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Title: The role of learning in the selection for dietary protein by sheep
Author: Arsenos, Georgios Ioanni
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2001
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The purpose of this thesis was to investigate in a series of five experiments the role of learning in the selection for dietary protein by sheep. Experiment 1 investigated whether an 'unlearned' appetite for dietary protein exists in sheep, and whether such an appetite depends on the previous protein feeding of the animal and the source of dietary nitrogen. No evidence was found for such an unlearned appetite; selection for protein was a learned response, which depended on the source of dietary protein of the foods offered as a choice. Subsequently, emphasis was given to the dietary factors that affect learning to select for dietary protein by sheep. This was done by the use of a classical conditioning methodology. Experiment 2 tested the hypothesis that a continuum links the development of learned preferences and aversions towards a food flavour associated with the post-ingestive consequences (PIC) induced by the administration of a rumen degradable protein (RDP) source. The results showed that sheep are able to distinguish between two flavoured foods associated with increasing doses of a RDP; whereas small doses led to the conditioned flavour preferences (CFPs), higher doses led to conditioned flavour aversions (CFAs). It was concluded that the diet selection for protein by ruminants could be influenced quantitatively by RDP provision. A model to account for the conditioned response of an individual sheep towards administration of increasing doses of the same nutrient was put forward. Experiments 3 and 4, tested whether a delayed type of learning could account for the development of CFPs and CFAs by sheep towards food flavours associated with PIC induced by the administration, at different points in time, of either a low or a high dose of RDP, respectively. The results showed that the temporal contiguity between the consumption of the flavoured food and the administration of the low or the high dose of RDP did not affect the development of either CFPs or CFAs. It was concluded that a process of delay learning applied to both the development of CFPs and CFAs by sheep.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available