Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua
Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Aquaculture Includes bibliographical references (leaves 114-128) The ontogeny of the corticosteroid stress response was examined in hatchery-reared Atlantic cod (Gadus morhua). Pooled whole-body samples of larvae at rest and following a 30 s...
Main Author: | |
---|---|
Other Authors: | |
Format: | Thesis |
Language: | English |
Published: |
2008
|
Subjects: | |
Online Access: | http://collections.mun.ca/cdm/ref/collection/theses4/id/148857 |
id |
ftmemorialunivdc:oai:collections.mun.ca:theses4/148857 |
---|---|
record_format |
openpolar |
spelling |
ftmemorialunivdc:oai:collections.mun.ca:theses4/148857 2023-05-15T15:26:51+02:00 Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua Westelmajer, Sarah Kate Matheson, 1981- Memorial University of Newfoundland. Faculty of Science; 2008 xii, 128 leaves : ill. Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses4/id/148857 Eng eng Electronic Theses and Dissertations (15.07 MB) -- http://collections.mun.ca/PDFs/theses/Westelmajer_SarahKate.pdf a2544298 http://collections.mun.ca/cdm/ref/collection/theses4/id/148857 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. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Atlantic cod--Effect of stress on Atlantic cod--Growth Atlantic cod--Larvae Ontogeny Text Electronic thesis or dissertation 2008 ftmemorialunivdc 2015-08-06T19:22:36Z Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Aquaculture Includes bibliographical references (leaves 114-128) The ontogeny of the corticosteroid stress response was examined in hatchery-reared Atlantic cod (Gadus morhua). Pooled whole-body samples of larvae at rest and following a 30 second (s) air exposure were taken at multiple intervals throughout development from 2 days pre-hatch up to metamorphosis at 59 days post-hatch (dph). Extracted samples were analysed using a commercially available enzyme-linked immunoassay kit, which was subsequently validated for use with whole-body samples. A significant increase in whole-body immunoreative corticosteroid (IRC) concentration in response to the air-exposure stress was observed in larvae at hatch (0 dph), which likely indicates the functioning of the hypothalamus-pituitary-interrenal axis (HPI) and thus the endogenous production of Cortisol by the larvae at this time. Two stress hyporesponsive periods (SHRP) were detected, between 0-30 dph and at 50 dph, and likely correspond with two critical periods of neurological and immunological development, during which the production and release of Cortisol is restricted. Potentially stressful aquaculture procedures should be avoided during these SHRPs. -- The effect of differentially enriched live-food organisms, rotifers (Brachionus plicatilis), and brine shrimp (Artemia sp.), on the lipid content, growth and stress tolerance of larval Atlantic cod was also examined. The lipid and fatty acid content of larval tissue was directly related to the lipid and fatty acid content of enriched live feed. Larvae fed rotifers and Artemia enriched with elevated proportions of the highly unsaturated fatty acids, DHA (docosahexaenoic acid; 22:6ω3), AA (arachidonic acid; 20:4ω6), and ω6DPA (docosapentaenoic acid; 22:5ω6) showed best overall growth and survival following an acute 15 s air-exposure and transfer stress. Differences in post-stress survival between treatments were most likely attributable to variations in larval EPA (eicosapentaenoic acid; 20:5ω3)/AA and DHA/DPA content. Corticosteroid levels remained elevated in larvae with maximal post-stress survivorship, and may indicate the requirement of larval cod for a prolonged rise in Cortisol following a stress event. Suggested DHA/EPA/AA ratios for rotifer and Artemia enrichments that yielded best growth and stress tolerance in Atlantic cod larvae were 7/2/1 and 5/2/1 respectively. Thesis atlantic cod Gadus morhua Newfoundland studies Rotifer University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
institution |
Open Polar |
collection |
Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
op_collection_id |
ftmemorialunivdc |
language |
English |
topic |
Atlantic cod--Effect of stress on Atlantic cod--Growth Atlantic cod--Larvae Ontogeny |
spellingShingle |
Atlantic cod--Effect of stress on Atlantic cod--Growth Atlantic cod--Larvae Ontogeny Westelmajer, Sarah Kate Matheson, 1981- Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua |
topic_facet |
Atlantic cod--Effect of stress on Atlantic cod--Growth Atlantic cod--Larvae Ontogeny |
description |
Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Aquaculture Includes bibliographical references (leaves 114-128) The ontogeny of the corticosteroid stress response was examined in hatchery-reared Atlantic cod (Gadus morhua). Pooled whole-body samples of larvae at rest and following a 30 second (s) air exposure were taken at multiple intervals throughout development from 2 days pre-hatch up to metamorphosis at 59 days post-hatch (dph). Extracted samples were analysed using a commercially available enzyme-linked immunoassay kit, which was subsequently validated for use with whole-body samples. A significant increase in whole-body immunoreative corticosteroid (IRC) concentration in response to the air-exposure stress was observed in larvae at hatch (0 dph), which likely indicates the functioning of the hypothalamus-pituitary-interrenal axis (HPI) and thus the endogenous production of Cortisol by the larvae at this time. Two stress hyporesponsive periods (SHRP) were detected, between 0-30 dph and at 50 dph, and likely correspond with two critical periods of neurological and immunological development, during which the production and release of Cortisol is restricted. Potentially stressful aquaculture procedures should be avoided during these SHRPs. -- The effect of differentially enriched live-food organisms, rotifers (Brachionus plicatilis), and brine shrimp (Artemia sp.), on the lipid content, growth and stress tolerance of larval Atlantic cod was also examined. The lipid and fatty acid content of larval tissue was directly related to the lipid and fatty acid content of enriched live feed. Larvae fed rotifers and Artemia enriched with elevated proportions of the highly unsaturated fatty acids, DHA (docosahexaenoic acid; 22:6ω3), AA (arachidonic acid; 20:4ω6), and ω6DPA (docosapentaenoic acid; 22:5ω6) showed best overall growth and survival following an acute 15 s air-exposure and transfer stress. Differences in post-stress survival between treatments were most likely attributable to variations in larval EPA (eicosapentaenoic acid; 20:5ω3)/AA and DHA/DPA content. Corticosteroid levels remained elevated in larvae with maximal post-stress survivorship, and may indicate the requirement of larval cod for a prolonged rise in Cortisol following a stress event. Suggested DHA/EPA/AA ratios for rotifer and Artemia enrichments that yielded best growth and stress tolerance in Atlantic cod larvae were 7/2/1 and 5/2/1 respectively. |
author2 |
Memorial University of Newfoundland. Faculty of Science; |
format |
Thesis |
author |
Westelmajer, Sarah Kate Matheson, 1981- |
author_facet |
Westelmajer, Sarah Kate Matheson, 1981- |
author_sort |
Westelmajer, Sarah Kate Matheson, 1981- |
title |
Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua |
title_short |
Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua |
title_full |
Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua |
title_fullStr |
Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua |
title_full_unstemmed |
Ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval Atlantic cod, Gadus morhua |
title_sort |
ontogeny of the corticosteroid stress response and effect of differentially enriched live feed on growth, lipid composition and acute stress tolerance of larval atlantic cod, gadus morhua |
publishDate |
2008 |
url |
http://collections.mun.ca/cdm/ref/collection/theses4/id/148857 |
genre |
atlantic cod Gadus morhua Newfoundland studies Rotifer University of Newfoundland |
genre_facet |
atlantic cod Gadus morhua Newfoundland studies Rotifer University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (15.07 MB) -- http://collections.mun.ca/PDFs/theses/Westelmajer_SarahKate.pdf a2544298 http://collections.mun.ca/cdm/ref/collection/theses4/id/148857 |
op_rights |
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. |
_version_ |
1766357333291565056 |