44. Does anticipation induce affective states with consequences for immunocompetence?

Abstract

The evaluation of affective states and their physiological effects may help improving animal welfare in pig husbandry. In an ongoing experiment, we use an anticipation paradigm to induce different affective states in pigs and investigate potential effects on neuroendocrine immunomodulation. For each trial, six female growing pigs are being housed in individual pens but with olfactory and acoustic contact to each other. Three of them are conditioned to a sound that is followed by a positive stimulus (food), a negative stimulus (air-puff) or a random choice of either a positive or a negative stimulus which are supposed to induce a positive, a negative or a conflicting anticipation, respectively. The other three pigs received unconditioned positive, negative or no stimuli and serve as controls. Within 4 weeks, we expect anticipation to induce long-lasting changes in mood. To test whether these changes result in neuroendocrine immunomodulation, we monitor heart rate (HR) and heart rate variability (HRV), salivary cortisol, lymphocyte proliferation and other immune parameters. First results suggest that the positively anticipating pigs react to the sound with an increase in HR and changes in HRV that indicate sympathetic activation. These animals also show a decrease in mitogen-induced T-cell proliferation. Salivary cortisol levels decrease during the experiment independent of treatment. Apparently, affective states can be induced by anticipation and may influence immunocompetence in pigs.