Comparing glucose acquisition strategies between two ancient fish species: lake sturgeon (Acipenser fulvescens) and North Pacific spiny dogfish (Squalus suckleyi)
| dc.contributor.author | Drummond, Jenna M. | |
| dc.contributor.examiningcommittee | Weihrauch, Dirk (Biological Sciences) | |
| dc.contributor.examiningcommittee | Yang, Chengbo (Animal Science) | |
| dc.contributor.supervisor | Anderson, Gary | |
| dc.date.accessioned | 2023-08-30T15:04:09Z | |
| dc.date.available | 2023-08-30T15:04:09Z | |
| dc.date.issued | 2023-08-18 | |
| dc.date.submitted | 2023-08-25T01:29:00Z | en_US |
| dc.degree.discipline | Biological Sciences | en_US |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | The uptake of glucose within the gastrointestinal tract (GIT) is largely unexplored in ancient fish such as lake sturgeon (Acipenser fulvescens) and North Pacific spiny dogfish (Squalus suckleyi). Interestingly, within the GIT of Acipenserids (e.g. A. fulvescens) and Chondrichthyes (e.g. S. suckleyi) evolved an organ with scroll-like folds termed the spiral valve. Due to its structure, the spiral valve presumably slows down the passage of chyme and increases the gastrointestinal epithelial surface area to maximize nutrient absorption, suggesting it to be primarily responsible for nutrient acquisition. However, there is currently minimal functional data supporting this claim, and no data examining the effect of feeding state. Here, I aim to determine the functional role of the spiral valve in carbohydrate digestion and glucose acquisition during different feeding states and to determine if this role changes in organisms with different life histories. To test this, I assessed glucose digestibility and transport capacity along the GIT of A. fulvescens and S. suckleyi in fed and fasted fish. Digestibility was assessed through biochemical assays for the carbohydrate digesting enzyme maltase, while transport capacity was determined via i) mRNA abundance of the primary dietary glucose transporter (SGLT1), and ii) through in vitro intestinal fluxes. There were no significant postprandial changes in sglt1 mRNA abundance in A. fulvescens in contrast to S. suckleyi, supporting their feeding strategies with A. fulvescens being continuous feeders and S. suckleyi being opportunistic feeders. In S. suckleyi, spiral valve in vitro glucose fluxes demonstrated changes in Km and Vmax in response to feeding, additionally supporting their opportunistic feeding strategy. The spiral valve played a primary role in glucose digestion and transport in S. suckleyi, whereas A. fulvescens utilized the anterior intestine in addition to the spiral valve. This demonstrates that the spiral valve may not always be the primary area of nutrient absorption as suggested by the literature, highlighting the importance of comparing morphological and functional studies. This study provides further insight into the functional role of the spiral valve in ancient fish along with increasing our understanding of the evolutionary history of glucose acquisition in vertebrates. | |
| dc.description.note | October 2023 | |
| dc.identifier.uri | http://hdl.handle.net/1993/37513 | |
| dc.language.iso | eng | |
| dc.rights | open access | en_US |
| dc.subject | glucose | |
| dc.subject | SGLT1 | |
| dc.subject | maltase | |
| dc.subject | gastrointestinal tract | |
| dc.subject | spiral valve | |
| dc.subject | ancient fish | |
| dc.title | Comparing glucose acquisition strategies between two ancient fish species: lake sturgeon (Acipenser fulvescens) and North Pacific spiny dogfish (Squalus suckleyi) | |
| dc.type | master thesis | en_US |
| local.subject.manitoba | yes | |
| oaire.awardNumber | 575328-2022 | |
| oaire.awardTitle | Alexander Graham Bell Canada Graduate Scholarships - Master's | |
| oaire.awardURI | https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744543 | |
| project.funder.identifier | https://doi.org/10.13039/501100000038 | |
| project.funder.name | Natural Sciences and Engineering Research Council of Canada |