Application of wireless electroencephalogram to measure stress in white pekin ducks
Date
2013
Authors
Journal Title
Journal ISSN
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Publisher
University of Delaware
Abstract
Stress in poultry can produce many undesirable effects on bird health and
overall production performance including decreased immune function and feed
efficiency (Horvath-Papp, 2008, 426). The objective of this study is to develop and
evaluate an additional potential measure to quantitatively assess stress through
evaluation of brain activity using electroencephalography (EEG). In three
experiments, White Pekin ducks (5-11 weeks old) were implanted with EEG
transmitters and treated with potential stressors. In Experiment 1, 16 straight-run
ducks were treated for 15 minutes in a controlled environmental chamber and treated
with three known stressors: auditory, mild electric shock, and ammonia. In
Experiment 2, 24 straight-run ducks were treated the same as in Experiment 1 but with
an extended trial time of 45 minutes. Electrocardiograms (ECGs) and blood
corticosterone were also analyzed for Experiment 2 as a standard measure of stress
against which any changes seen in the relative frequency bands of the EEG were
measured. In Experiment 3, 8 male ducks were treated the same as in Experiment 2
but in their respective holding pen rather than a controlled chamber. Mild electric
shock was compared to no shock and control trials. EEG analysis for Experiment 1
showed no differences between time periods for all frequencies for all treatments.
EEG analysis for Experiment 2 showed no differences between time periods for all frequencies for auditory and ammonia stimuli; however, a significant rise in the
relative delta frequency and a significant decrease in the relative alpha frequency was
seen during the stimulus period for mild electric shock stimuli. ECG results for
Experiment 2 showed no differences for auditory and control trials. Mild electric
shock heart rate increased during the middle and last 30 seconds of the stimulus period
and ammonia heart rate decreased during the middle and last 30 seconds of the
stimulus period. Corticosterone results for Experiment 2 showed a significant
difference between pre-treatment and post-treatment; however, there were no
differences between treatments or between treatments and control. EEG results for
Experiment 3 showed no differences between time periods for all frequencies for mild
electric shock, no shock, and control trials. Corticosterone results for Experiment 3
showed no difference between pre-treatment and post-treatment levels for no shock
trials. There was a significant decrease in post-treatment corticosterone levels for
control trials and a significant increase in post-treatment levels for shock trials when
compared to pre-treatment levels. The post-treatment corticosterone levels for mild
electric shock were significantly higher than control post-treatment levels. Based on
the results of all experiments, EEG is currently not a viable measurement of stress in
commercial poultry.