24.6 Sunday, Jan. 4 14:45 Perception of food affects corticosterone, behavior, and hypothalamic gene expression in the zebra finch ERNST, D.K.*; LANE, V.A.; BAKER, C.; TSAI, R.; BENTLEY, G.E.; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley firstname.lastname@example.org
Increase in food availability stimulates reproductive activity in zebra finches. It is not known if it is increased energy intake, the visual stimulus of food, or both that affects reproductive status. We hypothesize that physical interaction with food as well as visualization of food affects reproduction. To test this, singly-housed birds were videotaped for 1 hour and then randomly assigned to one of four groups: control (ad libitum food), 7 hours of complete food restriction, 7 hours of exposure to a food dish with seed hulls only (no nutritive value), or 7 hours of a food dish covered in clear plastic so birds were able to see food but not touch it (n=10 per group). At the end of treatment birds were videotaped for an hour followed by collection of tissue. Corticosterone was significantly higher in the food restricted group and the group receiving seed hulls than in controls (p<05). Birds exposed to seed hulls spent significantly more time at their food dish (p<.02) than did control birds or birds with plastic-covered food dishes, while food restricted birds spent an intermediate amount of time at their food dish. Total activity was higher than controls in all experimental groups (p<.05). Perception of food affected expression of neuropeptide Y and gonadotropin-releasing hormone in the hypothalamus (p<.05) and expression of steroidogenic enzymes in the testes. Overall, our data suggest that, while metabolically similar, a visual food stimulus affects zebra finches differently from a food stimulus that they can interact with but receive no nutritional value. These data highlight the importance of physical interaction with food when considering how food availability stimulates reproductive activity.