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Effects of Hyperoxia on Thermal Tolerance and Indicators of Hypoxic Stress in Antarctic Fishes That Differ in Expression of Oxygen-Binding Proteins

Devor, Devin Patrick
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1362666619

Abstract Details

2013, Master of Science (MS), Ohio University, Biological Sciences (Arts and Sciences).
Antarctic icefishes (Family Channichthyidae) are unique in lacking the oxygen carrier hemoglobin (Hb) in their blood, leaving them with only 10% of the oxygen-carrying capacity observed in closely related red-blooded fishes. Previous studies have shown that icefishes have lower critical thermal maxima (CTMAX) than red-blooded notothenioids and that there is a positive correlation between CTMAX and hematocrit, indicating that oxygen-carrying capacity may contribute to thermal tolerance. I tested the hypothesis that the lower CTMAX of icefishes is associated with their reduced oxygen-carrying capacity. I also hypothesized that, as temperature rises, correlates of oxygen limitation (hypoxia inducible factor-1α and lactate) would increase to a greater extent in icefishes compared to red-blooded fishes and that this increase would be minimized under hyperoxic conditions. I sampled Chaenocephalus aceratus (Hb-) and Notothenia coriiceps (Hb+) at three temperatures (ambient, 8°C, and CTMAX) during an experimental heat ramp (4°C * hr-1) under normoxia and environmental hyperoxia. I have determined that a 3- to 4-fold elevation in environmental oxygen does not extend CTMAX in either species despite a 1.7-fold reduction in plasma lactate accumulation and a 2- to 3-fold increase in oxygen utilization as indicated by the differences in arterial and venous oxygen (PaO2-PvO2). The absence of an effect of hyperoxia on thermal tolerance may be explained by the lack of increased cardiac (venous) oxygen supply. I have determined that cardiac lactate increases with temperature in the icefish, C. aceratus but not in N. coriiceps and that HIF-1α mRNA levels in the heart are insensitive to increases in both temperature and oxygen. My results indicate that the hearts of icefishes may be especially hypoxia-sensitive and that the inability to maintain cardiac metabolism may contribute to the relatively low thermal tolerances of channichthyid fishes.
Elizabeth Crockett (Advisor)
72 p.
Animal Sciences; Animals; Biology; Experiments; Molecular Biology; Zoology
Antarctic fish; thermal stress; hyperoxic treatment; icefish; Notothenioidei

Recommended Citations

Citations

  • Devor, D. P. (2013). Effects of Hyperoxia on Thermal Tolerance and Indicators of Hypoxic Stress in Antarctic Fishes That Differ in Expression of Oxygen-Binding Proteins [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1362666619

    APA Style (7th edition)

  • Devor, Devin. Effects of Hyperoxia on Thermal Tolerance and Indicators of Hypoxic Stress in Antarctic Fishes That Differ in Expression of Oxygen-Binding Proteins. 2013. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1362666619.

    MLA Style (8th edition)

  • Devor, Devin. "Effects of Hyperoxia on Thermal Tolerance and Indicators of Hypoxic Stress in Antarctic Fishes That Differ in Expression of Oxygen-Binding Proteins." Master's thesis, Ohio University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1362666619

    Chicago Manual of Style (17th edition)

ohiou1362666619
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This open access ETD is published by Ohio University and OhioLINK.