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After generations of artificial selection and domestication of animals for consumption, unintended consequences such as inbreeding depression have impacted production via impacts on growth and survival. Outcrossing is a common method used to negate these effects and introduce variation to the broodstock. This thesis aims to assess how animals respond to novel environments both behaviourally and transcriptionally to captivity. Seven wild-domestic hybrid stocks of Chinook salmon (Oncorhynchus tshawytscha) and a highly inbred domesticated stock population included as control were used in this study to determine what, if any, effects outbreeding has on the variation of behavioural and neural transcriptional phenotypes produced. Two behavioural assays were completed on the same set of individuals as juveniles and as adults to test for the occurrence of traits involved in the acclimation to new environments via traits such as sociality, exploration, activity, predator responsiveness and neophilia. These behaviours were then contrasted against performance at each time point and across life-history stage. We found inter-population variation in four distinct behavioural types and changes across ontogeny. In each life stage we demonstrated certain behaviours are linked to performance. Whole brain samples were collected from juvenile and adult fish to assess via qRT-PCR mRNA expression of genes associated with a variety of neural traits purportedly involved in acclimation: stress responses, synaptoplasticity and neurogenesis. A subset of transcriptional profiles and candidate genes related to neural stress responses and neuroplasticity were able to predict performance, however, there were no stock differences in their expression. As more animals are brought into captivity for consumption or conservation it is important to consider how behavioural and neural responses integrate to affect animal survival and develop efficient screening processes. |
