Physiological effects of elevated plasma corticosterone concentrations in broiler chickens. An alternative means by which to assess the physiological effects of stress

Abstract

Research on physical or psychological stress, in order to monitor objective parameters for animal welfare, is usually performed during experimental stress induction. To avoid treatment of animals with physical or physiological stress, addition of the stress-related hormone corticosterone to the drinking water, may serve as a practical alternative to reproducibly investigate hormone-related stress in broiler chickens. Rapid uptake of the hormone and distribution in the bloodstream were affirmed by elevated plasma corticosterone concentrations immediately after start of the treatment. The effect of hormone administration was evaluated by examination of corticosterone-sensitive organs. Comparable to the observations during physiological stress, we found in our model that uptake of endogenous corticosterone reduced body and spleen growth, increased heterophil counts, and decreased formation of antibodies against sheep red blood cells. Furthermore, corticosterone decreased adrenal gland responsiveness, measured by corticosterone production, after a challenge with adrenocorticotropic hormone. The simple performance, and the close relation between circulating corticosterone levels and heterophil counts, makes this an easy and quick method that is sensitive to increased levels of circulating corticosterone from base levels. The changed responsiveness of the adrenal glands to adrenocorticotropic hormone after increased circulating corticosterone levels may be an indication of the coping strategies during stress. Therefore, this test may be a promising tool in the research of adaptation to stress by broiler chickens.

Effects of housing conditions during the rearing and laying period on adrenal reactivity, immune response and heterophil to lymphocyte (H/L) ratios in laying hens

“…Accordingly, it has been shown that poultry exposed to various stressful environments or procedures have lower antibody production in response to a variety of antigens including SRBC (Siegel, 1985). Similarly, exposure to continuous infusions of ACTH (Mumma et al, 2006) or dietary corticosterone (Post et al, 2003), in order to mimic chronic stress, suppressed antibody responses to immunization with experimental antigens such as SRBC (Mumma et al, 2006) and vaccines used commercially, for example, infectious bronchitis virus vaccine (Shini et al, 2008). On the other hand, reducing stress during the laying period (Zulkifli et al, 2002) and enriching the cage environment (El-Lethey et al, 2000) led to increased anti-SRBC antibody titres.…”

Effect of mild heat stress and mild infection pressure on immune responses to an E. coli infection in chickens

“…Normally stress, and especially stress for longer periods (Hangalapura et al, 2003), has a negative impact on body weight gain, which may be a consequence of elevated corticosterone levels. It has been shown that feeding corticosterone to chickens reduces body weight gain (Post et al, 2003). The positive body weight gain in Hellevad chickens in treatment H2 in the present experiment might be caused by a reduced level of corticosterone or by reduced sensitivity to corticosterone as a reaction to the gentle stressor.…”

“…However, this was not the case, as there was no significant difference in E. coli antibody titres between the chicken strains 3 weeks after infection. Others have found that stress (El-Lethey et al, 2003) and the major stress hormone, corticosterone (Post et al, 2003), influence antibody responses. However, this was dependent on the antigen tested (El-Lethey et al, 2003) suggesting that the antigen tested in the present study might be of a stress-resistant character, or that the antigen load has actually been too small to provoke the humoral differences or that the increase in MHCII1 lymphocytes reflected an increased activation of T-cells rather than an increased % of B-cells.…”

Gnawing bones as enrichment for farmed blue foxes (Vulpes lagopus)

“…Buyse et al, 1987;Post et al, 2003;Lin et al, 2006), inflict involution of spleen (Malheiros et al, 2003;Post et al, 2003), and increase the mass of adrenals (Selye, 1950;see Mormede et al, 2007) and liver (Buyse et al, 1987;Malheiros et al, 2003;Lin et al, 2006). The mass of heart, for its part, can Table 2 Percentage of animals with bite marks on the leather side of their skin, severity of bite scars on a subjective scale where 0 denotes 'no bite marks' and 5 'almost the whole skin covered with marks' (mean 6 s.e.…”