Study type: Medical/biological study (experimental study)

Effects of prenatal exposure to a 50-Hz magnetic field on one-trial passive avoidance learning in 1-day-old chicks. med./bio.

Published in: Bioelectromagnetics 2010; 31 (2): 150-155

Aim of study (acc. to author)

To study memory impairment in newly hatched chicks following in ovo exposure (i.e. egg exposure) to a 50 Hz magnetic field of 2 mT (60 min/day) on embryonic days 12-18.

Background/further details

Chick learning was compared in two experimental groups: isolated and paired chicks (these two groups are known to experience different stress levels). 295 chicks were divided into the following groups: 1) magnetic field exposure - isolated chicks, 2) magnetic field exposure - paired chicks, 3) sham exposure - isolated chicks, and 4) sham exposure - paired chicks. Within each group, chicks were randomly and further divided into one of three testing time sets of 10, 30, or 120 min (according to different stages of memory formation following hatching).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 60 min/day on embyonic days 12 - 18

General information

chicks were divided into four groups: i) MF exposure - isolated ii) MF exposure - paired iii) sham exposure - isolated iv) sham exposure - paired

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 60 min/day on embyonic days 12 - 18
Exposure setup
Exposure source
Setup four sets of 250 turns of 1.68 mm copper wire wrapped horizontally around a 70 cm x 40 cm x 43 cm plastic frame; wooden box with eggs kept inside this coil
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - measured - -

Reference articles

  • Bao X et al. (2006): A possible involvement of beta-endorphin, substance P, and serotonin in rat analgesia induced by extremely low frequency magnetic field.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data demonstrated that magnetic field exposure in ovo during late incubation impaired young chick's memory in the passive avoidance test, depending on the stress level and the time of memory consolidation. Memory was intact at 10 minutes in both isolated and paired chicks with or without magnetic field exposure. However, magnetic field exposure did influence the performance of isolated chicks at 30 and 120 minutes, but not the performance of paired chicks.
With the exception of increased hatch weight in chicks exposed to magnetic field, there were no other obvious differences in hatching success, hatching time, and abnormalities.
The data suggest a potential disruption of memory formation following in ovo exposure to magnetic field, but this effect was only evident in the more stressed, isolated chicks.

Study character:

Study funded by

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