The ontogeny of sodium balance of rainbow trout (Oncorhynchus mykiss) and pink salmon (Oncorhynchus gorbuscha) during post-embryonic development in freshwater ...

• Main Author: Gallagher, Emily Jean
• Format: Text
• Language: English
• Published: University of British Columbia 2014
• Subjects: Oncorhynchus gorbuscha; Pink salmon
• Online Access: https://dx.doi.org/10.14288/1.0167632; https://doi.library.ubc.ca/10.14288/1.0167632

This thesis contributes to our general knowledge of ionoregulatory function in developing fish by characterizing the functional ontogeny of sodium (Na⁺) balance in salmonids reared in freshwater during early development. Chapter 2 investigated the plasticity of Na⁺ balance and transport capacity during a critical developmental transition from cutaneous-dominated to gill-dominated ionoregulation in the model teleost fish, the rainbow trout. Fish experienced very high resting unidirectional Na⁺ uptake rates early in development which were reduced to values typical of adults following yolk absorption. Maximal uptake rate (Jmax) for Na⁺ was high during early development and decreased following yolk absorption while uptake affinity decreased (Km increased) following hatch and increased following yolk absorption. It appeared that early in development, high Na⁺ uptake rates across cutaneous ionocytes were driven by high maximal uptake rate, while the gill ionocytes that dominate ionoregulation post-yolk absorption ...