Cortisol determination in hair and faeces from domestic cats and dogs

Evaluation of chronic stress status and quality of life in cats suffering from chronic kidney disease and suspected feline infectious peritonitis based on hair cortisol concentration analysis and a questionnaire

Hair cortisol concentration (HCC) and a questionnaire were used as indicators of chronic stress status and quality of life (QoL), respectively, in cats. To date, there has been limited research on the simultaneous application of both indicators in unwell cats. Our aim was to evaluate HCC and questionnaire data obtained from a healthy cat cohort (n = 61) and cat cohorts with either chronic kidney disease (CKD) (n = 78) or suspected feline infectious peritonitis (FIP) (n = 24). Furthermore, we also investigated the correlation between HCC and clinical pathological data. For this study, hair from the abdomen of cats was collected and analyzed for HCC using a commercial ELISA kit. Owners also completed a questionnaire, from which average-item-weighted-impact-scores (AWISs) were calculated. Cats with late-stage-CKD (median, HCC = 330.15 pg/mg, AWIS = -0.43) presented with a significantly higher HCC (p < 0.01) and a significantly lower AWIS (p < 0.01) than cats with early-stage-CKD (HCC = 183.56 pg/mg, AWIS = 1.08). Similarly, there were significant differences in both HCC (p < 0.001) and AWIS (p < 0.001) between cats with suspected FIP (HCC = 896.27 pg/mg, AWIS = -1.97) and healthy cats (HCC = 181.24 pg/mg, AWIS = 1.24). The degree of consistency between the HCC results and the questionnaire results reminds us that the severity of a chronic disease or the presence of a life-threatening disease can significantly increase stress and thus can affect the QoL of cats.

Changes in cortisol, cortisone and 11β-hydroxysteroid dehydrogenase type II activity in saliva during pregnancy and lactation in sows

The activity of the enzyme 11β-hydroxysteroid dehydrogenase type II (11β-HSD type II), which can be estimated by the combined measurement of cortisol and cortisone, is gaining importance as a marker for the assessment of stress in pigs. The aim of this study was to investigate the activity of this enzyme and the salivary concentrations of cortisol and cortisone in pigs during pregnancy, farrowing and lactation and to compare it with other stress-related biomarkers such as Chromogranin A (CgA), S100A12 and alpha-amylase. Salivary cortisone concentrations and 11β-HSD type II activity decreased after farrowing, while cortisol concentrations increased. Enzyme activity did not show significant correlations with any of the other stress-related biomarkers measured in this study. Overall, the results of this report indicate a different regulation of 11β-HSD type II activity and of cortisol and cortisone during pregnancy and lactation, which should be considered when evaluating these analytes in saliva during these periods.

Hair cortisol concentrations in clipped and combed hair and associations with characteristics, health status and stress in domestic cats

Hair cortisol concentrations (HCC) are measured to assess long-term HPA-axis activity and may represent a valuable non-invasive tool to evaluate chronic stress in cats. This study investigated combing as a novel, low-stress method for HCC assessment, as well as possible associations between HCC and cat characteristics in 167 owned cats. Hair was sampled at veterinary clinics through clipping and/or combing the cat, or at home by the owner combing the cat. A questionnaire was sent to cat owners, including inquiries about the cat's sex, health status, and exposure to stress. HCC was quantified using a commercial cortisol assay kit. Despite variations within and between sampling methods, Spearman's correlation and Bland-Altman plots revealed a moderate correlation between clipped and combed samples (rs = 0.61, LOA -5.51 ± 22.54). In multiple linear regression, variations in HCC were observed based on sex, health status and cat group size. No associations were found between HCC and stress as assessed by owners. Despite study limitations and remaining uncertainty regarding factors influencing HCC, combing presents a convenient approach for evaluating long-term HPA-axis activity in clinical settings. The association between health and HCC suggests alterations in cortisol levels that are related to disease processes and stress-inducing events associated with the disease.

Faecal Glucocorticoid Metabolites and Hair Cortisone/Cortisol Measurements in Domestic Pigs Exposed to Road Transportation and Dexamethasone Treatment

Pig homeostasis is challenged by stressful production practices, like road transportation. Glucocorticoids (GCs) are mediators of reactive homeostasis, and their concentrations are frequently used as a stress indicator. The adrenocortical activity of fattening female and castrated male pigs was monitored over a 5-day longitudinal study. A bi-factorial experimental design was applied on day 2; 18 pigs in pen 1 were transported for 3 h (T; 1.2 m2/pig), and 18 pigs were kept in pen 2 (NT). Ten pigs from each pen were treated with dexamethasone (T-D or NT-D), and eight with saline solution (T-SS or NT-SS). Adrenocortical activity was assessed by measuring the levels of faecal glucocorticoid metabolites (FGMs) and hair cortisol and cortisone. In T-SS pigs, the level of FGMs was higher after transportation than in NT-SS pigs. The level of FGMs of T-D pigs initially increased but then reached similar levels to those of NT-SS sooner than T-SS. In contrast, hair cortisol and cortisone did not respond to the treatments. Nevertheless, the hair cortisone/cortisol ratio increased due to transport and decreased after dexamethasone administration. Daily faecal sampling proved still more reliable than 60-day hair sampling for assessing adrenocortical activity. Transported pigs recovered their adrenocortical baseline levels within 24 h. Dexamethasone attenuated the response to transport.

Comparison of the Efficacy and Welfare of Different Training Methods in Stopping Chasing Behavior in Dogs

Controversy surrounds the efficacy and welfare implications of different forms of dog training with several studies asserting that electronic shock collars have negative welfare impacts while not being more effective than non-aversive methods. However, these studies did not specify the schedule and intensity of punishment used or the effectiveness of the training method. In the current study, we attempted to train dogs across six sessions to desist from chasing a fast-moving lure in one of three randomly assigned conditions and then tested for retention and generalization in four further test trials. Group A was trained with e-collars; Group B was trained with non-aversive methods and the lure moving as with Group A; and Group C was trained as for Group B but with the lure initially moving slowly before its speed was progressively increased. All dogs in Group A stopped running towards the lure after one or two sessions, and none chased the lure in the first three tests: 67% of these dogs chased the lure in the final test in a novel arena. None of the dogs in the either Group B or C successfully refrained from chasing the moving lure in training or any test. Video behavior coding indicated few stress-related behaviors across the training groups.

Assessing the effectiveness of cannabidiol additive supplementation on canine behavior and cortisol levels

In veterinary medicine, Cannabis has been used to treat pain conditions, inflammation, and seizures. However, little is known about its effect on dogs' behavior. This preliminary research aims to address this knowledge gap by evaluating the effectiveness of cannabidiol (CBD) oil in canine behavioral therapy. Twenty dogs, diagnosed with behavioral disorders and housed in a municipal shelter, participated in a double-blind trial. Ten dogs received CBD oil treatment, while the other ten received a control oil without CBD. Before (T0) and after (T1) the treatment, all the dogs underwent a temperament test to assess their behavior in the presence of four different stimuli: a human stranger, a novel object, a child-like doll, and a conspecific (another dog). Each stimulus was presented individually, and the dogs' behaviors were recorded on video and analyzed. Additionally, hair samples were collected using a shave-reshave technique for cortisol determination through Radio-Immuno-Assay. No behavioral differences were found between the two groups at both T0 and T1. There were no significant differences in the behavioral responses of either group when comparing T0 and T1. However, individual responses to the CBD oil treatment appeared to vary among subjects. A significant increase in hair cortisol levels (p-value <0.05) was observed in the group treated with CBD oil [T0 = 1.60 (1.44-1.93) pg/mg, T1 = 4.81(2.57-6.01) pg/mg]. These findings highlight the importance of individualized treatment when using Cannabis and encourage further research on the use of CBD oil in animal behavioral medicine.

The Impact of Environmental Enrichment on the Cortisol Level of Shelter Cats

Enriching cats' living environment in shelters is crucial in reducing their stress. Easier access to resources allows cats to display natural behavior. This study aimed to assess whether cats staying in an enriched environment would be less stressed than cats staying in a standard environment. The first group consisted of cats living in an environment with fewer resources (standard environment)-103 cats. The second group consisted of cats living in an enriched environment-76 cats. The research material consisted of hair collected to determine the cortisol level. The results indicate that cats from a more enriched environment have almost half the level of cortisol in hair than cats from an environment with fewer resources (0.059 ng/mg vs. 0.101 ng/mg; p = 0.000001).

The influence of selected factors on wool cortisol concentration in alpacas (Vicugna pacos)

Several internal and external factors can influence animals' hormonal activity. Cortisol level in hair and wool determines chronic stress, which is connected with the long-term HPA axis effect. Wool cortisol levels in alpacas have never been determined to this time. The study aimed to assess the influence of selected factors on wool cortisol concentration in alpacas. The study included 36 alpacas. Wool samples were collected during shearing in June 2021, cut with an electric clipper from the right shoulder and the rump. Wool samples were fragmented into proximal (winter-spring regrowth) and distal (summer-fall regrowth) segments. Alpacas' Heat Stress Index (HSI) for the summer of 2020 was 139.4, and 116 for the winter of 2021. The cortisol levels in the wool samples were determined with the General Cortisol ELISA Kit assay. The most significant differences in wool cortisol concentrations were caused by two factors: the wool segment (P < 0.001; η2 = 0.889) and the region on the body (P < 0.001; η2 = 0.876). Wool cortisol level was higher in the distal segment (referring to the summer-fall season) than in the proximal one (referring to the winter-spring season). It is suggested that alpacas can feel heat stress in summer (HSI = 139.4), which could influence higher cortisol levels in the distal segment. The wool cortisol level was higher in the rump samples than the shoulder ones. Therefore, it is essential in future studies that wool samples from all tested animals should be completed from the same body region. Differences among age and sex groups were also observed. Wool cortisol level was higher in older animals, as differences between age groups were observed in samples from the rump in the distal and proximal segments (distal, the rump younger*older: P < 0.001; η2 = 0.321; proximal, the rump older*younger: P = 0.007; η2 = 0.195). Males showed higher cortisol levels than females, as a difference between sexes was observed in samples from the rump in the proximal segment (P = 0.001, η2 = 0.271). This study emphasizes that various factors may significantly influence wool cortisol levels, which can be helpful in alpacas' welfare estimation using this hormonal indicator as a noninvasive long-term stress assessment method.

Investigation of Climate Effects on the Physiological Parameters of Dairy Livestock (Cow vs. Buffalo)

Nowadays climate change is affecting the planet's biodiversity, and livestock practices must adapt themselves to improve production without affecting animal welfare. This work investigates the influence that some climatic parameters such as Environment Temperature, Relative Humidity, Thermal excursion and Temperature-Humidity Index (THI), can have on milk quantity and quality in two different dairy species (buffaloes and cows) raised on the same farm. A further aim was to understand if THI threshold used for cows could also be used for buffaloes. The climatic parameters were recorded daily through a meteorological station located inside the farm. Milk quantity (converted into ECM) and quality (Fat Percentage-FP; Protein Percentage-PP; Somatic Cell Count-SCC) were measured. Data were analyzed with Spearman's correlation index, separately for buffaloes and cows. The results indicate a greater sensitivity of cows to heat stress and a strong negative correlation of the ECM with meteorological data (p < 0.01). The results of this study may stimulate the use of integrated technologies (sensors, software) in the dairy sector, since the IoT (sensors, software) helps to enhance animal well-being and to optimize process costs, with a precision livestock farming approach.

A matter of age? How age affects the adaptation of lactating dairy cows to virtual fencing

Virtual Fencing (VF) can be a helpful technology in managing herds in pasture-based systems. In VF systems, animals wear a VF collar using global positioning, and physical boundaries are replaced by virtual ones. The Nofence (Nofence AS, Batnfjordsøra, Norway) collars used in this study emit an acoustic warning when an animal approaches the virtual boundaries, followed by an aversive electrical pulse if the animal does not return to the defined area. The stimuli sequence is repeated up to three times if the animal continues to walk forward. Although it has been demonstrated that animals successfully learn to adapt to the system, it is unknown if this adaptation changes with animal age and thus has consequences for VF training and animal welfare. This study compared the ability of younger and older dairy cows to adapt to a VF system and whether age affected activity behavior, milk yield, and animal long-term stress under VF management. The study was conducted on four comparable strip-grazing paddocks. Twenty lactating Holstein-Friesian cows, divided into four groups of five animals each, were equipped with VF collars and pedometers. Groups differed in age: two groups of older cows (>4 lactations) and two groups of younger ones (first lactation). After a 7-d training, paddock sizes were increased by successively moving the virtual fence during four consecutive grazing periods. Throughout the study, the pedometers recorded daily step count, time spent standing, and time spent lying. For the determination of long-term stress, hair samples were collected on the first and last day of the trial and the hair cortisol content was assessed. Data were analyzed by generalized mixed-effect models. Overall, age had no significant impact on animal responses to VF, but there were interaction effects of time: the number of acoustic warnings in the last period was higher in younger cows (P < 0.001), and the duration of acoustic warnings at training was shorter for older cows (P < 0.01). Moreover, younger cows walked more per day during the training (P < 0.01). Finally, no effects on milk yield or hair cortisol content were detected. In conclusion, all cows, regardless of age, adapted rapidly to the VF system without compromising their welfare according to the indicators measured.

Behavioral activity patterns but not hair cortisol concentrations explain steers' transition-related stress in the first 6 wk in the feedlot

Stress during the transition of beef steers from ranch to feedlot may depend on steer source and preconditioning. The interplay between physiological and behavioral patterns of preconditioned (PC) and auction-derived (AD) steers, particularly after commingling, is poorly understood. Our objective was to evaluate whether hair cortisol (HC) concentrations were related to the health and performance of PC and AD steers and study behavioral activities after commingling over 6 wk in a feedlot. Steers, sourced either from ranch (PC, n = 250) or local auction (AD, n = 250), were assigned into 1 of 5 pens, 100% PC (100PC); 75% PC 25% AD (75PC); 50% PC 50% AD (50PC); 25% PC 75% AD (25PC), and 100% AD (0PC), each pen containing 100 steers. Pen was the experimental unit and individual steers were the observational unit where physiological and behavioral changes were measured. The study subsampled 225 steers (PC = 113 and AD = 112) which were equipped with CowManager ear tags to record behaviors. On day 40, hair samples from each steer were collected by clipping hair close to the skin. Data were analyzed using multiple linear, logistic regression, or multilevel negative binomial regression models depending on the outcomes. There was no difference in HC concentrations (day 40) between PC and AD steers (P = 0.66), and no association with Bovine Respiratory Disease (BRD)-related morbidity (P = 0.08) or average daily gain (ADG) (P = 0.44). After adjusting for source and commingling effects, HC concentrations did not affect time spent eating (P = 0.83), ruminating (P = 0.20), active (P = 0.89), or non-active (P = 0.32). PC steers spent more time eating and ruminating over weeks 1 to 4 (P < 0.01) and weeks 1 to 3, respectively (P < 0.05), and more time being active over weeks 1 and 2 compared to AD steers (P < 0.001), but less time being non-active than AD steers on weeks 1 to 3 (P < 0.001). Steers in 100PC and 50PC pens spent more time eating than steers in 0PC (P < 0.001), whereas steers in 25PC spent less time eating than steers in 0PC (P < 0.001). Steers in 0PC spent the most time being not active (P < 0.01). In conclusion, preconditioned steers spent more time eating, ruminating, and being active and less time being not active over the first 3 wk in the feedlot, regardless of commingling. The HC concentrations did not identify potentially lower stress related to ranch transfer and were neither associated with BRD-related morbidity nor ADG.

Hair cortisol levels in cats with and without behavioural problems

OBJECTIVES

The aim of the study was to analyse hair cortisol levels in cats whose owners had reported behavioural problems and undesirable behaviour. In addition, feline hair cortisol levels were compared between sexes, for indoor and outdoor cats and also for cats living in single or multi-cat households.

METHODS

In total, 55 cats participated in the study, including 31 females and 24 males from various households. The cats belonged to 25 different owners who answered a questionnaire survey. The biological material used for the research were 2-3 cm fragments of hair removed at the level of the skin with scissors by the owners from the cats' lumbosacral area. The cortisol concentration in the samples was determined with the DRG Salivary Cortisol HS ELISA. Statistical analysis of the results was performed with Statistica 13.3.

RESULTS

A tendency toward lower cortisol levels was found in outdoor cats vs indoor cats (U = 251.5, P = 0.066). It was also found that the cats exhibiting behavioural problems (eg, house soiling [eliminating outside the litter box]) or aggressive behaviour towards household members had statistically significantly higher hair cortisol levels (U = 162.0 [P = 0.027] and U = 9.0 [P = 0.040], respectively).

CONCLUSIONS AND RELEVANCE

High levels of stress in cats can affect their interactions with other cats and with humans. The incidence of undesirable behaviour was observed more frequently in indoor cats. Significantly higher cortisol levels were found in cats that eliminated outside the litter box or that showed aggression towards their owners.

Coat, Claw and Dewclaw 17-β-Estradiol and Testosterone Concentrations in Male and Female Postpubertal Cats: Preliminary Results

In the recent past, tissue materials such as hair/coat and nails/claws have proved to be useful for the study of long-term hormonal changes in humans and animals and shown to be advantageous in terms of being collectable without invasiveness, with a benefit in terms of animal welfare. However, studies using these tissue materials in cats are scarce, especially on sexual hormone measurement. In this study, the concentrations of 17-β-estradiol (E2) and testosterone (T) were assessed in 20 male and 18 female domestic postpubertal cats at the time of neutering/spaying during the breeding season. Hormones were measured in coat shaved from the forearm (ACOAT) and from the surgical area (SCOAT); claws were collected from the forearms (CLAWS) and the dewclaws (DCLAWS). Although all these tissue materials were shown to be useful for E2 and T long-term measurement, only T concentrations were higher (p < 0.001) in males from both ACOAT and SCOAT samples when compared to females and therefore useful for distinguishing between the two sexes. Within each sex, E2 and T concentrations can be assessed on coat, but also on the dewclaws, providing an alternative, practical, matrix for sexual steroid measurement in postpubertal cats during the breeding season.

Different Types of Glucocorticoids to Evaluate Stress and Welfare in Animals and Humans: General Concepts and Examples of Combined Use

The main glucocorticoids involved in the stress response are cortisol and cortisone in most mammals and corticosterone in birds and rodents. Therefore, these analytes are currently the biomarkers more frequently used to evaluate the physiological response to a stressful situation. In addition, "total glucocorticoids", which refers to the quantification of various glucocorticoids by immunoassays showing cross-reactivity with different types of glucocorticoids or related metabolites, can be measured. In this review, we describe the characteristics of the main glucocorticoids used to assess stress, as well as the main techniques and samples used for their quantification. In addition, we analyse the studies where at least two of the main glucocorticoids were measured in combination. Overall, this review points out the different behaviours of the main glucocorticoids, depending on the animal species and stressful stimuli, and shows the potential advantages that the measurement of at least two different glucocorticoid types can have for evaluating welfare.

Stress in wildlife: comparison of the stress response among domestic, captive, and free-ranging animals

The stress response, which involves joint activity of the nervous and endocrine systems, is one of the basic adaptive mechanisms that ensures the survival of the individual. The activation of the sympathetic nervous system, the sympathetic-adrenal-medullary axis, and the hypothalamic-pituitary-adrenal axis enables organisms to respond to endogenous and exogenous challenges. Repeated short-term stress leads to long-term stress, which disrupts physiological homeostasis. Unlike domestic animals, wild animals are not protected from environmental and weather influences or treated for diseases. In addition, climate change, habitat fragmentation and loss, and urban stressors (such as light, noise and chemical pollution; xenobiotics; traffic; and buildings) affect individual wildlife and populations. In this review, we have attempted to depict the magnitude of the stress response in wildlife and related domestic animals as well as in captive and free-ranging animals. The intensity of the stress response can be estimated by determining the concentration of glucocorticoids in body fluids, tissues, and excreta. A comparison of results from different studies suggests that domestic animals have lower fecal and hair glucocorticoid concentrations than related wild animals. Additionally, fecal and hair glucocorticoid concentrations in captive animals are higher than in free-ranging animals of the same species. As there are limited data on this topic, we cannot draw definitive conclusions about glucocorticoid concentration and stress response. Further studies are needed to clarify these issues.

Hair and Claw Dehydroepiandrosterone Concentrations in Newborn Puppies Spontaneously Dead within 30 Days of Age

The latest intrauterine fetal developmental stage and the neonatal period represent the most challenging phases for mammalian offspring. Toward the term of pregnancy, during parturition, and after birth, the hypothalamic−pituitary−adrenal axis (HPA) is a key system regulating several physiologic processes, through the production of cortisol and dehydroepiandrosterone (DHEA). This study was aimed to assess DHEA concentrations in hair and claws of 126 spontaneously dead newborn puppies, classified as premature puppies (PRE-P), stillborn puppies (STILL-P) and puppies that died from the 1st to the 30th day of life (NEON-P). The possible influence of newborn sex, breed body size, and timing of death on DHEA concentrations in both matrices was evaluated. Claw DHEA concentrations were higher in the PRE-P group when compared to STILL-P and NEON-P puppies (p < 0.05), whilst no significant differences were found in hair for all the studied factors. The results confirm the hypothesis that higher amounts of DHEA are produced during the intrauterine life in dogs, also in puppies that will die soon after birth.

Stress Concepts and Applications in Various Matrices with a Focus on Hair Cortisol and Analytical Methods

When studying stress in animals, it is important to understand the types of stress and their classification, and how to assess the stress levels in different animal species using different matrices accurately and precisely. The classification of stress types helps to distinguish between good stress (eustress) and bad stress (distress). Hence, first, it is crucial to assess the animal's level of stress in a non-intrusive manner and second to identify the type of stress that is best suited to its environment. Third, it is also important to analyze the obtained samples using a suitable method to increase the validity of stress hormone measurements. Therefore, in this review, we aim to: (1) explain the classification of stress, (2) discuss the wide range of body matrices (e.g., saliva, milk, hair, urine, feces, sweat, fins, etc.) that can be used as samples to evaluate stress levels, as well as their comparisons and limitations, and present the reliable matrices for measuring stress hormones with special emphasis on hair, (3) compare the analytical methods for measuring stress hormones after sample preparation. Despite some literature that does not include hair as a reliable matrix for evaluating stress levels, hair is one of the matrices for measuring long-term stress hormone accumulations. This review discusses some factors that influence the level of stress hormones in the hair. By understanding these issues, the scientific community will not only be able to improve the understanding of stress and biomarker evaluation but also suggest how to deal with the consequences of stress in future research.

Limitations of Spatial Judgment Bias Test Application in Horses (Equus ferus caballus)

Affective states are of increasing interest in the assessment of animal welfare. This research aimed to evaluate the possible limitations in the application of a spatial judgment bias test (JBT) in horses, considering the influence of stress level, personality traits, and the possible bias due to the test structure itself. The distinction between two positions, one rewarded (Positive) and the other not (Negative), was learned by 10 horses and 4 ponies,. Then, the latency to reach three unrewarded ambiguous positions (Near Positive, Middle, Near Negative) was measured. Furthermore, the validated Equine Behavior Assessment and Research Questionnaire (E-BARQ) was employed to assess personality traits. Fecal and hair cortisol levels were measured through radioimmunoassay (RIA), and the frequency of behavioral stress indicators was recorded. Results showed that horses that had the rewarded position (Positive) on the right approached Near Negative and Middle faster than those that had Positive on the left. Certain personality traits influenced the latency to reach Middle and Near Positive, but chronic stress did not seem to affect horses' judgment bias. This preliminary study highlighted several limitations in the employment of spatial JBT for the assessment of affective state in horses and that personality traits can partially influence the cognitive process. Further research is needed to refine the use of this test in horses, considering the peculiarities both of species and of individuals.

Application of Felid Hair for Non-Invasive Tracking of Animal Reproductive Status and Adrenal Activity

Hair can be a useful matrix to examine the hormonal status of an animal, although it is difficult to correlate the results to a specific time point. The aim of this study was to evaluate seasonal changes in cortisol and testosterone levels in the hair of four feline species (lynx, Lynx lynx, n = 8; Amur wildcat, Prionailurus bengalensis euptilurus, n = 8; caracal, Caracal caracal, n = 6 and domestic cat, Felis catus, n = 17) with different breeding strategies. Animals of both sexes were sampled over the year, once per season (every three months), and the concentrations of hair testosterone and cortisol were measured by EIA. Both hormones showed annual dynamic changes, which coincided with the reproductive seasonality of the studied species. Sexual differences in testosterone level were found only during the mating season (spring for lynx and Amur wildcats, spring-summer for domestic cats), when testosterone levels were higher in males than in females. Cortisol levels were higher in males than in females in domestic cats and Amur wildcat, but also only during the mating season. Seasonal increases in testosterone were observed in three seasonal breeders (lynx, Amur wildcat and domestic cat) but not in caracal, which had high testosterone levels over the whole year. In lynx and Amur wildcat, it decreased sharply in the summer. Cortisol levels increased during the mating period in domestic cat males and lynx of both sexes; in caracal, an increase in cortisol was related to the transfer of animals to smaller winter cages. Measurements of steroids in hair can provide a reliable method for evaluating the reproductive status and the activity of the hypothalamus-pituitary-adrenal axis in several felid species.

Effects of Saccharomyces boulardii Supplementation on Nutritional Status, Fecal Parameters, Microbiota, and Mycobiota in Breeding Adult Dogs

Simple Summary

The aim of this study was to evaluate the effect of the administration of Saccharomyces boulardii on the nutritional, immunological, inflammatory, stress status, and the gut composition in 25 healthy adult American Staffordshire Terrier dogs. Supplementation with S. boulardii significantly improved the intestinal status and induced a reduction of stress, a common condition affecting animals managed in a breeding environment.

Abstract

The aim of this study was to evaluate the effect of the administration of Saccharomyces boulardii on the nutritional, immunological, inflammatory, and stress status and on the composition of the gut microbiota and mycobiota in healthy adult dogs. A total of 25 American Staffordshire Terrier dogs were selected and randomly assigned to two groups: control (CTR, n = 12) and treated (TRT, n = 13) groups. No significant differences were found between the two groups regarding body weight, body condition score, and fecal score. No significant differences in microbiota/mycobiota, short chain fatty acids, indole/skatole, histamine, zonulin, or lactoferrin were detected. Indeed, supplementation with S. boulardii significantly decreased fecal calprotectin Immunoglobulin A, indicating an improvement in the gut well-being. Interestingly, fecal cortisol significantly decreased in dogs belonging to the TRT group compared to the CTR, suggesting both an improvement of the intestinal status and a reduction of stress, a common condition affecting animals managed in a breeding environment.

Are Hair Cortisol Levels of Humans, Cats, and Dogs from the Same Household Correlated?

Simple Summary

Dogs and cats are animals that have been accompanying humans for many years. There is no doubt that they are emotionally connected with people, although each of them in their own way. The study attempts to assess the emotional relationship between humans, dogs, and cats living in one household on the basis of the correlations between the hair cortisol level. The study involved 25 women who had at least one dog and at least one cat at home. Based on the study conducted, no significant correlation was found between the level of cortisol in the hair of the owners and their pets. There were, however, some interesting differences depending on the degree of emotional connection and the frequency of interactions.

Abstract

Human–animal interactions and the emotional relationship of the owner with the pet are the subjects of many scientific studies and the constant interest of not only scientists but also pet owners. The aim of this study was to determine and compare the hair cortisol levels of dogs, cats, and their owners living in the same household. The owners were asked to complete a questionnaire concerning the frequency of their interactions with pets and emotional relationship with each of their cats and each of their dogs. The study involved 25 women who owned at least one dog and at least one cat. In total, 45 dogs and 55 cats from 25 households participated in the study. The average level of hair cortisol of the owners was 4.62 ng/mL, of the dogs 0.26 ng/mL, and in the hair of cats 0.45 ng/mL. There was no significant correlation between the hair cortisol level of the owner and dog or the owner and the cat and between dogs and cats living together. A significant positive correlation was observed between the hair cortisol level in the owner and the pet, for dogs in which the owner performs grooming treatments once a week and for cats which are never kissed. Although our study did not find many significant correlations, studies using other stress markers might have yielded different results.

Assessment of blood and productive parameters in mid-lactation dairy cows fed different diets: replacement of corn silage with triticale silage

Corn crops require large amounts of resources that affect the environmental sustainability of dairy cow farming systems. The aim of the study was thus to investigate the effects of the replacement of corn silage (CS) with triticale silage (TS) by evaluating blood and productive parameters. The study lasted 7 weeks and involved two groups of 20 Italian Holstein Friesian dairy cows that were homogeneous in terms of parity (3±1.5), days in milk (DIM) (150±85.0), and daily milk production (26±4.6 kg).

Chemical analysis of feeds was carried out weekly. Dry-matter intake was estimated daily. At the beginning and end of the trial, haematological, metabolic, and immunological parameters were analysed. At the same, time body weight and body condition score were measured. Milk characteristics were also analysed weekly. Statistical analysis was performed by ANOVA on data of the second sampling, and a non-parametric test was performed to analyse BCS.

Regarding the haematological parameters in the two groups, only lymphocyte values were not in the normal range (2.86 and 2.50×109 L for CS and TS, respectively). Metabolic parameters were in the normal range except for blood ureic nitrogen (BUN; 13.65 and 14.04 mgdL-1), non-esterified fatty acids (NEFAs; 21.40 and 31.93 µmolL-1), and Cl (91.99 and 93.50 mmolL-1). Hair cortisol was low (0.94 and 0.91 pgmg-1), indicating the absence of stress signs, as confirmed by the results of other immunological parameters (serum lysozyme (SL), bactericidal activity (SBA), haptoglobin (HP), and oxygen free radicals (OFRs)).

Statistical differences were not found either for haematological or biochemical parameters. The total replacement of CS with TS did not affect milk yield and composition.

In conclusion, the replacement of CS by TS did not give rise to significant modifications in the parameters investigated and did not alter the health status of the animals, thus suggesting the feasibility of its introduction into the diet of mid-lactation dairy cows.

Evaluation of hair cortisol as an indicator of long-term stress responses in dogs in an animal shelter and after subsequent adoption

Shelter dogs are exposed to a variety of stressors. Among non-invasive techniques, hair cortisol concentration (HCC) is suggested an easy to collect biomarker for giving insight into long-term stress responses. We evaluated HCC as an indicator of long-term cortisol responses in dogs in an animal shelter over different chronological time points during sheltering and after adoption. Hair samples were collected from the neck region following a shave/re-shave protocol of shelter dogs (total n = 52) at four different time periods: T1 intake at shelter (pre-shelter period, n = 51); T2 after 6 weeks in the shelter (n = 23); T3 6 weeks after adoption (n = 24); T4 6 months after adoption (n = 22). HCC at T2 was significantly higher than HCC at T1, T3 and T4 (effect of sample collection moment: F_3,41 = 12.78, p < 0.0001). The dog’s weight class, age class, sex, reason for admission, kennel history and melanin type also explained HCC variability. No significant difference in HCC was found between shelter dogs T1 and control pet dogs in their own homes (n = 20, one sample, t = − 1.24, p = 0.219). A significant but moderate positive correlation between HCC and urinary cortisol:creatinine ratios was found (т = 0.3, p < 0.001). As HCC increased in the shelter, the use of this non-invasive parameter appears a useful additional tool in dog welfare research.

Chronic Stress Indicators in Canines

With a growing number of dogs abandoned, living in shelters, and being rehomed, it is important to distinguish behavioural responses due to stress in our domestic companions. Cortisol is involved in the stress responses in animals which generally enters the individual’s body into a “state of emergency”. Prolonged stress can lead to exhaustion, disease, and death. Chronic stress can be detected by evaluating cortisol concentration in hair. Most domesticated dogs respond well to hair collection, thus avoiding further stressors. The method is simple, relatively inexpensive, and non-invasive. Our experiment focused on assessing multiple parameters using a modified Canine Behavioural Assessment and Research Questionnaire to evaluate their significance with cortisol in hair samples from a diverse range of dogs. Each stress parameter was tested against cortisol concentration using a t-Test, i. e., the Paired Two Sample for Means. The effect of weight on cortisol levels was statistically significant (P = 0.03). This fact revealed that an increase in body weight correlated with an increase in cortisol levels.

Evaluation of hair and nail cortisol concentrations and associations with behavioral, physical, and environmental indicators of chronic stress in cats

Background

Chronic stress is implicated in behavioral and health issues in cats, but methods for recognition, evaluation, and measurement of stress are lacking. Cortisol concentration is typically used as an indicator of stress.

Objectives

To evaluate use of an enzyme immunoassay to quantitate hair and nail cortisol concentrations (HCC and NCC) in cats and evaluate associations between HCC and NCC and behavioral, physical, and environmental correlates of chronic stress in cats.

Animals

Forty‐eight adult, owned or community cats.

Methods

Cross‐sectional study. Nail clippings and hair were collected from cats. Medical history and cat daily lifestyle questionnaires were completed by owners or caretakers. A commercial laboratory performed cortisol extraction and quantification using a validated enzyme immunoassay kit. Correlational and regression analyses were used to evaluate associations between HCC and NCC and behavioral, environmental, and medical factors.

Results

Hair and nail cortisol concentrations were significantly associated (r_s = 0.70; P < .001), but HCCs varied widely within and among cats. Cats with litterbox issues had significantly increased HCC (P = .02) and NCC (P = .001) as compared to cats without litterbox issues. Cats with groomed coats had lower HCCs (P = .02) as compared to cats without groomed coats, whereas cats with dander and mats had higher NCCs (P = .01) as compared to cats without dander and mats.

Conclusions and Clinical Importance

The quantification of NCCs might improve identification and evaluation of chronic stress in cats. The variability of HCCs in individual cats warrants caution using this measurement in chronic stress studies.

Salivary Chromogranin A (CgA) Response to the Noradrenaline Transporter Blocker Atomoxetine in Dogs

Since salivary chromogranin A (CgA) is one of the known sympathetic adrenomedullar system (SAM) stress markers in humans and pigs, this study aimed to investigate whether salivary CgA in dogs reflects SAM activation. Our hypothesis was that salivary CgA would increase when central noradrenaline was pharmacologically induced. A selective noradrenaline transporter blocker, atomoxetine, was orally administered without causing any aversive responses in nine laboratory dogs to see if it would increase salivary CgA. Three treatment groups (i.e., atomoxetine, placebo, and pre-administration of a selective alpha-2 adrenoreceptor agonist (dexmedetomidine) followed by atomoxetine) were prepared with a randomized crossover design. Saliva sample collection, heart rate measurement and behavior observation were performed at Time 0 (baseline) and at 30, 60, 90 and 150 min after each treatment administration. The results demonstrated that salivary CgA significantly increased at 90 min in the atomoxetine treatment (p < 0.05), whereas it was not observed in the other two treatments. The present study showed that salivary CgA was increased by atomoxetine-induced SAM activation. However, this increase was blocked if dexmedetomidine was pre-administered. Overall, the results indicate that salivary CgA is a potential candidate for SAM-mediated stress markers in dogs. Further study to determine the dynamics of salivary CgA will be helpful in its practical use.

Do boars compensate for hunting with higher reproductive hormones?

The predation-stress hypothesis has been proposed as a general mechanism to explain the negative effect of predation risk on reproduction, through a chronic activation of the stress response. However, in some cases, stress appears to augment the reproductive potential of mammals. Wild boar (Sus scrofa) populations are on a rise worldwide, despite the high hunting pressure that they are exposed to. This hunting pressure instigates, among other effects, earlier sexual maturity in juvenile females, leading to the shortening of wild boars' generation time. The mechanism that underlies this earlier sexual maturity under high hunting pressure has not been examined to date. To explore the physiological effects that hunting has on the reproductive system and whether the stress response is involved, we examined steroid hormone levels in the hair of female wild boars in northern Israel, comparing populations exposed to high and low hunting pressure. Furthermore, we compared steroid levels in the hair of female wild boars that were roaming alone or as a part of a group. We found no hormonal signs of stress in the hunted boars. Cortisol levels were low in both the high and low hunting-pressure groups. Yet, progesterone levels were higher in females that were exposed to high hunting pressure. Females roaming in a group also had higher progesterone levels compared to females that were alone, with no distinguishable differences in cortisol levels. These elevations in reproductive hormones that were associated with hunting may lead to a higher reproductive potential in female wild boars. They further show that high hunting pressure does not necessarily lead to chronic stress that impairs the reproductive potential of female wild boars. This data suggests that a reproductive hormonal response may be one of the factors leading to the rapid wild boars population growth worldwide, despite the high hunting pressure.

Testosterone levels in hair of free-ranging male northern fur seals (Callorhinus ursinus) in relation to sampling month, age class and spermatogenesis

Information about the reproductive status of free-ranging pinnipeds provides useful insight into their population dynamics, which is essential to their management and conservation. To determine the reproductive status of individual animals, blood sampling is often required despite being impractical to collect in open water. Hair as an endocrine marker has been used to less invasively assess the reproductive status of terrestrial animals. However, it is unknown whether pinniped reproductive status can be assessed from hair samples. Here, we examine testosterone levels in hair obtained from 57 male northern fur seals and used it to compare their age class and spermatogenesis during the non-breeding season off Hokkaido. We isolated testosterone from the samples using gas chromatography and measured testosterone levels using time-resolved fluoroimmunoassay. Testosterone levels in hair increased towards the breeding season. In May, testosterone levels were the highest in seals aged between 4 and 7 years, followed by those over the age of 8 years and under the age of 4 years. Spermatids, the final phase of spermatogenesis, were present in the seals sampled between April and June, even though testosterone levels were low in April. The seals with spermatids in May showed the highest testosterone levels. Our results demonstrate that seals with higher testosterone levels in May are likely to be mature males (≥4 years). Since hair can be collected using biopsy darts in the field, it will be possible to less invasively determine testosterone levels of male seals in the future.

Analysis of Hair Cortisol as an Indicator of Chronic Stress in Pigs in Two Different Farrowing Systems

Confinement to farrowing crates is known to prevent sows from performing natural behavior, impairing animal welfare and possibly causing chronic stress. Hair cortisol analyses are increasingly used to detect chronic stress in animals. In the present study, hair samples were collected in the neck of sows kept either in farrowing crates (FC, n = 31) or in a loose-housing system (LH, n = 30) in six batches. Cortisol was extracted and analyzed using chemiluminescence immunoassay. Mean hair cortisol concentrations (HCC) did not differ significantly between the systems (LH: 1.85 ± 0.82 pg/mg, FC: 2.13 ± 1.53 pg/mg, P = 0.631). HCC was also not affected by other factors, such as sows' parity, number of piglets, skin lesion score or sow's weight loss during the farrowing period. However, highly significant differences were found in hair growth rates between different regions within the 20 × 30 cm shaving area. While the hair in both lateral parts of the shaving area grew almost identically (left: 7.48 ± 3.52 mm, right: 7.44 ± 3.24 mm, P = 1.00), the hair grew more in the area above the spine (12.27 + 3.95 mm, P < 0.001). In both systems, the mean individual lesion score of sows declined from the beginning to the end of the housing period (P < 0.001). No difference was found between FC and LH sows at any time (P > 0.05). Since neither the amount of skin lesions nor HCC differed between LH and FC sows, it may be concluded that confining sows in farrowing crates did not affect chronic stress levels. However, results may be affected by a downregulation of the hypothalamic-pituitary-adrenal axis during long-term stress, resulting in lower cortisol levels over time. HCC in sows may also be influenced by a dominant stressor, such as farrowing or the presence of suckling piglets. Thus, for a comparison of different farrowing systems regarding chronic stress, the use of hair cortisol measurement seems to be limited. The present results revealed that differences in hair growth rate within the same body region exist. This important finding should be considered when collecting hair samples in pigs, since hair cortisol concentrations may vary depending on hair growth and length.

Hair Cortisol Concentration as a Biomarker of Sleep Quality and Related Disorders

Cortisol is the end product of the hypothalamic-pituitary-adrenal (HPA) axis, and its production is increased mainly in stressful situations or in chronic disorders accompanied by stress enhancement. Altered cortisol concentrations have been reported in a number of neuropsychiatric diseases and sleep disorders. Cortisol concentrations have been measured using several methods, and in several matrixes, such as blood, saliva, and urine. However, lately, hair cortisol, for several reasons, has emerged as a promising biomarker of long-term retrospective HPA activation. Several experimental approaches for cortisol measurement with the corresponding concentration reference ranges and a summary of findings from scientific literature on this field are presented. There is evidence of a close relationship between HPA functional alteration and the development of neuropsychiatric disorders. Sleep disorders are the most common manifestation in several neuropsychiatric conditions, and have also been associated to cortisol alterations in both adults and children. Many studies indicate that hair cortisol constitutes a valuable tool for further contributing to existing data on salivary, plasma, or urinary cortisol concentrations in patients with sleep disorders.

Effects of feather processing methods on quantity of extracted corticosterone in broiler chickens

Corticosterone is known as a biological stress index in many species including birds. Feather corticosterone concentration (FCC) has increasingly been used as a measure for chronic stress status in broiler chickens. As sample preparation is the first step of analytical process, different techniques of feather matrix disruption need to be validated for obtaining better result in analysing corticosterone extraction. The current study was a validation of pulverizing the feather by bead beater (BB) and surgical scissors (SS) processing prior to corticosterone extraction in feather of broiler chickens. The type of feather processing prior to the hormone extraction may alter the final output. Thereby, finding a standard method according to laboratory facilities is pivotal. This study carried out to determine the effects of feather pulverization methods on the extraction amount of corticosterone in broiler chickens. Feathers were sampled from four weeks old Ross 308 broiler chickens (n = 12 birds). All broiler chickens were kept under the same environmental condition and had access to feed and water. Feather samples were assigned to one of the following processing methods 1) using a BB for pulverizing and 2) using a SS for chopping into tiny pieces. Each sample was duplicated into two wells during enzyme immunoassay (EIA) analysis to improve the accuracy of the obtained data. The results showed lower standard errors and constant output of FCC by using the BB method compared with the SS method. Overall comparison of FCC showed a significantly higher (p < 0.001) amount of the FCC in the BB compared with the SS. Overall, using the BB method is recommended over the SS method for feather processing due to the ability to homogenize a large number of samples simultaneously, ease of use and greater extraction of feather corticosterone.

Methods of Assessment of the Welfare of Shelter Cats: A Review

At any moment, there are millions of cats housed in foster care facilities for abandoned and stray animals for various reasons worldwide. Care, management and regulation among these facilities differ. Moreover, shelters can never substitute the full comfort of a good home for the animal, and the welfare of cats in shelters is a subject of discussion in many respects. Cats are animals sensitive to changes; for most of them, placement in a shelter is a stressful experience because of changes in routine, environment and the presence of other animals. Stress is reflected in changes in behaviour, causes fluctuations in physiological values and disrupts the immune system, which is a predisposition to the development or reactivation of disease. Evaluation of the presence and intensity of negative impacts is possible through the use of evaluation tools based on indicators that help set the environment and management of keeping so as to disrupt the quality of life as little as possible. Although a comprehensive and valid welfare tool that would evaluate animal-based and at the same time resource-based (or management-based) indicators of cats in shelters is not currently available, it is possible to use partial evaluation of individual welfare indicators to assess welfare. This review aims to provide the readers with an insight into current options of assessment of the welfare of cats in shelters with an emphasis on behavioural, physiological and health indicators with an application in both practical and scientific contexts.

Salivary cortisol as a marker of acute stress in dogs: a review

Public interest in the welfare of domestic dogs has increased in recent years. Dogs under human care should experience as little stress as possible, and as such it is necessary to measure and quantify their levels of stress. Stress parameters that can be measured noninvasively may help to identify the poor welfare of animals. This review aimed to determine whether and under what conditions the hormone cortisol in dog saliva can be used as a noninvasive acute stress marker. The use of salivary cortisol as a stress marker has some disadvantages, which can lead to data misinterpretations. A key factor is the standardized method of sampling and subsequent processing before analysis. In addition, possible circadian alternation and individual variability of cortisol hormone levels should be consistently considered during the preparation of the experimental scheme, statistical data processing and final interpretation of the results. Because of the complex nature of the stress response, the observation of salivary cortisol should be supplemented with behavioral observations, but it should be noted that behavioral stress symptoms may not always be positively correlated with stress hormone production. Besides behavioral observations, it is advisable to supplement the measurement of cortisol by other salivary stress markers of sympathetic-adrenal-medullary and hypothalamic-pituitary-adrenal pathways. This comprehensive assessment of the stress impact on the individual will enable one to characterize the level and type of stress.

Hair as an alternative noninvasive matrix: sources of variation in testosterone levels

Hair is one widely used alternative matrix for endocrine studies. Not only can it maintain hormone content during storage for long periods of time, but its collection also induces little to no stress. Noninvasive techniques have broadened the opportunities for endocrine research, particularly regarding wild animals. Despite its advantages, many sources of variation may affect the steroid concentration found in hair, such as body location harvested, fur color, reproductive status, and sex. Thus, domestic species, such as the dog, are an excellent and approachable model for understanding this variability. For such, we addressed diverse sources of variation in testosterone concentrations from 24 domestic dogs (Canis lupus familiaris) of the Poodle breed of various colors and neuter status, and from both sexes. The variation comprised the comparison between 2 different matrices (blood vs hair); 2 different extraction storage methods (refrigerator vs freezer); 3 body regions (head, torso, and limbs); 3 coat colors (black, brown, and white); different neuter status (intact vs castrated males) and, finally, sex. Our results showed no correlation between blood and hair testosterone concentrations. Additionally, we did not find differences related to the storage method, body region, or coat color. There were differences in concentration between males and females, but not between females and castrated males. We discuss hair testosterone levels exhibited reasonable stability, and we present practical applications for both domestic and wildlife animals.

Dogs' Stay in a Pet Hotel - Salivary Cortisol Level and Adaptation to New Conditions

The aim of this study was to assess salivary cortisol level in dogs during admission and a three-day stay in a pet hotel. The study involved 20 dogs admitted to a pet hotel for a stay lasting for at least three consecutive days. The study group consisted of 10 small dogs and 10 medium-sized dogs, eight females and 12 males. Saliva was collected each day to assess cortisol levels. A stay in a hotel is a stressful situation for dogs, as evidenced by the increase in the salivary cortisol level. The highest salivary cortisol level was observed on the day of admission to the hotel. The median salivary cortisol level in the dogs on the consecutive days was 2.7 ng/ml on admission, 2.1 ng/ml after 24 hours, and 1.9 ng/ml after 48 hours. Depending on the size of the dog, the median salivary cortisol level was 2.8 ng/ml, 2.9 ng/ml and 2.4 ng/ml in the small dogs and and 2.2 ng/ml, 1.7 ng/ml and 1.2 ng/ml in the medium sized dogs on the consecutive days.

Measurement of cortisol, cortisone and 11β-hydroxysteroid dehydrogenase type 2 activity in hair of sows during different phases of the reproductive cycle

Two sensitive assays based on AlphaLISA technology were developed and validated for the measurement of cortisol and cortisone in hair of pigs, that also enabled estimation of 11β-hydroxysteroid dehydrogenase type 2 activity. These assays were applied to hair samples from sows (n = 32) collected at 5 days before, and at 23 and 59 after farrowing, in reproductive cycles in two different periods: spring-summer (n = 16) and winter-spring (n = 16). The assays were precise (imprecision <12%) and accurate (recovery range, 80-115%) for cortisol and cortisone determination. Hair cortisone concentrations and the cortisone/cortisol ratio (an estimate of 11β-hydroxysteroid dehydrogenase isoenzyme type 2 activity) increased after farrowing more than cortisol, being these changes of higher magnitude during periods of higher atmospheric temperature. The measurement of hair cortisone concentrations and estimations of the activity of the 11β-hydroxysteroid dehydrogenase isoenzyme type 2, measured by the assays developed in this study, are complementary biomarkers to hair cortisol, and can increase at periods associated with stress, such as farrowing and lactation, especially at high atmospheric temperatures. .

Non-invasive Assessment of Fecal Stress Biomarkers in Hunting Dogs During Exercise and at Rest

Intense exercise causes to organisms to have oxidative stress and inflammation at the gastrointestinal (GI) level. The reduction in intestinal blood flow and the exercise-linked thermal damage to the intestinal mucosa can cause intestinal barrier disruption, followed by an inflammatory response. Furthermore, the adaptation to exercise may affect the gut microbiota and the metabolome of the biofluids. The aim of the present research was to evaluate the presence of a GI derangement in hunting dogs through a non-invasive sampling as a consequence of a period of intense exercise in comparison with samples collected at rest. The study included nine dogs that underwent the same training regime for hunting wild boar. In order to counterbalance physiological variations, multiple-day replicates were collected and pooled at each experimental point for each dog. The samples were collected immediately at rest before the training (T0), after 60 days of training (T1), after 60 days of hunting wild boar (T2), and finally, at 60 days of rest after hunting (T3). A number of potential stress markers were evaluated: fecal cortisol metabolites (FCMs) as a major indicator of altered physiological states, immunoglobulin A (IgA) as an indicator of intestinal immune protection, and total antioxidant activity [total antioxidant capacity (TAC)]. Since stool samples contain exfoliated cells, we investigated also the presence of some transcripts involved in GI permeability [occludin (OCLN), protease-activated receptor-2 (PAR-2)] and in the inflammatory mechanism [interleukin (IL)-8, IL-6, IL-1b, tumor necrosis factor alpha (TNFα), calprotectin (CALP), heme oxygenase-1 (HO-1)]. Finally, the metabolome and the microbiota profiles were analyzed. No variation in FCM and IgA content and no differences in OCLN and CALP gene expression between rest and training were observed. On the contrary, an increase in PAR-2 and HO-1 transcripts, a reduction in total antioxidant activity, and a different profile of microbiota and metabolomics data were observed. Collectively, the data in the present study indicated that physical exercise in our model could be considered a mild stressor stimulus.

Interplay between Neuroendocrine Biomarkers and Gut Microbiota in Dogs Supplemented with Grape Proanthocyanidins: Results of Dietary Intervention Study

Simple Summary

The connection between animal health and gut microbiota has been studied during the past years through different diet modulation experiments; however, there is still a paucity of information about the prebiotic functions in the gastrointestinal tract of companion animals. Considering this, a population of dogs living in the same environment has been subjected to a nutritional study, with different doses of proanthocyanidins extracted from grapevine supplied to the diet. Characterization of the gut microbiota and data from endocrine analysis in saliva have been collected. Dogs responded differently to the dietary intervention, and results underlined the existence of a difference between subjects in terms of fecal microorganisms and neuroendocrine markers, leading us to think the balance of gut microbiota is going to play a strong role in diet formulation based on host health modulation.

Abstract

Several studies on the interaction between gut microbiota and diets, including prebiotics, have been reported in dogs, but no data are available about the effects of dietary administration of grape proanthocyanidins. In the study, 24 healthy adult dogs of different breeds were recruited and divided in 3 groups of 8 subjects each. A group was fed with a control diet (D0), whilst the others were supplemented with 1 (D1) or 3 (D3) mg/kg live weight of grape proanthocyanidins. Samples of feces were collected at the beginning and after 14 and 28 days for microbiota, short chain fatty acid, and lactic acid analysis. Serotonin and cortisol were measured in saliva, collected at the beginning of the study and after 28 days. A significantly higher abundance (p < 0.01) of Enterococcus and Adlercreutzia were observed in D0, whilst Escherichia and Eubacterium were higher in D1. Fusobacterium and Phascolarctobacterium were higher (p < 0.01) in D3. Salivary serotonin increased (p < 0.01) at T28 for D1 and D3 groups but cortisol did not vary. Proanthocyanidins administration influenced the fecal microbiota and neuroendocrine response of dogs, but a high variability of taxa was observed, suggesting a uniqueness and stability of fecal microbiota related to the individual.

Hair cortisol analyses in different mammal species: choosing the wrong assay may lead to erroneous results

Wild animals are faced with a broad range of environmental stressors and research is needed to better understand their effect on populations. Hormone analysis based on enzyme immunoassays (EIAs) can provide valuable information on adrenocortical activity (stress), and assessment of cortisol in hair may allow the quantification of cortisol production. To validate hair hormone analysis, we compared two EIAs based on antibodies against cortisol-3-CMO-BSA and cortisol-21-HS-BSA for hair glucocorticoid (hGC) measurements in Egyptian mongoose, Iberian lynx, Alpine marmot, Asiatic black bear, spotted hyena and cheetah, with results obtained by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) measurements. Both EIAs were also characterized by HPLC immunograms. Our results revealed that the cortisol-21-HS EIA measured 2.3- to 12-fold higher hGC concentrations than the cortisol-3-CMO assay. In dependence of the species, high-performance liquid chromatography (HPLC) immunograms showed that up to 70% of immunoreactivities determined by the cortisol-21-HS constituted of unknown unpolar compounds leading to an overestimation of hGC. The cortisol-3-CMO EIA expressed a better specificity, with 32.1-67.4% of immunoreactivity represented by cortisol and cortisone. The LC-MS/MS analyses (gold standard) revealed that the cortisol-3-CMO EIA also resulted in an (up to 3-fold) overestimation of hGC, but EIA results were correlated with LC-MS/MS in the mongoose, the lynx, the spotted hyena and the marmot. No correlation was obtained for Asiatic black bears. As a result of our study, we strongly recommend to test any cortisol EIA for its specificity towards extracted hair components. In all analyzed species, except the Asiatic black bear, cortisone and cortisol were simultaneously present in hair extracts; consequently, an appropriate EIA should cross-react to these two glucocorticoid hormones and express negligible affinity towards substances with less polarity than corticosterone. Choosing the wrong EIA for hGC analyses may lead to overestimations of hGC or-in the worst case-to results that do not mirror real adrenocortical activity.

Evaluation of Hair Characteristics and Animal Age on the Impact of Hair Cortisol Concentration in Feedlot Steers

Hair cortisol is a novel biomarker of chronic stress. The objective of this study was to determine the effect of hair color and length, as well as, animal age on hair cortisol concentration in beef feedlot steers. Nineteen beef crossbred steers used for nutrition research and housed in a small feedlot setting were used for this study. Seven of the steers (680 ± 4.5 kg; ~9 years of age) were fitted with ruminal fistulas and duodenal cannulas. The other 12 steers (473 ± 3.1 kg; ~2.5 years of age) were fitted with only ruminal fistulas. Hair samples from each steer were collected throughout a period of 6 weeks from six different areas and analyzed for cortisol concentrations. One pre-determined area was shaved each week for 5 weeks (Weeks 1–5). During week 6, all five, previously shaved areas and an additional area was shaved to collect hair samples of various lengths. Hair length was recorded prior to the collection of each hair sample. Only data from the last week (Week 6) of collection were included in the analyses. Steers were categorized into one of three groups: old with black hair (OB, n = 3); old with white hair (OW, n = 3); young with black hair (YB, n = 12). Older steers exhibited greater hair cortisol concentrations than younger steers (P < 0.001). Hair cortisol concentration was not impacted by duration of growth (P = 0.33). Cortisol concentrations exhibited a weak, positive correlation with hair length (r = 0.33, P-value = 0.01). The average hair growth per week of beef steers in the winter months was calculated to be 0.90 mm. Further research should be performed to improve our understanding of the effect of hair characteristics, sampling methodologies and analysis techniques on hair cortisol concentrations.

Faecal metabolites and hair cortisol as biological markers of HPA-axis activity in the Rocky mountain goat

Monitoring glucocorticoids in faeces and hair is increasingly used in ecological studies and provides a powerful and minimally intrusive mean to identify physiological challenges faced by wild animals. Using a cortisol and a corticosterone immunoassays, we conducted an adrenocorticotropic (ACTH) challenge with five weekly repeated injections to validate the use of faecal glucocorticoid metabolites and hair cortisol concentration as biological markers of the HPA-axis activity in captive mountain goats (Oreamnos americanus). We also investigated the effect of endogenous (age, sex, reproductive status) and methodological (faecal sample collection date, freezing delay and hair type) variables on cortisol values using faecal and hair samples collected from marked wild mountain goats during a long-term study. The cortisol enzyme immunoassay was reliable for mountain goat faeces and hair, and was sensitive enough to detect a clear rise in glucocorticoid concentration following ACTH injections for both matrices. Age and sex had no detectable effect on faecal glucocorticoid metabolites, but hair cortisol concentration was higher in kids and yearlings than in older goats, and lower in adult males compared to adult females. Reproductive status had no detectable effect on both faecal and hair measurements. Faecal metabolite concentrations increased with sample collection date in late spring until mid-summer and decreased afterward until early fall. Guard hair had nearly twice as much cortisol per gram as undercoat hair. Prolonged delay to freezing reduced the concentration of faecal glucocorticoid metabolites, but degradation seemed limited when samples were exposed to wind and sun or when ambient temperature was low. We conclude that faeces and hair can be used as valid biomarkers of the HPA-axis activity in mountain goat provided that confounding variables are taken into account when interpreting measurements.

A systematic review of studies utilizing hair glucocorticoids as a measure of stress suggests the marker is more appropriate for quantifying short-term stressors

Quantitating glucocorticoids (GCs) in hairs is a popular method for assessing chronic stress in studies of humans and animals alike. The cause-and-effect relationship between stress and elevated GC levels in hairs, sampled weeks later, is however hard to prove. This systematic review evaluated the evidence supporting hair glucocorticoids (hGCs) as a biomarker of stress. Only a relatively small number of controlled studies employing hGC analyses have been published, and the quality of the evidence is compromised by unchecked sources of bias. Subjects exposed to stress mostly demonstrate elevated levels of hGCs, and these concentrations correlate significantly with GC concentrations in serum, saliva and feces. This supports hGCs as a biomarker of stress, but the dataset provided no evidence that hGCs are a marker of stress outside of the immediate past. Only in cases where the stressor persisted at the time of hair sampling could a clear link between stress and hGCs be established.