Abstract

Evaluation of metabolic activity associated with performance-based physical activity will increase our understanding of basic physiology which will enhance current management and conservation practices involving aquarium-based cetaceans. With the bottlenose dolphin (Tursiops truncatus) as a model species, this study was designed to characterize the proteome and other biochemical factors in plasma samples collected before and after a public swim interaction involving four young male animals. Blood samples were collected voluntarily from the ventral aspect of the tail flukes appoximately15 min before (n=4 samples) and 15 min after (n=4 samples) the first swim interaction of the day. Performance-based activates were reinforced with a prescribed diet and a regularly scheduled feeding regimen. Plasma extracted and trypsin-treated protein extracts were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). Additionally, conventional clinical biochemistry analysis was also performed on the plasma. Based on LC-MS/MS, mass spectra data were used to search the National Center for Biotechnology Information database restricted to Tursiops truncates. The search resulted in the identification of 196 unique proteins with a broad range of functional roles based on manual Gene Ontology analysis. Differential regulation of proteins was based on log mean fold change (FC) and statistical probability such that the abundance of lysozyme (FC -1.2036; p<0.058), an immune-related protein, and flavin reductase (FC -0.9702; p<0.004), a metabolic-related protein, were highest before compared to after the swim interaction; both proteins decreased by 58% and 52%, respectively. Correspondingly, 15 known proteins and other biochemical factors were highest before compared to after the swim interaction. Glucose, creatinine, alkaline phosphatase, blood urea nitrogen, calcium, and magnesium all decreased 3 to 26% (p<0.004 to 0.07). In conclusion, downregulation of immune- and metabolic-related proteins and multiple other biochemical factors after the swim interaction may represent a homeostatic response to high values in the absence of substantial food during an overnight fast or in anticipation of food before the swim interaction; thereafter, low values may represent a response to food consumption or satisfaction. While future studies are required for clarification, the novelty of the results suggests that performance-based physical activity which is reinforced with a regularly scheduled feeding regimen is not metabolically challenging in bottlenose dolphins.

Acknowledgements

The authors want to thank Dolphin Discovery for providing access to the dolphins and technical and professional support. In addition, we acknowledge the support provided by the Functional Genomics Center of Zurich (FGCZ) Switzerland and the services of Ross University School of Veterinary Medicine (RUSVM).

* Presenting author