Open-Field Temporal Pattern of Ambulation in Japanese Quail Genetically Selected for Contrasting Adrenocortical Responsiveness to Brief Manual Restraint

KEMBRO J. M.; SATTERLEE D. G.; SCHMIDT J. B.; PERILLO M. A.; MARIN R. H.

POULTRY SCIENCE

Poultry Science Association

Año: 2008 vol. 87 p. 2186 - 2195

0032-5791

Abstract Japanese quail selected for a reduced (LS, low stress) rather than an exaggerated (HS, high stress) plasma corticosterone response to brief restraint have been shown to possess lower fearfulness (e.g., comparatively enhanced locomotor activity when placed in an open field) and a nonspecific reduction in stress responsiveness. Detrended fluctuation analysis (DFA) provides information about the organization and complexity of temporal patterns of behavior. The present study evaluated the temporal pattern of ambulation of LS and HS quail in an open-field that represented a novel and therefore frightening environment. Time series of 4,200 data points were made for each bird by registering the distance ambulated every 0.5 s during a 35 min test period. Consistent with their known reduced fearfulness, the LS quail initiated ambulation significantly sooner (P < 0.02) and tended to ambulate more (P < 0.09) than did their HS counterparts. Detrended fluctuation analyses showed a monofractal series (i.e., a series with similar complexity at different temporal scales) in the birds that initiated their ambulatory activity in less than 600 s (72 % of the birds). Among those birds, a lower (P < 0.03) auto-similarity coefficient (á) was found in the LS quail than in their HS counterparts (á = 0.76 ± 0.03 and 0.87 ± 0.03, respectively), suggesting a more complex (less regular) ambulatory pattern in the LS quail. However, when the patterns of ambulation were re-examined considering only the active period of the time series, that is, after the birds had initiated their ambulation activity, monofractal patterns were observed in 97% of the birds and no differences between the lines were found. Collectively, the results suggest that during the active period of open-field testing, during which fear responses are likely less strong and other motivations are the driving forces of ambulation, LS and HS lines have similar ambulatory organization. (Key words: detrended fluctuation analysis, fractal, open-field behavior, corticosterone, Japanese quail)