Effects of stressful noise on eating and non-eating behavior in rats

Eating and other behaviors were measured in 36 food-deprived rats on 15 consecutive days during 20 min test sessions. During training sessions 1 to 5 all animals were habituated to the test boxes with white noise of 55 dB intensity. For sessions 6 to 10 noise intensity was increased to 95 dB for the experimental rats and to 60 dB for the control rats. The food intake of experimental rats was lower for stress session 1. The duration of eating behavior was lower, and durations of exploring, grooming and resting behaviors were higher for all stress sessions for rats exposed to 95 dB white noise. Speed of eating behavior was higher for all stress sessions in the experimental group. Defecation rate of the experimental rats was higher for all stress sessions. On post-stress sessions 11 to 15 animals were again tested under the stimulus conditions of the training period (55 dB). No significant effects were observed for this period. The results are discussed with respect to models of "stress-induced" eating and behavioral ecology.