Stress-related and ontogenetic aspects of metabolic depression in cunner (Tautogolabrus adspersus)

Alzaid, Abdullah (2012) Stress-related and ontogenetic aspects of metabolic depression in cunner (Tautogolabrus adspersus). Masters thesis, Memorial University of Newfoundland.

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    Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
    (Original Version)

Abstract

This thesis examined: 1) how ontogeny affects aspects of metabolic depression in the cunner; and 2) whether the stress response of adult cunner is modified during metabolic depression. The effect of decreasing temperature at 2°C per day on the metabolism of three size classes of ∼9°C acclimated cunner was studied. The onset-temperature for metabolic depression in cunner decreased with body size (age), i.e. 7°C in adult fish vs. 6°C and 5°C in small and young-of-the-year (YOY) fish, respectively. In contrast, the extent of metabolic depression was ∼80% (Q₁₀ = ∼15) for YOY fish, ∼65% (Q₁₀ = ∼8) for small fish, and ∼55% (Q₁₀ = ∼5) for adults. Stress hormone levels and steroidogenic transcript levels were measured in adult cunner acclimated at 0°C and 10°C. Fish at 10°C had 9.09 fold and 4.77 fold higher post-stress plasma epinephrine and norepinephrine levels, respectively, and 4.67 fold greater resting plasma cortisol levels (∼65 ng ml⁻¹) compared with 0°C fish (∼10 ng ml⁻¹). However, cortisol levels did not increase post-stress in 10°C fish, whereas 0°C fish had a 'typical' stress response with cortisol levels reaching ∼107 ng ml⁻¹ by 2 hours post-stress. Transcript levels of P450scc were 3.25 fold higher in the head kidney of 10°C fish compared with 0°C fish. However, there was no significant difference in StAR transcript levels in the head kidney of 10°C fish compared with 0°C fish. GR transcript levels were 1.70 fold and 1.29 fold lower in the head kidney and liver, respectively, of 10°C fish compared with 0°C fish.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/6078
Item ID: 6078
Additional Information: Includes bibliographical references (leaves 69-88).
Department(s): Science, Faculty of > Biology
Date: 2012
Date Type: Submission
Library of Congress Subject Heading: Cunner--Metabolism; Cunner--Effect of temperature on; Ontogeny; Metabolic disorders in animals

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