Daniel G. Satterlee

Adrenal Involvement in the Expression of Delayed-Type Hypersensitivity to SRBC and Contact Sensitivity to DNFB in Stressed Mice

Abstract The stress of immobilization has previously been demonstrated to suppress delayed-type hypersensitivity (DTH) responses to an iv injection of sheep erythrocytes (SRBC). However, immobilization enhances contact sensitivity reactions to the cutaneous application of 2,4-dinitro-l-fluorobenzene (DNFB). In the following experiments, both adrenalectomy and the corticosteroid inhibitor, metyrapone, were used to evaluate the influence of corticosterone on the expression of these cell-mediated immune events in stressed mice. Adrenalectomy and metyrapone after induction of the immune response abolished the suppression of DTH to SRBC that was observed in immobilized, control animals. In contrast, the immobilization-induced increase in contact sensitivity to DNFB was still observed after adrenalectomy or metyrapone treatment. Similar results were observed when mice were given metyrapone or adrenalectomized before sensitization. These data indicate that adrenal corticosteroids are involved in the stress-induced suppression of DTH to SRBC, but do not account for the stress-induced enhancement in contact sensitivity to DNFB.

Sociality in Japanese quail ( Coturnix japonica ) genetically selected for contrasting adrenocortical responsiveness

Abstract The growing realisation that selective breeding may offer rapid solutions to certain animal welfare problems and the associated production losses lends urgency to the search for suitable selection criteria. We have already shown that genetic selection of Japanese quail for a reduced (low stress, LS) rather than an exaggerated (high stress, HS) adrenocortical response to brief mechanical restraint was associated with marked reductions in underlying fearfulness, non-specific stress responsiveness and developmental instability. However, since genetic selection for one trait can also modify others, monitoring of other important characteristics is imperative before we can make any recommendations. Inappropriate levels of sociality (motivation to be near conspecifics) could cause pronounced social stress. The present study compared underlying sociality in LS and HS quail in two ways. In experiment 1, when undisturbed, same-line groups of six chicks were observed at 4 days of age we found that LS quail stayed closer together than HS ones. When naive, individually tested chicks were tested in a runway at 11–12 days of age in experiment 2, LS quail spent longer near a goal box containing cagemates than did the HS birds. Social proximity in the home cage and reinstatement responses in runway tests of social affiliation are positively related to underlying sociality. Therefore, these findings strongly suggest that underlying sociality is greater in quail of the LS than the HS line. Enhanced sociality could be regarded as an additional advantage of this type of selection programme, particularly if the phenomenon generalised to include commercially important species that are often housed at high stocking densities, like chickens or turkeys.