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Biological Sciences


Aquaculture, Behavioural transcriptomics, Chinook salmon, Probiotics, Triploid







Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


With an increasing human population, there has been increased production of fish to meet nutritional needs. Commercial aquaculture accounts for a significant portion of seafood production with salmonids being the major farmed finfish in Canada. To obtain greater biomass from aquaculture with minimal drawbacks (e.g., compromised flesh quality), triploidization has been implemented, altering ploidy from 2N to 3N, to induce sterility and promote energy investment towards somatic growth. Triploid individuals experience transcriptional and behavioural changes resulting in disease, mortalities, and reduced growth. Probiotic therapies (live microorganisms) have been recommended to potentially overcome drawbacks of triploidy and improve mass due to the purported benefits to the host. Through a behavioural genomics approach, I examined neural transcriptional profiles (i.e., relating to neural functions, stress response, appetite/metabolism, and growth) and combined these with behavioural profiles via behavioural assays (i.e., open field, novel object, predator, and mirror tests) in hatchery-reared juvenile Chinook salmon (Oncorhynchus tshawytscha). Siblings from 15 families were placed in four treatment groups: 2N-regular feed, 2N-probiotic feed, 3N-regular feed, and 3N-probiotic feed to determine mechanisms driving differential growth. I found no universal effects of treatments on growth. While triploid individuals had reduced mass, growth was influenced by transcription, including interactions between a bold/aggressive behavioural profile and Shh gene transcription. Probiotic therapy (i.e., Lactobacillus, Bifidobacterium, and Lactococcus) had no direct impact on mass, but increased mass when coupled with high gene transcription of p53. Through behavioural genomics, I uncovered important relationships and interactions that remain to be further described.