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Simple Summary: There are multiple physiological changes in response to stress across vertebrate species. These shift metabolism and organ functioning such that the animals can withstand the stress. Ours results show that nutritional deprivation and crowding stimulate both the activities of the opioid system and the adrenocortical axis stress response in chickens. The effects of stressors were examined on Met-enkephalin-related parameters and plasma concentrations of corticosterone in 14-week-old female chickens. Water deprivation for 24 h was accompanied by a tendency for increased plasma concentration of Met-enkephalin while plasma concentrations of corticosterone were elevated in water-deprived birds. Concentrations of Met-enkephalin were reduced in the anterior pituitary gland and adrenal gland in water-deprived pullets while proenkephalin (PENK) expression was increased in both tissues. There were changes in the plasma concentrations of Met-enkephalin and corticosterone in pullets subjected to either feed withholding or crowding. Concentrations of Met-enkephalin were increased in the anterior pituitary gland but decreased in adrenal glands in pullets subjected to crowding stress. The increase in the plasma concentrations of Met-enkephalin was ablated when the chickens were pretreated with naltrexone. However, naltrexone did not influence either basal or crowding on plasma concentrations of corticosterone. In vitro release of Met-enkephalin from the anterior pituitary or adrenal tissues was depressed in the presence of naltrexone. It was concluded that Met-enkephalin was part of the neuroendocrine response to stress in female chickens. It was concluded that stress influenced the release of both Met-enkephalin and corticosterone, but there was not complete parallelism. [ABSTRACT FROM AUTHOR]

This review provides an overview of the anatomy and physiology of the gastro-intestinal tract (GIT) of poultry, particularly of the domesticated chicken. The structure and functioning of the major regions of the GIT are discussed bringing together recent studies with the older, often neglected, literature. Attention is focused on the GIT as an immune organ and on GIT fermentation/bacterial colonisation. In addition, the interactions of nutrition with GIT biology are discussed. The roles of neuropeptides and hormones on the development and functioning of the GIT are extensively reviewed. [ABSTRACT FROM AUTHOR]

The study was performed to examine the actions of glucocorticoids on cytokine (TNF-α and IL-6) concentrations in blood plasma, adipose tissue and cytokines gene expression during acute (streptozotocin, STZ treatment) and chronic inflammation (overweight) in Swiss mice. The experiment was carried out on 6-week-old animals divided into two groups: I - non-obese (fed with a commercial food) and II - overweight mice (fed with a high-fat diet). In each group mice were divided into 4 experimental subgroups: I - control, II - acute inflammation (STZ), III - treated with glucocorticoids (DEX), and IV - STZ with DEX. After injections the animals were decapitated, blood and white adipose tissue (WAT) was quickly removed and directed to measure the plasma levels, tissue concentrations and gene expression of the cytokines (TNF-α, IL-6). Three weeks of treatment with a high-fat diet resulted in increased body weight gain and plasma level of cytokines, whereas did not change TNF-c and IL-6 mRNA gene expression in control animals. STZ, administered once, changed the TNF-α & and IL-6 concentrations in a different manner according to the diet. The TNF-a and IL-6 actions in mice white adipose tissue are down-regulated after glucocorticoids treatment only in overweight animals. The obtained results suggest that glucocorticoids' effects on adipose tissue immune response, both in a pro- and an anti-inflammatory manner, depend on the nutritional status.

Adult male mice were kept for one week either one or four animals per cage. Some were maintained under the same social conditions for an additional 9 days (controls); their counterparts were either grouped (4 per cage) or isolated (1 per cage). Changes in housing conditions caused a significant increase of plasma corticosterone measured 30 minutes after separation or grouping of SWISS, C57C3H, and BALB/c but not of C57BL/6 mice. Peritoneal inflammation was induced by i.p. zymosan injection on day 9 after changes in housing conditions when corticosterone was again at its initial level in each group. Peritonitis-connected pain symptoms, exudatory PMN numbers, and cytokine (IL-1beta and MPC-1) and corticosterone levels were compared between animals living in stable social conditions with those shifted 9 days earlier from separation to the group or vice versa. These factors were unaffected by social stress in C57BL/6 mice and in SWISS animals transferred from the group to isolation. In all other instances at least two parameters were significantly different in the post-stressed and control animals, being either enhanced or inhibited. In conclusion, social stress had long-term consequences on the course of inflammation in three out of four investigated strains of mice.

The local increase in Met-enkephalin level during zymosan-induced peritonitis may be related to its local production by exudatory leukocytes (as evidenced by our previous experiments) and influx from distal centers, as its level is significantly decreased in blood, inguinal lymph nodes, and some brain areas (striatum, hypothalamus, and pituitary gland).