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Effects of postnatal stress on tonic immobility in White Leghorn chicks (Gallus gallus domesticus)

Early life stress is something that animals used in production often have to experience. What we do not know is if there are any consequences of this treatment later on in life. Zebra finches postnatal treated with the stress hormone corticosterone showed an exaggerated and prolonged stress response later on. To examine the effects of early life stress 77 White Leghorn chicks were used, half of them was stressed from postnatal day 1-14 and then tested between 47-63 days of age. The tonic immobility (TI) test is a commonly used test to evaluate the fearfulness and stress reaction in fowl. The chicks were placed on their back in a V-shaped wooden cradle and TI was induced by applying light pressure on the breast and neck. The number of inductions required to induce TI was recorded as well as the time until the first alert head movement and the total duration of the TI. The birds were tested in a calm environment but also after a stressful situation. There were no differences in the total duration of the TI reactions. However, stressed animals tended to need more induction attempts than the control animals. While looking at the time elapsed until the first head movement stressed chicks had a significantly lower duration. This indicates a dullness or shift in the stress response of the treated birds and there seem to be a more exaggerated response in the males.
Date January 2010
CreatorsPersson, Mia
PublisherLinköpings universitet, Institutionen för fysik, kemi och biologi, Linköpings universitet
Source SetsDiVA Archive at Upsalla University
Detected LanguageEnglish
TypeStudent thesis, info:eu-repo/semantics/bachelorThesis, text

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