Latency to traverse a T-maze at 2 days of age and later adrenocortical responses to an acute stressor in domestic chicks.

MARIN R.H.; JONES, R. B.

PHYSIOLOGY AND BEHAVIOR

Año: 1999 vol. 66 p. 809 - 813

0031-9384

MARIN, R. H. AND R. B. JONES. Latency to traverse a T-maze at 2 days of age and later adrenocortical responses to an acute stressor in domestic chicks. PHYSIOL BEHAV 66 (5) 809–813, 1999.—Latencies to escape from a T-maze, and thereby reinstate visual contact with conspecifics, were measured in broiler chicks at 2 days of age. Chicks were assigned to high- (HP) or low- (LP) performance categories if their escape latencies fell below 25 s or above 75 s, respectively. These chicks were then housed socially in 10 same-category groups (5 HP, 5 LP), each comprising eight birds. At 15 days of age, one chick was taken from each of two randomly selected cages (1 HP, 1 LP) and immediately bled (undisturbed controls). 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 15 min before blood was collected. All chicks were sexed after bleeding. There were no differences between the plasma corticosterone (CS) levels of undisturbed (control) HP and LP chicks. Exposure to PWI significantly increased 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 responses 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 susceptibility. © 1999 Elsevier Science Inc.