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Opis: During their life, birds face several challenges which can threaten the stability of physiological functions. These situations typically trigger a cascade of endocrine secretions involving the hypothalamic–pituitary–adrenal (HPA) axis, and resulting in the release of both cortisol and corticosterone also in birds. The use of a non-invasive approach to collect samples of biological material derived from natural populations represents a greatly combination for an improvement of knowledge avoiding handling animals. Steroid concentrations in feathers are mainly acquired from the capillary around the follicle during the long period of feather grown reflecting their bloodstream concentrations. Accordingly, a chronic HPA axis activation could be assessed using molted feathers cortisol concentrations. Another hormone, dehydroepiandrosterone (DHEA), is secreted by adrenals and it could be assessed in molted feathers. This study was aimed to evaluate the feasibility of using feathers cortisol and DHEA concentrations to provide a retrospective assessment of the activity of the HPA axis in griffon vulture acquired for health monitoring purposes. For this, we introduced two groups of animals with a known health condition: one group composed by griffons that have experienced a long-term physiologically compromised period (PC group; n=8) and the other group composed by griffons physiologically not compromised (CTRL group; n=9). The feathers cortisol and DHEA analyses were carried out using RIA [1,2] adapted for feathers. The results revealed different feather hormone concentrations between the two groups of animals. The feathers cortisol had a median value higher in the PC group than in the CTRL group, with cortisol concentrations showing a central value 1.6 times higher in those animals that suffered a long-term physiological impairment. The PC group showed also (Kruskal- Wallis test) higher feather concentrations of DHEA (P=0.01) than the CTRL group. Pearson’s correlation coefficients were used to examine the associations between cortisol and DHEA, showing no correlation between cortisol and DHEA feather concentrations in the PC group (r=0.18, P=0.34) and a moderate positive correlation in the CTRL group (r=0.51, P=0.011). In conclusion, our study reveals that molted feathers can be an interesting way to evaluate the physiological status of wild animals by using a non-invasive approach. Our analyses reveal that in addition to cortisol also DHEA could be evaluated to better understand the relationships between these hormones and to determine the resilience condition of wild species.
Ključne besede: CORTISOL, DHEA, GRIFFON VULTURE, Gyps fulvus, FEATHER
Objavljeno v RUNG: 09.04.2019; Ogledov: 4466; Prenosov: 0
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Opis: Although steroidogenesis in maternal, placental and fetal compartments is interdependent, the maternal and fetal hypothalamic-pituitary-adrenal (HPA) axes represent separate biological systems, with dehydroepiandrosterone (DHEA) recognized as the main fetal steroid. Fetal steroids are likely to influence development and have long-term effects on HPA function. Hair analysis represents a promising methodological approach for the non-invasive measurement of steroids, allowing for a retrospective analysis of the total exposure to steroids over time, and avoiding the influence of acute events or circadian fluctuations (Schury et al. 2017, BMC Psychiatry 17:213). Hair coat DHEA (hcD) concentrations have been investigated in cows (Peric et al. 2017, Livestock Sci 202:39–43), but no studies have been performed on newborn calves. Hair samples of 12 beef calves (7 males, 5 females) were collected by shaving at calving (T0) and monthly up to 10 months of age (T1-T10), only on the re-growth area. Hair DHEA was analyzed by RIA2. Statistical analysis revealed that hcD concentrations in calves were influenced by age, with higher levels at T1 and T2 compared to the other samples (p < 0.05). HcD levels were not influenced by newborn gender, birth weight and Apgar score. These data demonstrate that DHEA is quantifiable in the hair coat of newborn calves, and that hcD levels are influenced by the age of calves. The higher accumulation of DHEA was detected from birth to 2 months of age, suggesting that DHEA continues to be secreted by the newborn calf also beyond birth and could be involved in the events occurring during the first months of age.
Ključne besede: hair, dehydroepiandrosterone, cattle, calf
Objavljeno v RUNG: 09.04.2019; Ogledov: 4432; Prenosov: 0
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Opis: Biometric measurements of horn, body and physiological variables of 35 Alpine ibex, Capra ibex ibex, (14 females and 21 males, age range: 2-15 years) were analysed in relation to gender and area of origin. Moreover, for the first time hair cortisol concentration was evaluated in this species. The ibexes were live-captured in spring in the Maritime Alps Natural Park. All the horn and body morphometric measurements were significantly different between genders and a statistical difference was found between horn and body data considering the area of origin of ibexes, with the exception of horn circumference and height as well of body and hock length. Among the physiological variables, female ibex showed higher heart rate and glycemia, but tended to have lower respiratory rate than male. The mean hair cortisol concentration was 22.40±1.44 pg/mg (±SE). A different distribution was described for the male hair cortisol concentrations compared to that in females. Obtained data indicate that the geographical area where Alpine ibex lives could affect the endurance of an ibex population but further investigations are needed to understand if intra- and inter-specific competition and different environment could be the basis of the HPA axis activation. Hair cortisol evaluation together with biometric values could be an interesting way to obtain information on the adaptation that the animal attempts to reach in relation to environmental factors and pursuing organism homeostasis. This feature could be important in attempting to preserve wildlife biodiversity that also depends from the state of animal welfare.
Ključne besede: allostatic load, Alps, ibex, biometry, hair cortisol
Objavljeno v RUNG: 06.03.2018; Ogledov: 5986; Prenosov: 0
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Opis: This study was conducted in order to assess the changes of cortisol and dehydroepiandrosterone (DHEA) concentrations in hair of Italian Simmental dairy cows managed indoor in tie-stall barns or grazing on high mountain pasture. In experiment I, animals were kept in tie-stalls throughout the year (n = 27). In experiment II, animals remained on mountain pastures during summer (from 20th June to 20th September) and then kept indoors in tie-stalls for the rest of the year (n = 18). At the end of July, following vertical transhumance, dairy cows were moved to a pasture located at a higher altitude. In the two studies, hair samples, obtained using clippers from the animal's forehead, were collected on the 20th June (P1), 20th July (P2), 20th August (P3), 20th September (P4) and 20th October (P5) and analysed for cortisol and DHEA. In experiment I, DHEA concentration was unaffected by sampling time (P > 0.05), whereas, cortisol/DHEA ratio was similar between P1 and P2 (P > 0.05) and then increased during the experimental period reaching the highest value at P5 (P < 0.05). In experiment II, dairy cows had higher concentration of DHEA during grazing compared to cows kept indoors (P < 0.05), conversely cortisol/DHEA ratio decreased from P1 to P2 (P < 0.05), remained constant from P2 to P3 (P > 0.05) and then increased from P3 to P4 (P < 0.05), the highest value was recorded at P5. In conclusion, cortisol and DHEA concentrations and their ratio measured in the hair of dairy cows can be useful to evaluate the allostatic load in animals managed indoor in tie-stall barn or grazing on mountain pasture.
Ključne besede: Dairy cow, Mountain pasture, Hair, Cortisol, DHEA
Objavljeno v RUNG: 28.05.2017; Ogledov: 6154; Prenosov: 0
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Opis: The experiment was aimed to evaluate the usefulness of hair cortisol concentrations (HCC) in revealing the activation of the hypothalamic-pituitary-adrenal (HPA) axis due to the passage of young bulls from genetic rearing stations to artificial insemination (AI) centre and the influence of this passage on hair testosterone concentrations (HTC). Hair samples on 33 yearling bulls were collected at the time of arrival (ST1) to the AI centre and 3 more hair samples (ST2, ST3, ST4) were collected at monthly intervals. After the end of quarantine each animal was submitted to the standard procedures for collection and production of semen. Overall HCC were significantly affected by period of collection (p<.01). In particular, HCC was higher in samples obtained after finishing the quarantine period (ST2) compared with those obtained on ST1. After ST2, the HCC decreased reaching at ST4 a value similar to that recorded at ST1. An effect of sampling time on HTC was not found (p>.05). The effect of breed was observed only for HTC that was higher in PRI than BS (p<.01). The HCC group have not influenced the semen variables (p>.05). On the contrary, the effect of breed was evident. The results of this study replicated the effects of a major environmental stressor on mean cortisol concentrations assessed in hair, and add to the growing body of evidence that HCC is an effective and simply collected marker for long-term activity of the HPA system in response to persistent environmental challenge.
Ključne besede: Hair, bulls, cortisol, testosterone, semen
Objavljeno v RUNG: 20.03.2017; Ogledov: 6924; Prenosov: 0
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