Rh. Marin et Rb. Jones, Latency to traverse a T-maze at 2 days of age and later adrenocortical responses to an acute stressor in domestic chicks, PHYSL BEHAV, 66(5), 1999, pp. 809-813
Latencies to escape from a T-maze, and thereby reinstate visual contact wit
h conspecifics, were measured in broiler chicks at 2 days of age. Chicks we
re assigned to high- (HP) or low- (LP) performance categories if their esca
pe latencies fell below 25 s or above 75 s, respectively. These chicks were
then housed socially in 10 same-category groups (5 KP, 5 LP), each compris
ing eight birds. At 15 days of age, one chick was taken from each of two ra
ndomly selected cages (1 HP, 1 LP) and immediately bled (undisturbed contro
ls). At the same time, another chick was taken from each of these boxes and
immersed up to its neck in warm water (partial water immersion, PWI) for 1
5 min before blood was collected. All chicks were sexed after bleeding. The
re were no differences between the plasma corticosterone (CS) levels of und
isturbed (control) HP and LP chicks. Exposure to PWI significantly increase
d circulating CS levels, and this elevation was more pronounced in LP than
in HP chicks. Male chicks also showed higher stress-induced adrenocortical
responses than did females. The present findings suggest that the T-maze re
sponses of young chicks might predict their later adrenocortical responses
to a known stressor. This relationship is discussed in terms of individual
differences in fearfulness, ability to cope with challenge, and/or stress s
usceptibility. (C) 1999 Elsevier Science Inc.