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The aim of this study was to determine physiological levels of stress hormones (e.g. cortisol and testosterone) in the blood of polar fox females characterized by a specific genotype and karyotype and also the type of behavior. In 2010, an estimation of the type of behavior of all females from a pack based on the type of behavioral response (empathic test, alimentary test, acoustic test) was provided. In the blood of 136 females randomly selected from the fundamental pack, physiological levels of stress hormones (e.g. cortisol and testosterone) were determined. Additionally, the analysis of polymorphism of karyotypes of 72 females in this group was conducted. Heritability and repeatability coefficients in the base levels of cortisol and testosterone in the blood serum was evaluated. The average basal level of cortisol in the blood serum of polar fox females was 46.04 ± 25.86 nmol/l, and testosterone 0.45 ± 0.22 nmol/l. The heritability coefficient of the basal cortisol level stated 0.30 ± 0.11 and testosterone 0.24 ± 0.13; the repeatability coefficient of the basal levels of cortisol was 0.42 and 0.37 of testosterone. The multivariate analysis of variance revealed non-significant differences between the studied groups of animals. Some tendencies were noted explaining the differentiation in hormone levels within particular effects (participation of genes of Finnish variety, karyotype and type of behavior: empathic test, alimentary test and acoustic test). The highest basal levels of cortisol (51.98 nmol/l) and testosterone (0.51 nmol/l) were found in the group of foxes of national breeding. The highest value of cortisol was obtained in the female group of 48 chromosomes (55.20 nmol/l) and lowest in a group of foxes with karyotype 2n = 50 (49.06 nmol/l). Studies have shown the highest physiological level of testosterone in the blood of gentle individuals. It was also noted that foxes with a high concentration of this hormone were simultaneously characterized by a low cortisol level.
Blood sampling, especially in young pigs, is a stressogenic procedure and brings about a release of various hormones to the peripheral blood. According to many authors blood collection, performed by means of a previously inserted catheter, has an advantage in comparison to traditional methods based on direct venapuncture. The purpose of the experiment was to carry out comparative investigations in respect to the level of adrenaline, noradrenaline and cortisol (stress hormones) during blood sampling from porkers. Two methods were used: a) a traditional one based on a direct venapuncture of the jugular anterior vein, and b) by means of a previously inserted catheter through the brachiocephalic vein to the jugular anterior vein. Blood samples were collected at 20, 40, 80, 110, 200 and 300 seconds counting the time from catching and immobilization of an animal to the end of blood sampling. The results did not reveal any significant differences in the level of the hormones in the blood samplings taken by both methods. The results proved that the stress aroused by the blood sampling was caused by catching and immobilization of animals and not by the method of blood aspiration. The traditional method of blood sampling (direct venapuncture) can be used in young animals housed in groups if the whole procedure does not last more than 22 sec., ie before the stress hormones are released in to the peripheral blood.
Out of 28 days old piglets qualified for fattening there were selected 10 dominant and 10 subordinate animals in which the level of catecholamines and cortisole was tested in the blood of the animals after their joining and later after 3 and 7 days. The studies revealed the appearance of emotional and somatic stress: it was decreasing slowly within 7 days in the dominant group, while in the subordinate group the somatic stress was unchanged to the end of the experiment and the signs of emotional stress appeared at day 3 and 7. The findings indicate the possibility of early adaptation of dominant individuals in contrast to subordinate ones to permanent acting stressors.
The cortisol level was estimated, before and after slaughter, in the serum of 80-days-old rams of the kamieniecka sheep (K) and their crossbred (F₁) with rams of the Berrichon du Cher (KxBCH), Blackhead (KxCz) and Ile de France (KxIF) race. The cortisol level tested before the preslaughter movement was different in the studied genetic groups of lambs. The highest initial concentration of the hormone was found in lambs of KxIF (40.10 nmol/l) and K (39.51 nmol/1). After the preslaughter stress, concentration of the studied hormone increased in all the lamb groups. The lowest stress sensitivity was observed in the lambs of pure K race, which has the smallest increase of the cortisol level (1.46 times more than the initial one). In crossbred groups of lambs, the highest stress sensitivity was observed in KxBCH Iambs. They had 3.72 times greater increase of the studied hormone level. A slightly lower stress sensitivity occured in KxCz (3 times greater) and KxIF (1.8 times greater). There was no significant difference between the temperature, measured per rectum, before and after the transport of animals.
The studies were carried out on 8 young pigs (30—45 kg of body weight) in order to assess the level of adrenalin, noradrenalin and cortisol in the plasma of animals forced to movement three times a day for 15 min at intervals of 45 min. The experiment lasted for 28 days. The blood was collected at day 1, 3, 7, 14 and 28 from the anterior intracranial vein. The indices of cellular immunity, i.e. the activity of neutral leukocytes (NBT) and the index of lymphocyte transformation were evaluated. It was found that prolonged intermittent physical stress brought about in young pigs a progressive decrease of the hormones and the immunological activity of leukocytes. No correlation between the level of cortisol and catecholamines was found.
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