastric biopsy specimens; while plasma cortisol levels was measured from peripheral blood samples. Data were analyzed using binary multivariate logistic regression. Results: there were 80 patients with functional dyspepsia with mean age of 38.9 years old. The morning cortisol levels was found significantly higher in the stress group. Higher IL-6 and IL-8 expressions were found in patients of non-stress group compared to those in the other group (IL-6: 73.28 (SD 16.60) vs. 72.95 (SD 19.49; and IL–8: 18.45 (SD 17.32) vs. 14.80 (SD 12.71)); although stastically not significant. There was greater Helicobacter pylori activity in the group with psychological stress compared to those in the non-stress group since there was antigen-antibody reaction invading the submucosa. The dominant determinant factor was the afternoon plasma cortisol levels. Conclusion: many factors can become the determinant factors for gastric mucosal damage; however, our study has demonstrated that the dominant factor is afternoon plasma cortisol levels.

CYP3A phenotyping provides a means for personalized drug therapy. We focused our attention on the plasma 6β-hydroxycortisol (6β-OHF) to cortisol ratio as an index for CYP3A phenotyping. In the present study, we developed a sensitive and reliable method for the simultaneous determination of 6β-OHF and cortisol in human plasma using high-performance liquid chromatography/tandem mass spectrometry together with picolinylester derivatization or nonderivatization methods and 6β-[9,11,12,12-²H4]hydroxycortisol and [1,2,4,19-13C4]cortisol as internal standards for in vivo CYP3A phenotyping in humans. The lower limits of quantification were 38.513 pg/mL for 6β-OHF and 38.100 pg/mL for cortisol. The relative error and relative standard deviation of the lower limits of quantification were <5% for both methods. The intraday and inter-day assay reproducibilities of the determined 6β-OHF and cortisol concentrations were consistent with the actual amounts added as relative errors and relative standard deviations for both methods, which were <5.4% and <3.9%, respectively. Both methods were applied for the quantification of plasma 6β-OHF and cortisol concentrations in healthy subjects taking oral contraceptives. The absolute concentrations and time course of 6β-OHF and cortisol were found to be consistent when measured using the 2 methods. The ratio as an index for in vivo CYP3A activity decreased after 21 days of taking oral contraceptives for both methods. To the best of our knowledge, this is the first study reporting the detailed investigation of accuracy and precision in the simultaneous measurement of 6β-OHF and cortisol in human plasma using liquid chromatography/tandem mass spectrometry coupled with stable isotope dilution method, which can be applied to CYP3A phenotyping. [ABSTRACT FROM AUTHOR]

Background: Hypertension is a major risk factor for cardiovascular diseases, one of the leading causes of death worldwide. Prehypertension is a precursor of hypertension, with high prevalence in young adults. Psychosocial stress can be one of the modifiable risk factors for hypertension. The objective of the study is to assess the relationship between coping mechanism to psychosocial stress and the blood pressure of young adults. Methods: A comparative crosssectional pilot study was conducted in 36 young adults aged less than 45 years. The pulse rate, blood pressure and body mass index of the respondents were recorded. Psychosocial stress was measured by plasma cortisol following an acute mental stress test; and the level of stress and the coping strategies to stress were assessed using validated Malay Version questionnaires: DASS-21 and Brief R-COPE questionnaires. Results: Forty four percent of subjects had normotension and fifty six percent had above-normal blood pressure (prehypertension and mild hypertension). Subjects with above-normal blood pressure were associated with high plasma cortisol levels (p = 0.032), and high body mass indexes (BMI) (p = 0.004). Maladaptive coping strategy was found to be associated with high stress scores (p = 0.019). The relationship between stress and cortisol was not significant, though a higher cortisol level was noted in the high blood pressure group. Conclusion: In conclusion, higher cortisol levels and greater BMIs were associated with above-normal blood pressure in young adults. These findings are useful for future research in this area, and the continuation of this study will hopefully yield a more significant relationship. [ABSTRACT FROM AUTHOR]

Major depression is a highly prevalent mood disorder, affecting about 350 million people, and around 30% of the patients are resistant to currently available antidepressant medications. Recent evidence from a randomized controlled trial (RCT) supports the rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression. The aim of this study was to explore the effect of ayahuasca on plasma cortisol and awakening salivary cortisol response, in the same group of treatment-resistant patients (MD) and in healthy volunteers (C). Subjects received a single dose of ayahuasca or placebo (dosing session), and both plasma and awakening salivary cortisol response were measured at baseline (before dosing session) and 48 h after the dosing session. Baseline assessment (D0) showed blunted awakening salivary cortisol response and hypocortisolemia in patients, with respect to healthy controls. Salivary cortisol was also measured during dosing session, and we observed higher increases for both C andMD that ingested ayahuasca than placebo. After 48 h fromthe dosing session with ayahuasca, patients' awakening salivary cortisol response is similar to the ones detected in controls. No significant changes in plasma cortisol levels were observed 48 h after the sessions. Therefore, these findings point to new evidence on the modulation of salivary cortisol levels as a result of an ayahuasca session, both in healthy and depressive volunteers. Considering that cortisol acts in regulation of distinct physiological pathways, emotional and cognitive processes, it is assumed to be critically involved to the etiology of depression and its regulation seems to be important for the treatment and remission of major depression, ayahuasca use as antidepressant should be further investigated. Moreover, this study highlights the importance of psychedelics in the treatment of human mental disorders. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of heat stress and month of birth on growth performance, pelleted starter intake, and stress-related hormones in Holstein calves. Birth weight and growth records, representing 4735 Holstein calves from a large commercial dairy herd in northern Mexico (25° N; 22.3 °C mean annual temperature) from 2013 to 2015, were analyzed. Temperature-humidity index (THI) at calving, season of birth, and month of birth were the independent variables, whereas growth traits were the dependent variables. Increased THI at birth from < 65 to > 85 units was associated with a decrease in birth weight from 39.3 to 38.7 kg. Calves subjected to high THI (> 75 units) at calving showed lesser (P < 0.01) pre-weaning gains (405 ± 97 g/calf/day), whereas those calves born with THI < 70 units presented the highest gains (466 ± 112 g/calf/day). Birth during the fall months reduced (P < 0.01) weaning weight by about 5 kg compared with winter months. Also, the pre-weaning average daily gain for calves born in the fall was about 70 g less (P < 0.01) than calves delivered in winter months. Plasma triiodothyronine and tetraiodothyronine levels were lower (1.02 ± 0.21 and 48 ± 7.9 ng/mL, respectively; P < 0.01) in summer and highest in winter (1.64 ± 0.48 and 66 ± 11 ng/mL, respectively). Mean plasma cortisol concentration was higher in heat-stressed calves born in summer (59 ± 40 ng/mL) than calves born in winter (20 ± 28 ng/mL). Pelleted starter intake 1 week before weaning was lowest (P < 0.01) in the fall (0.82 ± 0.26 kg/calf/day; mean ± SD) and highest in spring (1.26 ± 0.43 kg/calf/day). It was concluded that in this particular environment, heat stress affects birth weight and growth rate of Holstein calves. Thus, environmental management of the newborn calf during hot spring and summer months is warranted to optimize pelleted starter intake and calf growth rates. [ABSTRACT FROM AUTHOR]

Our goals were: (i) to determine whether sublethal concentrations of water-borne ammonia would prevent the formation of a dominance hierarchy, or alter its structure, in groups of 4 juvenile trout; (ii) to investigate the behavioral and physiological responses of individuals of different social rank exposed to a concentration of ammonia that still allowed hierarchy formation. Social hierarchies were created by using a technique in which a food delivery system that created competition also served to isolate individual fish for respirometry. Groups of 4 fish were exposed to elevated ammonia (NH 4 HCO 3 ) 12 h before first feeding; aggression was recorded by video camera during morning feedings. Experimental ammonia concentrations were 700, 1200 and 1500 μmol L −1 at pH 7.3, 12 °C (9.8, 16.8, and 21.0 mg L −1 as total ammonia-N, or 0.0515, 0.0884, and 0.1105 mg L −1 as NH 3 -N). Aggression was severely reduced by 1200 and abolished by 1500 μmol L −1 total ammonia, such that hierarchies did not form. However, groups exposed to 700 μmol L −1 total ammonia still formed stable hierarchies but displayed lower levels of aggression in comparison to control hierarchies. Exposure continued for 11 days. Physiological parameters were recorded on day 5 (end of period 1) and day 10 (end of period 2), while feeding and plasma cortisol were measured on day 11. In control hierarchies, dominant (rank 1) trout generally exhibited higher growth rates, greater increases in condition factor, higher food consumption, and lower cortisol levels than did fish of ranks 2, 3, and 4. In comparison to controls, the 700 μmol L −1 total ammonia hierarchies generally displayed lower growth, lower condition factor increases, lower O 2 consumption, lower cortisol levels, but similar feeding patterns, with smaller physiological differences amongst ranks during period 1. Effects attenuated during period 2, as aggression and physiological measures returned towards control levels, indicating both behavioral and physiological acclimation to ammonia. These disturbances in social behavior and associated physiology occurred at an ammonia concentration in the range of regulatory significance and relevance to aquaculture. [ABSTRACT FROM AUTHOR]